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Rover looks into crater
The spectacular high-resolution, color panorama from the Mars rover Opportunity at the edge of Endurance Crater is presented with expert narration by Steve Squyres, the mission's lead scientist. (2min 08sec file)
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The Columbia Hills
Explore the Columbia Hills at Gusev Crater where Spirit is headed in this computer-generated movie using imagery from orbit. Expert narration by Amy Knudson, science team collaborator. (3min 11sec file)
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May 6 rover briefing
The Mars rover Opportunity's arrival at Endurance Crater and Spirit's trek to the Columbia Hills are topics in this news conference from May 6. (42min 12sec file)
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April 28 rover briefing
Activities of the two Mars Exploration Rovers and new images are discussed in this briefing from April 28. (41min 08sec file)
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April 14 rover briefing
The software overhaul performed on both Mars rovers, new science information and photographs are discussed at this briefing from Wednesday, April 14. (31min 29sec file)
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Lion King panorama
The stunning "Lion King" high-resolution color panorama from the Opportunity rover shows the vast landing site. Expert narration by Jason Soderblom, science team collaborator. (2min 12sec file)
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Opportunity trench
Opportunity rover uses one of its wheels to dig another trench in the soil for science investigations. Narration by Jan Chodas, flight software manager. (25sec file)
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April 8 rover briefing
Officials discuss the extended missions for the Mars rovers and present the latest pictures at this briefing from Thursday, April 8. (34min 10sec file)
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April 1 rover update
New pictures and science results from the Spirit and Opportunity rovers on Mars are presented at this briefing from Thursday, April 1. (52min 57sec file)
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Spirit examines Mazatzal
Imagery from the Spirit rover shows the brushing and grinding work performed on the rock nicknamed "Mazatzal." Expert narration by science team member Hap McSween. (1min 37sec file)
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'Bounce' rock
Imagery from the Opportunity rover showing the rock nicknamed "Bounce" with expert narration by Jim Bell, lead scientist for the panoramic camera. (5min 29sec file)
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Panorama preview
The first slice of a high-resolution color panorama produced from Opportunity now outside its landing-site crater is revealed with expert narration by Jim Bell. (29sec file)
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March 26 rover briefing
The latest pictures and science results from the twin Mars Exploration Rovers Spirit and Opportunity are presented at this briefing on March 26. (50min 02sec file)
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Columbia Hills
Spirit looks forward to the Columbia Hills in the distance where the rover is headed in this imagery narrated by mission manager Matt Wallace. (50sec file)
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Spirit extends arm
Spirit's science instrument arm is employed to examine a light-colored rock as explained by Ray Arvidson, deputy principal investigator. (1min 35sec file)
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Plan for Spirit
The plan for Spirit trek to the hills is described by science team member Larry Crumpler. (2min 37sec file)
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Panorama in crater
A panorama of Eagle Crater where the Opportunity landed and has explored for the past two months is presented with narration by mission manager Matt Wallace. (2min 29sec file)
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Pan outside crater
Following its exit from Eagle Crater, Opportunity snapped this panorama looking back at the shallow crater in the flat plains of Meridiani Planum as presented with narration by mission manager Matt Wallace. (40sec file)
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Mars water discovery
Scientists present evidence from the Mars rover Opportunity during this Tuesday news conference that shows the landing site was once the bottom of a salty sea. (76min 48sec file)

Mars rover briefing
The latest pictures and science results from the twin Mars Exploration Rovers and future plans for Spirit and Opportunity are presented at this briefing Thursday. (59min 12sec file)

Crater panorama
The spectacular color panorama from the Mars rover Spirit shows the Bonneville Crater, the discarded heatshield and surround terrain is explained with expert narration by science team member John Grant. (2min 15sec file)

Scuffing the drift
Spirit's work to "scuff" or disturb the crusty surface from a wind drift is described in this imagery narrated by science team member John Grant. (1min 07sec file)

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Follow the missions of NASA's "Spirit" Mars Exploration Rover-A and "Opportunity" MER-B on the Red Planet! Reload this page for the very latest on both rovers. Use our text only page for faster downloads.

Opportunity resumed science operations after waking to Aerosmith's "Back in the Saddle" on its 65th sol, which ended at 2:02 a.m. PST on March 31. During the martian morning, the miniature thermal emission spectrometer and panoramic camera studied the atmosphere. "Bounce" rock was imaged by the panoramic camera.

Opportunity's instrument arm was then deployed to get a close-up view of "Bounce" using the microscopic imager. The rock abrasion tool team used some of these images to identify the exact target for next sol's grinding operation. The Moessbauer spectrometer was then placed on a designated target on the rock for an overnight integration.

In the afternoon, Opportunity took navigation and panoramic camera images and completed more miniature thermal emission spectrometer science.

Next sol, the rover's rock abrasion tool will grind into Bounce.

Spirit began sol 86, which ended at 2:20 p.m. PST on March 31, 2004, by waking up and heating the panoramic mast assembly to complete sky and ground stares with the miniature thermal emission spectrometer. Spirit completed the alpha particle X-ray spectrometer integration on the hole made by the rock abrasion tool and then took a 45-minute nap.

Once Spirit woke up, it began the 6-position rock abrasion tool brush mosaic on the target Missourion the rock called Mazatzal. Once this was completed successfully, the rovers arm was stowed.

Spirit then rolled backwards .9 meters (2.95 feet) to correctly position itself to acquire mini thermal emission spectrometer imaging of the newly brushed mosaic, and the previously ground hole. In addition, Spirit took sky and ground stares and panoramic camera images of the upcoming drive direction. The sol ended with mini thermal emission spectrometer stares at the Columbia Hillsand an afternoon pass by NASAs Mars Odyssey orbiter.

Sol 87, which ends at 3:00 p.m. PST on April 1, 2004, will be a driving day for Spirit as it begins what could be a record-breaking journey toward the Columbia Hills.

Since the rock abrasion tool completed a full-circle grind into the "New York" and "Brooklyn" targets on the rock "Mazatzal," it was time for Spirit to do some analysis. Spirit spent much of Sol 85, which ended at 1:41 p.m. PST on March 30, successfully operating the instruments on its robotic arm to take a more detailed look inside Mazatzal.

Although all the operations were completed successfully on Mars, the rover team spent most of the morning and afternoon on Earth worrying. After the team sent the uplink to Spirit, they waited for the standard "beep" that confirms the sequence reached Spirit and was activated. This beep, and an expected one 10 minutes later were not acquired, and engineers proceeded to trouble-shoot what might have gone wrong. No errors could be found, and finally a successful afternoon Odyssey communications pass provided 75 megabits of data, indicating that all the sequences were in fact onboard the rover and that all the planned sol activities had completed successfully. Like worried parents, the rover team members breathed a collective sigh of relief, and are now looking into possible causes of the failure to detect the beep.

As planned, Spirit began sol 85 by receiving the uplink and then taking a one-hour nap. After waking, the rover took panoramic camera images of the rock abrasion tool and of the ratted hole in Mazatzal. Before the panoramic camera work was done, Spirit took some final shots of "Bonneville" crater. Some of those images might contribute to a super-resolution image of the heatshield remnants on the far wall. Spirit also took some images to try to catch a dust devil in action.

After the panoramic camera activity, Spirit used the microscopic imager to take a 5-position pseudo-color mosaic of the Mazatzal rock abrasion tool hole. Then the Moessbauer spectrometer was placed in the hole and began an overnight integration.

A little after 2 p.m. Mars Local Solar Time, the last miniature thermal emission spectrometer sections of Bonneville crater were acquired, followed by a set of panoramic camera images of the drive direction. In the late afternoon, Spirit used the mini thermal emission spectrometer to acquire ground and sky stares, which will be complemented by another set early tomorrow morning. Shortly after the 2 a.m. Mars Global Surveyor pass, the arm will change tools from the Moessbauer spectrometer to the alpha particle X-ray spectrometer for an integration in the rock abrasion tool hole through 9:20 a.m Mars Local Solar Time on Sol 86.

The rock abrasion tool will be back to work on sol 86, which will end at 2:20 p.m. PST on March 31, 2004, brushing a 6-spot mosaic on another portion of the rock Mazatzal called "Missouri." The mini thermal emission spectrometer will analyze the brushed area and then Spirit will begin a 5-sol drive toward the Columbia Hills.

On Opportunity's 64th sol, which ended at 1:22 a.m. PST on March 30, the rover team analyzed the results of engineering activities run to investigate an error message they received from the rover on sol 63.

A problem with a secondary memory file was isolated and resolved. Just as an ordinary computer disk can have corrupted sections, a corrupted file in an area where rover commands are addressed and stored has been identified. Engineers have identified the location of the problem within the memory and figuratively fenced it off, containing it and preventing it from harming any future command sequences. This minor issue has not impeded the rover from resuming normal science operations on the next sol.

The wake-up song chosen for Opportunity on this quiet sol was "Stand" by REM.

The rover is currently at the rock dubbed "Bounce." Opportunity met this rock once before; while still cloaked in its protective lander and airbags, the rover bounced on the rock while on its way to a safe landing in "Eagle Crater." Miniature thermal emission spectrometer observations have shown Bounce is rich in hematite. In the coming sols, the rover's other spectrometers will examine the rock before the rock abrasion tool grinds into a designated target.

SUNDAY, MARCH 28, 2004
The angular nature of the rock called "Mazatzal" required some extra rodent power over the weekend. The latest grind by Spirit's rock abrasion tool (the RAT) resulted in that tool's deepest hole yet, nearly 8 millimeters (0.31 inches.) The rover was inspired to tackle the target "Brooklyn" right next to its "New York" bull's-eye by the Beastie Boys' "No Sleep Till Brooklyn" on its 83rd sol, which ended at 12:22 p.m. PST on March 28.

Spirit's 84th sol, which ended at 1:01 p.m. PST on March 29, was planned as a day of investigation. The miniature thermal emission spectrometer and panoramic camera made successful observations of the crater informally named "Bonneville," but planned operations of the rover arm were not executed due to a switch on the Moessbauer spectrometer getting momentarily stuck. After a successful Moessbauer integration, the instrument was pulled back from Mazatzal, but one of two contact switches did not indicate a no-contact condition. Although the instrument had been retracted, the rover's software interpreted this as an unexpected collision of the spectrometer with an object, so it terminated any further arm operations. The stuck switch flipped about three minutes later but the rover is programmed to wait until the false error is cleared by mission control.

On sol 85, Spirit will retake microscope images of areas on Mazatzal, and overnight Moessbauer and alpha particle X-ray spectrometer integrations will be repeated.

FRIDAY, MARCH 26, 2004
Spirit began sol 81, which ended at 11:02 a.m. PST on March 26, 2004, by stopping the alpha particle X-ray spectrometer integration and then imaging the instrument's placement with the hazard avoidance camera. The rest of this sol was all about grinding into the target "New York" on the rock named "Mazatzal."

The rock abrasion tool operated on the New York target for three hours and forty-five minutes and created an impression in the rock that was 3.79 millimeters (.15 inches) deep. The angular shape of Mazatzal and the fact that the rock is a little harder than previously abraded rocks allowed the more flat side of the circular target to receive a more intense grind. On sol 83, the science and engineering teams plan to again place Spirit's rock abrasion tool onto the rock, overlapping the already abraded area and reaching the area just to the left.

Spirit will spend most of sol 82, which will end at 11:42 a.m. PST on March 27, 2004, analyzing the rock abrasion tool impression with the microscopic imager, Moessbauer spectrometer and alpha particle X-ray spectrometer. The rover will also place the microscopic imager over a clean surface to the upper left of the ratted area and take some images.

The wake-up song today was "Boy from New York City" by The Manhattan Transfer, in honor of the grind on the New York target.

Spirit's odometer now reads: 492 meters - more than a quarter of a mile!

On sol 60, which ended at 10:44 p.m. PST on March 25, NASA's Mars Exploration Rover Opportunity had a quiet day continuing its research around the exterior of Eagle Crater.

Opportunity changed tools from the Moessbauer spectrometer to the alpha particle X-ray spectrometer around 11:30 Local Solar Time. In addition to the tool change, Opportunity took a comprehensive color high-resolution panorama with the panoramic camera. The rover team dubbed it the "Lion King Panorama" because it is a look around Opportunity¹s domain from a high vantage point -- much like the view from "Pride Rock" in The Lion King movie. The large panorama essentially filled the remaining flash memory volume onboard the spacecraft, requiring a plan for sol 61 that minimizes data collection. The miniature thermal emission spectrometer also collected remote sensing data.

The wake up song for sol 60 was ³The Circle of Life² by Elton John in honor of the Lion King panorama.

The plan for sol 61, which will end at 11:23 p.m. on March 26 PST, is to drive north to an area with dark material.

Here are the latest Spirit and Opportunity official status reports from mission control:

On sol 80, which ended at 1823 GMT on March 25, NASA's Mars Exploration Rover Spirit repeated overnight measurements of "Illinois" and "New York," two targets on the rock "Mazatzal." The measurements needed to be repeated because the alpha particle X-ray spectrometer's doors inadvertently did not open during the prior sol. In honor of doors being stuck partially open, sol 80's wake up song was "Open the Door" by Otis Redding.

Mazatzal is one of an apparent class of "light-toned rocks," which may be common in the area where Spirit landed in Gusev. This rock appears to be a "ventifact," which means it may have been carved by the steady winds that scientists know come from the northwest into the top area of this crater rim.

The plan for sol 81, which will end at 1902 GMT on March 26 PST, is to grind into Mazatzal with the rock abrasion tool.

Opportunity spent sol 59, which ended at 0604 GMT, placing the Moessbauer spectrometer on the bright material it approached yestersol, and conducting more remote sensing observations.

This relatively light workload allowed the rover to recover energy for the next sol's activities. Those will include completing an alpha particle X-ray spectrometer read on the same soil target and initiating the panoramic mosaic image from the rover's current position.

The wake-up tune for the sol was "59th Street Bridge Song (Feeling Groovy)" by Simon and Garfunkel.

Here are the latest Spirit and Opportunity official status reports from mission control:

NASA's Mars Exploration Rover Spirit awakened at 9:35 a.m. Mars Local Solar Time on Sol 79, which ended at 1743 GMT on March 24. An early morning review of the alpha particle X-ray spectrometer data revealed that the instrument's doors were not fully open and that the tool did not completely engage at the intended "New York" target on the rock dubbed "Mazatzal." The alpha particle X-ray spectrometer integration on "New York" will be repeated on sol 80.

Spirit took a nap until 12:45 Mars Local Solar time to conserve power for the upcoming grind on Mazatzal on sol 81. Once the rover woke up, it began the sequences of brushing and analyzing two targets, "New York" and "Illinois," on Mazatzal. Each target was brushed with the rock abrasion tool and then imaged with the microscopic imager and panoramic camera. The entire sequence ended with a Moessbauer spectrometer integration on the New York target.

Rover controllers plan to let Spirit rest until 4 a.m. Mars Local Solar time on Sol 80, when the tools on the robotic arm will be changed to place the alpha particle X-ray spectrometer on the brushed New York target. The rest of sol 80, which will end at 1823 GMT on March 25, will be spent analyzing the brushed and unbrushed areas of Mazatzal with the instruments on the rover's robotic arm.

The song "Come on Home" by Lambert, Hendricks and Ross beckoned Opportunity back toward its landing site crater to an area of bright material. The rover also began to image a panoramic mosaic of the plains on this sol, which ended at 0525 GMT on March 24.

Over the martian night, Opportunity will again wake up to take miniature thermal emission spectrometer measurements.

In the coming sols, the rover will use its spectrometers to investigate the bright material area and then move on to a specific target in the area dubbed "Bright Spot."

Here are the latest Spirit status report from mission control:

NASA's Mars Exploration Rover Spirit woke up at 7:24 a.m. Mars Local Solar time on sol 78, which ended at 1704 GMT on March 23, 2004, and began a day of observations in preparation for the sol 79 grind on the rock called "Mazatzal."

After waking, Spirit warmed-up the mast actuators for some early morning soil and atmosphere miniature thermal emission spectrometer observations. It then went back to sleep before beginning the morning direct-to-earth communication session with the high gain antenna.

At 10:00 a.m. Mars Local Solar time, Spirit began analyzing the soil targets "Saber" and "Sandbox" with the mini thermal emission spectrometer. It also took panoramic camera images of "Skull" and Saber. Then it was time to unfold the instrument arm to capture microscopic imager images of three targets on Mazatzal: "Arizona," "Illinois," and "New York." The New York target was further analyzed with a 17-hour Moessbauer spectrometer integration.

While the Moessbauer was integrating, Spirit proceeded to execute several mini thermal emission spectrometer and panoramic camera observations of interesting features in the surrounding area. The observations included images of "Bonneville" crater, "Saber," "Sandbox" and "Orange Beach."

Spirit had completed all these activities by 2:40 p.m. Mars Local Solar time and then took a siesta until the afternoon Odyssey UHF pass. During that pass, the rover captured mini thermal emission spectrometer ground and sky images. Before shutting down at 5 p.m. Mars Local Solar time, Spirit positioned the panoramic camera for a nighttime observation of the moon Deimos.

Sol 79, which ends at 1743 GMT on March 24, 2004, will be a momentous day for Spirit's rock abrasion tool; it will complete brushings on two Mazatzal targets.

Three weeks ago, NASA announced definitive evidence that Mars once featured an abundance of water supporting a habitable environment. But major questions remained. Today, scientists unveiled photographs from NASA's Opportunity rover showing cross-bedded sedimentary rocks indicating that at least at one point on the martian surface - Meridiani Planum - a shallow, salty sea once ebbed and flowed. Read our full story.

1904 GMT (2:04 p.m. EST)
NASA's Opportunity rover has demonstrated some rocks on Mars probably formed as deposits at the bottom of a body of gently flowing saltwater.

"We think Opportunity is parked on what was once the shoreline of a salty sea on Mars," said Dr. Steve Squyres of Cornell University, Ithaca, N.Y., principal investigator for the science payload on Opportunity and its twin Mars Exploration Rover, Spirit.

Clues gathered so far do not tell how long or how long ago liquid water covered the area. To gather more evidence, the rover's controllers plan to send Opportunity out across a plain toward a thicker exposure of rocks in the wall of a crater.

NASA's Associate Administrator for Space Science Dr. Ed Weiler said, "This dramatic confirmation of standing water in Mars' history builds on a progression of discoveries about that most Earthlike of alien planets. This result gives us impetus to expand our ambitious program of exploring Mars to learn whether microbes have ever lived there and, ultimately, whether we can."

"Bedding patterns in some finely layered rocks indicate the sand-sized grains of sediment that eventually bonded together were shaped into ripples by water at least five centimeters (two inches) deep, possibly much deeper, and flowing at a speed of 10 to 50 centimeters (four to 20 inches) per second," said Dr. John Grotzinger, rover science-team member from the Massachusetts Institute of Technology, Cambridge, Mass.

In telltale patterns, called crossbedding and festooning, some layers within a rock lie at angles to the main layers. Festooned layers have smile-shaped curves produced by shifting of the loose sediments' rippled shapes under a current of water.

"Ripples that formed in wind look different than ripples formed in water," Grotzinger said. "Some patterns seen in the outcrop that Opportunity has been examining might have resulted from wind, but others are reliable evidence of water flow," he said.

According to Grotzinger, the environment at the time the rocks were forming could have been a salt flat, or playa, sometimes covered by shallow water and sometimes dry. Such environments on Earth, either at the edge of oceans or in desert basins, can have currents of water that produce the type of ripples seen in the Mars rocks.

A second line of evidence, findings of chlorine and bromine in the rocks, also suggests this type of environment. Rover scientists presented some of that news three weeks ago as evidence the rocks had at least soaked in mineral-rich water, possibly underground water, after they formed. Increased assurance of the bromine findings strengthens the case rock-forming particles precipitated from surface water as salt concentrations climbed past saturation while water was evaporating.

Dr. James Garvin, lead scientist for Mars and lunar exploration at NASA Headquarters, Washington, said, "Many features on the surface of Mars that orbiting spacecraft have revealed to us in the past three decades look like signs of liquid water, but we have never before had this definitive class of evidence from the martian rocks themselves. We planned the Mars Exploration Rover Project to look for evidence like this, and it is succeeding better than we had any right to hope. Someday we must collect these rocks and bring them back to terrestrial laboratories to read their records for clues to the biological potential of Mars."

Squyres said, "The particular type of rock Opportunity is finding, with evaporite sediments from standing water, offers excellent capability for preserving evidence of any biochemical or biological material that may have been in the water."

Engineers at NASA's Jet Propulsion Laboratory (JPL), Pasadena, Calif., expect Opportunity and Spirit to operate several months longer than the initial rover's three-month prime missions on Mars. To analyze hints of crossbedding, mission controllers programmed Opportunity to move its robotic arm more than 200 times in one day, taking 152 microscope pictures of layering in a rock called "Last Chance."

MONDAY, MARCH 22, 2004
2325 GMT (6:25 p.m. EST)

Opportunity successfully emerged from the crater today, one martian-day later than planned after the rover experienced wheel slippage in the sandy soil.

Controllers sent the rover driving along the crater rim instead of a more direct path straight out, officials said.

The crater, dubbed "Eagle Crater," is approximately 22 meters (72 feet) in diameter.

The twin rover Spirit continues to explore the Bonneville Crater. Here is the latest mission control staus report: Spirit woke up on sol 77, which ended at 1624 GMT today, to "One Step Closer" by the Doobie Brothers, since the rover was to make its final approach to the rock target named "Mazatzal" today.

Before beginning the .9-meter (2.95 feet) drive to Mazatzal, Spirit analyzed the soil target "Soil 1" at its current location with the microscopic imager and Moessbauer spectrometer. During the Moessbauer integration, Spirit also took panoramic camera images and performed miniature thermal emission spectrometer analysis of the atmosphere and Mazatzal work area.

At 1:25 p.m. Mars Local Solar Time, Spirit completed the Moessbauer integration, took a few microscopic imager images of the impression left on "Soil 1" by the Moessbauer spectrometer and then stowed the instrument arm. Spirit then proceeded the short distance toward Mazatzal and took hazard avoidance camera images to confirm that its final resting place put the intended rock targets in reach of the instrument arm.

Following the drive, the rover acquired more panoramic camera and mini thermal emission spectrometer observations of the atmosphere, and of interesting areas near the Mazatzal site including targets named "Sandbox," "Saber" and "Darksands."

Spirit finished up sol 77 by getting the mini thermal emission spectrometer in position for morning observations on sol 78.

Spirit will spend most of Sol 78, which will end at 1704 GMT Tuesday, analyzing Mazatzal with the instruments on the robotic arm.

1800 GMT (1:00 p.m. EST)
The Mars rover Opportunity has been unable to drive out of the bowl-shaped crater it has been exploring for nearly two months, prompting controllers to plot a new route. Meanwhile, NASA officials on Tuesday will announce a "major scientific finding" from Mars.

"NASA's Opportunity tried driving uphill out of its landing-site crater during its 56th sol, ending at 0605 GMT today, but slippage prevented success," mission control reported.

"The rover is healthy, and it later completed a turn to the right and a short drive along the crater's inner slope. Controllers plan to send it on a different route for exiting the crater on sol 57."

Opportunity scored an "interplanetary hole in one" when it landed in the small crater on January 25 after its seven-month voyage spanning 300 million miles from Earth to Mars.

The rover is studying the Meridiani Planum region of Mars where it recently discovered evidence rocks at the landing site have been altered by water.

Tuesday's NASA news conference will be held at the agency's headquarters in Washington. The briefing begins at 2 p.m. EST (1900 GMT) with opening remarks from NASA Administrator Sean O'Keefe.

Presenting the discovery will be:

  • Dr. Ed Weiler, NASA's Associate Administrator, Office of Space Science
  • Prof. Steve Squyres, Cornell University, Ithaca, N.Y., and MER Principal Investigator
  • Prof. John Grotzinger, Massachusetts Institute of Technology, Cambridge, Mass, and a MER Co-investigator
  • Dr. Dave Rubin, U.S. Geological Survey Sedimentologist at the Pacific Science Center in Santa Cruz, Calif.
  • Dr. Jim Garvin, NASA Lead Scientist for Mars and the Moon, Office of Space Science, NASA Headquarters

This is the latest Opportunity status report as written by Mission Control for sol 54:

Opportunity flipped 115 meters (377.3 feet) on its odometer during the latest drives along the current soil survey campaign, surpassing the total drive distance of 1997's Sojourner rover. After performing a "touch and go" sequence at the third soil target south of the Challenger Memorial Station, Opportunity moved east to its fourth target. There the rover used its wheels to dig a trench that will be studied in coming sols.

The sol, which ended at 0246 GMT on March 20, started with brief alpha particle X-ray and Moessbauer spectrometer measurements on the soil target known as "Coconut2." These were followed by two sets of microscopic imager shots of Coconut2 and "ChocolateChip." The rover then stowed its arm and drove.

Remote sensing with the miniature thermal emission spectrometer and the panoramic camera remote sensing was performed before, during, and after the drive and trenching activities. Also, Opportunity took additional images with its navigation camera imaging in preparation for next sol's drive to the final site inside the crater.

To prepare for the trenching on this sol, the wake-up song was "I Feel The Earth Move" by Carole King.

FRIDAY, MARCH 19, 2004
This is the latest Spirit status report as written by Mission Control:

Spirit began the morning of Sol 74, which ended at 1425 GMT on March 19, by completing an alpha particle X-ray spectrometer integration on the target "Panda," inside the scuff on "Serpent" drift. Then Spirit placed the alpha particle X-ray spectrometer back down on the target "Polar" for a 30-minute integration. During that integration, Spirit took some images of disturbed soil with the panoramic camera, and acquired some ground temperatures with the miniature thermal emission spectrometer. Spirit then switched the tools on its robotic arm to the Moessbauer spectrometer for an hour-long integration on Polar. During that integration, the rover took some sky and ground measurements with the mini thermal emission spectrometer. Spirit finished its arm activities for the day by acquiring three microscopic images of Polar and three more of Panda.

Starting around 12:35 p.m. Mars Local Solar time, Spirit made a direct drive of about six meters (19.7 feet) to another section of the Serpent drift complex, called "Stub Toe." There the rover repeatedly scuffed the drift and advanced .15 meters (half a foot) in a series of five "scuff and drives." After the five scuffs and advances were made, Spirit roved forward another 3 meters (9.8 feet) and then looked back over its shoulder using the mini thermal emission spectrometer and navigation cameras to analyze the damage. The rover continued along the Bonneville crater rim with a 16-meter direct drive, and then an auto-navigation drive for 9 meters (29.5 feet). Spirit completed a final set of drives to set up for a touch and go on sol 75 at around 2:10 p.m. Mars Local Solar time. The total amount of driving for sol 74 was an impressive 34.3 meters (112.5 feet).

Spirit then took navigation camera and panoramic camera images of the drive directions for planning the sol 75 traverse. The rover acquired some mini thermal emission spectrometer reconnaissance images and then took a 30-minute siesta before the afternoon Odyssey relay pass. During that pass, Spirit used the mini thermal emission spectrometer to acquire a sky profile and ground temperature observations.

On sol 75, which will end at 1505 GMT on March 20, Spirit will place the microscopic imager on a soil target and drive about 22 meters (72.2 feet) around the Bonneville crater rim. Spirit will also conduct atmospheric observations with the mini thermal emission spectrometer and panoramic camera.

A major ingredient in small mineral spheres analyzed by NASA's Mars Exploration Rover Opportunity furthers understanding of past water at Opportunity's landing site and points to a way of determining whether the vast plains surrounding the site also have a wet history. Read the full story.

This is the latest Spirit status report as written by Mission Control:

Sol 72, which ended at 1306 GMT on March 17, was a day full of digging for NASA's Mars Exploration Rover Spirit. Spirit began the day taking panoramic camera and miniature thermal emission spectrometer observations of the drift dubbed "Serpent" before creating the "scuff" that would reveal the inside material at this location.

Then it was time to get into position. The rover drove about two-and-a-half meters (8.2 feet) to put the left front wheel up onto the drift. It then turned right and left five degrees to dig the left front wheel into the drift. When the "shimmy" was complete, Spirit backed 10 centimeters (3.9 inches) out of the hole. The digging and backing process was repeated four times to thoroughly scuff Serpent's side. Then Spirit backed up another meter (3.28 feet) to attain miniature thermal emission spectrometer, panoramic camera and navigation camera observations of the scuffed area. These observations will aid in in-situ target selection. To prepare for the upcoming in-situ work, Spirit drove forward 0.4 meters (1.3 feet) for additional imaging, and then drove forward a final 0.45 meters (1.5 feet) to put the scuff in the arm work volume.

Spirit spent the rest of the day obtaining navigation camera and panoramic camera observations of the intended drive direction around part of the crater rim. Spirit will do some work overnight, taking miniature thermal emission spectrometer thermal inertia and atmosphere measurements.

On sol 73, which will end at 1346 GMT on March 18, Spirit will conduct extensive microscopic imaging of sections of the drift, and run an overnight Moessbauer and alpha particle X-ray spectrometer integration.

The Mission Control status reports from today covering the activities of Opportunity and Spirit:

Opportunity reached the first of five targets in its current soil survey on the rover's 51st sol on Mars. The sol, which ended at 0047 GMT on March 17, began with a salute to the rover's intended target on the southern face of the crater it has been exploring since its early sols on Mars. "Song of the South" by Alabama was chosen to wake Opportunity for a busy sol that involved a 15-meter (49.2 feet) u-shaped drive toward the soil target.

Before the rover ventured away from the outcrop that has been the focus for most of its mission, alpha particle x-ray spectrometer observations were completed on the red rind dubbed "Shark's Tooth." The arm was stowed before Opportunity "scuffed" the rock "Carousel" with its front left wheel. Results of the experiment were imaged as Opportunity backed up and prepared to drive away from the outcrop.

Backing down toward the center of the crater and then arcing around the Challenger Memorial Station, Opportunity ultimately drove back up the slope to a position fairly close to the rim. On its way to the current soil target, the rover was also able to image the trench it dug on sol 23 from a different angle.

In the coming sols, Opportunity will use the instruments on its arm to examine all five soil targets identified for the soil survey.

Spirit began sol 71, which ended at 1226 GMT March 16, with a morning nap to re-charge after the record-breaking number of activities it accomplished on sol 70. After that, it was back to work. Spirit began by retracting the alpha particle X-ray spectrometer, closing the doors, and imaging the doors with the front hazard avoidance cameras to confirm that they were closed. Spirit then proceeded to observe a soil target with the microscopic imager, and it also used the panoramic camera to observe the magnets, do a sky survey and capture a dust devil movie.

Then it was time to drive. Spirit completed a 15-meter (49.2 feet) blind drive followed by a 3-meter (9.8 feet) auto-navigation drive around the south rim of "Bonneville" crater toward a drift named "Serpent." Once there, Spirit completed post-drive science observations and a miniature thermal emission spectrometer study of the atmosphere, ground and future drive direction.

Spirit's main objective on sol 72, which ends at 1306 GMT March 17, will be to disturb and analyze the material at Serpent. Spirit will drive over the dune and back up to an optimal observation position. It will then analyze the area with the panoramic camera and mini thermal emission spectrometer. Spirit will end the sol by driving back on top of the dune.

MONDAY, MARCH 15, 2004
The Mars Exploration Rover Spirit has returned a stunning panorama from the rim of Bonneville Crater. The 180-degree mosaic shows the crater's interior and surrounding terrain. The heat shield that protected Spirit during the fiery descent through the Martian atmosphere is seen sitting on the opposite side of the crater. Read full story.

Meanwhile, Opportunity has completed its 50th workday on Mars as the rover neared completion of the rock outcrop study.

"The rover arm, with the Alpha Particle X-ray Spectrometer at the ready, was placed on the rock called 'Shark's Tooth' for a 30-minute observation. The Microscopic Imager then took a series of pictures of the targets 'Enamel 1' and 'Lamination.' The focus then switched back to 'Shark's Tooth' for an examination by the Moessbauer Spectrometer," mission control reported.

"The sol also included many panoramic camera observations of targets with creative names like 'Patio Rug,' 'Anaconda Snake Den,' 'West Zen Garden' and 'Garter Snake.'

"The next sol calls for a final experiment at the outcrop called 'scuffing.' 'Scuffing' essentially turns one of the rover wheels into a tool to scrape a rock to help determine its hardness. The rock 'Carousel' will be scraped by Opportunity's front left wheel. After that experiment, the rover will begin its trans-crater traverse to five soil survey targets, the first of which will lead Opportunity up the sandy southern face of the crater."

SUNDAY, MARCH 14, 2004
Here is the latest update from mission control on the twin Mars Exploration Rovers:

NASA's Opportunity finished inspecting the "Berry Bowl" site and drove 10 meters (33 feet) toward a new target during its 48th sol on Mars, which ended at 2250 GMT Saturday.

The rover used all four tools on its arm during the morning, ending with a brushing by the rock abrasion tool, then post-brushing examinations with the microscope and alpha particle X-ray spectrometer. This closed out three sols of work at "Berry Bowl" to compare the composition of targets with and without groups of the BB-sized spherules believed to have formed while the local environment was wet.

Opportunity then stowed its arm and drove toward an area dubbed "Shoemaker's Patio" at the southwestern end of the outcrop the rover has been studying since it arrived on Mars. This informal name pays tribute to the late geologist Dr. Eugene Shoemaker of the U.S. Geological Survey. Opportunity's more specific target is a rock called "Shark's Tooth" at the near edge of the patio. The drive did not quite put that target within reach of the robot arm. Activities of the sol also included atmospheric observations with the panoramic camera and miniature thermal emission spectrometer, plus post-drive imaging with the navigation camera.

Mission controllers at JPL chose John Williams' "Jaws: Main Title and Fist Victim" as the wake-up song for sol 48.

During its 69th sol on Mars, ending at 1107 GMT Sunday, NASA's Spirit finished shooting frames with its panoramic camera for a full 360-degree color view of the surroundings visible from the crater rim where the rover is perched. Once the panorama frames are transmitted to Earth, scientists will use them and information from Spirit's miniature thermal emission spectrometer to assess the structures and composition of the crater interior and other surfaces in view.

Spirit did not move from its vantage point on the south rim of the crater nicknamed "Bonneville." An extra downlink session was added via relay by NASA's Mars Odyssey orbiter to accelerate getting the panoramic imaging data to Earth. The total amount of data received from Spirit during the sol through relays and direct-to-Earth transmission was 225 megabits.

In the martian afternoon, Spirit added a set of observations with the miniature thermal emission spectrometer in coordination with overhead passage of NASA's Mars Global Surveyor orbiter, which carries a similar spectrometer looking down. Events of the sol also included two camera sessions requested by engineers. The first was to get high-resolution images of Spirit's heat shield on the northern rim of "Bonneville." The other was to photograph wheel tracks to help rover mobility specialists assess slippage. For sol 69's wake-up music, the team spun John Lennon's "Watching the Wheels."

Plans for sol 70, ending at 1147 GMT Monday, feature more remote sensing from the rover's current location, before a drive along the rim begins on sol 71.

Spirit spent all of sol 68, which ended at 1028 GMT on March 13, at the "Bonneville" crater location. It began the morning operating the panoramic camera to acquire the first images of what will be a 360-degree shot of "Bonneville's" rim and basin, and the "Columbia Hills" to the southeast.

Spirit also moved the instrument deployment device, or rover arm, into position to acquire panoramic camera images of the magnets on the rock abrasion tool. It then placed the Moessbauer spectrometer on soil for a short integration after taking five microscopic imager images.

Around 13:35 Mars Local Solar time, one of Mars' moons, Deimos, passed in front of the sun. Scientists and rover controllers took this opportunity to image the moon's transit with the panoramic camera before completing mini thermal emission spectrometer observations of the crater interior.

Spirit's work isn't over though. The Moessbauer will continue analyzing the soil at "Bonneville's" rim through the night.

Sol 69, which will end at 1207 GMT on March 14, 2004, will also be a no-drive sol during which Spirit will acquire the second half of the 360-degree panoramic camera image of Bonneville. Spirit will also perform remote sensing of the inside of the crater and analyze soil targets with the Moessbauer and alpha particle x-ray spectrometer.

FRIDAY, MARCH 12, 2004
The Mission Control status reports from today covering the activities of Opportunity and Spirit:

On sol 47, which ended at 2210 GMT on Friday, March 12, Opportunity awoke to "No Particular Place to Go" by Chuck Berry in recognition of the stay at "Berry Bowl." Engineers also played "That's Amore" by Dean Martin in honor of the Phobos moon's transit across the sky.

Opportunity finished remnants of activities from the past sol's research at "Berry Bowl." The sol started with the hazard avoidance camera taking a picture of the "Berry Bowl" area as a context picture. The miniature thermal emission spectrometer then performed some "sky stares" of the atmosphere. At 11:30 Local Solar Time, the robotic arm started moving. It picked up the alpha particle X-ray spectrometer and moved to a new location nearby, then switched to the Moessbauer spectrometer. Both spectrometers are searching for clues about the chemical composition of the mysterious "blueberries."

Later, Opportunity took panoramic camera images of the suite magnet on the rover itself, which is collecting atmospheric dust samples to understand why the martian dust is so magnetic. The panoramic camera also took images of a target dubbed "Fool's Silver," which contains an interesting angular feature in the outcrop.

After all the morning's hard work, Opportunity took a short siesta to rest and recharge. Opportunity reawakened a few hours later to take more images of the atmosphere with the miniature thermal emission spectrometer and panoramic camera. Those were taken in the same locations as the morning measurements to compare the atmospheric data throughout the sol.

At 15:40 Local Solar Time, Opportunity took about a dozen images of the Sun to catch the eclipse by the martian moon, Phobos. Opportunity once again shut down for a nap and woke up at 4:53 Local Solar Time, sol 48, for a tool change and a communications session with the Odyssey orbiter. While the rover was awake for the Odyssey pass, the rover heated up the robotic arm, which had chilled to almost -80 degrees Celsius (-112 degrees Fahrenheit). The motors cannot move at that frigid temperature, so the rover arm heated for 32 minutes to surpass the operational temperature of 40 degrees Celsius (104 degrees Fahrenheit). As the rover arm quickly cooled, the heat lasted long enough (5 minutes) for the arm to twist its wrist and change instruments from the Moessbauer spectrometer back to the alpha particle X-ray spectrometer.

The rest of the plan for sol 48, which will end at 2249 GMT on Saturday, March 13, is to perform quite a few complicated maneuvers. Opportunity plans to brush an area with the rock abrasion tool, analyze the brushed area with the spectrometers, then drive 10 meters (33 feet) along the slippery slopes of the outcrop to "Shark's Tooth" in "Shoemaker's Patio."

Spirit woke up on sol 67, which ended at 0948 GMT March 12, 2004, to "On Top of the World" by the Carpenters. The song was fitting, as yestersols's drive put Spirit at the rim of "Bonneville" crater, but it took some additional maneuvering to get the rover perfectly placed for the 360-degree panoramic camera images it will take on upcoming sols.

Before beginning the sol 67 drive, Spirit completed an overnight alpha particle x-ray spectrometer integration and a couple of small panoramic camera shots of its surroundings.

Then the rover traveled 13 meters (42.7 feet) in a direct drive around some obstacles followed by a 1.4-meter (4.6 feet) automatic navigation drive. Spirit spent the afternoon using the mini thermal emission spectrometer to look at targets that will be analyzed more fully on sol 67, and then driving 0.9 meters (3 feet) forward to be able to access that area with the arm tomorrow.

Spirit put a total of 24.8 meters (81.4 feet) on the odometer today, partly due to some back and forth maneuvering it had to do to ensure a safe path. The final location has proven to be just right, and Spirit will stay put for a couple sols while it continues to investigate "Bonneville" crater.

Before the day was over, Spirit looked at the sun for an attitude update and then took front hazard avoidance camera images of the arm work volume, and a small navigation panorama of the crater. The rover also completed some mini thermal emission spectrometer analysis of the far side of the crater and finished the day with some panoramic camera images of the sunset.

On sol 68, which will end at 1028 GMT March 13, 2004, Spirit will begin a two-sol panoramic camera session and complete selected mini thermal emission spectrometer observations. The rover will also begin a very long Moessbauer integration on a soil target.

NASA's Spirit has begun looking down into a crater it has been approaching for several weeks, providing a view of what's below the surrounding surface. Read full story.

The Spirit rover has nearly reached its long-sought destination -- Bonneville Crater. On Tuesday, the craft conducted the longest directed drive to date.

"That drive was 27 meters (88.6 feet) toward the edge of Bonneville Crater," controllers said. "Spirit then attempted to use auto navigation to reach a target that was an additional 6 meters (19.7 feet) away. Sensitive obstacle avoidance software prevented Spirit from reaching the destination, and like yestersol, the rover completed several drives forward and back. Those drives resulted in a final odometer reading of 40.7 meters (133.5 feet) for the day, even though the total straight-line distance traveled was 30 meters (98.4 feet)."

Spirit has moved close enough to Bonneville's edge to take images with the navigation cameras that reveal the opposite rim of the crater, NASA reported.

The plan for Wednesday's workday, ending late this evening U.S. time, calls for Spirit to drive up to the summit of the rim and show us what's inside with a 180-degree navigation camera panorama.

Passing the halfway mark of its primary mission, the Mars rover Opportunity on Wednesday used the bristles of its Rock Abrasion Tool to brush away dirt inside and around the hole carved into the bedrock outcropping a day earlier.

Opportunity then snapped five microscopic images of the freshly brushed hole dubbed "Mojo 2," controllers reported.

"The Miniature Thermal Emission Spectrometer took measurements at three locations on the surface of Mars, and then pointed upwards to observe the atmosphere in four different directions. The panoramic camera was also busy taking images of the magnets around the Rock Abrasion Tool area, 'Mojo 2' post brushing, and a new area called 'Slick Rock,'" NASA said.

NASA will hold this week's rover status and science news conference on Thursday at 1 p.m. EST (1700 GMT).

After its earlier attempt stalled, Opportunity has successfully used the Rock Abrasion Tool to grind a 3.1 millimeter-deep (just over one-tenth of an inch) hole in the "Mojo 2" target on "Flatrock." The cutting occurred early Tuesday (U.S. time) -- the rover's 44th workday on Mars.

"Yesterday, diagnostic testing determined a voltage adjustment was necessary to overcome some mechanism 'stickiness' in the routine during which the Rock Abrasion Tool finds the highest point in the target area," NASA reported.

"The routine worked perfectly on this grind with the new voltage setting. After one hour and five minutes of successful grinding, the Rock Abrasion Tool grind motor stalled, probably while grinding into one of the spherules also known as 'blueberries.' These objects are known to obstruct the grinding tool and cause it to terminate its sequence."

The Mossbauer Spectrometer was placed on the freshly-cut rock hole Tuesday, followed later by the Alpha Particle X-ray Spectrometer.

Meanwhile, the Miniature Thermal Emission Spectrometer took two long atmospheric measurements and the panoramic camera was busy taking images of the RAT hole and surrounding target areas, controllers said.

Twin rover Spirit remains on the move, surpassing the 300-meter mark Monday night (U.S. time).

"Spirit completed another 29 meters (94 feet) of its drive toward the rim of Bonneville Crater on sol 64, which ended at 11:49 p.m. PST, bringing its total odometry to 314 meters (1,030 feet) -- 14 meters (45.9 feet) past the minimum mission success criterion," NASA said.

"Spirit began the morning with an 18-meter (59 feet) direct drive that safely maneuvered the rover through a field of rocks. Spirit then traversed 11 more meters (35 feet) using autonomous navigation and at 11:30 a.m. Mars Local Solar Time completed the drive. Spirit had some difficulty finding a way around an obstacle during the last portion of the commanded drive. That resulted in some repeated forward and backward maneuvering which left an interesting 'trench' for scientists to have the rover peer into.

"Spirit is climbing up a very steep part of Bonneville now, and ended this sol's drive tilted at a forward pitch of about 15 degrees."

Engineers believe they have determined why the rover Opportunity was unable to grind into the rock outcrop Sunday morning as planned.

"Using a combination of microscopic images, hazard avoidance camera images, and Rock Abrasion Tool tests on sol 43 (Monday), Opportunity's engineering team discovered that the grind motor of the Rock Abrasion Tool on Mars stalled prematurely during what's called the 'seek/scan' phase when the Rock Abrasion Tool instrument searches for the rock face. This resulted in no contact during the actual grind activity on sol 42 (Sunday).

"The most likely causes of the stall are dust and dirt accumulations and temperature variations on the instrument. The tests also confirmed that engineers can safely increase the motor voltage on the instrument to prevent a future stall."

The grinding has been rescheduled for Tuesday.

The Opportunity rover's Rock Abrasion Tool failed to grind a hole into the so-called "Flat Rock" area of the bedrock outcropping on Sunday morning.

Mission control said the operation "produced almost no discernable impression on the rock."

Controllers plan to run diagnostic tests early Monday "to aid with tuning parameters for a second grinding attempt."

"All indications are that the tool is healthy," NASA said.

Spirit continues cruising to Bonneville Crater, driving 26.15 meters (85.8 feet) on Saturday.

"Some of the drive maneuvered around obstacles. The net gain in the northeasterly direction toward the crater rim was 22 meters (72 feet), and that destination was estimated to be about 88 meters (289 feet) away from Spirit's new location," NASA reported.

That puts Spirit's odometer at 250.71 meters (822.5 feet).

The Spirit rover resumed driving Friday, leaving the "Middle Ground" area that it had explored for a week.

"In the Martian morning, Spirit's panoramic camera took the final frames needed for the camera team to assemble a full-circle color panorama after all the data reaches Earth," mission control reported.

"In the early afternoon, Spirit backed up 0.5 meter (20 inches), then edged forward 0.29 meters (11 inches) to sidestep a rock called 'Ingrid.' Then the rover advanced 28.5 meters (94 feet) toward its crater-rim destination. The drive took 45 minutes. From the new location, Spirit took forward-looking pictures for use in future drive planning. It also observed the ground and the sky with its Miniature Thermal Emission Spectrometer."

Spirit was scheduled to continue driving on its Saturday workday, which is known as sol 62.

Opportunity spent the overnight hours of Friday morning finishing an Alpha Particle X-ray Spectrometer observation at the "Last Chance" area of the rock outcrop and completed a morning set of panoramic camera and Mini-TES remote sensing observations.

"At 11:30 Local Solar Time, engineers retracted the Alpha Particle X-ray Spectrometer off the target, took a final set of 24 microscopic images, and stowed the arm for driving," controllers reported.

"Opportunity then scored another first by successfully using visual odometry to navigate autonomously on Mars. During a drive along the crater wall, the vehicle properly identified wheel slippage on the steep slope of the crater wall using features in the navigation camera imagery. This effectively provided a mid-course correction that landed the science and engineering team exactly at the target location where they want Opportunity to do work using the instruments on the rover arm on sol 41 (Saturday)."

Operating half-a-world away from Spirit, Opportunity's Saturday workday has been completed. The rover inspected a rock area called "Wave Ripple" with the arm, then drove to a new target dubbed "Flat Rock" near the south end of the outcrop that the rover has been examining for weeks, officials said.

"Although the rover wheels slip some in the local soil and the drive traversed a slope of 10 to 11 percent, Opportunity and engineers at JPL navigated the trip so well that a planned final approach to the target on sol 42 (Sunday) could be cancelled. The target is within the work volume of Opportunity's robotic arm.

"The drive was done in a series of one-meter (3.3-foot) segments making up a U-shaped path to the south and west. Each segment included a correction for slippage.

"Before starting the drive, Opportunity used its microscope for 50 images of 'Wave Ripple,' and examined the composition of the rock with its Alpha Proton X-ray Spectrometer and its Mossbauer Spectrometer."

The Mars Exploration Rover Spirit is completing its study of a rock named Humphrey, which had a small depression carved into it.

The planned four-hour Rock Abrasion Tool grind of Humphrey on Tuesday was cut short to only 20 minutes.

"The intricate slopes and cracks of the rock make it a challenging target for instruments. When sensors indicated a loss of contact with surface material, the software perceived a problem and the Rock Abrasion Tool was moved away from the rock," mission controllers reported.

"Engineers identified the software issue that caused the Rock Abrasion Tool to terminate its original planned grinding on sol 58. The minor bug will be fixed when new flight software is loaded at the end of March."

On Wednesday, Spirit successfully completed a two millimeter-deep grind (.08 inches) carve. A five-minute brush to clean the hole followed. The suite of science instruments then went to work studying the shallow cut.

The rover backed up 0.85 meters (about 2.8 feet) on Thursday, allowing the Miniature Thermal Emission Spectrometer and panoramic camera to observe Humphrey's RAT hole and previously brushed areas.

Meanwhile on Opportunity, the rover drove 4.25 meters (14 feet) Tuesday to the "Last Chance" area of the rock outcrop.

"With the moves of a tango dancer, the drive was another intricate study in, and challenge of, driving on a slippery, steep slope," mission control said.

"The rover was directed to: turn right, go forward, turn right, take images of 'Last Chance,' turn right, go forward, turn left, go forward, turn right, take images of 'Big Bend,' go straight, turn left and go straight! Due to the challenges of driving and pirouetting on such a steep slope (as steep as 22 degrees) the rover found it difficult to maintain a perfectly straight course, and Opportunity came up shy and right of the 'Last Chance' target by about 30 centimeters (about one foot)."

Wednesday saw the rover observe the atmosphere with the panoramic camera and Miniature Thermal Emission Spectrometer. Then, Mini-TES was used to stare at the ground for science observations. After making stereo microscopic images and Mossbauer Spectrometer readings of the soil target dubbed "Pay Dirt," Opportunity stowed its arm, took a panoramic camera image of "Last Chance," and drove a very short distance of 0.4 meters (16 inches) toward "Last Chance" to prepare for the deployment of the robotic arm.

On Thursday, put its arm through an extraordinary workout.

"The science and engineering team built a whopping 490 commands to accomplish the most complex robotic arm operations on Mars yet. Opportunity took three mosaics on the area dubbed 'Last Chance,' using the microscopic imager, creating 128 images in over 200 arm moves. Each 'frame' of these mosaics required multiple microscopic images," controllers reported.

"There are two reasons for this. First, the microscopic imager does not have auto-focus, so the team needed to have Opportunity take and return multiple images at each location at different distances from the rock to get at least one in focus. A second reason is that the team needed Opportunity to take an extra image at a slightly different angle for each frame to create the right conditions to build stereo and computer-generated graphics of the 'topography' of the rock area up close.

"After about two-and-a-half hours of microscopic imager maneuvers, the robotic arm placed the Mossbauer spectrometer on a location at 'Last Chance' called 'Makar.' Opportunity also used the panoramic camera to watch the rare solar crossing of the sun by the moon Diemos and took images of the sky in coordination with the European Space Agency's orbiter at Mars, Mars Express."

NASA's Opportunity rover, studying exposed bedrock in the crater where it landed by chance in January, has found clear evidence that Mars once supported a wet, habitable environment, one that would have been suitable for life, scientists announced today. Read our full story.

1907 GMT (2:07 p.m. EST)
Scientists have concluded the part of Mars that NASA's Opportunity rover is exploring was soaking wet in the past.

Evidence the rover found in a rock outcrop led scientists to the conclusion. Clues from the rocks' composition, such as the presence of sulfates, and the rocks' physical appearance, such as niches where crystals grew, helped make the case for a watery history.

"Liquid water once flowed through these rocks. It changed their texture, and it changed their chemistry," said Dr. Steve Squyres of Cornell University, Ithaca, N.Y., principal investigator for the science instruments on Opportunity and its twin, Spirit. "We've been able to read the tell-tale clues the water left behind, giving us confidence in that conclusion."

Dr. James Garvin, lead scientist for Mars and lunar exploration at NASA Headquarters, Washington, said, "NASA launched the Mars Exploration Rover mission specifically to check whether at least one part of Mars ever had a persistently wet environment that could possibly have been hospitable to life. Today we have strong evidence for an exciting answer: Yes."

Opportunity has more work ahead. It will try to determine whether, besides being exposed to water after they formed, the rocks may have originally been laid down by minerals precipitating out of solution at the bottom of a salty lake or sea.

The first views Opportunity sent of its landing site in Mars' Meridiani Planum region five weeks ago delighted researchers at NASA's Jet Propulsion Laboratory, Pasadena, Calif., because of the good fortune to have the spacecraft arrive next to an exposed slice of bedrock on the inner slope of a small crater.

The robotic field geologist has spent most of the past three weeks surveying the whole outcrop, and then turning back for close-up inspection of selected portions. The rover found a very high concentration of sulfur in the outcrop with its alpha particle X-ray spectrometer, which identifies chemical elements in a sample. "The chemical form of this sulfur appears to be in magnesium, iron or other sulfate salts," said Dr. Benton Clark of Lockheed Martin Space Systems, Denver. "Elements that can form chloride or even bromide salts have also been detected."

At the same location, the rover's Moessbauer spectrometer, which identifies iron-bearing minerals, detected a hydrated iron sulfate mineral called jarosite. Germany provided both the alpha particle X- ray spectrometer and the Moessbauer spectrometer. Opportunity's miniature thermal emission spectrometer has also provided evidence for sulfates.

On Earth, rocks with as much salt as this Mars rock either have formed in water or, after formation, have been highly altered by long exposures to water. Jarosite may point to the rock's wet history having been in an acidic lake or an acidic hot springs environment.

The water evidence from the rocks' physical appearance comes in at least three categories, said Dr. John Grotzinger, sedimentary geologist from the Massachusetts Institute of Technology, Cambridge: indentations called "vugs," spherules and crossbedding.

Pictures from the rover's panoramic camera and microscopic imager reveal the target rock, dubbed "El Capitan," is thoroughly pocked with indentations about a centimeter (0.4 inch) long and one-fourth or less that wide, with apparently random orientations. This distinctive texture is familiar to geologists as the sites where crystals of salt minerals form within rocks that sit in briny water. When the crystals later disappear, either by erosion or by dissolving in less-salty water, the voids left behind are called vugs, and in this case they conform to the geometry of possible former evaporite minerals.

Round particles the size of BBs are embedded in the outcrop. From shape alone, these spherules might be formed from volcanic eruptions, from lofting of molten droplets by a meteor impact, or from accumulation of minerals coming out of solution inside a porous, water-soaked rock. Opportunity's observations that the spherules are not concentrated at particular layers in the outcrop weigh against a volcanic or impact origin, but do not completely rule out those origins.

Layers in the rock that lie at an angle to the main layers, a pattern called crossbedding, can result from the action of wind or water. Preliminary views by Opportunity hint the crossbedding bears hallmarks of water action, such as the small scale of the crossbedding and possible concave patterns formed by sinuous crestlines of underwater ridges.

The images obtained to date are not adequate for a definitive answer. So scientists plan to maneuver Opportunity closer to the features for a better look. "We have tantalizing clues, and we're planning to evaluate this possibility in the near future," Grotzinger said.

JPL, a division of the California Institute of Technology in Pasadena, manages the Mars Exploration Rover project for NASA's Office of Space Science, Washington.

1903 GMT (2:03 p.m. EST)
The rover Opportunity has proved that liquid water once "drenched" the surface at its landing site on Mars, NASA space science chief Ed Weiler is announcing at a news conference underway.

Confirming that the planet had water is a "giant leap" in determining if Mars once had life, Weiler says.

While scientists and officials prepare for Tuesday's announcement regarding "significant findings" from Opportunity, the rover spent its workday completing an Alpha Particle X-ray Spectrometer measurement on Guadalupe. The rover then performed a series of backward drives to move away from the "El Capitan" site in the outcrop.

See an image from the rover as it backed away from the outcrop.

"The rover also got in some remote sensing, including Miniature Thermal Emission Spectrometer observations and panoramic camera imaging of the holes created by the Rock Abrasion Tool. In addition, the panoramic camera took images of a crater to the east," Mission Control said.

On the upcoming workday (Monday night/Tuesday morning U.S. time), Opportunity will take several short drives in the direction of the "Last Chance" target in the "Big Bend" area of the outcrop, NASA said.

Meanwhile on Spirit, the rover made a .55-meter (1.8 feet) re-approach to "Humphrey" on Sunday to get into position for grinding with the Rock Abrasion Tool. After the repositioning, the rover took panoramic camera and Mini-TES data of its rear tracks and the path in front of it, leading the way to Bonneville Crater.

See the three brush marks here.

Today, Spirit observed the area on Humphrey that was brushed by the Rock Abrasion Tool. An area just to the right of the brushed area, where the RAT will grind into the rock, was also examined, NASA reported.

"The morning hours found Spirit using its Alpha Particle X-ray Spectrometer on the intended grinding target to verify its similarity to the pre-brushed areas of the rock. The arm then switched out tools to the Microscopic Imager to get close-up views of the grinding target and the area to the right of it. The Mossbauer Spectrometer was then placed on the brushed area for another observation.

"Panoramic camera images were taken of the Rock Abrasion Tool magnets to study dust accumulation. The Miniature Thermal Emission Spectrometer performed a diurnal characterization on the nearby soil. This allows scientists to look at the temperature difference from day to night, revealing information about particle sizes within the soil."

Controllers now expect Spirit to carve into Humphrey on Tuesday.

Spirit gave the rock nicknamed "Humphrey" a good brushing on Saturday. Using the wire-bristled brush of the Rock Abrasion Tool, the rover cleared the dust off three patches on the rock.

"Brushing three different places on a rock one right after another was an unprecedented use of the Rock Abrasion Tool, designed to provide a larger cleaned area for examining," NASA reported.

"Afterwards, Spirit rolled backward 85 centimeters (2.8 feet) to a position from which it could use its Miniature Thermal Emission Spectrometer on the cleaned areas for assessing what minerals are present. Due to caution about potential hazards while re-approaching Humphrey, the rover moved only part of the way back."

Controllers hoped to finish the move and additional inspections of the brushed area today. The Rock Abrasion Tool could be used to grind into Humphrey on Monday.

Meanwhile on Opportunity, the rover used its Microscopic Imager for eight observations of the fine textures of an outcrop-rock target called "Guadalupe" on Saturday night.

"The observations include frames to be used for developing stereo and color views," scientists said.

"Opportunity also used its Mossbauer Spectrometer and, after an overnight switch, its Alpha Particle X-ray Spectrometer to assess the composition of the interior material of Guadalupe exposed yestersol by a grinding session with the Rock Abrasion Tool."

Once finished with the close-up inspection of Guadalupe, Opportunity will back up to give the panoramic camera and Miniature Thermal Emission Spectrometer good views of the area where the rock interior has been exposed by grinding, officials said.

Having completed its investigations at the first Rock Abrasion Tool grinding patch on the rock outcrop, the Mars rover Opportunity has moved slightly to reach the area dubbed "Guadalupe." On Friday night (U.S. time), the RAT was used to grind a tiny hole in this latest rock target.

"The rover looked at the patch with its microscope both before and after the grinding session. Then it placed its Mossbauer Spectrometer against the newly exposed interior material of the rock for a long reading of data that scientists use to identify what iron-containing minerals are present in the target," NASA reported.

"Opportunity also used its Miniature Thermal Emission Spectrometer during the sol to assess the composition of an outcrop feature dubbed 'Shoemaker Wall.' It took images of 'Guadalupe' with its panoramic camera before and after the use of the Rock Abrasion Tool.'"

On Saturday evening, Opportunity was scheduled to continue using its tools on the robotic arm to examine the rock interior exposed by the "Guadalupe" grind.

Meanwhile, Spirit approached a rock called "Humphrey" on Friday.

"The initial 3.5 meter (11.5 feet) drive toward the rock was cut short at only 2.5 meters (8.2 feet) due to a built-in software safety. Rover engineers quickly adjusted the software restriction and drove the final meter of that planned drive, plus the 0.9 meters (about 3 feet) that put the rover in the best position for brushing 'Humphrey' with the rock abrasion tool," NASA said.

"Before approaching the rock, Spirit used its Alpha Particle X-ray Spectrometer to investigate the areas the Rock Abrasion Tool will brush and grind.

"Unlike the last rock abrasion tool sequence on the rock called 'Adirondack,' the planned procedure for 'Humphrey' will include brushing three separate areas of the rock. After brushing, Spirit will back up and examine the brushed areas with the instruments on its arm. The science team will then decide the best place to grind into 'Humphrey' - it could be one of the three brushed areas or another section altogether. The hope is to remove as much dust as possible so the instruments on Spirit's arm can get a pre-grinding 'read' on the rock coating and then, after grinding, study beneath the coating and surface.

Once the RAT'ing and science collection is completed on Humphrey, Spirit will either "investigate an interesting rock behind it, or continue on toward Bonneville Crater."

Dust gradually obscures the Sun during a blue-sky martian sunset seen in a sequence of newly processed frames from NASA's Mars Exploration Rover Opportunity. Read full story.

2215 GMT (5:15 p.m. EST)
Spirit made a 0.85-meter (about 2.8 feet) drive to the target inside the "Middle Ground" area. The rover conducted an examination, using its Microscopic Imager and Alpha Particle X-ray Spectrometer, of the magnet arrays that are collecting airborne dust, NASA reports.

The rover will study the soil in its current location before approaching a rock called "Humphrey" for observations and then using the Rock Abrasion Tool to grind into it.

Opportunity continues to use its Mossbauer Spectrometer to look for iron-bearing minerals in the RAT hole it carved at the bedrock outcropping.

The data from the first Mossbauer spectrum of hole was received on Earth Wednesday afternoon. The Alpha Particle X-ray Spectrometer data from yestersol at this target was retransmitted to Earth again Wednesday to get missing packets of data that were not received during the first data communications relay, NASA said.

Opportunity also snapped pictures of the rock areas named "Maya" and "Jericho" with the panoramic camera and took Miniature Thermal Emission Spectrometer measurements of the sky and "El Capitan" throughout the sol.

On Thursday evening (U.S.) time, Opportunity will make a short move (10 to 20 centimeters or 4 to 8 inches) to the next Rock Abrasion Tool target site called "Guadalupe."

Meanwhile, controllers are changing their communications plans with Opportunity due to power considerations.

"The amount of power Opportunity is able to generate continues to dwindle due to the decreasing amount of sunlight (energy) reaching the solar panels during the Martian seasonal transition to winter. Because of this, the engineers are adjusting the roverÕs daily communications activities. To minimize power use for communications sessions, engineers began a new "receive only" morning direct-from-earth communication relay. This lower-power communication mode was successful. Opportunity will continue with this approach to maximize the available power for driving and science activities as Mars moves farther away from Earth and the Sun in its elliptical orbit.

"In conjunction with the morning communications session change, engineers added a second afternoon Mars Odyssey orbiter relay pass, which uses less power in transmitting data volume than direct-to-Earth communication. This additional Odyssey pass more than compensated for the elimination of the morning direct-to-Earth downlink. Engineers also continue to effectively use rover 'naps' throughout the day to maximize energy savings."

1815 GMT (1:15 p.m. EST)

On its most recent workday, Spirit drove about 3 meters to the center of the area dubbed Middle Ground, project manager Richard Cook told reporters in a telecon today. The rover snapped a 180-degree panorama using its Pancam. It will be studying the rocks and soil in this area over the coming days.

Meanwhile, Opportunity had a light work day. It was awake for only three hours during the daytime to relay data to Earth and then slept through the afternoon to recharge its batteries, Cook said. The rover has been using its instruments to probe the RAT hole during the night, including multi-hour observations with the Mossbauer Spectrometer, Cook reported.

"The rover has been doing a lot of science work at night, and the season on Mars is changing to winter, so the rover has less energy to work with than it did earlier in the mission. The Martian days are getting shorter and the sun angle is not allowing either rover to power up the solar panels as much as in the past," NASA says.

A full press conference is scheduled for 1 p.m. EST (1700 GMT) on Thursday for officials to give a full update on the rovers and their science activities.

The Mars rover Opportunity performed its first Rock Abrasion Tool grinding late Monday, cutting into the rock target dubbed as "McKittrick Middle Rat" at the El Capitan outcrop site. During the two-hour operation, Opportunity carved a hole about 4 millimeters (.16 inches) deep.

The science instruments will study the RAT hole over the next couple of days to determine if the rock's interior has the same composition and minerals as the outer surface. Scientists are trying to figure out what the exposed bedrock outcropping is made of.

Spirit finished its work at the trenching site and has driven about 50 meters in the past two days, reaching an area called "Middle Ground." It will be studying this region before continuing to move up to Bonneville Crater's rim.

The twin Mars Exploration Rovers spent the weekend hard at work on opposite sides of the planet as Opportunity examined exposed bedrock and Spirit studied the trench it dug in the soil.

Opportunity is using its arm to make close-up inspections of the "El Capitan" part of the street-curb-sized outcrop in the crater where the rover is working. Opportunity took 46 pictures with its microscope, examining several locations on "El Capitan" at a range of focal distances, NASA reported.

The Mossbauer Spectrometer and Alpha Particle X-ray Spectrometer studied the rock to assess what minerals and elements are present.

On Monday, Opportunity is scheduled to use the Rock Abrasion Tool to grind into part of El Capitan, giving the science devices a port hole to determine if the rock's interior is the same as the exterior.

Meanwhile, Spirit has spent a couple of days probing the wheel-dug trench nicknamed "Road Cut." Using the science instruments on its arm, the rover is collecting data about the subsurface soil exposed by the hole. A series of microscopic images of the trench floor and walls have also been obtained.

Spirit is preparing to resume driving to Bonneville Crater.

The next news conference on NASA Television is Thursday.

1812 GMT (1:12 p.m. EST)

Spirit successfully dug its first hole in the soil this morning, carving a trench 6 centimeters deep with its left front wheel so the science instruments can study the subsurface soil characteristics, mission manager Jim Erickson told reporters in a teleconference today.

The science observations will be performed over the next couple of days, studying the trench floor and wall. Spirit resumes its drive on the road to Bonneville Crater Monday.

Meanwhile, Opportunity finished studying its trench and drove 15 meters (50 feet) on the last workday, the longest drive that rover has made to date. Dodging the trench and lander, Opportunity cruised to nearly the opposite side of the crater to the bedrock outcrop, Erickson said.

The rover is doing soil studies today, then moving three-tenths of a meter forward to get its arm within reach of the El Capitan area of the outcrop to begin a detailed study.

From Mission Control:

By inspecting the sides and floor of a hole it dug on Mars, NASA's Opportunity rover is finding some things it did not see beforehand, including round pebbles that are shiny and soil so fine-grained that the rover's microscope can't make out individual particles.

"What's underneath is different than what's at the immediate surface," said Dr. Albert Yen, rover science team member at NASA's Jet Propulsion Laboratory, Pasadena, Calif.

Meanwhile, NASA's other Mars Exploration Rover, Spirit, has reached a site with such interesting soil that scientists have decided to robotically dig a hole there, too. Spirit's trenching at a shallow depression dubbed "Laguna Hollow" could answer questions about whether traits on the soil surface resulted from repeated swelling and shrinking of an upper layer bearing concentrated brine, among other possibilities.

Opportunity has manipulated its robotic arm to use its microscope on five different locations within the trench the rover dug on Monday. It has also taken spectrometer readings of two sites. "We've given the arm a very strenuous workout," said JPL's Dr. Eric Baumgartner, lead engineer for the arm. The accuracy of the tool placements -- within 5 millimeters, or less than a quarter inch -- is remarkable for mobile robotics on Earth, much less on Mars.

Once data are analyzed from the alpha particle X-ray spectrometer and the Moessbauer spectrometer about what elements and what iron-bearing minerals are present, the differences between the subsurface and the surface will be easier to interpret, Yen said.

While Opportunity has been digging and examining its trench this week, it has also been catching up on transmission of pictures and information from its survey last week of a rock outcrop along the inner wall of the small crater in which the rover is working.

Both rovers can communicate directly with Earth, but JPL's Andrea Barbieri, telecommunication system engineer, reported that 66 percent of the 10 gigabits of data they have returned so far has come via relays by NASA's Mars Odyssey orbiter and another 16 percent via relays by NASA's Mars Global Surveyor.

Based on the outcrop survey, scientists have chosen a feature they have dubbed "El Capitan" as the next target for intensive investigation by Opportunity.

"We've planned our assault on the outcrop," said Dr. Steve Squyres of Cornell University, Ithaca, N.Y., principal investigator for the rovers' science instruments. "The whole stack of rocks seems to be well exposed here," he said of the chosen target. Upper and lower portions appear to differ in layering and weathering characteristics. Planners anticipate that Opportunity's arm will be able to reach both the upper and lower parts from a single parking spot in front of "El Capitan."

Halfway around the planet, Spirit will be told to use a front wheel to dig a trench during the martian day, or "sol," that will end at 12:36 p.m. Friday, PST.

Some soil in "Laguna Hollow" appeared to stick to Spirit's wheels. Possible explanations include very fine-grained dust or concentrated salt making the soil sticky, said Dr. Dave Des Marais, a rover science team member from NASA Ames Research Center, Moffett Field, Calif. Pictures of the surface there also show pebbles arranged in clusters or lines around lighter patches Des Marais described as "miniature hollows." This resembles patterned ground on Earth that can result from alternating expansion and shrinkage of the soil. Possible explanations for repeated expanding and contracting include cycles of freezing and thawing or temperature swings in salty soil.

After trenching to seek clues about those possibilities, Spirit will continue on its trek toward the rim of a crater nicknamed "Bonneville," now estimated to be about 135 meters (443 feet) away from the rover. Spirit has already driven 128 meters (420 feet).

The rovers' main task is to explore their landing sites for evidence in the rocks and soil about whether the sites' past environments were ever watery and possibly suitable for sustaining life.

1830 GMT (1:30 p.m. EST)
The Mars rover Opportunity spent the past day continuing to study the wheel trench dug at Meridiani Planum. Further observations are planned today before the rover makes a 9-meter (30-foot) drive to the rock outcropping -- a specific area dubbed El Capitan -- to begin detailed science work there. The science arm will be put to use on Friday, NASA said.

Meanwhile, Spirit is using its full suite of instruments to study a depression called Laguna Hollow. The rover is preparing to do a trenching in this hollow.

Check back a little later for a full report from today's rover science news conference.

The first Mars Exploration Rover, beset for a time by computer troubles but now trekking on a geology adventure to an impact crater, has reached the midway mark of its primary mission. Read our full story.

1845 GMT (1:45 p.m. EST)
Opportunity spent the last day examining the small trench it created by spinning the right front wheel.

"We did a fairly complicated, probably the most complicated ever, set of Microscopic Imager observations of the trench that we have dug as well as getting the Mossbauer and APXS down there where they can do some observations overnight," Richard Cook, rover project manager, told reporters in a teleconference today.

"We have also done a little bit of long-distance remote sensing observations with the Mini-TES and Pancam looking over at the target that we probably are going to go to on the rock outcropping called El Capitan. So that information was acquired and sent to the ground as well.

"The plan for today is actually to do more of the same. They find the inside of this trench to be quite interesting, so the scientists want to spend another day doing another set of observations. Then we will probably start driving to El Capitan tomorrow at the earliest. In fact, it might even be delayed another day if they decide to drive around and look at this trench from the other side, which apparently there is some discussion of doing."

Meanwhile, Spirit has reached the midway point of its primary mission. It is completing the Sol 45 workday on Mars.

"Things continue to go well," Cook says.

Late last night/early this morning (U.S. time), the rover used its science arm to examine the spot reached the day before. Then Spirit resumed driving, moving to a flat depression called Laguna Hollow. It will remain there a day doing science measurements before making an approximate 40-meter drive Friday morning on the trek to Bonneville Crater.

Engineers believe the rovers will last well beyond their 90-day primary mission, allowing the craft to enter extended missions to continue exploring their respective landing locations on the opposite sides of Mars.

The next NASA news conference is scheduled for 1 p.m. EST on Thursday.

The Mars Exploration Rover Opportunity is putting its mark on the Red Planet, digging a small hole so its suite of science instruments can probe soil enriched with hematite, a mineral that typically forms in the presence of water. Read our full story.

Proving to be a real Mars hotrod, the Spirit rover has become the most traveled vehicle on the Red Planet, surpassing the distance accumulated by the Pathfinder rover nearly seven years ago. Read our full story.

2245 GMT (5:45 p.m. EST)
Latest report from Mission Control:

NASA's Mars Exploration Rover Opportunity has scooped a trench with one of its wheels to reveal what is below the surface of a selected patch of soil.

"Yesterday we dug a nice big hole on Mars," said Jeffrey Biesiadecki, a rover planner at NASA's Jet Propulsion Laboratory, Pasadena, Calif.

The rover alternately pushed soil forward and backward out of the trench with its right front wheel while other wheels held the rover in place. The rover turned slightly between bouts of digging to widen the hole. "We took a patient, gentle approach to digging," Biesiadecki said. The process lasted 22 minutes.

The resulting trench -- the first dug by either Mars Exploration Rover -- is about 50 centimeters (20 inches) long and 10 centimeters (4 inches) deep. "It came out deeper than I expected," said Dr. Rob Sullivan of Cornell University, Ithaca, N.Y., a science-team member who worked closely with engineers to plan the digging.

Two features that caught scientists' attention were the clotty texture of soil in the upper wall of the trench and the brightness of soil on the trench floor, Sullivan said. Researchers look forward to getting more information from observations of the trench planned during the next two or three days using the rover's full set of science instruments.

Opportunity's twin rover, Spirit, drove 21.6 meters closer to its target destination of a crater nicknamed "Bonneville" overnight Monday to Tuesday. It has now rolled a total of 108 meters (354 feet) since leaving its lander 34 days ago, surpassing the total distance driven by the Mars Pathfinder mission's Sojourner rover in 1997.

Spirit has also begun using a transmission rate of 256 kilobits per second, double its previous best, said JPL's Richard Cook. Cook became project manager for the Mars Exploration Rover Project today when the former manager, Peter Theisinger, switched to manage NASA's Mars Science Laboratory Project, in development for a 2009 launch.

Spirit's drive toward "Bonneville" is based on expectations that the impact that created the crater "would have overturned the stratigraphy and exposed it for our viewing pleasure," said Dr. Ray Arvidson of Washington University in St. Louis, deputy principal investigator for the rovers' science instruments. That stratigraphy, or arrangement of rock layers, could hold clues to the mission's overriding question -- whether the past environment in the region of Mars where Spirit landed was ever persistently wet and possibly suitable for sustaining life.

Both rovers have returned striking new pictures in recent days. Microscope images of soil along Spirit's path reveal smoothly rounded pebbles. Views from both rovers' navigation cameras looking back toward their now-empty landers show the wheel tracks of the roversÕ travels since leaving the landers.

Each martian day, or "sol" lasts about 40 minutes longer than an Earth day. Opportunity begins its 25th sol on Mars at 10:59 p.m. Tuesday, PST. Spirit begins its 46th sol on Mars at 11:17 a.m. Wednesday, Pacific Standard Time. The two rovers are halfway around Mars from each other.

1820 GMT (1:20 p.m. EST)
The Mars Exploration Rover Opportunity successfully made its first trench yesterday, digging a hole about 9 centimeters deep, 20 centimeters wide and 50 centimeters long with its right front wheel. The rover's science instruments will examine the trench to study the soil and its composition.

Meanwhile, Spirit used its arm last night to study the surface at its latest parking spot, then drove over 20 meters. The rover has now traversed 108 meters on Mars, breaking the previous record of 102 meters set in 1997 by the Mars Pathfinder rover called Sojourner.

We'll have a full report and video from today's news conference later this afternoon.

1816 GMT (1:16 p.m. EST)

The Spirit rover drove 27 meters overnight, moving ever closer to the Bonneville Crater. The craft performed more science activities with its arm during the just-completed workday, so time wasn't available for the maximum drive of 50 meters as originally scheduled.

Late tonight (U.S. time), Spirit will use its arm to "touch and feel" the current location. Then it will make a short drive over a two-hour period, mission manager Jim Erickson said.

On Tuesday night, the rover is expected to perform up to 50 meters of driving.

On Opportunity, the rover today will dig a shallow trench so its suite of mineral and elemental instruments can examine the soil at a site dubbed "Hematite Slope." The rover will lock one wheel in place and use its other five wheels to move a short distance. This procedure should create a two-and-a-half foot long, six-inch wide trench, Erickson said.

The arm will examine the trench tomorrow, followed by remote sensing work with the panorama camera and Mini-Thermal Emission Spectrometer on Wednesday.

Two news conferences are scheduled on NASA Television this week -- Tuesday and Thursday at 1 p.m. EST.

1818 GMT (1:18 p.m. EST)

Spirit is finishing its science work at the flaky-looking rock named Mimi. It has used its instruments to examine the rock, will take some microscopic images late tonight (U.S. time) and then resume its drive to the Bonneville Crater, mission manager Jim Erickson says.

The rover is about 270 meters from the crater. A 25-meter drive in planned for during the morning of its next workday and possibly another 25 meters later in the day, Erickson said.

The goal is to reach the crater in about 18 days, with some additional science stops expected between now and then.

Meanwhile, the Opportunity rover has reached the spot inside its small crater where it will perform a trenching job to dig a hole for soil studies. The soil is being examined today in preparation for the digging. The trenching is planned for tomorrow, followed by science investigations on Tuesday.

Also today, Opportunity's thermal emission spectrometer is looking up and a similar device on the orbiting Mars Global Surveyor spacecraft is looking down for joint atmospheric studies.

The Mars rover Spirit collected data with its Mini-Thermal Emission Spectrometer and snapped images with its panoramic camera overnight. The craft then drove for less than five minutes, moving 90 centimeters (2.95 feet) to a rocky area that has been dubbed "Stone Council."

The instrument arm was deployed to use the Alpha Particle X-Ray Spectrometer, Microscopic Imager and Mossbauer Spectrometer, mission manager Matt Wallace said.

Tonight, Spirit moves to a flaky-looking rock called "Mimi." You can see an image of the rock here.

Scientists say Mimi is different than any other rock seen at the Gusev Crater landing site. Its flaky exterior could have been caused by pressure -- either through burial or impact -- or may have once been a dune that was cemented into flaky layers, scientists say.

"The science community liked what they saw in Mimi and wanted to get a closer look," Wallace said.

Spirit has a long-term goal of reaching the Bonneville Crater in the distance. After the ongoing science activities are completed, rover will resume the drive Sunday night.

On the other side of Mars, Opportunity is completing study at the third of three observation points along the bedrock outcropping.

The rover is headed a bit south of its current position during a 9-meter drive to another spot where it will spend three days for soil studies, Wallace said. The craft will dig a shallow hole with its wheels in a patch of hematite-rich soil, allowing the science devices to examine the trench.

Opportunity was sent to the Meridiani Planum region of Mars to search for hematite -- a mineral that usual forms in the presence of water.

1915 GMT (2:15 p.m. EST)

Spirit continues its trek to Bonneville Crater, located 340 meters from the landing site. The rover has completed about 58 meters thus far, including 24 meters last night, Art Thompson, tactical uplink lead, told reporters during a news conference today.

It will spend the next day doing some science research before resuming the drive, he said.

On Opportunity, the rover has driven from the Bravo to Charlie location along the rock outcropping. A map of the cruise is available here.

In the coming days, Opportunity will use one of its wheels to dig a hole for soil studies.

1925 GMT (2:25 p.m. EST)

A missed communications window caused by a cold antenna motor on the Mars Exploration Rover Spirit prevented the robot from racking up any additional distance on its odometer Tuesday night. Read our full story.

The rover Spirit drove into the Martian history books Monday night by making the longest single-day traverse on the Red Planet, eclipsing the mark set by Mars Pathfinder's Sojourner rover in 1997. Read our full story.

This is the latest report from Mission Control:

NASA's Spirit rover has begun making some of its own driving decisions while its twin, Opportunity, is presenting scientists with decisions to make about studying small spheres embedded in bedrock, like berries in a muffin.

Both rovers are on the move. Late Sunday, Spirit drove about 6.4 meters (21 feet), passing right over the rock called "Adirondack," where it had finished examining the rock's interior revealed by successfully grinding away the surface. The drive tested the rover's autonomous navigation ability for the first time on Mars.

"We've entered a new phase of the mission," said Dr. Mark Maimone, rover mobility software engineer at NASA's Jet Propulsion Laboratory, Pasadena, Calif. When the rover is navigating itself, it gets a command telling it where to end up, and it evaluates the terrain with stereo imaging to choose the best way to get there. It must avoid any obstacles it identifies. This capability is expected to enable longer daily drives than depending on step-by-step navigation commands from Earth. Tonight, Spirit will be commanded to drive farther on a northeastward course toward a crater nicknamed "Bonneville."

Over the weekend, Spirit drilled the first artificial hole in a rock on Mars. Its rock abrasion tool ground the surface off Adirondack in a patch 45.5 millimeters (1.8 inches) in diameter and 2.65 millimeters (0.1 inch) deep. Examination of thefreshly exposed interior with the rover's microscopic imager and other instruments confirmed that the rock is volcanic basalt.

Opportunity drove about 4 meters (13 feet) today. It moved to a second point in a counterclockwise survey of a rock outcrop called "Opportunity Ledge" along the inner wall of the rover's landing-site crater. Pictures taken at the first point in that survey reveal gray spherules, or small spheres, within the layered rocks and also loose on the ground nearby.

NASA now knows the location of Opportunity's landing site crater, which is 22 meters (72 feet) in diameter. Radio signals gave a preliminary location less than an hour after landing, and additional information from communications with NASA's Mars Odyssey orbiter soon narrowed the estimate, said JPL's Tim McElrath, deputy chief of the navigation team.

As Opportunity neared the ground, winds changed its course from eastbound to northbound, according to analysis of data recorded during the landing. "It's as if the crater were attracting us somehow," said JPL's Dr. Andrew Johnson, engineer for a system that estimated the spacecraft's horizontal motion during the landing. The spacecraft bounced 26 times and rolled about 200 meters (about 220 yards) before coming to rest inside the crater, whose outcrop represents a bonanza for geologists on the mission.

JPL geologist Dr. Tim Parker was able to correlate a few features on the horizon above the crater rim with features identified by Mars orbiters, and JPL imaging scientist Dr. Justin Maki identified the spacecraft's jettisoned backshell and parachute in another Opportunity image showing the outlying plains.

As a clincher, a new image from Mars Global Surveyor's camera shows the Opportunity lander as a bright feature in the crater. A dark feature near the lander may be the rover. "I won't know if it's really the rover until I take another picture after the rover moves," said Dr. Michael Malin of Malin Space Science Systems, San Diego. He is a member of the rovers' science team and principal investigator for the camera on Mars Global Surveyor.

Opportunity's crater is at 1.95 degrees south latitude and 354.47 degrees east longitude, the opposite side of the planet from Spirit's landing site at 14.57 degrees south latitude and 175.47 degrees east longitude.

The first outcrop rock Opportunity examined up close is finely-layered, buff-colored and in the process of being eroded by windblown sand. "Embedded in it like blueberries in a muffin are these little spherical grains," said Dr. Steve Squyres of Cornell University, Ithaca, N.Y., principal investigator for the rovers' scientific instruments. Microscopic images show the gray spheres in various stages of being released from the rock.

"This is wild looking stuff," Squyres said. "The rock is being eroded away and these spherical grains are dropping out." The spheres may have formed when molten rock was sprayed into the air by a volcano or a meteor impact. Or, they may be concretions, or accumulated material, formed by minerals coming out of solution as water diffused through rock, he said.

The main task for both rovers in coming weeks and months is to explore the areas around their landing sites for evidence in rocks and soils about whether those areas ever had environments that were watery and possibly suitable for sustaining life.

1820 GMT (1:20 p.m. EST)
Orbital imagery showing the effects of Opportunity's landing can be seen here. A close-up view showing the lander and rover sitting inside the crater is available here.

1745 GMT (12:45 p.m. EST)
Mars rover Spirit has driven away from the rock Adirondack, officials are reporting at a news conference currently underway at the Jet Propulsion Laboratory.

On the other side of Mars, Opportunity stowed its science arm and began slowly driving along the exposed bedrock earlier today. The outcrop has been named "Opportunity Ledge."

Meanwhile, an incredible image taken by Opportunity has revealed the parachute and backshell from its descent module sitting on the gray plains outside the tiny crater where the rover landed. See the image here. Opportunity snapped a picture of the hardware after climbing up the side of the crater over the weekend.

Also today, navigation experts have announced their report on exactly where Opportunity landed.

We'll post a full story later today.

1910 GMT (2:10 p.m. EST)

The Mars Exploration Rover Spirit will leave its first rock subject late Sunday and begin the long journey toward an impact crater, a day later than planned after a self-imposed software hold. Meanwhile, Opportunity has commenced its examination of the rock outcropping at its landing site by taking amazing microscopic images. Read our full story.

Its two diamond-tipped teeth gnawing at 3,000 revolutions per minute, the Mars rover Spirit has bore a hole in Adirondack, providing scientists a window inside the volcanic rock. Meanwhile, Opportunity has completed its drive to a rock dubbed Snout. Read our full story.

2001 GMT (3:01 p.m. EST)
An image from Spirit showing the hole in Adirondack made during the grinding can be seen here.

1818 GMT (1:18 p.m. EST)
Spirit successfully completed its first RAT'ing early today, grinding into Adirondack with the Rock Abrasion Tool. A 2.7-millimeter deep, 45.5-millimeter diameter hole was cut into the hard rock to give the rover's science instruments a port to study the interior, said Stephen Gorevan of Honeybee Robotics, lead scientist for the RAT.

Meanwhile, Opportunity took more microscopic images of soil and finished its drive to the Snout rock, mission manager Matt Wallace said. Tomorrow, the rover will deploy its arm to begin studying its first target rock.

We'll post a full report later today.

Whipping half-inch stainless steel bristles against a pyramid-shaped rock, the Spirit rover has performed "the greatest interplanetary brushing of all time," a scientist joked Friday with the unveiling the latest images from Mars. Read our full story.

Driving up the inclined wall of the small crater the craft landed in, the Mars rover Opportunity was expected to arrive at the outer edge of bedrock outcropping early Saturday to begin its geologic work. Read our full story.

1820 GMT (1:20 p.m. EST)
Spirit's five-minute brushing of the rock Adirondack has yielded interesting results. The brush can be seen here.

A before-brushing image of the rock is here and this is the post-brushing view.

A microscopic view of the brushed area is also available.

Spirit will grind into the rock later today.

Meanwhile, Opportunity completed another drive today. It didn't quite reach the rock outcrop, so a 30-40 centimeter drive is scheduled for tomorrow before science investigations can begin this weekend, mission manager Matt Wallace says.

Opportunity completed an 11-foot drive early Thursday, moving from its initial parking spot reached after leaving the lander last weekend toward the rock outcrop in the wall of the crater the rover landed in. It will continue the drive to the exposed bedrock early Friday.

An image from the rover showing its tracks in the soil is available here. The rover made two arcs to the right, then one arc to the left, then a 30-degree turn in place, then a straight-ahead drive.

Originally slated to dig a hole with one of its wheels Friday, officials scrapped that plan and decided to continue moving to the outcrop. The trenching will be rescheduled when the rover reaches an area where the soil has a higher concentration of large-grain hematite, NASA said.

After waking up Thursday night/Friday morning (U.S. Time), the rover will drive about about five feet farther, possibly to within arm's reach of one of the rocks in the exposed outcrop, Mission Control reported.

Meanwhile, the Spirit rover fresh off its flash file system reformatting conducted Wednesday was scheduled to brush the rock nicknamed Adirondack today before examination with its science instruments.

The next rover news conference is scheduled for 1 p.m. EST Friday. We will update this page with more details at that time.

1605 GMT (11:05 a.m. EST)
The Jet Propulsion Laboratory reports that yesterday's erasing and reformatting of Spirit's flash file system was successfully completed. The rover will get back into its science game plan today, brushing the dust off its first rock and using the science instruments for further investigation.

On Opportunity, the rover was scheduled to make a 10-foot drive today to a spot where it will later spin one of its front wheels to dig a small hole in the soil for scientists to study.

Opportunity has examined its first patch of soil in the small crater where the rover landed on Mars and found strikingly spherical pebbles among the mix of particles there. "There are features in this soil unlike anything ever seen on Mars before," says the lead scientist. Read the latest Mission Control status report.

1920 GMT (2:20 p.m. EST)
Spirit is currently undergoing computer surgery to return the rover's flash memory system to a clean slate. Exactly two weeks after suffering an anomaly, the flash file system is being erased and reformatted today.

The work was pushed back a couple of days while testing was completed on Earth. But a day of science planned for Monday was thwarted by a glitch on the rover.

Mission manager Mark Adler provided this status briefing on Spirit during a news conference at about 1:20 p.m. EST:

"On Sol 30 (Monday) we attempted to do some science operations, we had a day to wait for the testing to be completed on the format operation in the testbed. So we were going to continue our arm operations on Adirondack and take some microscopic images and spectra. Unfortunately, at the beginning of that day we tried to do a Sun find and that Sun find did not succeed -- it was not able to complete the Sun find operation. As a result, the subsequent activities were not allowed to continue because the vehicle wasn't certain of what its attitude was.

"So we had to recover from that. We got a Sun find to work later in the day, but we did not succeed in the arm operations for that day. We believe the failure was related either to some activities that were ongoing on the spacecraft at that time that prevented an image to complete acquisition and analysis or there was a file used from the flash file system that was corrupted that may have also contributed to this.

"So this may, in fact, be related to the flash file system issue. That further bolsters our desire to format the flash file system and get ourselves back into a clean state.

"So Sol 31 (Tuesday) we did preparation for the format operation. We got the vehicle into a state where it was going to go sleep early, we were not going to do the overnight (communications) passes, to get the vehicle as cold as possible for this morning and to have as much power in the batteries because today the rover has a very, very long day.

"Poor rover was woken up by its alarm clock this morning at 6 a.m., much earlier that it's been woken up before. We got the rover up and we rebooted into the cripple mode so it doesn't use the flash memory so we can do our operations on the flash memory. We are doing those operations now.

"We are currently in a four-hour process, which started probably 20 minutes ago, that will go through and erase all the contents of the flash. That also provides us with a means of checking the flash hardware -- we are checking to make sure all of the flash hardware, all of the flash chips, are working because we are still not certain that there wasn't some hardware problem that contributed to what we found. We don't think there was but to be safe we want to make sure we check all of the flash memory to make sure it's good. So we are going through all 224 megabytes of the flash memory that is used for the file system and erasing it over the next couple of hours.

"After that we will reboot the system and reformat that flash file system and get it back and operating. We should have the system back in normal operational mode later this afternoon. We expect then we will reintroduce our Odyssey (communications) pass overnight and tomorrow morning we will be able to go back to our science operations."

Adler says engineers have cautiously approached the reformatting procedure to ensure no harm is caused.

"That's why we've spent four days testing this in the testbed. It's not an operation that we do lightly. We did go through a lot of testing to make sure the operation does exactly what we expect. We've reconstructed the environment in the testbed that the vehicle is going to be operating in. We verified also that there are no other things, other side effects that the flash format/erase operation could have on the rest of the vehicle.

"For example, we store our flight software images in another area of flash, separate from the flash file system. And we verified, in fact, that when we do this erase operation that there is no way those copies of flight software to be corrupted in any way. In fact, the sequence we've developed that's running today checks every step of the way that that doesn't happen and we'll abort if there is some issue that it sees and some side effects from the operation.

"This is an operation you don't do just willy-nilly. You have to make sure it works right and we've done that (on Earth). So we're doing it on the spacecraft right now."

If all goes well, Spirit will resume its study of Adirondack tomorrow by using the Rock Abrasion Tool to brush a portion of the rock's exterior and then allow its instruments to take images and measurements. On Friday, the Rock Abrasion Tool will actually grind into the rock, followed by further study with the instruments.

Future plans call for Spirit to depart Adirondack this weekend and begin driving, bound for a large crater over 800 feet away.

The next Mars news conference is scheduled for 1 p.m. EST Friday.

1800 GMT (1:00 p.m. EST)
Mars rover Opportunity has acquired microscopic images of the alien soil at its landing site. Check out the photo here.

NASA is currently holding a rover news conference. We'll post a full report this afternoon.

Lending a hand to unlock the geologic riddles of Mars, the rover Opportunity has extended its instrument-laden arm to begin probing soil on the floor of a small crater where the craft landed. Read our full story.

Meanwhile, NASA Administrator Sean O'Keefe today announced the Martian hills, located east of the Spirit Mars Exploration Rover's landing site, would be dedicated to the Space Shuttle Columbia STS-107 crew. Read the announcement.

NASA is not planning a Mars status briefing on Tuesday. The next news conference is scheduled for 1 p.m. EST (1800 GMT) on Wednesday.

1800 GMT (1:00 p.m. EST)
For those of you looking for a large version of the Opportunity panorama, a 9MB file is available here.

1750 GMT (12:50 p.m. EST)
The 360-degree, high-resolution color panorama taken by Opportunity was released today. You can view the image here.

Opportunity's arm extended can be seen here. A 3-D version is available here.

1715 GMT (12:15 p.m. EST)
The Mars rover Opportunity extended its robotic arm today, flexing the science boom to begin studying a patch of soil near the landing base.

Opportunity remains parked in the position it reached after driving off the lander Saturday. It will stay in that spot for several days while the soil investigations are completed. Then the rover will drive to the bedrock outcrop nearby.

The arm, known as the Instrument Deployment Device, or IDD, carries the Mossbauer Spectrometer, Alpha Particle X-Ray Spectrometer, Microscopic Imager and Rock Abrasion Tool.

Also during today's workday for Opportunity, the Rock Abrasion Tool was activated to ensure it was working. Next, the Microscopic Imager cover was successfully opened. Later, the arm maneuvered the Mossbauer and APXS instruments into view of the rover's cameras.

The first science observations are being made with the Microscopic Imager, giving scientists unique views of the soil. Tomorrow, the German Mossbauer instrument will examine the soil to look for iron-bearing minerals.

Meanwhile on Spirit, science operations are being performed today. The reformatting of the flash memory has been pushed back to tomorrow.

A week-and-a-half after falling ill to computer woes, NASA on Sunday declared its Mars Exploration Rover Spirit was healthy again.

"We have confirmed that Spirit is booting up normally. Tomorrow we'll be doing some preventive maintenance," mission manager Mark Adler said.

Read our full story.

1930 GMT (2:30 p.m. EST)
With the pop of a champagne cork, a scientist announced Saturday that the Mars rover Opportunity has found scattered across the landing site a mineral that typically forms in water. Read our full story.

1305 GMT (8:05 a.m. EST)

Mission Control at the Jet Propulsion Laboratory erupted in cheers and applause one more time early today as the Opportunity rover crawled off its lander and onto the dark, dusty floor of a martian crater. Read our full story.


1154 GMT (6:54 a.m. EST)
Scientists just proclaimed that Opportunity has verified the existence of gray hematite at the landing site. This is a mineral that usually, but not always, forms in the presence of water.

The Mars Exploration Rovers were sent to the Red Planet to look for proof of past water.

1150 GMT (6:50 a.m. EST)
Flight director Chris Lewicki reports that Opportunity's drive began at 4:50:07 a.m. EST (0950:07 GMT). It took 83 seconds to move about 10 feet, coming to rest at 4:51:30 a.m. EST (0951:30 GMT).

Confirmation was received on Earth just after 6 a.m. EST via the Mars Odyssey relay.

The rover is facing 32 degrees east of due north.

1124 GMT (6:24 a.m. EST)
A view from Opportunity looking back at the lander is available here.

1109 GMT (6:09 a.m. EST)
Opportunity has returned images showing the empty lander behind the rover and a view looking forward at the rock outcrop.

"Two for two, one dozen wheels on soil," flight director Chris Lewicki says as Opportunity joins Spirit on the surface of Mars.

A post-egress news conference is coming up at 6:45 a.m. EST.

1102 GMT (6:02 a.m. EST)
The Opportunity rover is a true Marsmobile! The craft has successfully driven off its lander base and is now standing on the floor of a small crater at Meridiani Planum. Opportunity's first drive has been accomplished six days and a few hours after landing -- two days ahead of schedule.

The rover will remain in its current position a few feet away from the lander for a couple of days, allowing its science arm to examine a patch of soil with the microscopic images and spectrometers. Opportunity will then drive to the bedrock outcrop along the crater wall about 25 feet northwest of the lander.

Opportunity is near the center of a crater 72 feet in diameter and 10 feet deep. On Friday, scientists unveiled a three-dimensional model of the crater, created from information in stereo images. This is the first time a crater on another planet has been mapped from inside the crater. See the model here.

1101 GMT (6:01 a.m. EST)
Opportunity rover data is now being received on Earth via Mars Odyssey orbiter. It will take a few moments before controllers will be able to verify whether the drive has occurred as planned.

1026 GMT (5:26 a.m. EST)
Mission Control has updated the schedule for receiving data from Odyssey. Information announcing Opportunity's drive is now expected around 5:55 a.m. EST.

"Twenty-nine minutes and counting," flight director Chris Lewicki tells his controllers.

1000 GMT (5:00 a.m. EST)
Mission Control just played the song "Going Mobile" by The Who to commorate Opportunity's first drive.

0955 GMT (4:55 a.m. EST)
The Deep Space Network communications system on Earth has received another beep from Opportunity. This signal indicates that the rover has reached the point in the command sequence to begin driving.

"Because of light time, the vehicle should already be on the surface at this time," flight director Chris Lewicki reported. It takes about 11 minutes for a signal to travel between Mars and Earth.

"But I want to know now," another controller could be heard saying.

Confirmation of a successful drive will be relayed through the Mars Odyssey orbiter around 6:15 a.m. EST.

0920 GMT (4:20 a.m. EST)
The Mars Odyssey orbiter will be passing over the Opportunity landing site to receive data and images from the rover that will confirm the drive has occurred. The information will be relayed to Earth, arriving around 6:15 a.m. EST.

0856 GMT (3:56 a.m. EST)
A beep has been heard from Opportunity, confirming that the Mars rover received the commands to perform the drive off the lander.

0826 GMT (3:26 a.m. EST)
Rover Mission Control has issued commands to Opportunity to begin the drive sequence. The craft will perform the 10-foot journey entirely on its own and without live interaction with ground controllers.

The honor of pushing the button to transmit the command from Earth to Opportunity was bestowed upon Kevin Burke, the lead mechanical engineer for the drive-off.

With the mouse click complete, applause broke out in the control room.

0820 GMT (3:20 a.m. EST)
Flight director Chris Lewicki has conducted the "go for egress" poll of his team in Mission Control. Everyone reported "go" status!

Shortly, commands will be issued to Opportunity to make the roll off the lander.

0802 GMT (3:02 a.m. EST)
Cable cut No. 3, severing the Opportunity rover's final umbilical to the lander, was successfully performed. The rover then inched slightly in a maneuver called "the bump" to ensure the drive system was working normally.

Controllers are examining data in preparation to giving approval for Opportunity's drive off the lander later this morning.

Ground controllers hope they fixed the computer ailment afflicting the Mars rover Spirit by purging hundreds of data files from its flash memory on Friday, reports said.

The massive batch of no-longer-needed files piled up on the rover and prevented its computer system from successfully accessing the flash memory. The flash memory stores engineering and scientific data.

With the files gone, Spirit was rebooted late Friday.

"I am pleased to report it appears to be working just fine," Glenn Reeves, chief engineer for the rover's flight software, was quoted as saying.

NASA officials indicated it would be another day or two before they will know for sure that Spirit is entirely healthy again.

As Spirit returns to action, the craft's Rock Abrasion Tool will be used in the next few days to reveal the interior of a rock dubbed Adirondack. The pyramid-shaped, football-sized rock is the first that Spirit drove to after leaving its lander base January 15.

Meanwhile, Opportunity remains set to join its sister-rover on the Martian surface early Saturday when it rolls off its lander base on the opposite side of Mars.

1805 GMT (1:05 p.m. EST)
"We are still working the anomaly on Spirit, we are still trying to recover the full capabilities of the system," mission manager Mark Adler said today.

On the Martian workday Thursday, controllers checked out the rover's science instruments while continuing to investigate the computer problems.

"We read out data from the Mossbauer Spectrometer and APXS (Alpha Particle X-ray Spectrometer) instruments. We also took several Pancam images with the panoramic imager up on the mast," Adler reported.

The new Pancam views can be seen here. The photo shows the calibration target, the sun and two rocks that Spirit will be investigating later.

"We also yesterday completed a scan of the flash memory. This provided us with some important diagnostic information. We are now able to tell that when we mount the flash memory, it does in fact take a lot of the system RAM in the process. In fact, more system RAM than is available. So that's helping confirm the theory we had that the reason the restarts were hanging up was because we were running out of memory when we are trying to mount the flash memory.

"We still don't know if the number of files is the cause of that or what other characteristics of the contents of the flash file system are causing this. But that is what we are going to try and find out today.

"Today on Sol 27 we are going to continue with the task trace that is going on right now -- about 10 a.m. on Sol 27," Adler told reporters at the 12 noon EST briefing.

"We are going to take some pieces of memory after the rover is run up in the mode where it's not working properly and see if that shows trace information about what routines are running when the system hung up and not able to complete the reset.

"After that, we are going to bring the system back up in what we call the cripple mode where we are able to have normal operations in the mode in which we are able to take pictures and you are able to use the instruments. And in that mode we are going to delete from the flash memory -- the flash file system -- a large number of files that were left over from the cruise phase of the mission before landing," Adler said.

Engineers think that by deleting that batch of files, the rover might not require as much memory when trying to use the file management system.

"After that we are going to try and reboot in the normal mode, the non-cripple mode, and see if the system comes up. We are hopeful that it will come up. At that point, we'll resume normal operations and begin to do some housekeeping on the system (and) begin to playback some data in the flash in preparation for possibly a flash file formatting on tomorrow on Sol 28."

Spirit could resume full, normal operations on Sunday, a week-and-a-half after being sidelined by the computer trouble.

If the file deletion doesn't fix the problem, controllers will get the rover back into the cripple mode and form a new plan of attack for tomorrow.

1740 GMT (12:40 p.m. EST)
The Mars Exploration Rover Opportunity will be driving off its lander even earlier than envisioned yesterday. The $400 million craft is now slated to reach the surface by early Saturday morning (U.S. time). Read our full story.

Launched to Mars folded and crouched in its landing cocoon, NASA's Opportunity rover has nearly completed the complex blossoming into a road-ready vehicle and could take its first drive onto the Red Planet's surface Saturday night. Read our full story.

1740 GMT (12:40 p.m. EST)
Opportunity is another step closer to driving off the lander in a few days. The Mars rover extended its two back wheels today to give the vehicle the desired wheelbase length.

On Wednesday, the screw jack mechanism elevated Opportunity's body so its two front wheels could unfold. The rocker-bogie suspension system was then locked into place. With the rover supporting its own weight, the lifting mechanism was retracted back into the lander this morning.

Tonight, the middle two wheels will be released from their stowed position and the science arm will be unlatched from its launch location.

Also on the just-completed Martian workday, Opportunity used the Mini-Thermal Emission Spectrometer instrument to observe a portion of the landing site terrain, including the rock outcrop. However, the data was not returned to Earth before the rover went to sleep for the night.

Meanwhile, controllers today will perform health checks on Spirit's camera mast as they prepare that rover for returning to science operations next week. Last night, the rover sent back its first image since developing computer troubles a week ago.

There is no Mars rover status news conference today. The next briefing is scheduled for Friday at 12 noon EST (1700 GMT).

Working as space-age surgeons 100 million miles away, ground controllers are trying to precisely pinpoint the software glitch that halted the Mars rover Spirit's mission to explore Gusev Crater last Wednesday. If successful, officials say the robot geologist could be out of recovery and back at work early next week. Read our full story.

2110 GMT (4:10 p.m. EST)
NASA today announced plans to name the landing site of the Mars Opportunity rover in honor of the Space Shuttle Challenger's final crew. The area in the vast flatland called Meridiani Planum, where Opportunity landed this weekend, will be called the Challenger Memorial Station. Read the announcement.

1755 GMT (12:55 p.m. EST)
Scientists have just released an amazing color version of the rock outcrop panorama first seen in black and white form yesterday. You can download it here.

New close-up views of the rock formations at landing site are available here and here.

Also, click here to see views of the marks that the lander's airbags made in the soil. You can compare the airbag markings with this ground testing image.

1734 GMT (12:34 p.m. EST)
At the daily status briefing now underway, officials report that Opportunity successfully stood up and deployed its front wheels overnight. A lift mechanism in the lander base jacked up the rover, allowing the front two wheels to be released from their launch stowage locations and extend into position.

The Sol 5 workday that begins late tonight (U.S. time) will see the lift mechanism retracted out of the rover's way and the deployment of the rear wheels.

If all continues to go well, Opportunity could drive off the lander as early as Sunday night.

1730 GMT (12:30 p.m. EST)
Aerosmith has finished its space chat with Expedition 8 commander Mike Foale aboard the International Space Station. NASA TV will switch to the Mars briefing momentarily.

1700 GMT (12:00 p.m. EST)
The airing of today's Mars rover news conference is being delayed on NASA TV to show the band Aerosmith touring International Space Station Mission Control at Houston's Johnson Space Center. The band is in town for Sunday's Super Bowl performance.

We'll update this page once the briefing begins -- as officials report on the scheduled efforts to deploy Opportunity's front wheels and the release of stunning new color imagery of the rock outcrop at the landing site.

The discovery of layered rocks in the Martian bedrock next to the Opportunity's landing platform has scientists anxiously awaiting the rover's exploration of the terrain beginning next week. Read our full story.

NASA memorialized the Apollo 1 crew - Gus Grissom, Ed White and Roger Chaffee - by dedicating the hills surrounding the Mars Exploration Rover Spirit's landing site to the astronauts. The crew of Apollo 1 perished in flash fire during a launch pad test of their Apollo spacecraft 37 years ago today. Read the announcement.

1820 GMT (1:20 p.m. EST)
Opportunity mission manager Jim Erickson provided this report about the rover's science arm heater situation during today's status news conference:

"There is one new issue with the vehicle. We have discovered that there is a power loss that's going on in the vehicle. We think we know what's going on there.

"There is a set of thermostatic-controlled heaters. One of them is located physically in the shoulder joint of the instrument arm. Normally this is enabled by the ground and then a thermostat on the side of the rover determines what the air temperature is and, if it's cold enough, it turns on this heater in this arm to keep it up in temperature for operation.

"Normally we don't always want it on because we aren't normally always operating the arm. Right now, we are believing it is going to be on continuously whenever it's cold enough.

"We have multiple investigation paths underway on this -- one making sure that our current theory of what this current draw is is correct, and others to begin to explore the issues of are there operational workarounds to keep this under control or possible solutions to be able to turn it off when we want it to be off."

In response to questions after his briefing, Erickson also had this to add:

"Right now we are seeing about a 15-watt resistance that's being dissipated somewhere. We have evidence this is where it's going to. At this point, I would like to have a little more time to look at what we are seeing from the vehicle before we make any judgments on exactly what's there."

Erickson said it's too soon know what impact this issue might have.

"It's not on continuously, let me make sure that is clear. It is only when the thermostat brings it on during the cold period of the day. We use it to keep the rover's shoulder mechanism warm enough to operate correctly. Apparently it is going to be warm enough to operate correctly whether we want it to be operated or not!

"We are very paranoid people. So now that we're thinking about having this on all of the time, if that's really the problem, we have already asked people to start thinking about 'well, is this something long-term that might be an issue?' We just have to have time to have those people go back, do their analysis and come let us know. We always assume there is a problem until we prove otherwise."

1745 GMT (12:45 p.m. EST)
The new imagery showing the rock outcrop that has scientists excited can be downloaded here.

A three-dimensional version, for those of you with 3-D glasses, can be seen here.

Also, a computer animation image has been created showing the rover at the outcrop.

1730 GMT (12:30 p.m. EST)
The Mars rover Opportunity successfully deployed, pointed and began using its high-gain communications antenna overnight, officials report. The antenna provides a path for large amounts of data to be transmitted from the rover to Earth.

Also, the second of the three umbilical cable bundles running from the lander to rover has been cut.

On the workday that begins tonight, Sol 4, a lift mechanism on the lander base will raise up the rover, allowing the front wheels to be unfolded from their stowed launch position and locked into place. These are just the first steps to get the rover configured to drive off the lander late next week.

Controllers are looking at an issue on Opportunity. Telemetry from the rover indicates a small power draw, which engineers suspect is a heater on the science arm's shoulder joint that is operating during the cold period of the each day instead of simply when the arm is being used. Mission manager Jim Erickson says it is too soon to say what, if any, impact this will have.

Overall, he says Opportunity is in "pretty good shape."

Meanwhile, the science team is giddy from new imagery taken by Opportunity showing finely-layered rocks in the light-colored, tabular-shaped outcrop formations near the rover landing site. It isn't yet known if the layering was caused by water or volcanic activity. Opportunity will drive to the rock outcrop after leaving the lander to begin extensive examination with its suite of science instruments.

NASA's Mars Exploration Rover Spirit appeared to be teetering on the brink of failure last week when ground controllers lost contact with the craft sitting in Gusev Crater, its arm extended to a rock as the scientific adventure was beginning. Now, engineers are cautiously hopeful that Spirit will soon be restored to full working order. Read our full story.

1830 GMT (1:30 p.m. EST)
The latest color postcard from the Opportunity shows the small crater that the rover is sitting in. You can download the image here.

Scientists say this is the darkest landing site ever visited by a Mars spacecraft. The rim of the crater is approximately 32 feet from the rover. The crater is estimated to be 65 feet in diameter.

There are rock outcrops dispersed throughout the crater. The soil appears to be a mixture of coarse gray grains and fine reddish grains.

Data taken from the camera's near-infrared, green and blue filters were combined to create this approximate true color picture. The view is to the west-southwest of the rover.

1730 GMT (12:30 p.m. EST)
Opportunity is currently asleep after successfully completing its Sol 2 workday. It will be awakened tonight for Sol 3 in which the lollipop-shaped high-gain communications antenna will deploy and begin service for relaying large amounts of data from the rover. In addition, the Pancam camera package will continue its work to image landing site.

Mission manager Jim Erickson says controllers are making "steady progress" to prepare Opportunity for eventually driving off the lander. The roll is expected late next week.

1701 GMT (12:01 p.m. EST)
The post-landing health checks of Opportunity's Microscopic Imager, Alpha Particle X-Ray Spectrometer and Mossbauer Spectrometer have been completed. Steve Squyres reports that all appear to be "in perfect health."

The devices are located on the rover's science arm, and will be used for close-up examination of soil and rocks at Meridiani.

0500 GMT (12:00 a.m. EST)
NASA plans a 12 noon EST (1700 GMT) news conference from the Jet Propulsion Laboratory to update the activities with Opportunity and Spirit rovers. Watch this page for details then.

0400 GMT (11:00 p.m. EST Sun.)
Mission Control is preparing the science activities for the Opportunity rover to perform.

The batch of science-related commands for the rover include health checks of the Alpha Particle X-Ray Spectrometer and Mossbauer Spectrometer, a test image of the Microscopic Imager and snapping photos of the landing site using the panoramic camera.

0318 GMT (10:18 p.m. EST Sun.)
After receiving health data from Opportunity in this communications window, controllers report there are no computer faults, the power currents are good and no significant problems noted.

0301 GMT (10:01 p.m. EST Sun.)
"I see that our first command radiated to Opportunity on the surface has been received and acted upon. We are commandable," says flight director Chris Lewicki, confirming that the communications link to Opportunity is operating properly.

0249 GMT (9:49 p.m. EST Sun.)
Mission Control has just acquired signal from Opportunity as scheduled. The rover is beginning Sol 2 -- its first full day on Mars.

"X-band system is working on the surface of Mars," flight director Chris Lewicki reported as communications were successfully established.

This is a planned 45-minute communications session between the rover and Earth in which health data will be received and controllers will verify earlier sequence commands transmitted did arrive onboard Opportunity.

Earlier communications sessions were performed using the Mars Global Surveyor and Mars Odyssey orbiting around the planet. The craft received data from the rover and relayed the information to Earth.

Read our earlier Mission Status Center coverage.

Spirit Poster
This new poster features some of the best images from the Mars Exploration Rover Spirit.