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Countdown to Impact

Impactor release: Sunday 2:07 a.m. EDT
Impact with comet: Monday 1:52 a.m. EDT
First post-impact photo: Monday 2:08 a.m. EDT

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Photo: Impactor deploy

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The Mission

NASA's Deep Impact spacecraft will fire a projectile into the heart of Comet Tempel 1 to expose materials frozen inside the rocky snowball since the solar system formed four billion years ago.

Mission overview

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Follow NASA's Deep Impact space probe as it hits Comet Tempel 1, giving humanity the first glimpse into the frozen heart of the rocky snowball. Reload this page for the very latest on the mission.

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MONDAY, JULY 4, 2005
2130 GMT (5:30 p.m. EDT)

Elated scientists studying a treasure trove of data from NASA's Deep Impact mission said today the 820-pound probe that slammed into comet Tempel 1 at some six miles per second early today excavated a large crater in its icy crust, blowing enormous amounts of dust and gas into space. Read our full story.

1846 GMT (2:46 p.m. EDT)

Scientists say it could take a week of image processing before they can determine the exact size and depth of the crater. It is believed the crater is large, certainly bigger than a house.

1808 GMT (2:08 p.m. EDT)

"The flyby spacecraft is in great shape," Grammier says in releasing an amazing picture from the mothership taken after passing the comet and looking at the backside of the nucleus.

The craft's memory is virtually full with images and data. All of that information is still being played to Earth.

1804 GMT (2:04 p.m. EDT)

An update news conference is beginning at JPL.

1700 GMT (1:00 p.m. EDT)

An additional post-impact image has been released from the Hubble Space Telescope showing an extraordinary cloud of gas and debris blown out from the comet. You can see all of Hubble's picture here.

1000 GMT (6:00 a.m. EDT)

A scientific smart bomb crashed into Comet Tempel 1 early today, blasting a sparkling shower of icy debris into space in a 23,000-mph Fourth of July spectacular 83 million miles from Earth. Read our full story.

0930 GMT (5:30 a.m. EDT)

"This mission is truly a smashing success," said Andy Dantzler, director of NASA's Solar System Division. "Tomorrow and in the days ahead we will know a lot more about the origins of our solar system."

"What a way to kick off America's Independence Day," said Deep Impact project manager Rick Grammier of NASA's Jet Propulsion Laboratory, Pasadena, Calif. "The challenges of this mission and teamwork that went into making it a success, should make all of us very proud."

0908 GMT (5:08 a.m. EDT)

The Hubble Space Telescope snapped an image of Comet Tempel 1 a few minutes after this morning's impact. You can see the picture here.

0842 GMT (4:42 a.m. EDT)

"The optics survived beautifully," A'Hearn says of the mothership's medium- and high-resolution telescope instruments. It has been suggested that the spacecraft could be sent to observe other comets if it survived the Tempel 1 encounter.

0827 GMT (4:27 a.m. EDT)

"We only have 10 percent of the data," Mike A'Hearn says, noting there is much more to be revealed. The mothership has the rest of the images and information from the instruments stored aboard. It will be playing the data to Earth over the next day.

0818 GMT (4:18 a.m. EDT)

Rick Grammier, Deep Impact project manager, says the mothership spacecraft has survived the close encounter with Comet Tempel 1. The impactor hit right on target. None of the team's contingency plans had to be used.

0812 GMT (4:12 a.m. EDT)

"There is a comet up in the sky asking 'what in the heck happened?!'" JPL director Charles Elachi joked as he opened the post-impact news conference now underway.

0745 GMT (3:45 a.m. EDT)

The Faulkes Telescope in Hawaii captured these before and after images that show the comet increases in brightness following the impact. See the pictures here.

0715 GMT (3:15 a.m. EDT)

A scientific smart bomb crashed into Comet Tempel 1 early today, blasting a shower of icy debris into space in a 23,000-mph Fourth of July spectacular 83 million miles from Earth. Read our full story.

0650 GMT (2:50 a.m. EDT)

A post-impact news conference is coming up at 4 a.m. EDT from the Jet Propulsion Laboratory.

0645 GMT (2:45 a.m. EDT)

Don Yeomans, Deep Impact project scientist from the Jet Propulsion Lab, says he never expected such a large blast from the impact.

"I'm at a loss to explain how on Earth our little washing machine-sized impactor caused such a disturbance some 83 million miles away. This is going to take some work to explain this. It certainly has taken me by surprise. And I suspect some of my colleagues up in the science area are equally surprised."

0637 GMT (2:37 a.m. EDT)

"It's been a smashing success!" says Yeomans.

0632 GMT (2:32 a.m. EDT)

Pictures from the impact are available here.

0629 GMT (2:29 a.m. EDT)

More remarkable images are being received showing the bright ejecta from the impact zone.

0626 GMT (2:26 a.m. EDT)

"I think it was worth every cent that we have spent (for) the insight we are going to get," JPL director Charles Elachi says.

0619 GMT (2:19 a.m. EDT)

"It is absolutely stunning," says Al Diaz, the NASA associate adminstrator for science.

0618 GMT (2:18 a.m. EDT)

The medium-resolution telescope images from the mothership showing the impact are now being received.

0617 GMT (2:17 a.m. EDT)

Several congressmen representing Southern California are mingling about the control room, offering their congratulations on this morning's spectacular success.

0615 GMT (2:15 a.m. EDT)

A little more than 20 minutes after closest approach, the mothership should be out of the danger zone. The craft will begin a 9-minute maneuver to repoint its instruments to the comet to commence its "look back" observations.

0611 GMT (2:11 a.m. EDT)

"I don't know how this could have gone any better," Yeomans says.

0609 GMT (2:09 a.m. EDT)

While the science collection has stopped during the shield mode, the mothership keeps its dish-shaped main communications antenna pointed at Earth. This allows the relay of stored pictures and data back to eagerly awaiting scientists.

0605 GMT (2:05 a.m. EDT)

An image from the mothership showing the impact is available here.

0605 GMT (2:05 a.m. EDT)

The mothership should be going into the shield mode now about 420 miles from the comet nucleus.

0603 GMT (2:03 a.m. EDT)

About 50 seconds before closest approach, the flyby craft orients itself with protective shielding guarding against a destructive hit by comet dust and ending its observations of the nucleus.

"We've designed extra shielding on certain parts of the spacecraft. So when I say it turns to shield mode, what that means is it actually places those shields in the direction of the cometary dust and debris. That is meant to protect the spacecraft itself from any particle hits," Rick Grammier said.

0603 GMT (2:03 a.m. EDT)

The mothership has begun taking the highest resolution images of the impact crater.

0601 GMT (2:01 a.m. EDT)

The final picture from the impactor was received 3.7 seconds before impact!

0600 GMT (2:00 a.m. EDT)

"We hit it exactly where we wanted to," Yeomans says.

0600 GMT (2:00 a.m. EDT)

The mothership is continuing to zoom toward the comet. It should pass about 310 miles below the nucleus a few moments from now.

0558 GMT (1:58 a.m. EDT)

AMAZING PICTURES are being received from the mothership showing a massive blast as the impactor collided with Comet Tempel 1!

0557 GMT (1:57 a.m. EDT)

Mission control has erupted into applause, confirming a successful impact!

0553 GMT (1:53 a.m. EDT)

A stream of pictures are flooding into the Jet Propulsion Laboratory from the impactor of its final moments before smashing into oblivion.

0552 GMT (1:52 a.m. EDT)

Telemetry lock with the impactor has been lost.

0551 GMT (1:51 a.m. EDT)

Tempel 1 is hurtling through space at approximately 6.3 miles per second. At that speed you could travel from New York to Los Angeles in less than 6.5 minutes.

0550 GMT (1:50 a.m. EDT)

The mothership is about to switch to onboard sequences for observing the impact.

0549 GMT (1:49 a.m. EDT)

Mission managers put the odds at least 50-50 of dust hitting the impactor that will end transmission of its images during the final 10 seconds before impact. The final potential image that could be transmitted in its entirety is one scheduled at about two seconds before impact, with a scale of about 20 centimeters (approximately 8 inches) per pixel, NASA says.

0546 GMT (1:46 a.m. EDT)

The exact moment of the impact could verify a few moments before or after 1:52 a.m. EDT.

0545 GMT (1:45 a.m. EDT)

Excellent performance is being reported from the final targeting maneuver by the impactor. The spacecraft is now fixed on its current course for the comet strike.

0544 GMT (1:44 a.m. EDT)

Eight minutes to go.

0543 GMT (1:43 a.m. EDT)

The impactor is targeting the lower edge of the nucleus, which is brighter than the center in the images being received from the approaching spacecraft. That should permit an even better view for the mothership when it passes below the comet shortly after the hit.

0540 GMT (1:40 a.m. EDT)

The burn is in progress.

0540 GMT (1:40 a.m. EDT)

This final thruster burn for the impactor spacecraft should last 44 seconds and consume 0.37 kilograms of fuel.

0539 GMT (1:39 a.m. EDT)

Standing by for the final maneuver.

0536 GMT (1:36 a.m. EDT)

Click here to see a spectacular image from the mothership of the comet nucleus.

0532 GMT (1:32 a.m. EDT)

Time to impact is now 20 minutes. The kinetic energy released as the impactor smashes into the comet nucleus is expected to be 19 gigajoules -- similar to detonating 4.5 tons of TNT. The time it takes for the crater to form could vary, depending on the properties of the comet nucleus material, but is expected to be on the order of four minutes, NASA says.

0529 GMT (1:29 a.m. EDT)

The impactor could do one final maneuver in about 10 minutes.

0528 GMT (1:28 a.m. EDT)

The propulsion system engineer reports everything looks good on the impactor following the second maneuver. Controllers report that the craft has 6.5 kg of thruster fuel remaining.

0522 GMT (1:22 a.m. EDT)

One of the latest high-resolution pictures from the mothership shows a large feature on the comet nucleus -- either a large depression/crater or a hill with a shadow being cast.

0519 GMT (1:19 a.m. EDT)

The second autonomous targeting maneuver has been completed by the impactor. Time to impact is now 33 minutes.

0516 GMT (1:16 a.m. EDT)

The impactor has created a very tiny course tweaking maneuver using just 0.36-kg of thruster fuel.

0506 GMT (1:06 a.m. EDT)

"The navigation team has done a marvelous job," says Don Yeomans, Deep Impact project scientist from the Jet Propulsion Lab. "Even if we didn't do any course corrections, we'd hit (the comet)."

0500 GMT (1:00 a.m. EDT)

The window for a second impactor course correction burn is coming up in a quarter-hour or so.

0452 GMT (12:52 a.m. EDT)

Sixty minutes to go!

0450 GMT (12:50 a.m. EDT)

Grammier says the shape of Tempel 1's nucleus is appearing to be more banana-shaped than pickle-shaped as earlier believed by scientists.

"(The comet) is presenting a very strange shape to us. We've been watching it all day as we get closer. We initially thought that this thing was something like a pickle. As we're getting closer, it's more like it's a banana. And the latest resolution that we have in the rotation ... is that we're looking at the end of (the nucleus), and the end of it is basically triangular."

0442 GMT (12:42 a.m. EDT)

Just 70 minutes remain before the expected impact time. "We're doing quite well," says Rick Grammier, Deep Impact project manager.

0434 GMT (12:34 a.m. EDT)

Mission control does confirm that the first targeting maneuver by the impactor was a full success. The craft has the opportunity to perform two more burns in the final 35 minutes before the comet collision to further refine the trajectory.

0432 GMT (12:32 a.m. EDT)

The initial look at the impactor's health following the first targeting maneuver indicates everything is fine.

0425 GMT (12:25 a.m. EDT)

The thrusters are firing, the impactor's propulsion engineer in the mission control reports.

0420 GMT (12:20 a.m. EDT)

The impactor has generated a maneuver sequence to fire its thrusters for just over 20 seconds.

0418 GMT (12:18 a.m. EDT)

The first targeting maneuver by the impactor using its autonomous onboard guidance is coming up in about three minutes.

0414 GMT (12:14 a.m. EDT)

"The thing that's really cool about this mission is there's nothing subtle about Deep Impact. It is something anyone can understand. We're trying to smack a comet as hard as we can with a hunk of copper, we'll be going about 23,000 miles per hour, and we're going to watch happens," Deep Impact mission manager Dave Spencer says.

"And we actually get a surprising about of excellent science data from this impact. We don't know what the interior of a comet is composed of. We don't know what it's densely packed or loose. And we're going to learn a lot about comets."

0406 GMT (12:06 a.m. EDT)

In the last two hours before impact there's little the flight control team can do. "We're just riding it out," Spencer says. The autonav system remains in control with good guidance solutions being generated.

0404 GMT (12:04 a.m. EDT)

The navigation appears to be perfect, Spencer says. The impactor is pointed within two kilometers of the target spot. The autonav will drive the craft to a sun-lit impact point.

0402 GMT (12:02 a.m. EDT)

"We're in the climax now," says Deep Impact mission manager Dave Spencer. The autonav pictures are being processed from the impactor.

0354 GMT (11:54 p.m. EDT)

The impactor's autonomous navigation imaging of the comet has just begun. The autonav software will guide the projectile to Tempel 1 over the next two hours and control three upcoming engine firings to tweak the trajectory on the way.

0349 GMT (11:49 p.m. EDT)

The copper mass in the impactor spacecraft equals about 45,000 pennies, Mike A'Hearn says.

0345 GMT (11:45 p.m. EDT)

A jar of peanuts is being passed around the control room. This is a tradition in which the controllers have a handful for good luck.

0338 GMT (11:38 p.m. EDT)

Engineers are looking at some oscillations with the mothership's high-gain antenna, though this doesn't appear to be a significant issue.

0334 GMT (11:34 p.m. EDT)

Flight controllers report all systems aboard the mothership and impactor spacecraft remain in good shape.

0300 GMT (11:00 p.m. EDT)

"If all goes well, the impactor spacecraft will be taking pictures all the way in to the point of impact, sending those images back the flyby spacecraft, providing us with some of the most astonishing pictures of a comet ever taken," says Deep Impact mission manager Dave Spencer.

"Our impactor spacecraft is not capable on its own of communicating directly with Earth. So telemetry and images from this craft are transmitted to the flyby (mothership), which turn takes its images, telemetry and that of the (impactor) and sends it down to Earth," Jennifer Rocca, the mission systems engineer, explained.

"For the comet encounter, Deep Impact employs a strategy called 'live-for-the-moment.' To the flight team this means we try our best to transmit the highest priority images from both flyby and impactor before the flyby reaches its closest approach to the comet. This allows us to capture our very best data even if the flyby suffers damage as it flies close to Tempel 1."

The mothership has a communications antenna about the size of a home rooftop satellite TV dish for transmissions to and from mission control. Tonight's impact is timed to allow overlapping coverage between two primary Deep Space Network receiving stations at Canberra, Australia and Goldstone, California.

0222 GMT (10:22 p.m. EDT Sun.)

Time to impact is now 3 hours, 30 minutes.

"Comets have been around for four-and-a-half billion years, since the formation of the solar system. The Deep Impact project will for the first time is going to allow us to actually look inside by impacting the surface of the comet, kicking up material that we can then take images of and take measurements of to figure out what is exactly inside a comet," says Dave Spencer, Deep Impact mission manager at JPL.

"One of the neat things about Deep Impact is we really don't know what to expect. We know so little about comets," he continued. "We don't know if it is going to be hard like a block of ice or whether it is going to be soft and fluffy. So just the form of the impact crater that is made is going to be very interesting to us."

0053 GMT (8:53 p.m. EDT Sun.)

The Deep Impact mission is five hours away from its violent rendezvous with Comet Tempel 1 about 83 million miles from Earth. No problems are being reported by NASA and the impact is still expected around 1:52 a.m. EDT (0552 GMT).

Coming up in about three hours at 11:53 p.m. EDT (0353 GMT), the autonomous navigation goes to work on the spacecraft.

"The autonav is like we have a little astronaut on board," said Rick Grammier, Deep Impact project manager at JPL. "It has to navigate and fire thrusters three times to steer the wine cask-sized impactor into the mountain-sized comet nucleus closing at 23,000 miles per hour."

It takes about 7.5 minutes for communications to travel from Earth to the spacecraft. As such, piloting the impactor via remote control is not a suitable option. A pioneering technology of spacecraft thinking for themselves was proven aboard the Deep Space 1 probe several years ago, allowing the Deep Impact mission to use this technique.

The "autonav" software on both mothership and impactor spacecraft will begin taking images of the comet nucleus at 15-second intervals two hours before impact. The autonav then performs image processing, orbit determination and maneuver computations, officials explained.

"All of that has to work perfectly in order for us to hit a bull's-eye on the Fourth of July," said Dave Spencer, Deep Impact mission manager at JPL.

The impactor will conduct up to three thruster firings to fine-tune its flight path as it closes in on the comet nucleus. The first is scheduled 90 minutes before impact, followed by a second one 35 minutes before impact and a final firing 12.5 minutes before impact. The maneuvers will use four 22-newton thrusters firing in pulses varying in length from .015 to 0.5 second each. The projectile will be trying to hit a sun-lit portion of the comet's nucleus.

"We are really threading the needle with this one," Grammier said. "In our quest of a great scientific payoff, we are attempting something never done before at speeds and distances that are truly out of this world."

SUNDAY, JULY 3, 2005
2130 GMT (5:30 p.m. EDT)

NASA's Deep Impact mission moved into its final stages today, with one spacecraft hurtling toward a suicidal July Fourth comet collision and another positioning itself to study the crash and relay close-up pictures from the doomed probe back to Earth. Read our full story.

1833 GMT (2:33 p.m. EDT)

The spacecraft are 225,000 miles from Comet Tempel 1. Impact time is still expected at 1:52 a.m. EDT (0652 GMT).

1810 GMT (2:10 p.m. EDT)

Both the mothership and the impactor are within a kilometer of their intended trajectories for tonight's comet encounter, says Rick Grammier, Deep Impact project manager.

1804 GMT (2:04 p.m. EDT)

"The flyby spacecraft is ready. The impactor spacecraft is where it is supposed to be. Everything looks green," says Andy Dantzler, director of the Solar System Division from NASA Headquarters.

1802 GMT (2:02 p.m. EDT)

"You are witnessing with us one of the most daring and risky space missions that we've ever undertaken. Last night we successfully pulled the trigger," JPL director Charles Elachi just told reporters gathered at a mid-day status briefing.

0737 GMT (3:37 a.m. EDT)

"It went great. Went like clockwork. Very good, we're very excited," Rick Grammier, Deep Impact project manager, says of this evening's events.

"It looked just like one of our simulations," added Keyur Patel, deputy program manager. "In fact, people were commenting they couldn't tell the difference."

"The systems were all nominal and we were within about a half a kilometer, I believe, of our target point before release. The release went very well," Grammier said in his brief address to reporters gathered at JPL tonight.

"As soon as we did release, we got positive confirmation that the separation had occurred and the systems were nominal after that. The S-band locked up with the impactor spacecraft and we got confirmation that it was doing fine and detumbling according to the plan.

"The flyby executed its divert burn just beautifully. Initial estimates ... are within about 1 percent of what we wanted on the burn. Now we've just taken another status poll, all systems are green.

"We did get a picture of the impactor from the flyby after release, which was great; we didn't know if we'd quite get that or not, so that was a very good thing."

Read our earlier Mission Status Center coverage.



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