Detailed maps showing the path that Atlantis would take into Kennedy Space Center and Edwards Air Force Base during four landing opportunities spread across three orbits on Sunday can be seen here.

Mission Control just passed along the news to the Atlantis crew about the nomination of former astronaut Charlie Bolden to be the NASA administrator and Lori Garver as the deputy.

"Roger, thanks for the news on the announcement, I guess it wasn't any of us on the flight after all," commander Scott Altman replied.

Earlier this week, the subject of a new administrator came up during the astronauts' live phone call from President Obama.

"We're soon going to have a new NASA administrator," Obama told the astronauts. "I can't disclose it to you because I've got to have some hoopla on the announcement back here on Earth. But I can assure you that it's a high priority of mine to restore that sense of wonder that space can provide and to make sure we've got a strong sense of mission, not just within NASA but to the country as a whole."

Atlantis commander Scott Altman jokingly asked the president, "just so we're sure, the new administrator's not any of us on the flight deck right now, is it?"

Obama laughed, and said "I'm not going to give you any hints."

"Thank you very much, fair enough, sir," Altman said.

Nineteen years after helping launch the Hubble Space Telescope, Charles F. Bolden Jr., a former fighter pilot, Marine Corps major general and veteran space shuttle commander, has been selected by the Obama administration to serve as the space agency's next administrator. Lori Garver, a former NASA associate administrator for policy and plans and a space policy advisor to the Obama campaign, will serve as Bolden's deputy.

Read our full story.

Mission Control has updated the landing times and strategy for Sunday. The day's first landing orbit will be KSC-only, followed on the subsequent orbit with both KSC and Edwards available, then another orbit with only Edwards available. Here's the latest numbers (all times Eastern):

ORBIT...SITE...LANDING

Sunday, May 24:

196.....KSC....10:09 AM
197.....EDW....11:40 AM
197.....KSC....11:48 AM
198.....EDW....01:17 PM

The crew has now finished backing out of the deorbit preparation checklist.

Faced with dismal weather in Florida but a chance for improvement Sunday, the Atlantis astronauts were ordered to back out of landing preparations and to stay in orbit a second extra day in a row in hopes of getting back to Florida Sunday.

Read our full story.

The payload bay doors have swung open again and the crew received approval from Mission Control to get out of the re-entry spacesuits.

"We are confident we are in a good config," CAPCOM just told commander Scott Altman about the earlier cooling system concern. And with that, the crew is "go" to proceed with steps to back out of the deorbit preparations and reopen the payload bay doors.

Flight controllers believe there's probably ice in the cooling lines and the issue will be cleared once the shuttle radiators are reactivated and the orbiter is reoriented to the normal attitude in space.

If the cooling situation turns into a real problem, NASA could still have the crew deorbit and land at Edwards Air Force Base today where the weather is fine.

The astronauts have reported a issue in reconfiguring the orbiter cooling system. Mission Control just told the crew to keep the payload bay doors closed and remain suited up.

Meanwhile in Washington, the official nomination of former astronaut Charlie Bolden as the new NASA administrator has been made by President Obama. Lori Garver would be the deputy administrator.

President Obama said, "These talented individuals will help put NASA on course to boldly push the boundaries of science, aeronautics and exploration in the 21st century and ensure the long-term vibrancy of America's space program."

Here's an updated look at the opportunities to land the space shuttle on Sunday at Kennedy Space Center in Florida and Edwards Air Force Base in California (all times Eastern):

ORBIT...SITE...LANDING

Sunday, May 24:

196.....EDW....10:02 AM
196.....KSC....10:11 AM
197.....EDW....11:40 AM
197.....KSC....11:49 AM

ANOTHER DAY IN SPACE. For the second straight day, persistent unfavorable weather conditions at the Florida spaceport have prevented shuttle Atlantis from returning from space. NASA has decided to keep Atlantis aloft an additional 24 hours in hopes for a break in the weather at Kennedy Space Center for touchdown at 10:11 a.m. EDT on Sunday.

The backup landing site at Edwards Air Force Base in California has a good, stable weather outlook for Sunday if Florida remains "no go."

The crew is performing an alignment of the inertial measurement units. Debates on the landing plan continue in Mission Control.

Still watching the weather and awaiting a decision from Mission Control.

Maps showing Atlantis' path to either Edwards Air Force Base or Kennedy Space Center on the Orbit 181 landing opportunities can be seen here.

The next available deorbit burn would ignite at 9:28:46 a.m. EDT to land in California at the backup site of Edwards AFB at 10:45 a.m. EDT.

Performing the deorbit maneuver a few minutes later at 9:45:26 a.m. EDT would set up Atlantis for landing at the Kennedy Space Center in Florida at 10:54 a.m. EDT.

Mission Control has not made any decisions about the upcoming landing options. Florida has not been ruled out, although the weather doesn't look promising. Diverting to California is a real possibility, but that's not been picked yet. And there's always the chance that officials could decide to keep Atlantis in orbit an additional day and try again tomorrow.

The weather at Edwards is stable and favorable.

WAVEOFF. The day's first shot at landing has been cancelled due to the weather conditions at the Kennedy Space Center. Atlantis and crew will add another orbit to their mission and look for the next set of deorbit opportunities that would bring the shuttle into a landing at either Edwards Air Force Base in California at 10:45 a.m. EDT or Kennedy at 10:54 a.m. EDT.

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The latest data from Mission Control shows the upcoming deorbit burn ignition time will be 8:01:36 a.m. EDT. The twin braking rockets will fire for two minutes and 32 seconds, slowing the shuttle by about 175 mph.

The deorbit burn will put Atlantis into a 344 x 31 mile trajectory for entry over the Pacific Ocean and bound for landing at Kennedy Space Center. Once at the spaceport, the shuttle will make a 240-degree right-overhead turn to align with Runway 33 for touchdown at 9:15 a.m. EDT.

The runway selection is a change. Earlier plans called for a Runway 15 approach.

All of this depends on the weather being acceptable and Mission Control giving approval for the deorbit burn. Once that burn is performed, there's no turning back. So the weather must be judged to be within limits for a safe landing about 90 minutes before the actual touchdown.

Commander Scott Altman and pilot Greg Johnson are getting suited up first. They'll be strapping into their flight deck seats shortly.

Now three hours from the scheduled touchdown at the Kennedy Space Center. But will the weather improve? There's a large area of rain due east of the spaceport and some showers south of the Cape. Chief NASA astronaut Steve Lindsey is flying weather reconnaissance around Central Florida this morning and feeding his real-time observations back to Mission Control as entry flight director Norm Knight decides whether to land on the day's first deorbit opportunity or wait until a later orbit.

The astronauts have been given a "go" to start suiting up. Weather is considered "dynamic" and "right on the border" this morning at Kennedy Space Center, the astronauts were just told by Mission Control.

The onboard software switch is underway. Next, the star trackers on the nose of Atlantis will be stowed for entry.

Mission Control has given the crew a "go" to transition the onboard computers from the OPS-2 software used during the shuttle's stay in space to OPS-3, which is the software package that governs entry and landing.

Space shuttle Atlantis' clam-shell payload bay doors have been closed and locked in preparation for today's descent into Earth's atmosphere and landing at Kennedy Space Center. The deorbit burn is scheduled for 8:01 a.m., with touchdown at 9:15 a.m. EDT, weather permitting.

The port door is shut.

Atlantis' left-hand door is now closing. Standing by for the starboard door to swing shut.

The crew completed the work to bypass the shuttle's radiators on the insides of the payload bay doors and checked out of the ship's flash evaporator cooling system that is used while the doors are closed for entry.

The "go" for payload bay door closing has been voiced up to commander Scott Altman from Mission Control.

Commander Scott Altman and his crewmates, facing more stormy weather at the Kennedy Space Center, readied the shuttle Atlantis for a day-late re-entry Saturday while flight controllers assessed the forecast and options for landing in Florida or California.

Read our full story.

Mission Control told the crew that the game plan this morning will proceed further along the preparation timeline than yesterday. Specifically, the crew will close the payload bay doors at the scheduled 5:21 a.m. EDT time to support the first Kennedy Space Center deorbit burn opportunity. However, the astronauts won't be asked to don their spacesuits on-time if the Florida weather continues to look "no go" this morning. The preps would pause at that point.

When and where will space shuttle Atlantis land today? The day's first opportunity is 9:15 a.m. EDT at the Kennedy Space Center in Florida, but the weather outlook isn't much better than it was yesterday. The subsequent orbit provides opportunities to land at Edwards Air Force Base in California at 10:45 a.m. EDT or Kennedy Space Center at 10:54 a.m. EDT.

Meteorologists are worried about thunderstorms and low clouds at the Cape today.

The official weather forecast from the Spaceflight Meteorology Group is calling for scattered clouds at 2,000 feet, another level of scattered clouds at 4,000 feet, a broken deck of clouds at 12,000 feet, seven miles of visibility, a southeasterly wind from 120 degrees of 8 peaking to 12 knots.

The concerns will be the chance of rainshowers or thunderstorms within 30 miles of the Florida spaceport and the cloud deck at 4,000 becoming more widespread and forming a ceiling that violates the shuttle landing weather rules.

Edwards AFB looks ideal with just a few high cirrus clouds at 25,000 feet, good visibility and southwesterly winds 9 peaking to 15 knots.

Detailed maps showing the path that Atlantis would take into Kennedy Space Center and Edwards Air Force Base during six landing opportunities spread across four orbits on Saturday can be seen here.

The Atlantis astronauts have begun their 8-hour sleep period. Wakeup time for Saturday's landing is scheduled for 1:01 a.m. EDT.

A new product has arrived in our online store: COLBERT patches to commemorate the space station treadmill named for Stephen Colbert, host of Comedy Central's nightly "The Colbert Report" show. The patch is available for U.S. shoppers and Worldwide store.

You can read more about the naming contest in our earlier story.

Quick maps showing the paths Atlantis would take to the main landing opportunities on Saturday show the first two KSC orbits here and here. The first Edwards ground track is posted here.

The Kennedy Space Center will remain the primary landing site of choice, but diverting Atlantis to the alternate facility at Edwards Air Force Base in California will be an option tomorrow. Entry flight director Norm Knight has decided to call up support at the military facility, where weather conditions are expected to be just fine. The outlook for Florida on Saturday is slightly better than today, yet still iffy at best.

If KSC remains "no go" tomorrow but there's some realistic hope of acceptable weather on Sunday, NASA could decide to keep the shuttle in orbit an additional day. But managers want the shuttle on the ground at one of the landing sites no later than Sunday.

Here's an updated look at the deorbit and landing opportunities for KSC and Edwards on Saturday (all times Eastern):

ORBIT...SITE...DEORBIT.....LANDING

Saturday, May 23:

180.....KSC....08:02 AM....09:16 AM
181.....EDW....09:30 AM....10:45 AM
181.....KSC....09:46 AM....10:54 AM
182.....EDW....11:12 AM....12:24 PM
182.....KSC....11:21 AM....12:33 PM

The latest version of the NASA TV Schedule is posted. (.pdf download)

Here's an updated look at the opportunities to bring the shuttle home this weekend at Kennedy Space Center, Edwards Air Force Base in California and White Sands, New Mexico (all times Eastern):

ORBIT...SITE...LANDING

Saturday, May 23:

180.....KSC....09:16 AM
181.....EDW....10:46 AM
181.....KSC....10:54 AM
182.....EDW....12:24 PM

Sunday, May 24:

196.....EDW....10:01 AM
196.....NOR....10:04 AM
196.....KSC....10:10 AM
197.....EDW....11:39 AM
197.....NOR....11:42 AM
197.....KSC....11:48 AM

The first Kennedy Space Center landing opportunity on Saturday will be 9:16 a.m. EDT.

AN EXTRA DAY IN SPACE. Faced with bleak odds that unfavorable weather at the Kennedy Space Center would improve for a safe landing of the space shuttle later this morning, Mission Control has decided to cancel the day's only remaining deorbit opportunity and keep Atlantis in orbit. The astronauts will get a bonus day in space and target a landing on Saturday.

Mission Control just told commander Scott Altman that officials continue to evaluate the weather and no decision has been made one way or the other about resuming deorbit preparations and closing the payload bay doors.

All remains in a holding pattern while flight controllers watch to see if the weather clears up enough for Atlantis to land in Florida later this morning. The next window for the shuttle perform a deorbit burn is 10:33 a.m. EDT, leading to a touchdown at Kennedy Space Center around 11:39 a.m. EDT.

Meteorologists are worried about thunderstorms, low clouds and crosswinds at the Cape today.

The official weather forecast for Saturday at the Kennedy Space Center from the Spaceflight Meteorology Group is calling for scattered clouds at 4,000 feet, another level of scattered clouds at 7,000 feet, a broken deck of clouds at 15,000 feet, seven miles of visibility, a southeasterly wind from 130 degrees of 10 peaking to 16 knots.

The concerns will be the chance of rainshowers or thunderstorms within 30 miles of the Florida spaceport and the cloud deck at 7,000 becoming more widespread and forming a ceiling that violates the shuttle landing weather rules.

If the landing is delayed to Sunday, the Kennedy Space Center forecast improves a bit to include scattered clouds at 3,000 feet, a broken deck of clouds at 15,000 feet, seven miles of visibility, a southeasterly wind from 130 degrees of 7 peaking to 12 knots, only a chance of showers within 30 miles but no concerns about a ceiling.

NASA could opt to activate the backup landing facility at Edwards Air Force Base in California either Saturday or Sunday. The alternate site has a "go" weather forecast both days this weekend.

Based on the amount of consumables and supplies left aboard Atlantis, NASA wants to have the shuttle safely back on Earth no later than Sunday.

Looking ahead to the second and final landing opportunity of the day, assuming the weather does improve, the shuttle's 60-foot-long payload bay doors are scheduled to be closed at 7:53 a.m., followed by the transition of onboard computers to the software for entry and the crew donning its spacesuits.

A final decision whether to perform the deorbit burn would come from Houston around 10:15 a.m., leading to ignition of Atlantis' braking rockets at 10:33 a.m. to start the trek home. The shuttle would hit the upper atmosphere at 11:07 a.m.

Touchdown on Runway 15 at Kennedy Space Center is targeted for 11:39 a.m. EDT.

LANDING DELAYED ONE ORBIT. Entry flight director Norm Knight has scrubbed the first of two landing opportunities for today due to poor weather at the Kennedy Space Center. Atlantis' mission will be extended at least one additional orbit as Mission Control evaluates the weather over the next 90 minutes to decide whether to resume preparations for a landing at 11:39 a.m. EDT or not. For now, the astronauts have paused their prep work and left the payload bay doors open.

You can see the path Atlantis would follow into the Florida spaceport on the next landing opportunity here.

If the weather doesn't get better and the next landing opportunity is waved off too, then Atlantis would stay in space an extra day.

Another weather briefing underway in Mission Control.

No decisions have been made about today's landing. However, the crew has been instructed by Mission Control to hold off -- at least for now -- performing the preparatory steps to reconfigure the ship's cooling systems in advance of closing the payload bay doors.

The official forecast for both landing opportunities at Kennedy Space Center are "no go" due to thunderstorms, low cloud ceilings and crosswinds.

The outlook for Saturday is a little better, with only "a chance" of thunderstorms and low clouds. Sunday's forecast predicts a chance of showers.

The entry team of flight controllers in Mission Control has received a detailed weather briefing on the outlook for today. CAPCOM astronaut Greg H. Johnson (no relation to Atlantis pilot Greg C. Johnson) gave this update to commander Scott Altman a few moments ago:

"We have just talked to the weather folks and what we've got in Florida is a very dynamic situation," Johnson said. "There are thunderstorms that are stretching from the southeast over Bermuda to the northwest and going through the circle, the 30-nautical-mile circle around the Cape. There are some clear areas to the south and we think over time, that line could move a little north or it might stay the same. The air is saturated.

"We're also looking at ceilings, the crosswind is just right at the limit, so there are a lot of issues against us. However, it's a dynamic situation and we're going to keep our eyes on it closely. We view our next decision point, based on the weather, just prior to payload bay door closing (around 6:09 a.m.). And so, we'll get a better update on the weather at that point and our plan is to press on, at least up to that point, in deorbit prep. How copy?"

"Houston, copy that, understand the Cape weather system that's there and the dynamics that are involved," Altman replied. "We concur, we're pressing ahead, we'll have another tagup at payload bay door closing."

The astronauts have begun the deorbit preparation timeline. Closing of the payload bay doors is scheduled for 6:09 a.m. EDT.

The official weather outlook from the Spaceflight Meteorology Group looks iffy for landing at best due to a possible low-cloud ceiling and thunderstorms around the landing strip today.

The latest forecast calls for a few clouds at 2,000 feet, a broken deck at 4,000 feet and another broken level at 10,000 feet, 7 miles of visibility, easterly winds of 12 peaking to 19 knots and thunderstorms within 30 miles.

The outlook for Saturday has scattered clouds at 3,000 feet, a scattered or possibly broken deck at 7,000 feet and a broken level at 15,000 feet, 7 miles of visibility, easterly winds of 10 peaking to 16 knots and a chance of showers or thunderstorms within 30 miles.

The alternate landing site at Edwards Air Force Base in California looks good.

Space shuttle Atlantis will be heading back to Earth today, weather permitting, and the seven astronauts just received a wakeup call from Mission Control to get the day started.

The crew has a couple of hours to eat breakfast and go about their morning routine before beginning the deorbit preparation timeline at 4:49 a.m. EDT.

The ship's 60-foot-long payload bay doors are scheduled to be closed at 6:09 a.m., followed by the transition of onboard computers to the software for entry and the crew donning its spacesuits. A decision from Houston if the weather odds are worth the crew suiting up is expected around 6:50 a.m.

A final decision whether to land ontime will come from Houston around 8:30 a.m., leading to ignition of Atlantis' braking rockets at 8:49 a.m. to start the trek home. The shuttle would hit the upper atmosphere at 9:29 a.m.

Landing on Runway 15 at the Kennedy Space Center is scheduled for 10:00 a.m. EDT.

If the weather or a problem forces entry flight director Norm Knight to scrub the day's first re-entry opportunity and keep Atlantis in space, there is a backup option available one orbit later. That would begin with a deorbit engine firing at 10:33 a.m. and touchdown in Florida at 11:39 a.m. EDT.

NASA is not calling up support from the alternate landing site at Edwards Air Force Base in the Mojave Desert of California today. The space agency wants to get Atlantis back to the Florida spaceport and the spacecraft has enough consumables and supplies to remain aloft through the weekend if needed.

Maps showing the path that Atlantis would take into the Kennedy Space Center for either of today's two landing opportunities can be seen here.

Watch this page for continuing updates throughout the day as the astronauts prepare for the return to Earth.

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Landing of Atlantis at Kennedy Space Center is planned for Friday, but the weather forecast is not optimistic. Here's an early look at the opportunities to bring the shuttle home this weekend at Kennedy Space Center, Edwards Air Force Base in California and White Sands, New Mexico (all times Eastern):

ORBIT...SITE...LANDING

Friday, May 22:

165.....KSC....10:00:31 AM
166.....KSC....11:39:18 AM

Saturday, May 23:

180.....KSC....09:16 AM
181.....EDW....10:48 AM
181.....KSC....10:54 AM
182.....EDW....12:27 PM
182.....KSC....12:32 PM

Sunday, May 24:

196.....KSC....10:10 AM
197.....EDW....11:39 AM
197.....NOR....11:42 AM
197.....KSC....11:48 AM
198.....EDW....01:18 PM
198.....NOR....01:20 PM

With the shuttle Atlantis in good shape and no problems with its protective heat shield, NASA managers today released the shuttle Endeavour from stand-by duty for a possible launch on an emergency rescue mission. The Atlantis astronauts, meanwhile, pressed ahead with preparations for landing Friday, keeping tabs on threatening weather in Florida.

Read our full story.

The crew is taking a break from packing for tomorrow's landing to give live interviews with U.S. television networks ABC, CBS, NBC, CNN and Fox. These are the first and only media interview sessions scheduled during the hectic mission to Hubble.

Atlantis' Ku-band communications antenna used to downlink television will be folded back into the payload bay and stowed after the interviews are finished.

An eight-hour sleep period for the astronauts will begin at 6 p.m. EDT. Wakeup time for landing day is 2:01 a.m. EDT. If the weather improves, Atlantis will land tomorrow at Kennedy Space Center in Florida just after 10:00 a.m.

The seven astronauts are speaking live with Sen. Barbara Mikulski of Maryland and Sen. Bill Nelson of Florida. The video link from Atlantis is being broadcast live in a Senate committee hearing room on Capitol Hill.

The latest version of the NASA TV Schedule is posted. (.pdf download)

The power conservation steps taken by the Atlantis astronauts to turn off unnecessary equipment in order to extend the landing opportunities an extra day have paid off. The cryogenic reactants of liquid hydrogen and liquid oxygen used by the orbiter's fuel cells to generate electricity have enough supplies to power landing opportunities through Monday, though NASA would want the shuttle on the ground by Sunday to preserve a backup day in case of a hardware problem prevented the deorbit burn.

The plan going into landing will see just Kennedy Space Center available on Friday, both KSC and Edwards Air Force Base players on Saturday and then the "pick 'em day" would be Sunday in which Atlantis has to land somewhere that day.

Mission Control just told commander Scott Altman that the landing strategy will focus solely on the Kennedy Space Center for Friday despite the gloomy weather forecast. If the weather does not permit a landing tomorrow in Florida, the shuttle would remain in space and NASA would look at Kennedy on Saturday and also have the backup site at Edwards Air Force Base in California available. There's also the chance Atlantis could stay in orbit through Sunday to await improved conditions in Florida.

The weather is supposed to gradually improve through the weekend in Florida, while the alternate site in the high desert of California looks favorable as a backup.

Ground tracks showing Atlantis' path into the Kennedy Space Center for Friday's two landing opportunities are posted here.

The Atlantis astronauts tested the shuttle's re-entry systems early Thursday and began packing for landing Friday, weather permitting, to close out a successful mission to overhaul the Hubble Space Telescope. The flight plan calls for a de-orbit rocket firing at 8:49:16 a.m. Friday, setting up a landing on runway 15 at the Kennedy Space Center at 10:00:31 a.m. A second landing opportunity is available one orbit later, at 11:39:18 a.m.

Read our full story.

Weather continues to be a concern for Friday's planned landing at the Kennedy Space Center due to possible a low-cloud ceiling, rain, thunderstorms and even lightning.

The latest forecast calls for a few clouds at 2,000 feet, a broken deck at 4,000 feet and another broken level at 10,000 feet, 7 miles of visibility, easterly winds of 12 peaking to 19 knots and a chance of thunderstorms within 30 miles.

The outlook for Saturday has scattered clouds at 3,000 feet, a scattered or possibly broken deck at 7,000 feet and a broken level at 12,000 feet, 7 miles of visibility, easterly winds of 9 peaking to 14 knots and a chance of showers or thunderstorms within 30 miles.

The alternate landing site at Edwards Air Force Base in California looks good.

The 44 thrusters on Atlantis' nose and tail have been systematically fired as part of normal day-before-landing checks. Mission Control says the hot-fire test, as well as the earlier flight control system checkout, were normal with no problems experienced.

The crew is completing the flight control system checkout, starting up one of the Auxiliary Power Units for the orbiter's hydraulics and moving the aerosurfaces through a planned test pattern.

Next, the astronauts will perform the reaction control system hot-fire. The 38 primary and 6 vernier thrusters on the nose and tail of the shuttle will be pulsed twice as part of the continuing entry and landing checks for tomorrow's homecoming by Atlantis.

The Atlantis astronauts have been been awakened for their final full day in space on the STS-125 mission. Today will be spent packing the crew cabin for tomorrow's return to Earth, plus testing the shuttle's thrusters and checking the various flight controls for the landing.

President Barack Obama called the crew of the shuttle Atlantis late Wednesday and congratulated the astronauts on the successful overhaul of the Hubble Space Telescope. He also promised to name a new NASA administrator soon, although he provided no clues as to who might get the nod.

Read our full story.

The Atlantis astronauts are about to go to sleep. Tomorrow's wakeup time is 3:01 a.m. EDT, continuing the shift earlier and earlier to prepare for Friday morning's landing time.

The three-man crew of the International Space Station explored a strange new world Wednesday, boldly going where no other astronauts have gone before: toasting each other with sips of recycled sweat and urine in a major milestone for the lab complex.

Read our full story.

Today's Mission Management Team meeting formally determined shuttle Atlantis' heat shield is free of damage and ready for re-entry Friday.

"We have cleared the (thermal protection system) and the vehicle for a safe deorbit, entry and landing," chairman LeRoy Cain says.

With rainy weather possible in Florida on Friday, the Atlantis astronauts were asked to power down less-critical equipment Wednesday to conserve hydrogen and oxygen for the shuttle's fuel cell system in case landing is delayed. Touchdown currently is planned for 10:01 a.m. Friday, but additional opportunities on both coasts are available Saturday and Sunday.

Read our full story.

Mission Control just told commander Scott Altman that there are no areas of concern from yesterday's heat shield inspections.

The weather outlook for the Kennedy Space Center for Friday's planned landing of shuttle Atlantis indicates there could be low-cloud ceiling, rain, thunderstorm and even lightning concerns.

The latest forecast calls for a few clouds at 2,000 feet, a scattered or possibly broken deck at 4,000 feet and broken at 10,000 feet, 7 miles of visibility, easterly winds of 11 peaking to 17 knots and a chance of thunderstorms within 30 miles.

Florida has been trapped under a weather system for the past few days.

With the Hubble Space Telescope safely on its way after a successful overhaul, the Atlantis astronauts are enjoying a day off Wednesday, relaxing after five back-to-back spacewalks. At the Kennedy Space Center, NASA has continued preps to ready the rescue shuttle just in case it's needed.

Read our full story.

The revised plan for today, given that the crew shifted its sleep period 30 minutes earlier, can be seen in the latest version of the NASA TV Schedule. (.pdf download)

The original TV theme song of Star Trek was the wakeup music played by Mission Control moments ago as the astronauts begin Flight Day 10. The crew will enjoy off-duty time today to rest and relax after the hectic mission to Hubble, as well as hold the in-flight news conference with reporters and make a ship-to-ship call to the space station residents.

Mission Control says that analysis of the inspection data shows both of the wing leading edges on shuttle Atlantis appear to be in good shape and ready for entry. Work to clear the nose cap continues.

With the space shuttle facing retirement next year after eight more flights - and with the program basking in the success of its fifth and final mission to overhaul the Hubble Space Telescope - one of the observatory's senior scientists Tuesday lamented the loss of the winged orbiters in favor of new, less capable rockets.

Read our full story.

Inspections of the reinforced carbon-carbon wing leading edge panels on the right wing have been completed. The astronauts will stow the inspection boom, get some dinner and they hope to begin tonight's sleep period about 30 minutes ahead of schedule, perhaps by 8 p.m. EDT.

Analysts on the ground will review all of the data collected during the inspections and should have a final decision by tomorrow afternoon if Atlantis is safe for re-entry.

Laser scans of the left wing are complete. The crew will collection digital images of the wing panels now.

The port wing inspections have now started.

The gray nose of Atlantis is being inspected now.

The right wing was scanned using the laser and camera package of the Orbiter Boom Sensor System. The crew will swung the boom in position to inspect Atlantis' nose cap next.

Scans up and down the right-hand wing are continuing.

Inspections of Atlantis' starboard wing have begun. The survey is similar to the inspections performed the day after launch. Today's results will be compared with the earlier data to ensure the orbiter's wing leading edge panels and nose cap are free of any space debris impacts that could have occurred during the mission.

Our Hubble deploy story has been updated to add a quote from Mike Griffin.

Atlantis' robot arm has grappled the orbiter inspection boom that's stowed on the starboard side of the payload bay. The astronauts will use that boom to survey the wing leading edge and nose cap for any signs of space debris or micrometeoroid damage suffered during the mission.

The orbit adjust burn has been completed.

The twin orbital maneuvering system engines on the tail of Atlantis were fired for two minutes and 23 seconds, changing the shuttle's speed by 234.8 feet per second and moving the shuttle from a near-circular orbit to an elliptical one.

The orbit was 350 by 343 miles and the post-maneuver orbit is 350 by 184 miles.

The lower altitude for part of each orbit reduces the statistical chance that Atlantis could suffer a space debris hit, since the high perch where Hubble resides is considered to have more debris.

Now a distance of 8,000 feet as Atlantis rapidly moves away from the space telescope.

Atlantis is more than 4,000 feet from Hubble now.

The repaired Hubble Space Telescope, boasting two new instruments, new gyros, fresh batteries, a new science computer, a refurbished star sensor and two instruments brought back to life by spacewalking astronauts, was released from the shuttle Atlantis today after a historic fifth and final orbital overhaul.

Read our full story.

Flying more than 1,000 feet below the Hubble Space Telescope, the shuttle Atlantis just performed a thruster firing to accelerate its departure from the observatory.

Hubble is in the hands of its ground control team. Several months of testing is planned for the equipment installed and repaired during the servicing mission. The first release of images from the new science instruments is expected in early September.

The communications link between Atlantis and Hubble has been turned off.

Now 760 feet. Coming up on the second separation thruster burn by Atlantis.

Atlantis is 650 feet from Hubble, moving behind and below the telescope.

Mission Control says the distance between Atlantis and Hubble is now 410 feet.

The deployment came on the 119th orbit of Atlantis' mission as the shuttle passed 350 miles over the northwestern coast of Africa.

Atlantis already 150 feet from the telescope as it backs away.

Astronomy's iconic orbital observatory -- the Hubble Space Telescope -- has been deployed by the space shuttle Atlantis astronauts after a dramatic five-spacewalk servicing that should allow the spacecraft to continue probing the mysteries of the Universe for several more years.

This fifth and final shuttle flight to overhaul Hubble installed two new science instruments, performed ambitious repairs on two broken instruments, replaced the observatory's 19-year-old battery packs, refurbished the pointing and control system with an upgraded guidance sensor and six fresh gyroscopes, changed out the partially failed science instrument command and data handling unit, mounted a capture mechanism on the craft for future use and added thermal shielding on equipment bay doors. All in all, every single task planned for the Atlantis mission was successfully achieved.

Just after the robot arm lets go and backs away, commander Scott Altman will perform a small separation maneuver using Atlantis' thrusters. A larger burn will come a half-hour after deploy to accelerate the departure of the shuttle from the vicinity of Hubble.

Five minutes from setting Hubble free.

The uplink of commands to Hubble has been completed and the crew is "go" for the release of the observatory at 8:57 a.m. EDT.

Clocks counting down to the opening of the deployment window. Final steps are being performed to ready the telescope and Atlantis to part company.

Astronaut John Grunsfeld says the aperture door is fully open.

Hubble's aperture door is being reopened to let the light of the Universe back into the telescope.

Houston just advised the crew that there's still "a lot" of commanding left to be completed from Hubble ground control. That means deployment might not occur at 8:57 a.m. as currently targeted.

Landing of Atlantis at Kennedy Space Center is planned for Friday. Here's an early look at the opportunities to bring the shuttle home this weekend (all times Eastern):

ORBIT...SITE...DEORBIT.......LANDING

Friday, May 22:

165.....KSC....08:50 AM......10:01 AM
166.....KSC....10:35 AM......11:39 AM
167.....KSC....12:19 PM......01:17 PM

Saturday, May 23:

180.....KSC....08:02 AM......09:16 AM
181.....KSC....09:46 AM......10:54 AM
182.....KSC....11:30 AM......12:32 PM

Sunday, May 24:

196.....KSC....08:57 AM......10:10 AM
197.....EDW....10:24 AM......11:39 AM
197.....NOR....10:29 AM......11:42 AM
197.....KSC....10:42 AM......11:48 AM
198.....EDW....12:07 PM......01:18 PM
198.....NOR....12:13 PM......01:20 PM

The astronauts have put Hubble into the desired position and orientation for deployment above the starboard wing of Atlantis.

Hubble is hovering over the payload bay as the robot arm slowly moves the giant telescope through pre-planned waypoints.

The deployment time for Hubble has slipped four minutes to ensure a good S-band communications link. So the new release time is 8:57 a.m. EDT, the opening of a quarter-hour deploy window.

After almost six days anchored in space shuttle Atlantis' payload bay undergoing an extensive overhaul to repair broken parts and receive new equipment, the Hubble Space Telescope has been detached from the servicing platform. The observatory is in the hands of the shuttle's robot arm for maneuvering out of the bay and into the proper position for deployment about 90 minutes from now.

All three latches restraining Hubble to the support platform.

Commander Scott Altman has inhibited Atlantis' thrusters for this period of time when the robot arm will hoist the telescope off the servicing support table in the payload bay.

Astronaut Megan McArthur, operating the shuttle Atlantis' robot arm, locked onto the 24,500-pound Hubble Space Telescope at 6:45 a.m. today as the crew geared up to unberth and release the upgraded observatory following a dramatic five-spacewalk overhaul, the telescope's fifth and final shuttle servicing.

Read our full story.

Space shuttle Atlantis' 50-foot robot arm has grappled the Hubble Space Telescope for today's work to unberth the observatory from the payload bay and deploy the spacecraft.

Flight Day 9 that will see the Hubble Space Telescope deployed from the space shuttle has begun for the Atlantis astronauts following a musical wakeup call by the Dave Matthews Band moments ago.

The shuttle's robot arm will capture a grapple fixture on the telescope around 6:15 a.m. EDT, then lift the observatory off the servicing platform in the payload bay about an hour later. The telescope's aperture door is scheduled to be reopened around 8:15 a.m., leading to release of Hubble to fly free and resume its orbital life at 8:53 a.m. EDT.

The astronauts will spend the rest of their day performing inspections of the shuttle's heat shield to look for any space debris or micrometeoroid impact damage that could have occurred during the mission.

Wednesday is planned to be an off-duty day and Thursday is the standard pre-landing preparation day. Landing at Kennedy Space Center is scheduled for Friday morning.

NASA officially moved up Atlantis' re-entry by one orbit in hopes of better, more stable weather in Florida. Friday's deorbit burn would occur at 8:51 a.m. EDT, with touchdown on the concrete runway at 10:03 a.m. EDT.

The new landing time and other changes to the flight plan can be seen in the latest version of the NASA TV Schedule. (.pdf download)

A comprehensive directory of more than 200 videos from the STS-125 mission to service the Hubble Space Telescope is posted for Spaceflight Now+Plus users to watch or download. See the full listing here.

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The Fine Guidance Sensor installed today has passed its functional tests, according to Hubble control.

The functional tests of the new battery pack installed today have been run successfully, Hubble controllers report.

Mission Control says NASA is looking at moving up Friday's planned landing of space shuttle Atlantis, currently scheduled for about 11:41 a.m. EDT at the Kennedy Space Center, to an orbit earlier that morning to take advantage of likely better weather at the Florida spaceport. Exact times are still being worked out.

Astronomer-astronaut John Grunsfeld, veteran of seven Hubble Space Telescope spacewalks and a self-described "Hubble hugger," inadvertently bumped into one of the observatory's two low-gain antennas toward the end of an otherwise smooth spacewalk today, knocking off a small end piece. Groaning with disbelief, Grunsfeld said, "oh, I feel terrible."

Read our full story.

The servicing platform holding Hubble is rotating the telescope into the proper position for tomorrow's deployment. It had been turned to provide good access for today's spacewalk work on the side of the observatory.

The high-gain antenna booms have been deployed, now the dishes are being gimbaled.

EVA ENDS. Repressurization of the shuttle's airlock module began at 3:22 p.m. EDT, marking the official end of today's EVA and the final servicing spacewalk to the Hubble Space Telescope.

The EVA by John Grunsfeld and Drew Feustel lasted 7 hours and 2 minutes. The five spacewalks during Atlantis' mission have added up to 36 hours and 56 minutes, which is more EVA time spent in a single trip to Hubble than ever before.

The excursion brings to 166 hours the total Hubble servicing spacewalk time accumulated over five missions and 23 EVAs.

The observatory will be released from the space shuttle tomorrow.

The booms holding Hubble's two dish-shaped high-gain antennas are unfolding in preparation for tomorrow's deployment of the telescope from Atlantis. The booms had been retracted prior to the shuttle's rendezvous.

Spacewalkers are about to enter the airlock as the crew inside the shuttle gets ready to watch Hubble's high-gain antennas redeploy.

"Sorry, Mr. Hubble," Grunsfeld said as he put the cover back on the Hubble low-gain antenna. "Have a good voyage."

Mission Control says the Hubble low-gain antenna bumped by Grunsfeld's backpack a short time ago still works. But a small cap popped off and could cause a thermal concern for it in the future. So the spacewalkers are going to go back out there and put the cover back on.

Spacewalkers to stop airlock ingress, pending any work on the low-gain antenna.

Airlock ingress underway.

Back at the telescope to remove a protective cover around the low-gain antenna on the bottom of Hubble, Grunsfeld reported bumping the antenna and knocking a piece off.

Astronaut John Grunsfeld removed tattered insulation from the Hubble Space Telescope today and installed cookie sheet-like panels in its place over three equipment bays to complete the final objectives of a five-spacewalk overhaul.

Read our full story.

The foot restraint platform on the end of Atlantis' robot arm that has been used throughout the mission for the spacewalkers to stand upon was just removed and stowed for landing.

Both of the spacewalkers are just outside the airlock to put away their equipment, do some tool inventories and prepare to enter back inside the shuttle.

The final task on the final spacewalk of the final servicing mission to Hubble is now complete. Every planned job on this overhaul of the telescope has been accomplished, and now the spacewalkers are ready to proceed into payload bay cleanup chores before returning to the airlock.

Spacewalker John Grunsfeld is finishing the New Outer Blanket Layer install on Bay 7.

Spacewalkers are going to press ahead with the final insulation installation on Bay 7. That's the last task for the servicing.

The New Outer Blanket Layer has been installed on Bay 8 that contains equipment for the telescope's pointing control and safemode systems.

Five hours into the planned six-hour EVA.

Grunsfeld is trying to remove what's left of the old blanketing on the Bay 8 door.

The spacewalkers are moving to the Bay 8 insulation panel work, which was deferred from yesterday's EVA because of bolt problems made the STIS instrument repair job run longer than envisioned.

Read our full story on the progress of today's spacewalk.

The pizza sheet-like insulation panel, known as the New Outer Blanket Layer or NOBL, has been installed on the Bay 5 door. This particular equipment bay contains Hubble communications equipment such as solid-state recorders.

Spacewalker John Grunsfeld has peeled away the old multi-layered insulation on Bay 5 door of the telescope's equipment section. This bay houses communications gear.

Four hours and counting on the EVA clock. The spacewalkers' remaining task today is the installation of three insulation panels to cover sections of the telescope where the existing thermal blankets have degraded.

A good aliveness test on the new FGS has been reported from Hubble ground control.

The 10-year-old Fine Guidance Sensor removed from Hubble and replaced by an newer model has been packed away inside the shuttle's payload bay for the return trip home aboard Atlantis.

Now the spacewalkers are moving the old FGS from its temp stowage bracket to the carrier box.

The bay doors have been closed and locked around the new Fine Guidance Sensor.

An updated Fine Guidance Sensor, one of three such devices that help the Hubble Space Telescope lock onto stars during observations as part of the spacecraft's pointing and control system, has been successfully installed.

This milestone marks full mission success for the servicing flight's priority criteria. The spacewalkers still plan to install as many as three new thermal panels on the telescope, but that work is just gravy.

Hooking up the connectors between the telescope and FGS.

Now closing the main latch to secure FGS in place.

Passing three hours into the EVA. The spacewalkers are getting the FGS lined up for insertion into the telescope.

The new FGS has been pulled up out of the enclosure box in the payload bay for the transfer to Hubble.

The lid to the launch carrier containing the new FGS is open.

The old FGS has been temporarily anchored onto a fixture on the sidewall of the payload bay while the spacewalkers get the new device out of the launch carrier and install it into Hubble. Later, the 10-year-old FGS will be stowed in the carrier for return to Earth.

A Fine Guidance Sensor installed during the third servicing mission in 1999 has been removed from the observatory. It will be replaced with a refurbished unit.

A handle has been mounted onto the exposed surface of the Fine Guidance Sensor for the spacewalkers to pull the unit out of the telescope.

Phew for the spacewalkers. They have gotten the latch loosened in preparation for removing FGS.

Still no luck with the latching bolt.

The main latch holding the FGS inside Hubble wouldn't release on the first try. The spacewalkers will get a different tool and try some more torque.

Both spacewalkers are demating sets of connectors on both sides of the Fine Guidance Sensor.

Lending extra muscle by spacewalker John Grunsfeld has the doors now open to remove the Fine Guidance Sensor.

Passing two hours into the spacewalk. The astronauts are trying to access the bay where one of the Fine Guidance Sensors is located for its removal and replacement. Grunsfeld is having some trouble releasing the torque on the door restraints.

The bay access door on Hubble has been closed, the latches tightened and the battery replacement task has been completed smoothly.

A good aliveness test on the new battery module, Hubble ground control says.

The new power package has been installed in the Hubble Space Telescope.

Feustel has the old battery pack secured in the payload bay for landing.

Grunsfeld has engaged 14 bolts to mount the battery module to the telescope. Next, he'll connect the half-dozen umbilicals.

Bolting of the new pack to Hubble is underway.

The handoff between the two spacewalkers of the old and new batteries has occurred in the payload bay. The 19-year-old box will be stowed aboard the shuttle for return to Earth by Feustel while Grunsfeld heads back up to the telescope to install the new package.

The 475-pound box containing three of Hubble's nickel-hydrogen batteries, original equipment launched aboard the telescope in April 1990 and now operating at half their capacity, has been removed by spacewalker John Grunsfeld.

The umbilicals have been disconnected, now time to unbolt the old battery pack.

Now unhooking connectors on Hubble's old battery pack.

The bay door holding the batteries has swung open. The three batteries are packaged into one box that's bolted to the inside surface of that door.

While Grunsfeld gets the 19-year-old batteries out of Hubble, fellow spacewalker Drew Feustel is down in the payload bay readying the new battery pack for removal from their launch restraints.

Working on the end of space shuttle Atlantis' robot arm for the first time during the mission, astronaut John Grunsfeld is opening up the small equipment bay on the Hubble Space Telescope that houses the old battery pack to be replaced today.

Feustel egressed the airlock first to begin setting up equipment. Grunsfeld now has emerged and will hop aboard the shuttle's robot arm for today's maneuvering around the payload bay.

EVA BEGINS. After five servicing missions that have repaired and improved the Hubble Space Telescope, even rescuing the observatory from the brink, the shuttle Atlantis astronauts are ready to perform one final spacewalk today to install another set of batteries, a fine guidance sensor and thermal insulation panels in preparation for redeploying the telescope tomorrow.

Astronauts John Grunsfeld and Drew Feustel switched their suits from orbiter-provided power to internal batteries at 8:20 a.m. EDT, marking the start of this planned six-hour EVA.

Airlock depressurization has begun.

Running ahead of schedule, astronauts John Grunsfeld and Andrew Feustel are suiting up for the Atlantis crew's fifth and final spacewalk today, a six-hour excursion to equip the Hubble Space Telescope with a second three-battery power pack, a refurbished fine guidance sensor and fresh equipment bay insulation panels. One panel was deferred from a spacewalk Sunday when the crew ran out of time. Grunsfeld and Feustel plan to install it today if time is available.

Barring a future mission to drive Hubble safely out of orbit at the end of its life, this is the last time any astronauts will touch the space telescope and the end of today's spacewalk promises to be an emotional moment for Grunsfeld, an astronomer-astronaut and self-described "Hubble hugger" making his third visit to the iconic observatory.

Read our full story.

Preparations for today's EVA are running about an hour ahead of schedule. John Grunsfeld and Drew Feustel are suited up in the airlock and the 40-minute breathing of pure oxygen by the spacewalkers just started. That will be followed by depressurization of the airlock.

The astronauts have been awakened to start Flight Day 8.

The astronauts have gone to sleep after a long, tough day of spacewalking activities. One more EVA is left for the mission, and the crew will be awakened at 5:31 a.m. EDT to begin preps for the excursion that's scheduled to commence around 9:15 a.m. EDT.

EVA ENDS. Repressurization of the shuttle's airlock module began at 5:47 p.m. EDT, marking the official end of today's spacewalk by Mike Massimino and Mike Good.

The EVA lasted 8 hours and 2 minutes. This fourth of five planned spacewalks during Atlantis' mission adds up to 29 hours and 54 minutes of EVA time thus far.

The excursion brings to 159 hours and 4 minutes the total Hubble Space Telescope servicing spacewalk time accumulated over five missions and 22 EVAs.

One more spacewalk is planned for tomorrow by John Grunsfeld and Drew Feustel to complete the final EVA to repair and upgrade the observatory over its two-decade life.

The servicing platform holding Hubble is rotating the telescope. It had been turned this morning to provide good access for today's spacewalk work on the side of the observatory.

The airlock's outer hatch is closed, now 7 hours and 54 minutes into the EVA.

Hubble ground controllers report that STIS safed itself during the functional testing when a low thermal limit was hit, Mission Control says, adding that engineers believe the instrument is OK. The test sequence will be restarted.

Held up by a stripped screw, spacewalker Michael Massimino applied brute force muscle power to an otherwise delicate operation, breaking off an offending handrail and then carefully unscrewing more than 100 small fasteners to get inside a dead science instrument aboard the Hubble Space Telescope.

After pulling out a blown power supply circuit board, Massimino and crewmate Michael "Bueno" Good carefully installed a replacement card, closed the instrument up and began collecting tools and equipment while engineers at the Goddard Space Flight Center sent commands to verify electrical connectivity in a quick-look "aliveness" test.

Read our full story.

Now preparing to ingress the airlock.

The spacewalkers are going through tool inventories and such as the EVA winds down.

The shroud doors are closed, latched and the bolts torqued.

With a successful aliveness test now complete on STIS, ground controllers are moving ahead to perform the more-thorough functional test.

Mike Good is closing Hubble's aft shroud doors.

A good aliveness test on the newly repaired STIS instrument is being reported from the Hubble ground control center.

Massimino is cleaning up the worksite inside the telescope as the EVA passes the six-and-a-half-hour mark. Still to come is closure of the Hubble shroud doors and putting away tools and equipment in the payload bay.

Given that the STIS task took much longer than scheduled because of the handrail bolt problem, Mission Control has decided to cancel the other task originally planned for this EVA -- the installation of a replacement external thermal blanket panel on the Hubble. That job could be performed tomorrow during the final EVA.

Ground controllers will start the aliveness test on the newly repaired STIS.

Instead of reinstalling the electronics module's original cover and its hundred screws, the spacewalkers have put a new cover plate over the box that's secured with just two main latches.

Nearing completion of the STIS repair task, spacewalker Mike Massimino has inserted a new power supply circuit card into the instrument's main electronics box.

The replacement card has been taken out of its launch enclosure.

Six hours into the EVA. The Low-Voltage Power Supply-2 circuit card, or LVPS-2, that was blamed for knocking the Space Telescope Imaging and Spectrograph out of service in August 2004 has been removed from the instrument by Mike Massimino.

Mike Massimino, now back in the aft shroud of Hubble, has the open electronics module of STIS in front of him. He is beginning work to remove the failed circuit card.

The spacewalkers are working together in the payload bay to stow the cover assembly.

The cover assembly has been handed out of the telescope to Mike Good.

The fastener capture plate, along with the contained screws and the STIS instrument's cover, has been removed in one piece by spacewalker Mike Massimino. Fellow astronaut Mike Good then cut some wires connected to the cover. The internal electronics module is now exposed for the spacewalkers to pull out the failed circuit board.

The final fasteners are being released.

Releasing of batch No. 2 comprised for 56 fasteners is now complete.

Passing the five-hour mark in the EVA.

Twenty of the second batch of screws now released.

The first batch of screws -- some 39 of them -- has been completed. Massimino will change bits on his power tool for the next batch, which is a different size.

About one-quarter of the screws have been loosened thus far.

The methodical process of releasing more than 100 tiny fasteners on the STIS instrument is underway at last.

Now back at the worksite inside Hubble, the spacewalkers are "ready to get back on the script."

Massimino has completed the suit oxygen recharge in the airlock and heading back to the telescope.

Applying brute force to an interfering handrail locked in place by a stripped screw, astronaut Michael Massimino got a good grip, braced himself and and pulled the top of the handrail away, shearing off the recalcitrant screw and clearing the way for a long awaited instrument repair on the Hubble Space Telescope.

Read our full story.

Spacewalker Mike Massimino is en route back to the airlock to get the replacement mini-power tool. The original one they had taken to the worksite has stopped working.

If Massimino goes back to the airlock to get the spare power tool, he could recharge the spacesuit oxygen supply. That would mean the spacewalk duration limiter becomes Good's suit battery at 9 hours.

Now the mini-power tool to be used in releasing the hundred tiny screws appears to be dead. A spare is in the airlock.

The fastener capture plate is now in place.

Massimino is having a problem getting the fastener capture plate seated properly.

The fastener capture plate is being mounted onto the Space Telescope Imaging and Spectrograph. This plate is designed to ensure all of the tiny screws that will be released by Massimino are contained and cannot escape into the telescope.

Anchors for the fastener capture plate are being installed on STIS.

The handrail has been stowed away in a protective enclosure. The spacewalkers are taking a breath and getting tools reorganized before proceeding with the originally scheduled plan.

Mission Control says the spacewalkers can now proceed with the normal plan to mount the fastener capture plate onto STIS in preparation to remove over a hundred tiny screws and get into the instrument's electronics.

Spacewalker Mike Massimino has manually pulled the handrail to break the bolt and clear this obstruction to proceed with the STIS instrument repair.

Massimino is wrapping the handrail bolt holes with tape to keep the objects from floating freely into the telescope when the spacewalker tries to muscle the handrail out of the way.

Engineers on the ground have used a training unit to see if the spacewalker could bend the handrail and break the bolt that's still engaged. The ground test showed it could be done with a lot of muscle.

Trying to remove a hand rail to clear the way for a long-awaited attempt to fix a failed spectrograph on the Hubble Space Telescope, astronaut Michael Massimino ran into a stubborn fastener and apparently stripped the head during repeated attempts to drive out the recalcitrant screw with a power tool. The bright yellow handrail must be removed to make room for attachment of a custom capture plate needed to safely remove 111 small non-captive screws holding an instrument cover plate in place.

Read our full story.

Another option under discussion in Mission Control is trying to bend the handrail out of the way, possibly breaking the bolt. Three of the rail's four bolts were removed without problem. Just one remain in the way.

Now 2.5 hours into the EVA. The spacewalkers are going to go back into the payload bay to retrieve some more tools. Until this handrail is removed, the astronauts cannot proceed with the work to open the instrument cover plate, get inside STIS to extract the failed circuit card and repair the device.

Plan B is to remove other sets of bolts that hold the handrail's posts in place. Originally, the spacewalkers were just going to remove the rail itself and leave the posts in place. But given the bolt problem, the whole thing may have to come off.

"It ain't turnin,'" Massimino says.

Massimino has retrieved a replacement tool bit from a box down in the payload bay.

The spacewalkers are going to get a fresh bit for the power tool to try again in getting this bolt removed. The handrail has to be taken off in order to dig into the STIS instrument.

Three of the handrail's four bolts have been disengaged. But No. 4 is the problem.

The bolt head appears to be worn down and stripped now. Efforts to get the bolt removed haven't worked. The ground and crew are debating options.

Massimino is fighting with one of the bolts on that handrail that won't release.

Now 90 minutes into the spacewalk. The STIS work is expected to take about four hours to complete. The job is much like yesterday's Advanced Camera for Surveys repair, with the spacewalkers opening up an instrument never meant to be repaired in space to remove failed circuit cards and fix the faulty power supplies.

Special tools to remove a handrail from STIS have been installed. The handrail has to come off in order to open up the instrument for repairs.

The Space Telescope Imaging Spectrograph, or STIS for short, was installed on the Hubble Space Telescope in 1997 during the second servicing mission. The instrument stopped working in 2004 due to a power supply failure.

A backgrounder fact sheet on STIS and the repair can be downloaded here.

Massimino took a few minutes to move a cable from the neighboring NICMOS instrument out of the way before standing up on the foot platform inside the telescope.

Mike Massimino is climbing into the Hubble Space Telescope to reach the STIS instrument. He'll install a foot restraint to stand on. Mike Good is anchored on the end of Atlantis' robot arm to assist in today's work.

The astronauts have retrieved tools from storage carriers in the payload bay, including the special capture plate to be used when the spacewalkers remove more than 100 screws from the STIS intrument today. Now, Mike Good is opening up the doors on Hubble's side, below one of the solar arrays, to access the instrument.

Both spacewalkers have emerged from the airlock. They're getting things organized before heading up to the telescope for the start of today's repair work.

EVA BEGINS. Astronauts Mike Massimino and Mike Good switched their suits from shuttle-provided power to internal batteries at 9:45 a.m. EDT, marking the start of this planned 6 1/2-hour EVA to fix another Hubble instrument.

The 40-minute breathing of pure oxygen by the spacewalkers has been completed. Depressurization of the airlock has started.

The crew had to adjust part of Mike Good's spacesuit. Based on the work left to go, Mission Control projects the EVA should begin around 9:45 a.m.

Pressing ahead with a complex overhaul of the Hubble Space Telescope, astronauts Michael Massimino and Michael "Bueno" Good are gearing up for a planned six-and-a-half-hour spacewalk to install insulation and repair a sophisticated spectrograph that broke down in 2004, the victim of a blown power supply.

Read our full story.

Mike Massimino and Mike Good are getting suited up for their second spacewalk of the Atlantis mission. The EVA, which is the fourth overall for the flight, is scheduled to start around 9:15 a.m. EDT.

A functional test of the Hubble Space Telescope's Advanced Camera for Surveys, overhauled during a spacewalk Saturday by astronauts John Grunsfeld and Andrew Feustel, indicates success reviving the instrument's heavily used wide-field channel, officials said early Sunday. But testing shows the overhaul failed to resolve power problems with the camera's stricken high-resolution channel and it appears "down for the count."

Read our full story.

The astronauts have been awakened to start Flight Day 7.

Engineers evaluating data from a functional test of the Hubble Space Telescope's Advanced Camera for Surveys, overhauled during a spacewalk Saturday by astronauts John Grunsfeld and Andrew Feustel, reported power problems with the instrument's high-resolution channel.

Read our full story.

Hubble ground controllers report the functional testing has been completed on the wide-field channel of the Advanced Camera for Surveys that engineers hope Saturday's spacewalk repairs would restore to use. A power failure a couple of years ago took that portion of the camera out of use, and the astronauts replaced failed circuit cards and installed a new power source to bypass the old electronics. Tonight's testing is finished and that data is being reviewed.

The high-resolution channel of the instrument, which was not directly repaired Saturday but engineers thought they could develop a workaround to route power to that system with the new hardware installed by the astronauts, does show a continued power problem tonight.