Mission Status Center

Astronauts Steve Bowen and Mike Good, working at the far left end of the International Space Station's main power truss, successfully replaced four massive solar array batteries today, leaving just two power packs to be installed during a third spacewalk Friday.

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The two spacewalks so far on Atlantis' mission total 14 hours and 34 minutes.

This was the fifth EVA in the career of Steve Bowen and third for Mike Good. Bowen has accumulated 34 hours, 30 minutes and Good has 23 hours, 7 minutes of spacewalking time on their previous excursions.

EVA ENDS. Repressurization of the Quest airlock module began at 1:47 p.m. EDT, marking the official end of today's spacewalk by Steve Bowen and Mike Good. The EVA lasted 7 hours and 9 minutes.

The mission's third of three spacewalks is planned for Friday starting around 6:45 a.m. EDT when Good and Garrett Reisman head outside to finish the job of replacing the two remaining batteries on the station's Port 6 truss, plus an assortment of other tasks as time allows.

The airlock hatch has been closed and locked. Standing by for repressurization.

The spacewalkers are climbing into the airlock to finish this successful outing that accomplished everything planned and more. They untangled the cable on Atlantis' inspection boom sensor, installed four new batteries on the space station's oldest power truss and finished the activation tasks for the new Ku-band communications antenna.

The spacewalking duo is heading for the airlock now to wrap up this EVA.

The gimbal locks have been released, completing the final planned task of the Atlantis mission for the space station's new space-to-ground communications antenna.

The SGANT uses Ku-band communications for high-speed transmissions between the International Space Station and Earth via NASA's Tracking and Data Relay Satellites.

This new antenna becomes a redundant path for the communications, backing up the original Ku-band system installed early in the station's life on STS-92 in 2000.

Live television, voice and payload data rely upon SGANT, along with other two-way communications like phone calls and email.

Passing the six-and-a-half hour mark of the spacewalk.

Mike and Steve are working together to unbolt the locks that have held the antenna dish's gimbals stationary for launch.

After their success in torquing the structure, the "go" has been given to remove the precautionary tether installed around the antenna and boom on Monday. They'll also release the gimbal locks on the dish to free it for use.

The astronauts report a good "wiggle" test of the antenna, no motion and no gap. So the structure appears to be firmly affixed to the Z1 truss.

The spacewalkers are cranking the four bolts on the interface between the Ku-band dish and its support pedestal.

Steve has climbed to the Z1 truss atop the International Space Station where the new space-to-ground communications antenna was installed on Monday's spacewalk. Mike is en route. They are going to attempt putting additional torque on bolts to make the antenna sturdier.

The spacewalkers will have some available minutes before ending the EVA. Mission Control is considering going up to the Z1 truss and having the crew use a new procedure to apply more torque to the bolts that attach the new Ku-band antenna dish and its support boom. During the assembly of the antenna system Monday, the spacewalkers reported a gap between the two parts.

Tool inventories are underway before the spacewalkers make their way toward the airlock.

To recap, spacewalkers Steve Bowen and Mike Good successfully installed four new batteries into the International Space Station's Port 6 truss Channel B power string today. Four old batteries were removed, three of which have been stowed in the cargo carrier for landing and one is temporarily stowed on the side of the station.

Friday's spacewalk by Good and Garrett Reisman will exchange the two remaining old batteries inside the truss with fresh ones, plus pack the launch pallet with those old batteries and the one left hanging out today.

Installing three fresh batteries was the plan for today, getting four done was the goal. The spacewalkers just achieved that goal as this is smooth EVA progresses at the far port-end of the International Space Station.

After shepherding the fourth new battery to its new home on the Port 6 truss, the spacewalkers are ready to slide it into the slot. This will be the last of the fresh packs to be installed today.

Mission Control just told the crew that the temporarily stowed old battery, the one that was removed from the Port 6 truss first this morning, will remain anchored on the side of the space station until Friday's spacewalk.

Brand new battery No. 4 is off the pallet and in the hands of the spacewalkers to install.

That old battery has been deposited onto the pallet. It's the fourth removed from the station and the third to be stowed for landing. The first unit removed this morning remains temporarily stowed on the side the station, waiting for an open slot on the carrier at the end of this EVA, if time permits.

CAPCOM Chris Cassidy says a full motion checkout of the pan and tilt unit on the Orbiter Boom Sensor System after spacewalker Steve Bowen untangled a pinched cable has gone well.

Now moving into the second-half of this task to replace the half-dozen batteries in the Port 6 truss's Channel B power string. The spacewalkers just pulled out the fourth old battery from the space station.

Spacewalkers Mike Good and Steve Bowen have successfully installed on the P6 truss their third battery of the day. These new batteries have an average design life of 6.5 years, each measure 40 by 36 by 18 inches and have a mass of 375 pounds. They have 38 nickel hydrogen cells.

Retrieval of the third new battery is underway.

Now passing the four-hour mark into today's spacewalk. The duration is limited to approximately seven hours based on spacesuit consumables.

Steve has locked the old battery onto the carrier for the ride home. Next, he will work to get out the third new battery for the space station to fill the current vacant slot.

Atlantis astronaut Piers Sellers is overseeing the robotic arm controlling the pallet today. He talked about the EVA in a pre-flight interview:

"This one's good stuff. They're going to be working all the way out on one extreme end of the space station, on the P6 truss, the port-most point of the space station. The idea is to swap out some batteries; EVA 2 and EVA 3 have got the task of swapping out six batteries.

"So they'll go all the way out there and then we'll take the arm with this big pallet full of batteries and hold it out in front of them. They'll be basically pulling these big batteries off, each one the size of a cupboard or a file cabinet, take these off and swapping them with the old ones, put the old ones on the pallet and the idea is to swap them all out and then bring the old ones home for refurbishment."

The third old battery that's been in space nearly 10 years was just disengaged by spacewalker Mike Good and handed to Steve Bowen as the astronauts continue to work together in swapping out the power packs.

"The pace is exceeding expectations by a bit," spacewalk choreographer Tony Antonelli reports from inside Atlantis.

The P6 truss has received its second new battery. The goal is getting two more installed during this spacewalk, then finish the final pair of power packs during Friday's EVA.

Mike has this battery lined up and ready to be plugged in.

The second new battery of the day has been unbolted from the launch pallet for the spacewalkers to carry over to the P6 truss installation site.

Mission Control reports that the spacewalkers are about 20 minutes ahead of timeline as they work to unload the second new battery.

Spacewalking astronauts Steve Bowen and Mike Good have secured this second old battery into the one open slot on the launch carrier. The original old battery remains temporarily anchored on top of the P6 truss as part of this carefully thought out juggle of new and old power packs.

The second old battery has been removed from its slot on the P6 truss.

The spacewalkers have installed their first new battery on the Port 6 truss, the original power module launched to the International Space Station in November 2000 aboard shuttle Endeavour's STS-97 mission.

The six batteries being replaced this week by the Atlantis crew are part of the truss' Channel B power string. A half-dozen batteries in the Channel A string were successfully replaced last summer by the STS-127 crew.

Steve previewed this spacewalk in a pre-flight interview:

"Now EVA 2 really is dedicated to one thing and that's changing out six batteries at the end of the port truss. We hope to get four of them done. That would be a very successful EVA. But really it's just that one task over and over again.

"We take a battery out of the truss and stow it so that there's a hole, you know. It's like that game when you're moving things around and you want to move things around and make a nice pattern, you need a hole to start with. So then we'll take one off the pallet which the arm will be holding out there and we'll put that in the hole in the truss and we'll take out the next one. Just do that so that hopefully we'll get four batteries done on EVA 2."

The first of the fresh new batteries for the International Space Station's power system has been pulled off the launch carrier by Steve Bowen. The station's arm is holding the carrier as close to the worksite as possible. This particular pallet also carried the new communications antenna and Dextre fixture that were unloaded during Monday's spacewalk. The structure will hold the old batteries during their return to Earth aboard the shuttle.

The first battery has been removed by spacewalker Mike Good. It will be temporarily stowed nearby while the spacewalkers retrieve a new battery from the launch carrier and install that. This initial old battery will get stowed in the carrier later in the EVA.

Out at the worksite, Mike installed handholds onto the first battery that will be removed from the Port 6 truss and is starting to unbolt it.

Atlantis commander Ken Ham gave an overview of the battery replacement work in a pre-flight interview:

"On that EVA the railcar is going to be all the way down the port side of the space station, all the way out on the left wing, if you will. The arm is still based on that, on the railcar. They're going to pick up the ICC, that giant rack with the batteries on it, and extend the arm as far out as it'll reach, past the first set of solar arrays -- Mission Control will lock that set of solar arrays so it can't move, it can't gimbal around -- and reach over the top of them and then out between those two sets of solar arrays.

"Out there is a bank of batteries. There are a couple of banks of them but we're going to replace six of those batteries and that is likely 1 1/2 to two full EVAs worth of work.

"Steve Bowen is the EV 1 on that one and he's leading Mike Good out there to start that whole operation. We're hoping that they can get four of six batteries done in one EVA and then when they go back out on EVA 3, Mike Good is going to be the EV 1, the one in charge of that operation, and Garrett, from the first EVA, gets to go out and be his EV 2 and help finish up those batteries as well as anything that may not have gotten finished from EVA No. 1."

Passing the 90-minute mark into the EVA. The spacewalkers are finishing the set-up tasks before getting into the physical removal and replacement of the batteries.

Mike is working to release the torque on each of the six old batteries.

Spacewalker Mike Good previews the battery replacement work in this preflight interview:

"So for EVA 2 it's my turn to go out the door with Steve. It's battery day, okay. We're taking up six new batteries. We're going replace six batteries that are out there on the end of the P6 truss. So we have these new batteries. We got the old batteries out there and we just have to swap them out.

"But these aren't double A's. These are big. They are about the size of a big suitcase, maybe two suitcases. Hopefully we won't have to pay the luggage fees going up there. I think that it's included. But these are about four hundred pounds each so I think we're over our weight limit, as well.

"We'll take those out there and take them off the pallet and put them into the truss out there and then we'll take the old ones off the truss and put them back onto the pallet.

"We have six batteries. What we're hoping to get done on that spacewalk is four of them. It'll take pretty much the whole time, about six-and-a-half hours to get out there, all the way out there, translate out there to the end of the truss and do four of the six batteries and come back inside. That'll be a full day's work."

Steve just hopped out of the foot-restraint and will go join Mike at the Port 6 truss.

After testing the pan and tilt unit, Steve wants to adjust the cables a little more.

Steve used a wire tie to prevent the cables from snarling again. A test of the pan and tilt unit is underway to verify good mobility.

With a simple flick, Steve has untangled the pinched cable on the Orbiter Boom Sensor System's pan and tile unit. That snag prevented the primary sensor from being used during Atlantis' heat shield inspections on Saturday.

Mission managers added this quick fix to today's spacewalk so the boom's full capabilities can be used during further inspections later in the mission.

The latest version of the NASA Television schedule (Rev. E) can be downloaded here.

As Mike heads outward to the P6 truss and the early setup steps for the battery work, Steve has stopped near the mobile transporter where he's going to climb into a foot-restraint platform and fix that snagged cable on the inspection boom sensor package.

Both spacewalkers have emerged from the airlock. This is Steve's fifth EVA. He did three during the STS-126 shuttle flight to the station in 2008 and Monday's excursion for a total lasting 27 hours and 21 minutes of spacewalking time. Mike has two EVAs to his credit from the final Hubble Space Telescope servicing flight last year totaling 15 hours and 58 minutes.

EVA BEGINS. The spacewalkers switched their suits to internal battery power at 6:38 a.m. EDT, marking the official start time for today's EVA by "Steveo" Bowen and Mike "Bueno" Good. This is the second of three spacewalks planned during Atlantis' mission at the International Space Station.

The EVA is getting underway 37 minutes ahead of schedule and 67 minutes ahead of the original pre-flight timeline.

The depressurization has been completed and the Quest airlock's outer hatch leading to space is now open.

Depressurization is pausing at 5.0 psi for a planned leak check.

Airlock depressurization is in work.

Astronauts Steve Bowen and Mike Good are gearing up for a planned six-and-a-half-hour spacewalk, the first of two devoted to replacing six of the International Space Station's oldest solar array batteries.

Read our full story.

Steve Bowen and Mike Good have moved into the section of the airlock that will be depressurized shortly. And the inner hatch has been closed.

Final steps in the suitup process are being completed now. The spacewalkers are being outfitted with the SAFER backpacks that would enable an untethered astronaut to fly back to the station.

The latest version of the NASA Television schedule (Rev. D) can be downloaded here.

Inside the Quest module of the space station, the spacewalkers are getting suited up for today's EVA.

The wakeup call has sounded for the astronauts to begin Flight Day 6, which will be devoted to the second of the mission's three spacewalks. Houston hopes to get the EVA underway by 7:15 a.m. EDT.


Read our earlier status center coverage.