Realtime coverage of STS-133 EVA No. 2

CBS News

08:25 PM EST Update: NASA managers pleased with progress of Discovery's final mission

With the shuttle Discovery's extended mission heading into the home stretch after a second successful spacewalk Wednesday, mission managers say the goal now is to help the International Space Station's crew unpack and outfit the newly installed Permanent Multipurpose Module, or PMM, before the shuttle departs Sunday.

During the first five days of docked operations, the Discovery astronauts have installed the PMM, attached an external spare parts platform to the station's solar power truss, staged a pair of successful maintenance spacewalks and started the PMM unloading process.

An extra day was added to Discovery's mission to give the shuttle crew more time for PMM unloading and to help move packing material and no-longer-needed items to the Japanese HTV cargo ship before it undocks March 28.

"I feel happy and contented," said space station Flight Director Royce Renfrew. "Actually. I'm a happy flight director. All of our big objectives for the mission have been accomplished. We've installed the ELC (External Logistics Carrier), we've installed the PMM and activated it yesterday. That was beautiful to watch, all the robotics and all the structures and mechanisms, that was just great.

"And then two days ago, we conducted the first EVA, and that was flawless. Today we conducted the second EVA of the mission and it was flawless, we got a whole bunch of get-aheads (done). I was very happy about that.

"The remainder of the mission, however, is just as important as all the stuff we've done, especially with the addition of the plus-one day to the mission to try to get the ISS in the best possible configuration we can get it in before (Discovery) has to leave and then HTV has to leave right after that. We have a lot of work to do in front of us. It's conceivably not as glamorous as installing modules ... and doing spacewalks, but it is absolutely just as important."

05:05 PM EST Update: Spacewalk ends

Astronauts Alvin Drew and Stephen Bowen ended their second spacewalk 16 minutes early Wednesday after Drew's helmet lights came loose and could not be reattached. The six-hour 14-minute spacewalk ended at 4:56 p.m. EST (GMT-5) when the astronauts began repressurizing the International Space Station's Quest airlock module.

Astronaut Stephen Bowen, left, attempts to reattach Alvin Drew's helmet lights. (Photo: NASA TV)
Despite the slightly early termination, Bowen and Drew already had accomplished all the planned objectives of the spacewalk and were working on additional "get ahead" items when Drew's helmet lights detached. Bowen attempted to reattach the unit, but he was not successful. Drew then made his way back to the airlock, followed a few minutes later by Bowen.

Working separately throughout most of the excursion, Bowen and Drew vented residual ammonia from a coolant pump scheduled for return to Earth this summer; moved an equipment platform from the Columbus lab module to the shuttle Discovery's cargo bay; installed a light on the station's solar power truss; mounted a new camera on a robot arm extension; and installed protective covers over three camera lenses.

The astronauts also repositioned a camera sunshade that had slipped out of position, removed no-longer-needed insulation and tightened up a loose fitting that is part of a coolant system repair station. Most of the spacewalk tasks were unfinished items left over from earlier spacewalks that NASA is trying to wrap up before the shuttle fleet is retired later this year.

This was the 155th spacewalk devoted to station assembly and maintenance since construction began in 1998, the fourth so far this year, the second for Drew and the seventh for Bowen. Total space station EVA time now stands at 973 hours and 53 minutes. Bowen's total -- 47 hours and 18 minutes -- moves him up to sixth on the list of most experienced spacewalkers.

02:35 PM EST Update: Astronauts move into home stretch of mostly smooth spacewalk

Astronauts Stephen Bowen is running about 40 minutes ahead of schedule performing maintenance tasks outside the International Space Station. Riding on the end of the station's robot arm, Bowen has moved an equipment platform from the Columbus laboratory module to the shuttle Discovery's cargo bay, installed a new camera and removed no-longer-needed insulation on a robot arm extension known as DEXTRE. Now off the arm, Bowen currently is installing a protective lens cover over a robot arm elbow camera.

Fellow spacewalker Alvin Drew is running a bit behind schedule after struggling to pack up an ammonia vent line tool and a cantankerous hose used to vent residual ammonia in a coolant system pump. Drew also has installed a new light fixture on a crew equipment cart and adjusted a misaligned sunshade on an external camera. He is now moving to the port side of the station's solar power truss to adjust the insulation on a cooling system valve before troubleshooting a loose fitting intended for use during coolant system repair work.

12:40 PM EST Update: Bowen stows Columbus equipment platform

Anchored to the end of the space station's robot arm, astronaut Stephen Bowen removed an equipment mounting platform from the European Space Agency's Columbus module and carried it to the shuttle Discovery's cargo bay for return to Earth. Fellow spacewalker Alvin Drew, meanwhile, packed up an ammonia vent tool he used earlier to get rid of trapped ammonia coolant in a failed pump module.

Astronaut Stephen Bowen, anchored to the end of the space station's robot arm, carries an equipment platform to the shuttle Discovery for return to Earth. (Photo: NASA TV)

The astronauts have had no major problems, but they are running roughly 15 minutes behind schedule. It took Drew a bit longer than expected to pack up the vent tool and he was told to re-charge his suit's oxygen supply during an already planned trip to the Quest airlock module.

11:35 AM EST Update: Coolant pump ammonia successfully vented

Astronaut Alvin Drew, using equipment he set up during a spacewalk Monday, vented residual ammonia from a coolant pump module to "safe" the device for return to Earth this summer aboard the shuttle Atlantis.

While Drew was working on near the Quest airlock to vent the pump module, crewmate Stephen Bowen made his way to the European Space Agency's Columbus module where he plans to remove an equipment support platform mounted on the outboard end of the lab module.

Riding on the end of the space station's robot arm, Bowen plans to move the equipment platform to the shuttle Discovery's cargo bay for return to Earth.

10:45 AM EST Update: Spacewalk begins

Floating in the Quest airlock module, astronauts Stephen Bowen and Alvin Drew switched their spacesuits to battery power at 10:42 a.m. EST (GMT-5) to officially kick off a planned six-and-a-half-hour spacewalk to perform a variety of maintenance chores outside the International Space Station.

The start of the spacewalk came 24 minutes late because of troubleshooting to replace a damaged O-ring seal in Bowen's spacesuit.

Here is an updated timeline of the crew's activities based on the actual start time (in EST and spacewalk elapsed time; Bowen is EV-1; Drew is EV-2):

10:42:00 AM...00...00...EVA-2: Suits to battery power (official start time)
10:47:00 AM...00...05...Airlock egress
11:12:00 AM...00...30...EV1: Station arm (SSRMS) setup
11:12:00 AM...00...30...EV2: Vent ops and QD bag cleanup
12:12:00 PM...01...30...EV1: Equipment platform retrieval from Columbus module
12:12:00 PM...01...30...EV2: Cargo pallet insulation removal
12:42:00 PM...02...00...EV1: Columbus platform installed in shuttle cargo bay
12:42:00 PM...02...00...EV2: Jettison stowage bag pickup
12:57:00 PM...02...15...EV2: Light install on astronaut equipment cart
01:12:00 PM...02...30...EV1: DEXTRE camera installation
01:47:00 PM...03...05...EV1: DEXTRE insulation removal
01:57:00 PM...03...15...EV2: P1 vent line insulation
02:12:00 PM...03...30...EV1: SSRMS cleanup
02:17:00 PM...03...35...EV2: P1 grapple beam troubleshooting
03:12:00 PM...04...30...EV1: SSRMS elbow camera cover install
03:27:00 PM...04...45...EV2: Node 3 insulation removal
03:27:00 PM...04...45...EV1: P1 grapple beam troubleshooting/get ahead
04:02:00 PM...05...20...EV1: DEXTRE lens cover install
04:02:00 PM...05...20...EV2: POA cover install
04:22:00 PM...05...40...Get aheads
04:42:00 PM...06...00...Cleanup and ingress
05:12:00 PM...06...30...EVA-2: Airlock repressurization

09:04 AM EST Update: Astronauts replace damage O-ring in Bowen's spacesuit

Astronaut Michael Barratt holds up a damaged O-ring seal found in Stephen Bowen's spacesuit. (Photo: NASA TV)
The Discovery astronauts, troubleshooting a leak in astronaut Stephen Bowen's spacesuit, briefly interrupted spacewalk preparations today to replace a damaged O-ring seal in the suit's carbon dioxide removal system.

It was not immediately clear what the problem was. After an initial leak test failed, Michael Barratt and Paolo Nespoli removed Bowen's helmet and gloves, inspected the seals and but the gear back on. The suit then failed a second leak test, prompting the astronauts to take off the helmet again and to check Bowen's boots. Again, no problems were found.

A few minutes later, Barratt reported finding a "smoking gun" -- a damaged O-ring seal in a lithium hydroxide canister used to scrub carbon dioxide from the suit's air supply. Unable to find a replacement in the airlock, the astronauts were told to use a different type O-ring instead to avoid having to open the Quest module, a procedure that would have taken a half-hour or more.

Before installing the replacement O-ring, the astronauts looked for any fragments of the original while engineers at the Johnson Space Center considered the possible impacts of debris inside the suit's air system. Barratt said no fragments could be seen, adding that the damage to the leaking O-ring did not appear fresh.

Barratt and Nespoli then re-installed the lithium hydroxide canister and carried out another leak check. This time, Bowen's suit passed.

"Good leak check," Barratt reported. "Rock solid."

The troubleshooting delayed spacewalk preparations by about 15 minutes. But the EVA remains on track to start around 10:18 a.m. EST (GMT-5).