Spaceflight Now STS-102

Marathon spacewalk sets new record

Posted: March 11, 2001
Updated: 10:15 a.m. EST

  Voss on arm
Jim Voss rides the shuttle's robot arm with the space station in the background. Photo: Spaceflight Now/NASA TV
In a marathon spacewalk marked by unexpected glitches and lost hardware, two astronauts mounted critical equipment on the hull of the international space station today. They then stood by in Discovery's cramped airlock for nearly three hours while their crewmates struggled to reposition a shuttle docking port.

In the end, all of the major objectives of the spacewalk were met, but it required a "determined" effort by the astronauts and flight controllers at the Johnson Space Center in Houston.

A robot arm work platform somehow was lost in space, work to wire up a cable tray was deferred to a second spacewalk to make up lost time and problems with a computerized TV alignment system delayed re-attachment of the docking port.

It took astronaut Andrew Thomas, operating Discovery's robot arm, two tries to finally get the docking port properly aligned and locked in place.

But in the end, he was successful, clearing the way for spacewalkers Susan Helms and James Voss to repressurize Discovery's airlock, officially ending the 101st spacewalk in U.S. spaceflight history.

While the marathon excursion seemed grueling to reporters, at least, lead flight director John Shannon said "I would not use the word 'grueling' at all. I would say 'deliberate' is the right word for this day."

"We knew this one was going to be tough because it was ambitious, it was success oriented," he said. "We had many, many discussions as to whether this day had too much stuff in it and it was right on the edge, I think.

"But we decided that hey, if we could get this stuff done we ought to get it done while we were out at vacuum."

  PMA with Moon
The robot arm releases its grip on PMA-3 as a full moon passes in the background. Photo: Spaceflight Now/NASA TV
The spacewalk began at 12:12 a.m. and ended at 9:08 a.m. Official duration was a record eight hours and 56 minutes. The old record of eight hours and 29 minutes was set during a satellite repair mission in May 1992.

But the new record, like Roger Maris' home run mark, deserves an asterisk. Shuttle spacewalks are measured from the time the crew switches to internal battery power to the time the airlock is repressurized.

But Voss and Helms reconnected their suits to shuttle air and power at 6:55 a.m. after six hours and 43 minutes. While still in vacuum, their spacesuit batteries and oxygen tanks were no longer needed, making comparisons with other shuttle spacewalks somewhat academic.

In any case, it was the 17th spacewalk devoted to construction of the international space station and the 61st in the 20-year history of the space shuttle program. U.S. and Russian spacewalkers have now logged 117 hours and 40 minutes building and outfitting the space station.

Voss, making his third spacewalk, and Helms, making her first, are part of the space station's second full-time crew. Their commander, Russian cosmonaut Yury Usachev, officially transferred to the space station early Saturday, replacing Expedition One crew member Yuri Gidzenko.

Voss will join him aboard the station overnight Sunday, replacing Sergei Krikalev, and Helms will move in Wednesday, replacing Expedition One commander William Shepherd.

The goal of this morning's spacewalk, the first of two planned for Discovery's mission, was to mount an attachment cradle and a cable tray to the Destiny laboratory module that will be used during a shuttle visit next month to anchor the station's Canadian-built robot arm.

The second objective was for Thomas to reposition a shuttle docking port, moving pressurized mating adapter No. 3 - PMA-3 - from the Unity module's downward-facing, or nadir, hatch to the module's port hatch.

A close up of Voss soon after he climbed out of the airlock hatch. Photo: Spaceflight Now/NASA TV
The move was required to free up Unity's nadir port for attachment early Monday of a pressurized cargo module loaded with five tons of equipment and supplies, including the lab's first suite of scientific experiments.

The first item on the agenda today was for Voss and Helms to disconnect power and data cables running between Unity and PMA-3.

And right off the bat, they ran into problems.

Moments after Voss floated into the cargo bay, a hydrazine detection package managed to float out of the shuttle Discovery's airlock. Voss, working with robot arm operator James Kelly, managed to snag the errant package a few moments later.

"This was an exciting EVA," lead spacewalk planner Kieth Johnson reflected after the fact. "You're always interested when the first thing the crew says when they open up the hatch is 'oops, we lost a few pieces of hardware.'"

On his way to the PMA-3 work site, Voss floated past the Destiny lab module's picture window and paused to look inside.

"Tell the station guys I'm at their window," Voss called. "No one's home. Where's my commander, Yury? OK. Going on."

He then marveled at the view, saying "it's surreal, watching the orbiter float over the ocean."

About a half-hour into the spacewalk, Voss reported an attachment device used to help anchor an astronaut to the end of the shuttle's robot arm, managed to float free and was lost in space.

"The PAD (portable foot restraint attachment device) has become disconnected and was untethered and was released into the bay," Richards told Houston. "We don't think we can retrieve it. Do we have a spare pad in the node bag?"

"Stand by, we're checking.," astronaut Gerhard Thiele replied from mission control.

"We're talking to the ground and seeing where the spare PAD is if we have one," Richards said. "So let's just slow down..." As it turned out, a second PAD was stored in a bag of tools lashed to the Unity module's hull so the loss had no immediate impact.

  Voss leaves hatch
Voss leaves the hatch at the start of the spacewalk. Photo: Spaceflight Now/NASA TV
Voss then turned his attention to detaching and "dead facing" eight cables between the space station and the PMA-3 docking port on Unity's Earth-facing hatch. To his dismay, the first connector initially refused to come off as expected.

"It's not my day apparently, Paul," Voss radioed. "The very first connector, 606, I am unable to release the bale completely. It came about half way and stuck. I'm working on it... I got it! It just took a whole lot of force."

The other connectors, while tighter than he expected, also came free as required in preparation for moving the docking module to Unity's port hatch.

But Voss had considerable trouble reconnecting a cable providing power to the common berthing mechanism holding PMA-3 in place. The cable had to be properly connected before the crew could remove PMA-3 and reposition it on Unity's port hatch.

Finally, after removing an O-ring inside the connector, Voss was able to seat the cable properly.

"I did it, it's on!" Voss called.

"OK, good work, Jim," Paul Richards called from Discovery's cockpit.

"Discovery, Houston, smiling faces down here. Good job," Thiele radioed from mission control.

"Yeah, those O-rings didn't' seem to be helping very much," Voss commented. "I guess they serve a purpose. Sure makes it hard to get them on."

As it turned out, such O-rings are not needed in space.

"Paul, when we encounter another problem with an O-ring, you can remove them," Thiele advised. "They are only used for ground operation."

Voss laughed in apparent disbelief.

"OK, copy that," Richards replied. "That's a good heads up to keep things flowing, thank you."

With PMA-3's electrical disconnection complete, Voss and Helms began work to mount a cradle assembly on the Destiny module's hull that will serve as the mounting point for a pallet carrying the station's robot arm.

Along the way, Helms took a break to radio a happy birthday to her mother, Dori, in Albuquerque, N.M.

  PMA move
The PMA docking adapter is moved to its new location. Photo: Spaceflight Now/NASA TV
"While I have a minute here I just want to say happy birthday to my mother," she said as the shuttle-station complex passed over Europe. "I think she's 68 today. And Mom, I just couldn't think of a better way to spend your birthday. Sorry I'm not with you, though."

"I'm sure she'll be happy watching you doing a really good job on this EVA," said Richards from Discovery's flight deck. "It'll make her a very happy and proud mom."

"I'm not sure she'd want to be with me right now," Helms replied.

The astronauts had no major problems mounting the cradle assembly, but by that point they were running an hour behind schedule because of work to pull a spare PAD from a station tool bag and the problems encountered with the PMA-3 cable fittings.

As a result, the spacewalkers were told to defer connecting wires in the robot arm's cable tray, leaving that task to Thomas and Richards during a spacewalk overnight Monday.

"Oh, my goodness! Take a look at the view," Helms exclaimed as the shuttle-station complex sailed 236 miles above the Middle East.

"Yeah, it's really pretty," Voss said.

"Oh, my goodness," Helms repeated. "Look at that!"

Once they were finished with the rigid umbilical, Voss and Helms packed up their tools, returned to Discovery's airlock and hooked their spacesuits up to shuttle power and air. Thomas then used the orbiter's robot arm to move PMA-3 to Unity's port hatch.

The spacewalkers stood by in the airlock in case Thomas needed help properly positioning PMA-3 for docking. As it turned out, the attachment process was stretched out due to problems with a computerized television positioning system.

After one failed attempt to attach the docking port, a second attempt was made using digital position data from the robot arm. The procedure work, clearing Voss and Helms to finally end their spacewalk.

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Jim Voss and Susan Helms are assisted into the lower part of their space suits prior to the first spacewalk of the mission.
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A camera mounted in Discovery's overhead cockpit window captures a "rear-view mirror" angle of the shuttle's dawn liftoff. Mission commander Jim Wetherbee narrates.
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Space shuttle Discovery lifts off at dawn from the Kennedy Space Center carrying a new crew and supplies to the International Space Station.
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NASA animation shows Discovery's approach and docking to the international space station, which will occur in a different fashion on this mission. This occurs on Flight Day 3.
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