Spaceflight Now: Space Station/STS-98

Astronauts sail through second successful spacewalk

Posted: February 12, 2001

Spacewalk hangs from the space station today with Atlantis' nose and the Earth in view. Photo: NASA TV/Spaceflight Now
The Atlantis astronauts staged a near-perfect spacewalk Monday, connecting a shuttle docking port to the $1.4 billion Destiny laboratory module, installing a mounting fixture for a new robot arm and opening the lab's picture window on the world.

While spacewalkers Thomas Jones and Robert Curbeam were outfitting the lab module's exterior, the station's three-man crew - commander William Shepherd, Yuri Gidzenko and Sergei Krikalev - was busy completing the lab's initial internal activation and checkout.

They took a break toward the end of the shuttle crew's spacewalk to open a just-installed shutter on the lab's Earth-facing 20-inch-wide window to film Jones and Curbeam using a large-format IMAX camera.

"You guys have done an outstanding job today and we got a lot done," pilot Mark Polansky radioed as the spacewalk wound down. "So why don't you come on inside and we'll give you something to drink and a hot meal. Tom, you can go ahead and head in first."

"Sounds like an offer I can't refuse," Jones replied.

The spacewalk began at 10:59 a.m. EST when Jones and Curbeam switched their suits to internal battery power. It ended at 5:49 p.m. with the start of airlock repressurization for a duration of six hours and 50 minutes.

This was the 99th U.S. spacewalk, the 59th carried out by shuttle astronauts and the 15th devoted to space station assembly. Altogether, U.S. and Russian spacewalkers have now logged 103 hours 18 minutes building the international outpost, including 14 hours and 24 minutes logged so far by Jones and Curbeam.

"It's been another very, very good day, things have gone extremely well," said lead flight director Robert Castle.

The major goal of the spacewalk was to mount a shuttle docking port known as PMA-2 on the Destiny module's forward hatch.

PMA-2 had been bolted to the Unity module's forward hatch, but it was removed Saturday and temporarily mounted on a structural truss so Destiny could be installed in its place.

Atlantis is docked to a downward facing port called PMA-3. Thanks to the work done today, future shuttle crews will dock to PMA-2 on Destiny's forward port. PMA-3 will be relocated to Unity's port-side hatch on the next shuttle mission to free up the downward-facing port for the Italian-built cargo storage modules carrying experiment racks and other gear.

The shuttle Discovery, hauled to launch pad 39B today for launch to the station March 8, will be the first orbiter to dock at the newly installed forward port.

"The major critical activity to get done today was moving PMA-2 back to the front of the lab," Castle said. "This is the docking port that will be used for subsequent shuttle missions, including the one that rolled out the pad today. So we were very interested in getting that done.

"It's currently in what we call the 'acquire bolt position' on the common berthing mechanism. We're waiting several hours for it to thermally equalize because it got very, very cold up on the Z1 (truss). We'll finish torquing all those bolts down tonight. We anticipate no problems."

Lead spacewalk planner Kerri Knotts said Jones and Curbeam accomplished all of their objectives "and then some." Work done today included:

  • Attachment of PMA-2 to Destiny's forward port
  • Connection of electrical umbilicals between the lab and PMA-2
  • Installation of mounting hardware that will anchor the station's Canadian-built robot arm when it is delivered in May
  • Attachment of a spacewalk slidewire and other assembly aids on the hull of the lab
  • Installation of a non-propulsive vent on Destiny's lower hull
  • Attachment of thermal covers on the trunnion pins used to hold the lab in place during launch
  • Installation of the lab's protective window shutter, allowing the window to be used for the first time
Connection of the PMA-2 electrical umbilicals and the installation of the window shutter originally were planned for the crew's third and final spacewalk Wednesday. But Jones and Curbeam were able to squeeze them into today's excursion.

"While the EVA was going on, the station crew was continuing to work on lab outfitting," Curbeam said. "They're finishing connecting the atmosphere revitalization rack and we're going to be powering that rack up and doing a full systems checkout on it a little bit later today."

The lab's guidance and navigation system computers are now fully operational and earlier this afternoon, the station's four massive control moment gyroscopes began spinning up for a critical series of tests.

Up until this point, the station's orientation has been controlled by rockets on the Russian Zarya and Zvezda modules. Once checked out and operational, the gyroscopes will enable NASA to take over day-to-day operation of the station, controlling its orientation without the need for experiment-jarring rocket firings.

Castle said it would take the gyroscopes about six hours to reach their operational spin rate. Testing will begin around 9 p.m. this evening.

"We will then proceed and we'll be doing some more control authority testing tomorrow morning and then, after a sufficient amount of that, we'll actually hand over control tomorrow to the CMGs to control the mated attitude of the stack."

Translation: If all goes well, flight controllers will switch the station over to gyro control at some point Tuesday. The shuttle will resume control during the crew's third and final spacewalk Wednesday.

But Castle said checkout and tests of the gyros and the lab computers necessary to control should be complete in time for the station to begin full-time gyro operations as soon as Atlantis departs.

Video vault
After temporary storage on the Z1 truss, PMA No. 2 is mounted to the Destiny module's back end for use by docking space shuttles in the future.
  PLAY (239k, 22sec QuickTime file)
Watch a complete preview of the mission's second spacewalk with NASA animation and narration by Kerri Knotts, the STS-98 lead EVA officer.
  PLAY (546k, 1min55sec QuickTime file)

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