Spaceflight Now: Space Station/STS-98

Atlantis bids farewell to space station today

Posted: February, 16 2001

Animation shows Atlantis undocking from the space station. Photo: NASA TV/Spaceflight Now
The combined crews of the shuttle Atlantis and space station Alpha completed a final day of equipment transfers Thursday and readied the two spacecraft for undocking Friday to close out a full week of work to install and activate the new Destiny lab module.

Hatches between Atlantis and the station will be closed shortly after 7 a.m. EST Friday and if all goes well, the shuttle will fall straight away from Alpha just past 9 a.m. EST.

With shuttle pilot Mark Polansky at the controls, Atlantis will slowly drop to a point about 450 feet directly below the station, oriented with its tail in the direction of travel and its belly facing Earth.

"It's really just sort of a docking in reverse," Polansky said. "So I think the main thing is we'll just take it very slowly and follow our cues. ... Anytime you're maneuvering two spacecraft in close proximity to each other, there's always a lot that's involved."

After reaching a point 450 feet below the station, Polansky will manually fly the shuttle through a half loop around the complex for a detailed photo survey, first passing directly in front of Alpha and then to a point directly above it.

At that point, Polansky will first Atlantis' maneuvering jets to leave the area for good.

"I'm just looking forward to backing off, seeing Alpha from 450 feet or so and getting to do a fly around and getting some great vistas while everybody is hopefully snapping lots of great pictures from both sides," Polansky said during a news conference Thursday. "I just think it will be the experience of a lifetime."

Flight controllers originally planned a full 360-degree loop around the station, but the maneuver was cut in half to make additional propellant available for reboosting the station's altitude.

During a series of lengthy low-power rocket firings, the shuttle's maneuvering jets increased the station's altitude by about 16 miles. Cutting the fly-around maneuver in half saved enough fuel to gain an extra few thousand feet of altitude for the station.

Illustration of the station at the completion of Atlantis' visit. Photo: NASA
"If we saved that propellant to go all the way around, it would have cost a half a mile or so of reboost altitude," said lead flight director Robert Castle. "So we looked at it and said if we can get the photography we want with a half loop, then we'd rather have the half mile of altitude."

The primary goal of the 102nd shuttle mission was accomplished last Saturday when the $1.38 billion Destiny laboratory module was attached during the first of three spacewalks by Atlantis astronauts Thomas Jones and Robert Curbeam.

The new module was outfitted and, for the most part, successfully activated over the next five days. The astronauts also transferred 3,000 pounds of equipment and supplies to the station and moved another 850 pounds of trash and discarded equipment from the station to the shuttle for return to Earth.

The only problem of any significance was the failure of a vacuum pump in a rack of lab equipment designed to scrub carbon dioxide from the station's air supply.

Until the problem can be fixed, the on-board crew will continue relying on a Russian Vozdukh CO2 scrubber in the Zvezda command module. Among the equipment ferried up to the station aboard Atlantis was a backup Vozdukh system.

The only other issue under analysis was the unexpected spin-down of a stabilizing gyroscope Thursday. The station is equipped with four massive gyroscopes controlled by computers in the Destiny module.

When control moment gyro No. 2 began slowing down Thursday, its control computer turned power to the unit off, then on again. The gyro promptly spun back up to 6,600 rpm and appeared to be operating normally.

The addition of the roomy Destiny module provides welcome elbow room for Shepherd, Krikalev and Gidzenko, making the trip from the far end of Zvezda to the forward port of the laboratory something of an adventure.

Krikalev, a Mir veteran and one of the world's most experienced space fliers, said he can float from one end of the station to the other in just 15 seconds or so. But Shepherd said "it's something you have to get used to."

"Sergei's had a lot of practice on Mir, but it was kind of a new environment for me," Shepherd said. "There are a lot of things to bump into so you have to restrain yourself from going too fast. But after a while, you can probably float 20 to 30 feet between having to touch something for a little stability or some more motion.

"Really, we've been on here for three and a half months. It's starting to look like home. When I first (got here), everything was kind of new and different. I'm getting really used to looking at Russian hardware as well as U.S. hardware, it all looks very familiar to me.

"I can be upside down and it still makes sense," Shepherd said. "I guess that's just part of the adaptation we have up here."

Asked if he will miss Alpha when a replacement crew arrives in March, Alpha's skipper said he's looking forward to flying home.

"I kind of look at it kind of like a cruise at sea," he said. "The first month, you're kind of overjoyed and by the fourth or fifth month, you're ready to come home.

"And that's pretty much where I am now. We've done got a lot of good work behind us and I think we'll be happy to turn a good ship over to the next crew."

Video vault
Atlantis undocks from the international space station and performs a "fly-around" maneuver as shown in NASA animation.
  PLAY (320k, 39sec QuickTime file)

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