Spaceflight Now: STS-106 Mission Report

Spacewalking astronauts to wire up station modules

Posted: September 11, 2000

The Atlantis astronauts were awakened at 8:01 p.m. this evening to begin preparations for an overnight spacewalk to wire up the international space station's new Zvezda command module.

Astronaut Edward Lu and cosmonaut Yuri Malenchenko plan to float into Atlantis's cargo bay around 1:06 a.m. Monday to begin a six-and-a-half-hour excursion to connect four power cables between Zvezda and the Zarya module and four video and data cables. The spacewalk could begin a half-hour or so ahead of schedule if the astronauts are ready.

See our timeline of the spacewalk.

Astronaut Ed Lu and cosmonaut Yuri Malenchenko rehearse making cable connections on a training mockup of the service module during a training session in the hydrolab at Star City. Photo: NASA-JSC
The STS-106 spacewalk is not particularly challenging as these things go, but it will offer the astronauts one of the best views in the solar system as they make their way up the towering 142-foot-long spacecraft.

Atlantis is attached to a pressurized mating adaptor, or PMA, attached to one end of the multi-hatch Unity node, launched by NASA in December 1998. At the other end of the Unity module is another PMA that connects to the Russian-built NASA-financed Zarya propulsion module, launched in November 1998.

Zarya, in turn, is attached to the Zvezda module and the Progress 251 supply ship is docked to a port at the far end of the new command module.

While Zvezda is physically attached to the station, it is not yet electrically connected. That is the job facing Lu and Malenchenko.

The power cables they plan to install, in a strip of four stretching 26.9 feet, will permit electricity generated by future U.S. solar arrays to power systems in Russian modules as needed. The video and data cables, also in a strip of four, stretch 16 feet.

"As the station gets bigger and the solar arrays start to get blocked (by other modules), we need to share power between the different segments and the different modules," said lead flight director Phil Engelauf.

"And these external cables will be connected up in anticipation of ... when we will start generating power."

The spacewalkers also plan to hook up a 20-foot-long fiber optic telemetry cable that will be used during future Russian spacewalks and re-mount a Russian magnetometer on an extended boom near the rear of Zvezda. The magnetometer will provide a backup means of determining the station's orientation in space.

Astronaut Lu practices installation of magnetometer on the service module in the hydrolab at Star City. Photo: NASA-JSC
"When they're working on the magnetometer boom, they'll be about 110 feet away The magnetometer is located near the far end of Zvezda. To get there, Lu and Malenchenko, carrying cable spools and tools, will ride the shuttle's robot arm from Atlantis's payload bay to Zarya 45 feet away. From there, they will pull themselves, hand over hand, along handrails up to the magnetometer work site using two safety tethers each.

"When they're working on the magnetometer boom, they'll be about 110 feet away from the space shuttle, which is twice as high as astronauts were when we worked on the top of the Hubble Space Telescope," said Mike Hess, a NASA spacewalk planner.

"So it'll be a very different view for this crew, it'll be the equivalent of working on about the 11th story of a 13-story building when they're working on the magnetometer."

Lu, who will be identifiable by red stripes on his spacesuit, said he and Malenchenko are "really looking forward to getting a chance to see this view, of looking down and seeing the space shuttle with the Earth in the background. We're expecting a pretty incredible view."

That view comes at a price, however: The distance Lu or Malenchenko might have to quickly traverse in an emergency to reach the safety of the shuttle's airlock.

Spacewalk outside the international space station during last shuttle mission in May. Photo: NASA-JSC
But Hess said the spacewalkers could make it back into the airlock in 10 to 15 minutes if necessary and each spacesuit has a 30-minute supply of emergency oxygen.

"The added risk involved in the EVA is in terms of rapid safing," Hess said. "From a rapid safing standpoint, we're still within our 30-minute limit, which is what the suit can easily take care of. So we should easily be able to get back inside if there's a problem."

Once the magnetometer head is mounted on its boom, Lu and Malenchenko will work their way back "down" the station stack toward the shuttle, stopping at the Zvezda-Zarya docking interface to hook up the power and data cables.

As they did going "up" the stack, the spacewalkers will take special care to avoid protruding antennas on the Zarya module and two docking targets on Zvezda's hull. "They'll snake over one target and under another," Hess said.

The astronauts will float into the space station for the first time Monday night to begin transferring supplies and equipment into the outpost. The goal is to outfit and activate the Zvezda module, which will provide the station's initial crew quarters and the propulsion needed to maintain a safe orbit.

Mission Status

See the Status Center for full play-by-play coverage.

Flight Plan
Upcoming major events for the crew of Atlantis:

All times EDT (GMT -4 hours).

Video vault
Space shuttle Atlantis docks with the International Space Station high above Kazakhstan.
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NASA animation shows Atlantis approaching and docking to the international space station during the STS-106 mission.
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A tracking camera located on the beach north of launch pad 39B watches space shuttle Atlantis climb into the morning sky on Sept. 8.
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Atlantis blasts off and rolls to a heads-down position for its trek toward orbit as seen in this dramatic tracking camera footage.
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A tracking camera captures the separation of the twin solid rocket boosters from Atlantis.
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