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Space station briefing
International Space Station officials preview the upcoming Expedition 9 spacewalk to replace a faulty power control box that supports one of the U.S. control moment gyros. (66min 08sec file)
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Spacewalk previewed
The Expedition 9 crew describes their upcoming spacewalk in Russian spacesuits, life aboard the space station and the view of Earth in this interview with Bill Harwood of CBS News. (20min 19sec file)
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Expedition 9 arrives
The Soyuz TMA-4 spacecraft carrying the Expedition 9 crew docks to the space station's Zarya control module as seen by a video camera on the capsule. (4min 40sec file)
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Soyuz docking
The elbow camera on the space station's robotic arm provides this view of the Soyuz capsule's docking to the Zarya module. (2min 45sec file)
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Expedition 9 launch
The next space station crew is safely launched aboard the Russian Soyuz rocket from Baikonur Cosmodrome. (3min 32sec file)
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Suit problem ends station spacewalk
Posted: June 24, 2004

Station commander Gennady Padalka, U.S. flight engineer Mike Fincke and Russian ground controllers are troubleshooting a problem with Fincke's Orlan spacesuit that forced the crew to abort a planned six-hour spacewalk today.

Another attempt could be staged as early as June 29, assuming Russian engineers can resolve the apparent oxygen leak that derailed tonight's excursion just 14 minutes and 22 seconds after it began. Four Orlan suits are on board the station and mission managers could simply opt to use one of the others. But nothing has been decided at this point.

"Hey, Dan, how'd you like my EVA?" Fincke radioed mission control in Houston after re-entering the space station and doffing his suit.

"Yeah, we're thinking you might have set a record there for one of the shortest," replied astronaut Dan Burbank from the Johnson Space Center. "But yeah, it's a shame we couldn't have finished this today, but there will be another day here."

"Absolutely, and I'm really grateful to the Russian specialists to catch that leak as fast as they did, because that could have gotten into our reserves and we didn't have to go there," Fincke said. "So that was pretty good. We just came back in, shut the door and we'll just live to fight another day. And that's a good thing."

Padalka and Fincke began the spacewalk, the first for the Expedition 9 crew, at 5:56 p.m. EDT when the Pirs airlock module hatch was opened to space. The goal of the spacewalk was to replace an electronic component that failed in April, shutting down one of the station's three operational control moment gyroscopes. The gyros are used to stabilize and re-orient the lab complex.

Fincke exited the airlock module first, but within minutes, Russian flight controllers noticed a decrease in pressure in his primary oxygen tank.

"Check the pressure in the prime bottle and tell us what the rate is over the course of three minutes, how quickly the pressure is dropping," a controller radioed.

"Say again?"

"What is the pressure?"

"310," Fincke replied.

A few moments later, the pressure had dropped to 300. Mission controllers in Moscow promptly radioed Padalka, telling him to call off the spacewalk.

"Copy, 300. Gennady, you need to return. Something is not right. The pressure in Michael's prime bottle is falling. So close the hatch. And you may need to switch to your backup bottle."

"Copy that," Padalka replied. "OK, Michael, we're going back in."

After re-entering the airlock, the spacewalkers closed the hatch, connected their suits to station supplies and repressurized the Pirs module. Padalka doffed his suit and assisted Fincke in some preliminary troubleshooting, but Russian engineers were not able to immediately identify the problem.

Fincke passed on "condolences" to the planners who spent days designing the complex spacewalk. "We're going to get through this yet," he radioed. "Hang in there, everybody."

"We copy that. And oh by the way, welcome to the world of seasoned EVA members," Burbank joked. "Complete with a malfunction as well."

"Yeah, I could have done without the malfunction, but that's OK," Fincke said. "Yeah, I've got experience now. They can't call me a rookie. Thanks guys, and we'll be in touch."

Padalka and Fincke originally planned to wear U.S. spacesuits and to exit the station from the U.S. Quest airlock, which is attached to the starboard side of the station's Unity module. The component that must be replaced, a remote power control module, or RPCM, is located on the station's S0 truss atop the U.S. Destiny laboratory module, just a few feet away from the airlock.

From a management standpoint, the entire spacewalk would be carried out under the authority and direction of flight controllers at the Johnson Space Center.

But during tests last month, the cooling system in one of the two NASA suits failed to operate properly. Three U.S. suits are onboard the station, but one already was sidelined with technical problems. Without two operational suits, NASA and Russian flight planners had to come up with an alternative approach.

The solution was to have Padalka and Fincke don Russian Orlan suits and exit from the Pirs airlock. But that strategy posed several major challenges that conspired to delay the spacewalk by more than a month.

Those challenges included:

Management: Because the astronauts will exit and re-enter the station using the Russian airlock, Russian flight controllers were responsible for initial operations, handing off to Houston when the spacewalkers made it to the U.S. segment of the station. They would resume active control when Padalka and Fincke returned to the Russian segment.

Translation Path: To make it the S0 worksite, Padalka and Fincke were required to exit the Pirs module and pull themselves across a long Russian boom to the front of the Russian Zarya module. From Zarya, the astronauts had to make their way across to the U.S. Unity module, around the Quest airlock module and up to the S0 truss. A fairly tortuous path as spacewalks go, flight controllers said they did not expect any problems.

Communications: The Orlan spacesuits require the use of antennas mounted on the back of the Zvezda command module. At the S0 work site, the astronauts could run into blockage problems preventing normal communications through mission control near Moscow. The astronauts practiced hand signals for emergency use and planned to periodically venture to the top of the S0 truss to permit transmission of spacesuit telemetry to Moscow.

The station uses four control moment gyroscopes to maintain the lab's orientation in space without having to tap into limited supplies of on-board rocket fuel. But one gyro, CMG-1, failed in 2002 and cannot be replaced until next year, during the first post-Columbia shuttle mission.

CMG-2 shut down April 21, when a field effect transistor in a ciruict inside the RPCM failed. As a result, the station is down to just two operational stabilizers and one of those, CMG-3, has shown subtle signs of unusual behavior in recent months due to presumed lubrication issues. Should one of the two remaining gyroscopes shut down for any reason before CMG-2 can be brought back on line, station crews would have to begin firing rocket thrusters to maintain the lab's orientation.

Enough fuel is available to support normal station operations for six months, but both sides want to restore CMG-2 to normal operations as soon as possible.

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