Expedition 9 Spacewalks and Cargo Ships
Expedition 9's tour of duty -- which initially included two spacewalks and the arrival of two Progress resupply vehicles -- is getting a little busier. Mission managers have added a third spacewalk to fix a hardware problem.
One of the Station's three functioning Control Moment Gyros (CMGs), which help stabilize the orbital laboratory, failed shortly after the Expedition 9 crew came aboard. The problem appears to be with the gyro's RPCM (Remote Power Controller Module), which is basically a circuit breaker on the outside of the Station.
Image right: ISS Progress 11 departs the International Space Station. This cargo ship is similar to the Progress 14 and 15 spacecraft that will arrive at the Station during Expedition 9's tour of duty.
The problem isn't considered a safety issue, and the other two gyros can keep the Station in the right position. If one of those were to fail, Russian thrusters could be used to keep the Station in place.
Expedition 8 Commander Michael Foale said this is the type of failure that has been anticipated and planned for, and said he has no anxiety about the issue. "There is no crisis involved in this whatsoever," Foale said. "It's more a matter of how you plan this -- what's the best way to do it -- details like that that have to be worked out."
The first Expedition 9 spacewalk, or Extravehicular Activity (EVA), will take place on June 24.
"I've been trained by the best instructors both in Houston and Moscow," said Fincke, "and we're ready for whatever comes."
The objectives of the other two spacewalks are to continue the external outfitting of the Zvezda Service Module and to install cameras, communications gear and navigational aids to Zvezda for the arrival of the European Space Agency's Automated Transfer Vehicle (ATV). The unpiloted ATV is a cargo ship similar to the Progress vehicle, but larger.
The crew is slated to conduct all three spacewalks from the Pirs Docking Compartment wearing Russian Orlan spacesuits. The training they received for the spacewalks is an example of thorough training that a crew receives for the Station. Padalka talked about the training in a preflight interview.
"Yes, of course, both the spacewalks are scheduled, yes, in Orlan," he said, "but we are well trained to use [the U.S.] EMU, in case of a malfunction, in case of emergency situation. In this case we can use an EMU with no problem. And in this case we can depress and repress in [Joint] Airlock instead of the Docking Compartment."
ISS Progress 14, arrived at the Station on May 27. It launched from Baikonur Cosmodrome.
The Progress is an automated, unpiloted cargo version of the Soyuz spacecraft. The Progress is used to bring supplies and fuel to the International Space Station. Once the Progress has served out its usefulness, it is loaded with the Station's discarded items and commanded to undock from the ISS and burns up in Earth's atmosphere.
+ Expedition 9 Overview