NASA is preparing to use the International Space Station (ISS) as a "safe haven" in case the Space Shuttle is damaged on its return to flight (RTF) mission, STS 114/ Discovery, now set for launch on 16 March next year at the earliest.
"We will insist on some capability [to shelter the Shuttle crew] for STS 114 and STS 121 before we will commit to flight," says Shuttle programme manager Bill Parsons. While NASA plans to have a second Shuttle on standby for STS 114 and 121/Atlantis, the second RTF mission, it would take some time to launch a rescue mission.
NASA is assessing the ISS's ability to support the seven-strong Shuttle crew as well as the two station occupants. Parsons says "conservative" engineering estimates indicate the ISS, with the Shuttle docked, should support them for 46-57 days "or longer, depending on how pessimistic we are".
It is assumed that additional life-support supplies required to guarantee contingency capability will be carried to the ISS on the Shuttle. "We may have to adjust the manifest and carry additional lithium-hydroxide canisters [to scrub carbon dioxide from the air] and other consumables depending on the condition of the ISS as we approach 114," Parsons says.
ISS programme manager Bill Gerstenmaier says there is still time to add equipment to Russian Progress and Soyuz launches planned before the RTF, "but the right place to put them is on the Shuttle - it has a lot more up-mass capability and stowage is getting tight on the ISS". The decision to reduce the crew from three to two after the Shuttle was grounded has helped, Parsons says, as the ISS has good reserves of consumables.
The robot-arm extension boom for on-orbit inspection of any Shuttle damage "looks like it will be delivered in time" for the RTF mission, he says, although sensor testing continues.
GRAHAM WARWICK / WASHINGTON DC
Source: Flight International
