"Allen Thomson" wrote in
ups.com:

Question: Why not use the one presumably available Soyuz
(besides the docked life-boat one) to reduce a crew of
nine to six, thus buying some time?

Actually, there is some consideration of using the docked lifeboat one.
There's a safety tradeoff here, though: you can only bring home crewmembers
that already have Soyuz seatliners, which limits you to bringing home the
ISS crew rather than three members of the shuttle crew. So you get longer
consumables lifetime, at the price of removing the crewmembers best trained
to deal with an ISS contingency after the Soyuz leaves.

"Presumably available" is a bit strong; looking over the history of Soyuz
in the ISS era, the next Soyuz typically doesn't ship to Baikonur until
about three months after the previous one was launched. So you don't have
100% coverage unless you accelerate the pipeline. And you still have the
seatliner issue; since there will typically be multiple shuttle launches
over the life of that Soyuz, you'd have to get all the shuttle crewmembers
fitted for them.


--
JRF

Reply-to address spam-proofed - to reply by E-mail,
check "Organization" (I am not assimilated) and
think one step ahead of IBM.