In article ,
jeff findley wrote:

You get around these issues by doing multiple EVA's. One suit can be
used for multiple EVA's per shuttle/station mission. The first walk
to Columbia could have been used to deliver O2 tanks and CO2
scrubbers, so time would not have been as important of an issue as
safety during the subsequent EVAs.

Jeff

Well, IIUC, there are other issues involving shuttle EVAs that can't be
alleviated simply by ferrying over O2 cyclinders and LiOH cannisters.
For one thing, the shuttle airlock can only fit three people (and I
think that's only been done on one EVA years ago - the usual is two).
That issue may or may not be significant in light of the next issue,
which is this: the EVA suits aren't charged with cabin air, they are
charged by the shuttle ECLSS high-pressure 02. Also, the shuttle ECLSS
pressurizes the airlock (I think) rather than the airlock being
pressurized by a simple vent/pressure equalization valve from the
orbiter mid-deck. Either way, the number of airlock cycles you can go
through is limited and you run the risk of mechanical failures each time
you cycle the lock.

I would think, all things considered, that you'd probably want to ferry
over as many people per EVA as possible. It limits the number of
airlock cycles necessary, reduces the amount of time the orbiters must
spend in close, station-keeping proximity and gives you the most
operational flexibility in planning the return of the rescue mission.

--
Herb Schaltegger, Esq.
Chief Counsel, Human O-Ring Society
"I was promised flying cars! Where are the flying cars?!"
~ Avery Brooks