On Thu, 18 Sep 2003, Sander Pool wrote:
> As far as I can tell we did a lot more Shuttle flights than capsule flights,
> no?
Correct, but there is no question that capsules are easier and quicker to
design and develop. The recent tightening of the schedule for OSP is
going to push the contractors very strongly toward capsules.
> There's also no mention of reusability of these new capsules.
NASA's not used to thinking in those terms, but there's no particular
reason why capsules can't be reusable, given replacement of inherently
expendable items like ablators. Land touchdown would help considerably --
getting all the seawater out of Apollo capsules was quite a chore.
> They'd have to forget about bringing satellites
> back to earth I'd say but I don't think we've done that too often anyway.
Capsules can carry modest amounts of return cargo, but anything big
wouldn't fit (unless you build a very large capsule!). As you say, it's
not something that's really been done much. Lack of large return
capability would require revisions to some things, e.g. the MPLM system
for carrying supplies up to the station does assume that the modules come
back.
> ...They'd need a different (telescopic)
> robotic arm so that's good news for Canada :-)
Depends on what you're doing. For station operations, the station arm
will handle most arm chores just fine.
> Mostly payloads will be shot
> into orbit on disposable rockets I suppose.
Not just "mostly". No matter what OSP looks like, it will go up on an
expendable rocket.
> I wonder why any satellites were
> deployed by the shuttle at all? The cost per Lb must have been higher than
> using a standard rocket, no?
Very much depends on how you do the accounting -- an area that NASA was
notoriously slippery on. Some satellites (e.g. LDEF) had to be
returnable, or otherwise used human capabilities during deployment.
In fact, most satellite owners would really prefer to do final assembly
and checkout in orbit, after the bouncy, noisy part is over... but it
was difficult to pursue that much with the shuttle.
Henry Spencer
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