Re: modular aproach etc

Derek Lyons wrote:
"Danny Dot" <don't.mail.me@xxxxxx> wrote:

"Derek Lyons" <fairwater@xxxxxxxxx> wrote in message
news:4521dcea.1436295125@xxxxxxxxxxxxxxxxxxxxx
"Lee Jay" <ljfinger@xxxxxxx> wrote:

If you have a huge capsule like craft - then you aren't launching 'as
little mass as possible'. You can't have it both ways.

I see Lee's point.

Lee doesn't actually have a point - he is repeating the memes of the
anti-shuttle community without actually having any understanding of
the issues involved.

Ummm...you don't know me. I'm not anti-shuttle at all. I just realize
that wings and landing gear weigh more than a chute. The shuttle is a
capsule with wings. The presurized cabin is not much more than a
pretty large and well-appointed capsule. The wings and gear (and tail,
and APUs, and large TPS etc.) are just to get the capsule back into the
atmosphere in one piece. They are large and heavy, much heavier than
other approaches to the same problem.

That's true for the one small corner of the potential mission space
that putting satellites in orbit represents - but what of the
*remainder* of that space? Once again - the train halts.

No it doesn't. The capsule approach has nothing to do with launching
unmanned objects. You can do that separately or combined but even the
shuttle does these two things pretty separately. The cargo bay isn't
presurized. The cargo bay is a satellite launch system that's pretty
much separate from the presurized crew cabin. You could do the same
thing but leave the cargo bay up there (or toss it back for burn up)
and get the crew cabin back using a capsule-style approach. The only
advantage the shuttle approach has is the ability to bring large items
back. We haven't done much of that, though I'd personally donate money
just for a Hubble retrieval mission when the time comes.

Total launch mass is a huge cost driver.

That's true of *every mode of transport ever devised by man*.

No it's not. In some modes, mass is crucial, in other modes, it's
relatively unimportant. Spacecraft are the most sensitive by far,
ships are the least sensitive (since they don't have to climb hills).

Lee Jay

.

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