Re: modular aproach etc

"Lee Jay" <ljfinger@xxxxxxx> wrote:

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.

Unless the 'you' (that you actually are) differs greatly from the
'you' (who posts to Usenet) - then yes, I do 'know' you. (Though you
may not 'know' yourself - a lot of people spout these memes from
independent discovery without realizing that they are repeating
something long existing.)

I'm not anti-shuttle at all.

That's very hard to believe when you write postings explaining how the
Shuttle Is Bad and the True Path Lies Elsewhere. (Especially when
such postings are based on a Shuttle that has little to do with the
real one.)

I just realize that wings and landing gear weigh more than a chute.

True - but irrelevant to any rational discussion of a space transport
system. *Unless* you believe in the illusory goal of being 'cheap'
and 'efficient' over the short term - in place of the goal of being
affordable and functional over the long term.

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.

In a world where the Shuttle doesn't have a cargo bay - you'd have a
point. But in this world, it does have a cargo bay.

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.

Only if you believe you can seperate out one part of an interdependent
system and handwave the remainder away.

You can do that separately or combined but even the shuttle does these
two things pretty separately.

Not the Shuttle we currently have - which you, again, confuse with
some illusory strawman shuttle.

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.

You claim the train hasn't halted - yet here you not only put the
brakes on your intellectual train, you pour cement around the wheels,
puncture holes in the fuel tank, and then pile bricks on the track.

(Not to mention getting basic facts wrong - like ignoring the
existence of an airlock.)

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.

Actually - we've brought numerous large and/or heavy objects back.
Spacelab, Spacehab, LDEF, any number of terrestrial and astronomical
science packages.

As far as advantages go...

A properly done shuttle utterly eliminates the need for rendezvous
procedures, docking hardware, and independent flight capability for
the payload. It eliminates the parasitic weight of a shroud for the
payload.

A properly done shuttle allows the performance of discrete scientific
and/or engineering tasks to packaged into a single flight. It ensures
that the payload and it's operators arrive on orbit, together, always.
(Which last can reduce programmatic risk.)

etc... etc...

Now, nobody will argue that the current Shuttle is a bad way of doing
these things - but you make the mistake of believing that the current
Shuttle equates to all reusuable winged spacecraft, and condemm them
all equally (and wrongly).

Total launch mass is a huge cost driver.

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

No it's not.

Yes - it is. There is not one single mode of transport where the
focus isn't on maximizing performance per pound. Period. There is
not one single mode of transport where the weight of the transport is
not a primary cost and design driver.

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).

If you thinks ships aren't sensitive to mass - you know far, far less
than you think you do. Among other things - ships don't have to climb
hills, but they do have to propel their own weight *exactly as does
every other mode of transport*. And *just like every other form* they
are sensitive to the distribution of that weight.

D.
--
Touch-twice life. Eat. Drink. Laugh.

-Resolved: To be more temperate in my postings.
Oct 5th, 2004 JDL
.

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