Re: An alternative to Orion/Constellation?

Derek and Jeff bring up several very good points.

I don't have the time right now to go into full detail
in expounding upon my responses, but I'll give you
a brief response now and hopefully a better follow-up
later.

Replies welcome....

Derek Lyons wrote:
"Jeff Findley" <jeff.findley@xxxxxxxxxxxxxx> wrote:
"David Spain" <nospam@xxxxxxxxx> wrote in message news:88GdnZ3vC-NLfm3UnZ2dnUVZ_vmdnZ2d@xxxxxxxxxxxxxxx

Such a vehicle would be much more expensive to develop than Orion.

Yes definitely. I'm not opposed to spending money if its in the right
direction.


Shuttle costs got out of control when we decided to make it big enough
to carry a significant payload other than people [1].
One of the biggest problems with the shuttle is complexity. Making
it smaller wouldn't have made it (much) less complex. Some things could
have been cheaper (i.e. TPS due to smaller surface area and fewer tiles),
but other things would remain the same in terms of complexity (life support, crew cabin, computers, control surfaces, windows, and etc).

Many people also forget *why* the Shuttle grew like it did. Once the
unmanned heavy lift launcher was removed from the equation, NASA had
little choice. Leaving aside the niggling detail that the heavy lift
never really was in the equation in the first place in the minds of
those paying the bills.

Yes. We should have preserved ELVs for heavy lift. Saturn 1B would have
been good to have kept around.

If it were just to ferry people it could have been made a lot smaller
with a lot more launch options which would have improved the economies
of everything.

The economies of everything except actually accomplishing anything
other than limited 'spam in a can' missions. If you're going to LEO
you need a destination - Apollo had to have one provided (Skylab or
Soyuz), while the Shuttle carries it's destination on its own back.

We should be focusing on building what I call a 'traveling space habitat'.
Something on the order of a very small space station that can be sent out
of low Earth orbit (LEO) on orbital exploration missions. First to the moon, then maybe Venus, and eventually Mars.

Of course, building such a station would be a massively expensive
enterprise - one made even worse by the need to make it survive and
operate in three very different enviroments.

Yes. But it would also allow us to explore interplanetary space over
decades.


It would be self-sufficient and fully reusable and capable of supporting
a 6 person crew nearly indefinitely.

You (David) have no idea of the vast expense and complexity that
simple sentence implies.


I totally agree. I'm not arguing from a cost perspective, but from a value
perspective. If such a thing could operate for 2 or more decades I'd think
we'd get plenty back in return. This is a *lot* harder to do than Constellation.
But putting people on the moon at the time of Kennedy's speech seemed at
the time pie in the sky too. If Eisenhower had been able to stay for a 3rd
term, there'd likely have been no moon program, certainly not one with
delivered results by 1969.

Think about the trillions already gone thanks to credit default swaps
and mortgage derivatives, and even the loftiest cost projections pale
in comparison.

How much would it help to reduce the crew size. Say from 6 to 3? Can you
give me any ball park figures on crew/cost ratios?

[1] The other reason I remember was the unique ability to 'retrieve' payload from orbit.
IIRC this was done exactly *once* with a comm sat (whose PAM module failed to ignite?) and failed to achieve proper orbit. IIRC, the company
that lost the satellite received an insurance payout and the insurer got
back the retrieved satellite which I assume they sold to someone else to
try again? It appears that this once taunted feature of the shuttle was
never really that important.
You forgot LDEF, which was an important thing to retrieve:
http://en.wikipedia.org/wiki/LDEF

Not just LDEF. Consider also Spacelab/Spacehab, and the Hubble
restraint/repair facility. There's also the radar experiment that was
modified and reflown. There's also the experiments reflown after the
ATO.

LDEF is the biggie, but there's also the smaller stuff too.

In fact, the argument could be constructed that the most important
thing recovered by the Shuttle - is the Shuttle itself.


Interesting point! I had not thought of it that way, but in retrospective
it certainly looks true!

[2] No I'm *not* implying that a White Knight could do the job. Only something new that was designed for a much, much smaller shuttle that
launches from the carrier craft using (expendable) rocket assist with
only OMS pods and wings for return from orbit where it would glide to
a respectable runway landing.

Do the math. Your carrier aircraft is going to have to be really huge for such a proposal. Note the size of the shuttle ET. You're going to need a tank almost that size to get your smaller space plane to orbit (no SRB's means the liquid rocket engines would be doing more of the work).


Yes, the math says it's better cost-wise to use ELVs no argument from me.

Many people fail to realize that while WK/SS is an excellent point
solution to what it does - it doesn't scale well at all.


To your knowledge or my knowledge, yes. But who is making that claim
besides yourself? Do you have cites? What does Rutan say?

As an aside, I don't for the life of me understand this compulsion to throw
everything out with each new generation of space transport and start over.

When we do this, I'll get back to you.

How much of Mercury/Gemini/Apollo went into shuttle?


My whole engineering career in the commercial sector has seen incremental
improvements where technology is refined and refined.

What kind of engineering? I.E. lets compare apples to apples.

D.

OK fair enough. The space development part of aerospace hasn't proceeded this
way. Why not? Why is space so vastly different an engineering discipline from
even aeronautics that the principles of incremental improvement don't apply?
Are we really talking engineering or policy?

Dave
.

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