On Mon, 13 Feb 2006 12:29:04 -0500, in a place far, far away, "Will
McLean" made the phosphor on my monitor glow in
such a way as to indicate that:

The CEV is sized to carry up to six, and the shuttle can't carry
anything like fifty thousand pounds of payload to ISS.

I wasn't thinking ISS per se, just LEO. But it can still carry a lot.
And bring it back, which CEV will be unable to do.


The CEV should be able to bring back a fair amount unmanned, although
not as much as the shuttle.

Nowhere near as much, and only in small pieces.

NASA figures
that it can do the ISS crew rotation and logistics with six or seven
CEV flights.

I assume that that's why they've oversized the CLV--otherwise, you
could have a lot smaller vehicle that could just deliver the crew in a
CM, and then mate it to the SM/LSAM in LEO. OK, so what's their
estimate of the costs for those six or seven flights?


They claim they can do the ISS crew rotation and resupply with the CEV
for $1.5 billion less than the shuttle (Budgeted at $4 billion for
2006).

Beware of NASA cost analysts bearing claims...

I'll bet that they're not amortizing *any* of the development costs in
that claim.

Plus more reboost capacity than the shuttle.

That's because they're not reboosting it very smart. It doesn't make
sense to reboost using the Shuttle, given its own mass. It would be
better to have a smaller tug that you'd refuel.

Even if the savings are half that amount, that adds up to real
money over time.

Yes, *if*.

Marginal costs for the shuttle include failure costs

No, they don't. Average costs do, but not marginal costs.


The chance of failure becomes zero when you're grounded. That sounds
like a marginal cost to me.

If you want to play that game, then you have to do it as an expected
value, which is pretty low on any given flight.


What makes you think that CEV/CLV won't have failures and standdowns?



I think it will have less of them because there are fewer ways for the
simpler vehicle to fail. And standdowns can be less protracted when the
return to flight doesn't have to be a manned one without an escape
system. Titan standdowns haven't been nearly as protracted as shuttle
ones

No, but Titan has effective standdowns even when it's supposedly
operational, considering what a pad queen it is.

nor was the post Apollo 13 standdown. Also, replacing a capsule
is less expensive than replacing the orbiter.

That's certainly the case. One wonders what the eventual production
run and fleet size will end up being.

Also, shuttle maintains the standing army to
service a large, complex, finicky tile covered orbiter with wings,
control surfaces, hydraulics, landing gear and maintenance intensive
main engines.

The army may not be as large, but if you think that CEV won't have
one, you're fooling yourself.

The shuttle standing army is so huge that even a moderate reduction
adds up to significant savings. A billion here and a billion there and
pretty soon it adds up to real money.

Not if you have to spend a bunch of billion up front, when the
billions are worth a lot more.

Note that I'm not defending the Shuttle, or advocating its
continuance. I just think that if the goal is to reduce costs, this
is just about the worst possible approach to that, short of continuing
Shuttle.