The Delta V Heavy

When TSTO EELVs start regularly making the ISS run after the collapse of
ESAS and VSE, then soon there will be a market for on orbit upper stages
and their engines. I mean, why would you want to throw away a perfectly
good vacuum startable upper stage, after you've put it up into orbit?


You'd have to figure out how to refuel it, and how you deliver that fuel.

robert casey wrote:

When TSTO EELVs start regularly making the ISS run after the collapse
of ESAS and VSE, then soon there will be a market for on orbit upper
stages and their engines. I mean, why would you want to throw away a
perfectly good vacuum startable upper stage, after you've put it up
into orbit?


You'd have to figure out how to refuel it, and how you deliver that fuel.

Why would I want to do that. I'll pack up the engine and ship it back to
Earth, and then add another hotel room to my solar power satellite.

Then I'll rent you attachment space.

robert casey wrote:

You'd have to figure out how to refuel it, and how you deliver that fuel.

And how to seat the propellants if you wanted to fire it up on-orbit.

Pat

"Pat Flannery" wrote in message
...


robert casey wrote:

You'd have to figure out how to refuel it, and how you deliver that fuel.

And how to seat the propellants if you wanted to fire it up on-orbit.

The refueling problem is the bigger problem.

The fuel settling problem has *already* been solved by all upper stages
which are restartable. It's essentially a non-issue.

Jeff
--
Life is too short to let anyone out of my killfile.

On Wed, 21 Nov 2007 09:30:54 -0500, in a place far, far away, "Jeff
Findley" made the phosphor on my monitor
glow in such a way as to indicate that:


"Pat Flannery" wrote in message
...


robert casey wrote:

You'd have to figure out how to refuel it, and how you deliver that fuel.

And how to seat the propellants if you wanted to fire it up on-orbit.

The refueling problem is the bigger problem.

But one that must be solved if we're serious about being a spacefaring
nation and society.

Pat Flannery wrote:


robert casey wrote:

You'd have to figure out how to refuel it, and how you deliver that fuel.

And how to seat the propellants if you wanted to fire it up on-orbit.

This is a critical enabling technology in my COTS proposal. We don't
want big settling solids, they weight too much, and we only need to
circularize, migrate, and possibly reboost the stack after docking.

The idea, of course, is continuous settling along the entire trajectory
to apoapsis, which must be included in the calculations, with a higher
thrust circularization along an arc of apoapsis. This also provides the
minor housekeeping gravity necessary for residual fuel scavenging and
settling the fuel for the minor thrust required to circularize.

Reboost is another problem, as rendezvous takes much more time. We're
working on some direct ascent trajectories, so who knows. One thing I do
know, however, is that vastly better software for analyzing these things
is now available, and by the time this hardware is ready, it should be
an order of magnitude or so better than we have now, which in my
opinion, is pretty darn good right now, and fun as hell. If I had time.

Jeff Findley wrote:
"Pat Flannery" wrote in message
...

robert casey wrote:
You'd have to figure out how to refuel it, and how you deliver that fuel.
And how to seat the propellants if you wanted to fire it up on-orbit.

The refueling problem is the bigger problem.

The fuel settling problem has *already* been solved by all upper stages
which are restartable. It's essentially a non-issue.

Actually, no, it is an issue, because upper stages traditionally use
consumables, typically hydrazine, which weighs a lot, and the thrust of
an upper stage engine is high, and the weight of the upper stage is low.

We need settling for much smaller thrust and much higher masses, and
also for reboost of the entire stack after docking. Thus the situation
is much different, especially because the main engine (presumably an
SSME oe equivalent) can only be ground started. So really, the entire
philosophy of just load it up with hydrazine is obsolete, especially if
we expect lots of upper stages involved in ISS service and resupply.

So you see, the entire philosophy of expendability has to be entirely
reexamined in light of the problems of ESAS collapse and ISS service.

Jeff

Jeff Findley wrote:
The refueling problem is the bigger problem.

The fuel settling problem has *already* been solved by all upper stages
which are restartable. It's essentially a non-issue.



But there's no reason for the upper stage used to launch Ares 1 to be
restartable. Putting ullage pods on it, like were used on the S-IVB of
the Saturn V, would simply add more weight to a already overweight vehicle.
Of course, given the mass fraction of a LOX/LH2 powered vehicle, the big
problem as you say would be getting enough propellants into orbit to
refuel it.
Maybe it's time to dust off the Sea Dragon plans?:
http://en.wikipedia.org/wiki/Sea_Dragon_%28rocket%29

Pat

"kT" wrote in message
...
Boeing has already successfully demonstrated the water recovery of an
SSME. So I guess I'm just standing on the toes of giant's, am I not?

Does that include *reuse* of said engine, at less cost than the usual
recovery and refurbishment method? If so, which engine and which Shuttle
launch?

On Wed, 21 Nov 2007 12:04:51 -0600, in a place far, far away, Pat
Flannery made the phosphor on my monitor glow in
such a way as to indicate that:



Jeff Findley wrote:
The refueling problem is the bigger problem.

The fuel settling problem has *already* been solved by all upper stages
which are restartable. It's essentially a non-issue.



But there's no reason for the upper stage used to launch Ares 1 to be
restartable.

Except to circularize. But if you don't want a stable orbit out of
it, no, no reason to restart at all.