Newsgroups: sci.space.shuttle
Path: utzoo!henry
From: henry@utzoo.uucp (Henry Spencer)
Subject: Re: Shuttle's Future?
Message-ID: <1988Feb3.140727.13026@utzoo.uucp>
Organization: U of Toronto Zoology
References: <191800002@trsvax>
Date: Wed, 3-Feb-88 14:07:10 EST

> Does anyone know the current status of plans to replace the SRBs with liquid
> rocket boosters?

What plan?  They're doing some more paper studies, that's all.

> What is the estimated development time for liquid boosters, 

Depends:  are we assuming Wernher von Braun is developing them, or are we
assuming today's NASA is developing them? :-(  I'd be surprised to see
NASA able to do it in less than five years, even if they got started
seriously today.  One headache is that the US has no *big* non-hydrogen
liquid engines today (boosters should not use hydrogen, it's too bulky
and doesn't buy much in that application).

> and what increase in payload could reasonably be expected?

It depends.  Right off the bat, probably zero, because things like landing
weight in the event of an abort are among the major limitations today, and
liquid boosters wouldn't help there.  Disregarding that, I'd expect a fair
increase, limited ultimately by other considerations to, well, I dunno,
fifty percent??  (Getting it that high would take other changes, mind you.)

> I am also curious about the status of shuttle derived HLLVs.  Are any plans
> for shuttle derived launchers firm, ie funded in one way or another?

In a word, no.

> what is the expected development time for said vehicle, and what projected
> payload?

Much depends on which of said vehicles you are discussing.  In general, as
you depart farther from the current design, the payload and the development
time both rise.  A medium-departure design (replace orbiter with payload
pod and recoverable engine capsule) could have several times the current
shuttle payloads, maybe 8-10 years down the road.  The only design that NASA
has taken seriously in recent years was the "Shuttle-C" concept, essentially
a minimum-departure design throwing away a stripped-down orbiter on each
flight (!), which a friend at Boeing described as "the second worst shuttle-
derived expendable design I've ever seen".

> What is the status of the replacement shuttle orbiter?  Has it been funded and
> if so, when is its expected completion (a name would be nice too)?

It's underway.  Don't expect it for 3 or 4 years, I forget the exact date.
That's assuming it doesn't get cancelled.  It has not been named yet.

> Also, what is the status of Shuttle launched upper stages?  I know that the
> vehicle which the Galileo probe was to have used has been deemed too risky,
> what are the planned alternatives?

Shuttle-Centaur, originally planned for Galileo, Ulysses, and other things,
is dead.  There is no direct replacement.  The heaviest available is the IUS
(anybody but me remember when the I meant "interim"? :-( ), which is what
Galileo is using now.

> When is the next scheduled Shuttle launch?  I heard a rumor about August...

So did I.  I don't have firmer info.  The June plan is definitely off due
to the SRB problem in the December test.  August is probably the minimum
slip assuming everything else works.
-- 
Those who do not understand Unix are |  Henry Spencer @ U of Toronto Zoology
condemned to reinvent it, poorly.    | {allegra,ihnp4,decvax,utai}!utzoo!henry