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Date: Sat, 19 Dec 92 05:04:57
From: Space Digest maintainer <digests@isu.isunet.edu>
Reply-To: Space-request@isu.isunet.edu
Subject: Space Digest V15 #571
To: Space Digest Readers
Precedence: bulk
Space Digest Sat, 19 Dec 92 Volume 15 : Issue 571
Today's Topics:
Aurora
planetary accretion simulation question
SSTO Concepts FAQ
Why have both manned and auto capability on DC-[XY1] & Buran?
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----------------------------------------------------------------------
Date: 18 Dec 92 16:19:18
From: Steinn Sigurdsson <steinly@topaz.ucsc.edu>
Subject: Aurora
Newsgroups: sci.space
In article <BzGHpy.BEL@brunel.ac.uk> mt90dac@brunel.ac.uk (Del Cotter) writes:
In article <STEINLY.92Dec16152132@topaz.ucsc.edu> Steinn Sigurdsson writes:
>In article <BzCzo5.76z.1@cs.cmu.edu> nickh@CS.CMU.EDU (Nick Haines) writes:
>
> Assuming that it's launching from the continental USA. Seems much more
> likely to me (given the sightings over the Netherlands as well) that
> one of the long-runway US bases in the UK or Germany is `home' to an
> Aurora.
>
>Nah, not isolated enough, rumour seems to be that the forward
>base is a US NATO base in Scotland.
Yes, Scotland's still in the UK at time of writing...
But I can pretend can't I... ;-)
(What's a US NATO base?)
Ouch, humiliation, I'll be banned from soc.culture.british,
- if it's any excuse I have vague memory of reading the original
post as "bases in the Netherlands or Germany"...
There is no such thing as a US NATO base, they are all RAF bases
I gather, but in practise some are all US (except maybe for an RAF
liasion) and nominally assigned as such through NATO rather than
a bilateral agreement...
| Steinn Sigurdsson |I saw two shooting stars last night |
| Lick Observatory |I wished on them but they were only satellites |
| steinly@lick.ucsc.edu |Is it wrong to wish on space hardware? |
| "standard disclaimer" |I wish, I wish, I wish you'd care - B.B. 1983 |
------------------------------
Date: Fri, 18 Dec 1992 19:08:19 EST
From: ANDERSM@QUCDN.QueensU.CA
Subject: planetary accretion simulation question
Newsgroups: sci.space
Couldn't find any info on this in the FAQs. Whatever happened to the program
written by Sagan's group? It was called ACRETE or ACCRETE or something very
similar. I'd be somewhat interested in running simulations of this sort just
for fun. Are there extant (free) programs, what platforms do they run on, have
there been significant theoretical developments since Sagan's model, and
similar questions.
Mark Anderson
Queen's University Graduate Studies
------------------------------
Date: 18 Dec 92 16:13:24
From: Steinn Sigurdsson <steinly@topaz.ucsc.edu>
Subject: SSTO Concepts FAQ
Newsgroups: sci.space
Nntp-Posting-Host: topaz.ucsc.edu
In-Reply-To: dietz@cs.rochester.edu's message of Fri, 18 Dec 1992 02:59:23 GMT
Sender: news@CRABAPPLE.SRV.CS.CMU.EDU
Source-Info: Sender is really isu@VACATION.VENARI.CS.CMU.EDU
In article <1992Dec18.025923.12966@cs.rochester.edu> dietz@cs.rochester.edu (Paul Dietz) writes:
In article <STEINLY.92Dec17183740@topaz.ucsc.edu> steinly@topaz.ucsc.edu (Steinn Sigurdsson) writes:
>Now, DC-1 wants something like 300 tons total, so 75 tons LH2
>and 225 tons LOX? That's still 30 fuel trips, maybe doable with
>three shifts in 24 hours, but I don't think you can do it in 8 hours?
>Not with one crew.
You mixture ratios are off. The oxygen/hydrogen mixture ratio
in the SSME is 6; in the Saturn J-2, 5.5. At a ratio of 6
this would be about 43 tons of hydrogen and 257 of oxygen.
About 20 trips.
Ouch, I'm not doing well here, for some reason I was thinking
4:1 and writing 3:1...
However, the launcher would almost certainly have fuels piped to it
directly from remote storage tanks, as NASA currently does at the
shuttle pads.
But now we're getting further and further from the "DC concept"
with fixed launch platforms and some serious ground infrastructure instead,
at this point an honest cost evaluation should include running
the tank farm and pipes, those are fixed costs almost independent
of flight rate and this starts to look more like the shuttle.
No more popping off from the nearest convenvient airport at
short notice...
| Steinn Sigurdsson |I saw two shooting stars last night |
| Lick Observatory |I wished on them but they were only satellites |
| steinly@lick.ucsc.edu |Is it wrong to wish on space hardware? |
| "standard disclaimer" |I wish, I wish, I wish you'd care - B.B. 1983 |
------------------------------
Date: Sat, 19 Dec 1992 00:06:53 GMT
From: "Edward V. Wright" <ewright@convex.com>
Subject: Why have both manned and auto capability on DC-[XY1] & Buran?
Newsgroups: sci.space
In <1992Dec18.011309.12639@bby.com.au> gnb@baby.bby.com.au (Gregory N. Bond) writes:
>I understand the DC-X will, like the xUUSR Buran shuttle, have
>capabilities for both unmanned automatic operation and piloted
>operation. I suspect similar capability is expected for DC-Y and DC-1
>should they be built.
No, DC-X is unmanned and not large enough to carry a pilot.
>Given that the thing can fly automatically, why add pilots?
McDAC has said that operational flights will be controlled
automatically, and the flight crew will be passengers rather
than pilots. Of course, they said the same thing about
Project Mercury once, too. I don't expect it will true
today any more than it was then.
>I'm not sure what manned piloting means in this context, and what it
>gains over auto operation; especially since providing space, controls,
>seats, life support etc for the pilots is very expensive on the mass
>budget.
Machines break.
A Boeing 747 is capable of taking off from an airport runway, flying
from Los Angeles to Sydney, and landing. Automatically. But airlines
still have pilots.
------------------------------
End of Space Digest Volume 15 : Issue 571
------------------------------