Date: Sat, 19 Dec 92 05:04:57 From: Space Digest maintainer 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? Welcome to the Space Digest!! Please send your messages to "space@isu.isunet.edu", and (un)subscription requests of the form "Subscribe Space " to one of these addresses: listserv@uga (BITNET), rice::boyle (SPAN/NSInet), utadnx::utspan::rice::boyle (THENET), or space-REQUEST@isu.isunet.edu (Internet). ---------------------------------------------------------------------- Date: 18 Dec 92 16:19:18 From: Steinn Sigurdsson Subject: Aurora Newsgroups: sci.space In article mt90dac@brunel.ac.uk (Del Cotter) writes: In article Steinn Sigurdsson writes: >In article 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 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@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" 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 ------------------------------