reyn@trsvax.UUCP (01/20/88)
Does anyone know the current status of plans to replace the SRBs with liquid rocket boosters? What is the estimated development time for liquid boosters, and what increase in payload could reasonably be expected? 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? If so, what is the expected development time for said vehicle, and what projected payload? 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)? 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? When is the next scheduled Shuttle launch? I heard a rumor about August, and I hoped that they meant '88. John Reynolds
henry@utzoo.uucp (Henry Spencer) (02/03/88)
> 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
bob@its63b.ed.ac.uk (ERCF08 Bob Gray) (02/09/88)
In article <1988Feb3.140727.13026@utzoo.uucp> henry@utzoo.uucp (Henry Spencer) writes: >> 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. Somewhere, at the back of my memory, I remember an article on development work being done by the DoD on SRBs using composite materials to reduce their weight. This was supposed to make it easier to launch polar orbiting missions from Vandenberg. This was about three or four years ago, before challenger. Does anyone know what happened to this work? And if work has been done on this, why hasn't that work been used in the SRB re-design. Other than not being done by MT, that is. FOOTNOTE: There has been speculation here that thanks to the presidential elections, it would be politically unacceptable to risk re-launching the shuttle. Remember the weather will be getting cold again, if there is any more delay in the launch schedule, and no-one will be willing to risk annother explosion just before the new president is elected. Bob.
henry@utzoo.uucp (Henry Spencer) (02/18/88)
> Somewhere, at the back of my memory, I remember an article on > development work being done by the DoD on SRBs using > composite materials to reduce their weight... > > This was about three or four years ago, before challenger. > Does anyone know what happened to this work? Ah yes, the filament-wound casings. They were tested and pretty much seemed to work. There were (unofficial) grave doubts that they would ever be reusable (although it is not clear that reuse of the metal casings is really all that worthwhile). I believe they currently are pretty much in limbo -- the USAF requirement for them has sort of quietly gone away, and it's not clear that NASA trusts them enough to use them. They are of rather more complex construction, with more joints (the field joints themselves have to be metal, so each filament-wound segment is two metal rings joined by a composite main body), and that's enough to make people nervous these days. At the very least, nobody is going to want to fly with them until they've undergone some more stringent ground tests, and that won't happen until the more stringent testing of the metal SRBs is fairly well complete. -- Those who do not understand Unix are | Henry Spencer @ U of Toronto Zoology condemned to reinvent it, poorly. | {allegra,ihnp4,decvax,utai}!utzoo!henry