AEGQC@CUNYVM (Audra G.) (11/29/90)
The latest issue of _Analog_ has an article describing how the shuttle could be adapted as a moon ship. Apparently if the ship either carried two extra boosters or was refueled in orbit, it would be able to reach and return from lunar orbit, using a LEM-like craft carried in the cargo bay to get people to the surface of the Moon and back. If this is indeed doable (and the article had a lot of mathematics), I would like to ask if, if still more tanks were added in orbit, the shuttle could be used to reach further celestial bodies as well. Any thoughts? --Shangti
stramm@beowulf.ucsd.edu (Bernd Stramm) (11/29/90)
AEGQC@CUNYVM (Audra G.) writes: >The latest issue of _Analog_ has an article describing how the shuttle >could be adapted as a moon ship. Apparently if the ship either carried >two extra boosters or was refueled in orbit, it would be able to reach >and return from lunar orbit, using a LEM-like craft carried in the cargo >bay to get people to the surface of the Moon and back. Some of the "science fact" in Analog is just a tad speculative IMHO, and some engineering solutions a touch kludgy. (Not everybody with a PhD knows what they are doing.) In this particular case, refuelling would only help if the main engines were restartable, and I don't think they are (not even close, considering the considerable effort in refurbishing them for the next flight). And then you would be lugging all this mass (wings and such) out to the moon where it's not really useful. If you're going to use the shuttle at all, should it not be easier to just fuel up the 'LEM-like' craft in LEO and send it on? >If this is indeed >doable (and the article had a lot of mathematics), I would like to ask if, ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ Don't let that impress you, really. If basic assumptions don't hold, the prettiest math does no good. >if still more tanks were added in orbit, the shuttle could be used to reach >further celestial bodies as well. Any thoughts? --Shangti Problems with extended stay, which it's not designed for I guess, and reentry velocity when you come back. Cheers, Bernd.
hwt@bwdlh490.BNR.CA (Henry Troup) (11/29/90)
This got kicked around here a while ago. The major problem is that the shuttle engines (SSME) are not restartable. That's a truly major problem! Henry Troup - BNR owns but does not share my opinions | The .signature is the P.O. Box 3511, Stn. C. Ottawa, Ontario, Canada K1Y 4H7| lowest form of humour uunet!bnrgate!hwt%bwdlh490 HWT@BNR.CA +1 613-765-2337 |
ems@aristotle.JPL.NASA.gov (Eric Slimko) (11/30/90)
In article <90332.182944AEGQC@CUNYVM.BITNET>, AEGQC@CUNYVM (Audra G.) writes: > The latest issue of _Analog_ has an article describing how the shuttle > could be adapted as a moon ship. Apparently if the ship either carried > two extra boosters or was refueled in orbit, it would be able to reach > and return from lunar orbit, using a LEM-like craft carried in the cargo > bay to get people to the surface of the Moon and back. If this is indeed > doable (and the article had a lot of mathematics), I would like to ask if, > if still more tanks were added in orbit, the shuttle could be used to reach > further celestial bodies as well. Any thoughts? --Shangti Not to flame against the shuttle, but we have enough problems trying to make it work at what its designed for, let alone something way beyond its design specifications. :) I would guess the article included a lot of math about thrust, orbital mechanics and the like showing that it is theoretically possible, but did they consider things such as a stress analysis to the vehicle during orbit insertion? I think that a Earth-Moon "ferry" would have to be designed from the ground up for that purpose. -- Eric Slimko | Jet Propulsion Laboratories ems@aristotle.jpl.nasa.gov | NASA/CalTech
cage@fmeed1.UUCP (Russ Cage) (11/30/90)
In article <90332.182944AEGQC@CUNYVM.BITNET> AEGQC@CUNYVM (Audra G.) writes: >The latest issue of _Analog_ has an article describing how the shuttle >could be adapted as a moon ship. Yes, you can make a garbage truck do 120 MPH too, but WHY? I calculated the amount of fuel required to send a Shuttle to the moon. It amounts to many Shuttle payloads worth. It is very inefficient to send along 69,000 lbs of external tank and 140,000 lbs of superfluous airframe, engines and thermal protection on a moon trip to carry a 48,000 lb payload. And that's just for starters. Combine this with the Orbiter's limited in-space endurance, the non-restartability of the SSME's (how do you do your lunar-orbit injection and return to earth?), and a host of other factors, it makes no sense whatsoever to even think about sending a Shuttle orbiter to the moon. By the time you spent the money to do it, you could have been there already using something else. -- Russ Cage Ford Powertrain Engineering Development Department Work: itivax.iti.org!cfctech!fmeed1!cage (CHATTY MAIL NOT ANSWERED HERE) Home: russ@m-net.ann-arbor.mi.us (All non-business mail) Member: HASA, "S" division.
rambler@pnet51.orb.mn.org (Dan Meyer) (12/02/90)
AEGQC@CUNYVM (Audra G.) writes: >The latest issue of _Analog_ has an article describing how the shuttle >could be adapted as a moon ship. Apparently if the ship either carried >two extra boosters or was refueled in orbit, it would be able to reach >and return from lunar orbit, using a LEM-like craft carried in the cargo >bay to get people to the surface of the Moon and back. If this is indeed >doable (and the article had a lot of mathematics), I would like to ask if, >if still more tanks were added in orbit, the shuttle could be used to reach >further celestial bodies as well. Any thoughts? --Shangti What about 1/2 the cargo bay for fuel, and half the cargo bay for an LEM ? or maybe pick the LEM up in earth orbit, and drag it along behind as sort of a "Space Trailer", using all of the cargo bay for fuel. maybe even send the LEM to a Lunar Orbit, then making an EVA to it from the shuttle. Just some dangerous random thoughts -- Dan Meyer Remember: " Buffalo never Oink " Seen on a South Dakota travel brocure. Advertisment: Try the Railway Post Office , a railfan BBS ! (612) 377-2197. UUCP: {crash tcnet}!orbit!pnet51!rambler ARPA: crash!orbit!pnet51!rambler@nosc.mil INET: rambler@pnet51.orb.mn.org
mlindroos@abo.fi (12/03/90)
In article <3550@orbit.cts.com>, rambler@pnet51.orb.mn.org (Dan Meyer) writes: > AEGQC@CUNYVM (Audra G.) writes: >>The latest issue of _Analog_ has an article describing how the shuttle >>could be adapted as a moon ship. Apparently if the ship either carried >>two extra boosters or was refueled in orbit, it would be able to reach >>and return from lunar orbit, using a LEM-like craft carried in the cargo >>bay to get people to the surface of the Moon and back. If this is indeed >>doable (and the article had a lot of mathematics), I would like to ask if, >>if still more tanks were added in orbit, the shuttle could be used to reach >>further celestial bodies as well. Any thoughts? --Shangti > > What about 1/2 the cargo bay for fuel, and half the cargo bay for an LEM ? > or maybe pick the LEM up in earth orbit, and drag it along behind as sort of a > "Space Trailer", using all of the cargo bay for fuel. maybe even send the LEM > to a Lunar Orbit, then making an EVA to it from the shuttle. > > Just some dangerous random thoughts As for the problem with the main engines (we've been told here that they are not restartable), would it be possible to use the extra fuel for the OMS engines instead...? (my guess is it won't be, anyway). BTW, do you think the shuttle would survive the atmospheric re-entry: a spacecraft returning from the moon is after all moving at higher velocities (11 km/s?) when it hits the upper atmosphere than the shuttle was designed for (6-7 km/s). Or would it be possible to avoid the problem by first performing an aerobraking maneuver, the re-enter and land? The soviet Zond 5-8 lunar probes used this technique in the late sixties. MARCU$
v071pzp4@ubvmsb.cc.buffalo.edu (Craig L Cole) (12/04/90)
In article <7089.275a4245@abo.fi>, mlindroos@abo.fi writes... >As for the problem with the main engines (we've been told here that they are >not restartable), would it be possible to use the extra fuel for the OMS >engines instead...? (my guess is it won't be, anyway). This was my suggestion to the NASA Outreach program - the OMS are capable of burns long enough to propel the shuttle toward the Moon, but I had no idea how much fuel would be required. I suggested adding additional OMS tanks to the rear of the shuttle a la Extended Duration Orbiter kit, or mounting tanks to the outside of the shuttle back by the OMS fuel connections. These tanks could be lofted by an expendable. Along with a lunar module, etc. This way, none of it actaully has to fit in the cargo bay. >BTW, do you think the shuttle would survive the atmospheric re-entry: a >spacecraft returning from the moon is after all moving at higher velocities (11 >km/s?) when it hits the upper atmosphere than the shuttle was designed for >(6-7 km/s). Or would it be possible to avoid the problem by first performing an >aerobraking maneuver, the re-enter and land? The soviet Zond 5-8 lunar probes >used this technique in the late sixties. I may be mistaken, but back in the Apollo days, they skipped the capsule across the atmosphere before actaully deorbiting to slow it down a bit. Craig Cole V071PZP4@UBVMS.BITNET V071PZP4@UBVMS.CC.BUFFALO
cage@fmeed1.UUCP (Russ Cage) (12/06/90)
In article <7089.275a4245@abo.fi> mlindroos@abo.fi writes: >As for the problem with the main engines (we've been told here that they are >not restartable), would it be possible to use the extra fuel for the OMS >engines instead...? (my guess is it won't be, anyway). It would be easy to carry extra OMS fuel; it has been proposed before, and I've seen depictions of orbiters with a rack of fuel tanks taking up the back half of the cargo bay. The problem is the low impulse of the OMS engines. To do a trans-lunar injection burn, decelerate into lunar orbit, and burn again to return to earth takes something like a million pounds of OMS fuel. This is about 20 Shuttle payloads worth. Forget the idea of taking a Shuttle orbiter to the moon. It's stupid. Consider that the weight of the Shuttle's wings, tail, engines, landing gear, thrust structure and thermal protection system is probably 130,000 of its 160,000 lbs weight. Eliminate that and you've cut the fuel requirements by 4/5. Then dump the OMS engines and their fuel, and carry a single RL-10 engine burning hydrogen and oxygen. (These ARE restartable, and have never failed to start or restart.) This cuts the required fuel drastically, and the cost of launching it. What you wind up with would be much smaller and cheaper than a Shuttle orbiter for the same payload, and it could be built of off-the-shelf engines and other parts. -- Russ Cage Ford Powertrain Engineering Development Department Work: itivax.iti.org!cfctech!fmeed1!cage (CHATTY MAIL NOT ANSWERED HERE) Home: russ@m-net.ann-arbor.mi.us (All non-business mail) Member: HASA, "S" division.
henry@zoo.toronto.edu (Henry Spencer) (12/06/90)
In article <3550@orbit.cts.com> rambler@pnet51.orb.mn.org (Dan Meyer) writes: >What about 1/2 the cargo bay for fuel, and half the cargo bay for an LEM ? As people have pointed out repeatedly, it is far better to take the fuel and the LEM *out* of the cargo bay and send *them* to the Moon without taking a shuttle orbiter along for the ride. The parts of the orbiter that are actually useful on a lunar trip can be packaged much more compactly into something resembling the Apollo CSM, and the result will be much more useful payload delivered to the Moon. A shuttle orbiter is mostly dead weight on such a trip, and hauling that much useless mass to the Moon and back is *EXPENSIVE*. -- "The average pointer, statistically, |Henry Spencer at U of Toronto Zoology points somewhere in X." -Hugh Redelmeier| henry@zoo.toronto.edu utzoo!henry
petej@phred.UUCP (Pete Jarvis) (12/06/90)
In article <7089.275a4245@abo.fi> mlindroos@abo.fi writes: > >As for the problem with the main engines (we've been told here that they are >not restartable), would it be possible to use the extra fuel for the OMS >engines instead...? (my guess is it won't be, anyway). >MARCU$ The OMS engines use hypergolic fuel (nitrogen tetroxide and monomethyl hydrazine, I believe). The only current way to add to the OMS fuel supply is to install what is called an "OMS kit". There are provisions for extra fuels tanks. The electrical and plumbing are already available for this. There are no current plans to use the "kit" at this time. Peter Jarvis.......