craig@think.COM (Craig Stanfill) (09/26/88)
The recent discussion of how a heavylift booster might be constructed
from space shuttle components sounds encouraging. My understanding
is that the SSME is much more efficient than engines from the Saturn
days. Also, by the standards of large solid-fuel boosters, the Shuttle
SRB's aren't _too_ awful in terms of how often they blow up; with the
limited redesign just completed they might actually be reasonably safe.
Of course, it is a littly looney putting men on top of solid-fueled
boosters.
We've now paid for developing some nice engines, which I believe are
the longest lead-time and most expensive (development-wise) components
of a launch system. If we can use them as the basis for a family of
expendables, we'll undo part of the damage of the past several years.
If Shuttle engines are produced in sufficient quantity to be usable in
expendables, the cost ought to come down and the reliability ought to
increase.
There are, however, some fundamental questions:
1. How much better are SSME's than other liquid-fueled engines?
2. How do the SRB's compare to other large solids in terms
of reliability and cost?
3. How would the cost & lead time for developing a launch vehicle
based on Shuttle components compare with developing one from
scratch?
4. How would the cost of developing a family of launch vehicles
(varying the number of SSME's and SRBs) compare with the
cost of independent development efforts?
5. Is it plausible that shuttle-based launch vehicles could
replace the Titan?
bturner@hpcvlx.HP.COM (Bill Turner) (09/28/88)
> If Shuttle engines are produced in sufficient quantity to be usable in > expendables, the cost ought to come down and the reliability ought to > increase. Totally ignorant question, but what the hell? Would it be possible to design at least the first stage to be recoverable? Sort of like the SRBs which are retrieved. At least, save the engines. (Course, after the splashdown/recovery, I don't know if I'd trust 'em...)
campbelr@hpsel1.HP.COM (Bob Campbell) (09/28/88)
These are coming from different sources, and all but the SSME do not specify altitude that the thrust is measured at, but might help you compare the sizes involved. Engine thrust -------------------------------------------------- SSME 417,300 lbs (sea level) 512,300 lbs (vacuum) Saturn V Stage 1 7,570,000 lbs (5 F-1 engines - LOX/RP-1) Stage 2 1,125,000 lbs (5 J-2 engines - LOX/LH2) Stage 3 230,000 lbs (1 J-2 engine - LOX/LH2) Titan III-E Stage 0 2,400,000 lbs (solid motor) Stage 1 520,000 lbs Stage 2 101,000 lbs Stage 3 30,000 lbs If you want more information, get thee to the local library. If you are not looking at building a rocket, the basics of propulsion are not too difficult to pick up. Bob Campbell Some times I wish that I could stop you from campbelr@hpda.hp.com talking, when I hear the silly things you say. Hewlett Packard - Elvis Costello
leonard@bucket.UUCP (Leonard Erickson) (09/29/88)
In article <28624@think.UUCP> craig@think.COM (Craig Stanfill) writes:
<Of course, it is a littly looney putting men on top of solid-fueled
<boosters.
I wonder if Alan Shepard (Mercury-Redstone) and Gagarin (early Soviet
boosters were solid fueled too, as I recall) would agree with you?
--
Leonard Erickson ...!tektronix!reed!percival!bucket!leonard
CIS: [70465,203]
"I used to be a hacker. Now I'm a 'microcomputer specialist'.
You know... I'd rather be a hacker."henry@utzoo.uucp (Henry Spencer) (09/30/88)
In article <28624@think.UUCP> craig@think.COM (Craig Stanfill) writes: > 1. How much better are SSME's than other liquid-fueled engines? In terms of performance, they are quite a bit better than the other big liquid-fueled engines that are in production today. When you factor in reliability and cost, the picture may not be quite so rosy, especially if you are comparing to no-longer-available engines like the F-1. The SSMEs win, basically, because they are the only big hydrogen engines you can get (outside the USSR, anyway). > 2. How do the SRB's compare to other large solids in terms > of reliability and cost? Knowing NASA, the cost is probably a bit on the high side. Reliability is okay, given that no solid has exactly a glorious reliability record. > 3. How would the cost & lead time for developing a launch vehicle > based on Shuttle components compare with developing one from > scratch? Depends on who's doing it. If it's the government, using Shuttle hardware certainly is a considerable win. > 4. How would the cost of developing a family of launch vehicles > (varying the number of SSME's and SRBs) compare with the > cost of independent development efforts? Not clear exactly what you mean, but varying the number of SSMEs, in particular, isn't a big deal if you don't want big variations. Varying the number of SRBs is a bigger problem because the current launch facilities are built for exactly 2 SRBs per vehicle. > 5. Is it plausible that shuttle-based launch vehicles could > replace the Titan? No, because the shuttle and its derivatives are NASA vehicles, and the Titan is a USAF vehicle, and that alone ensures that the Titan will be continued. Remember that Titan launches, production, and development went on (albeit slowly and with some difficulty) even when official government policy was "all expendable launchers are to be discontinued in favor of the shuttle". -- The meek can have the Earth; | Henry Spencer at U of Toronto Zoology the rest of us have other plans.|uunet!attcan!utzoo!henry henry@zoo.toronto.edu
knudsen@ihlpl.ATT.COM (Knudsen) (09/30/88)
Thanks for those thrust figures. Assuming that by SSME you meant ONE engine, the Orbiter packs 1.5M lbs thrust without the SRBs. This is what it goes into orbit with. It's still only 1/5 of a Saturn 1st stage (or almost exactly one F1 engine), but if you look at the thrust figures for the 2nd or 3rd stage of the Saturn or Titan, you see that the Shuttle blows everything else away in terms of thrust into orbit. Gratned much of that thrust goes into the ET and the orbiter that has to return to Earth, leaving a fraction for the payload, but still I was impressed. I was pretty impressed late this morning too :-) :-) :-)! How about when they got to T-30 sec and announced that no, they were NOT going to hold....
mjohnson@encad.Wichita.NCR.COM (Mark Johnson) (10/01/88)
In article <1074@bucket.UUCP> leonard@bucket.UUCP (Leonard Erickson) writes: >I wonder if Alan Shepard (Mercury-Redstone) and Gagarin (early Soviet >boosters were solid fueled too, as I recall) would agree with you? NO NO NO NO NO!!!! The Redstone booster was a liquid fueled vehicle, as was the Atlas, the Titan, AND the USSR's RD-107 standard booster (used for Vostok, Voskhod, Sputnik, etc). The RD-107 was a low-tech booster with a cluster of 20 fairly small kerosene/LOX motors running at about 1100 psi chamber pressure but it was indeed a liquid burner. The Shuttle is the first attempt anywhere that I know of to actually build man-rated solid motors (although they would have been used on the Titan 3 which would have lofted the Air Farce (-: MOL project, which was cancelled). I think we've paid pretty dearly for this so called 'cost saving' on those solids. -- Mark Johnson (Mark.Johnson@Wichita.NCR.COM) NCR Engineering & Manufacturing-Wichita, KS phone: (316)636-8189 email:...!rutgers!hplabs!hp-sdd!ncr-sd!ncrwic!encad!mjohnson US snailnet: 3718 N. Rock Rd., Wichita, KS 67226
henry@utzoo.uucp (Henry Spencer) (10/02/88)
In article <1074@bucket.UUCP> leonard@bucket.UUCP (Leonard Erickson) writes: ><Of course, it is a littly looney putting men on top of solid-fueled ><boosters. > >I wonder if Alan Shepard (Mercury-Redstone) and Gagarin (early Soviet >boosters were solid fueled too, as I recall) would agree with you? Probably. The Redstone that launched Shepard was a liquid-fuel rocket. Ditto the Atlas (orbital Mercury flights), Titan 2 (Gemini), and Saturn (Apollo). Ditto the "A" booster that launched Gagarin (and, slightly souped up, still launches Soyuz). The shuttle is the first man-rated booster to use solids in a significant role, although small solids have been used for things like retrorockets for a long time. -- The meek can have the Earth; | Henry Spencer at U of Toronto Zoology the rest of us have other plans.|uunet!attcan!utzoo!henry henry@zoo.toronto.edu
tomas@Apple.COM (Tom Taylor) (10/03/88)
In article <1074@bucket.UUCP> leonard@bucket.UUCP (Leonard Erickson) writes: >In article <28624@think.UUCP> craig@think.COM (Craig Stanfill) writes: ><Of course, it is a littly looney putting men on top of solid-fueled ><boosters. > >I wonder if Alan Shepard (Mercury-Redstone) and Gagarin (early Soviet >boosters were solid fueled too, as I recall) would agree with you? I looked it up this weekend... The Redstone booster uses liquid oxygen, ethel alcohol, and water as its fuel. Tom Taylor Development Systems Group
campbelr@hpsel1.HP.COM (Bob Campbell) (10/05/88)
> Thanks for those thrust figures. Assuming that by SSME you meant > ONE engine, the Orbiter packs 1.5M lbs thrust without the SRBs. > This is what it goes into orbit with. Your welcome. As you assumed, the figures are for one SSME. > I was pretty impressed late this morning too :-) :-) :-)! > How about when they got to T-30 sec and announced that no, they > were NOT going to hold.... I was going to strangle Peter Jennings for talking over the NASA people that could be heard in the background. Whatever happened to remaining quiet for the last minute??? It did leave my knuckles white, but then we drift . . . ------------------------------------------------------------------------- Bob Campbell Some times I wish that I could stop you from campbelr@hpda.hp.com talking, when I hear the silly things you say. Hewlett Packard - Elvis Costello