philj@tekig5.PEN.TEK.COM (Phil Jansen) (11/30/89)
Hi. I heard a rumor that NASA was working on improving the shuttle main
engine thrust by 50% (maximum power right now is 104% -- they froze the
standard thrust rating at 100% power, then kept improving the engine).
My question is, why improve thrust to ~150%? Since the shuttle was designed
for only 3G's of acceleration, what good does the extra power do? Doesn't it
just mean you use your fuel faster?
Thanks for your explanations.
--
If you repeat things often enough, they become true.
Phil Jansen If you repeat things often enough, they become true.
philj@tekig5.pen.tek.com If you repeat things often enough, they become true.jbayer@ispi.UUCP (Jonathan Bayer) (11/30/89)
philj@tekig5.PEN.TEK.COM (Phil Jansen) writes: >Hi. I heard a rumor that NASA was working on improving the shuttle main >engine thrust by 50% (maximum power right now is 104% -- they froze the >standard thrust rating at 100% power, then kept improving the engine). >My question is, why improve thrust to ~150%? Since the shuttle was designed >for only 3G's of acceleration, what good does the extra power do? Doesn't it It means that the shuttle would be able to carry a larger load into space. I don't know how true this rumor is, since they are having problems making sure the current engines continue to run reliably. JB -- Jonathan Bayer Intelligent Software Products, Inc. (201) 245-5922 500 Oakwood Ave. jbayer@ispi.COM Roselle Park, NJ 07204
dodson@mozart.uucp (Dave Dodson) (11/30/89)
In article <5104@tekig5.PEN.TEK.COM> philj@tekig5.PEN.TEK.COM (Phil Jansen) writes: >Hi. I heard a rumor that NASA was working on improving the shuttle main >engine thrust by 50% (maximum power right now is 104%). >My question is, why improve thrust to ~150%? Since the shuttle was designed >for only 3G's of acceleration, what good does the extra power do? Doesn't it >just mean you use your fuel faster? If an SSME failure occurs early in the flight, it is impossible to reach orbit, presumably because the remaining two engines cannot burn the fuel fast enough to impart the required energy in a timely fashion. If the remaining SSMEs could be throttled up, the Return to Launch Site and trans-Atlantic abort modes might be reduced or eliminated. Furthermore, it might be possible to use more thrust while the system is heavy to improve the payload-to-orbit capability, throttling down appropriately to prevent overstressing anything. ---------------------------------------------------------------------- Dave Dodson dodson@convex.COM Convex Computer Corporation Richardson, Texas (214) 497-4234
nickw@syma.sussex.ac.uk (Nick Watkins) (12/04/89)
In article <5104@tekig5.PEN.TEK.COM> philj@tekig5.PEN.TEK.COM (Phil Jansen) writes: >My question is, why improve thrust to ~150%? Since the shuttle was designed >for only 3G's of acceleration, what good does the extra power do? Doesn't it >just mean you use your fuel faster? Power = Force X Velocity so at constant V, more power is more thrust. Force = Mass times acceleration so at constant acceleration, more thrust is more payload. Shuttle payload is less than advertised so any improvement is worthwhile. >Thanks for your explanations. You're welcome. I've been teaching mechanics lately :-) Nick > If you repeat things often enough, they become true. >Phil Jansen If you repeat things often enough, they become true. >philj@tekig5.pen.tek.com If you repeat things often enough, they become true. -- Nick Watkins, Space & Plasma Physics Group, School of Mathematical & Physical Sciences, Univ. of Sussex, Brighton, E.Sussex, BN1 9QH, ENGLAND JANET: nickw@syma.sussex.ac.uk BITNET: nickw%syma.sussex.ac.uk@uk.ac
petej@phred.UUCP (Pete Jarvis) (12/04/89)
In article <5104@tekig5.PEN.TEK.COM> philj@tekig5.PEN.TEK.COM (Phil Jansen) writes: >Hi. I heard a rumor that NASA was working on improving the shuttle main >engine thrust by 50% (maximum power right now is 104% -- they froze the > >My question is, why improve thrust to ~150%? Since the shuttle was designed >for only 3G's of acceleration, what good does the extra power do? Doesn't it >just mean you use your fuel faster? > >Phil Jansen If you repeat things often enough, they become true. Yes, they are working on an improved engine design. They aren't doing it to make the Shuttle go faster, but to allow for heavier payloads. I believe another reason is to use them on the Shuttle-C, a cargo version of today's Shuttle. ..........Peter Jarvis.......... Physio-Control Redmond, WA.
john@frog.UUCP (John Woods) (12/07/89)
In article <5104@tekig5.PEN.TEK.COM>, philj@tekig5.PEN.TEK.COM (Phil Jansen) writes: > Hi. I heard a rumor that NASA was working on improving the shuttle main > engine thrust by 50% (maximum power right now is 104% -- they froze the > standard thrust rating at 100% power, then kept improving the engine). > My question is, why improve thrust to ~150%? Since the shuttle was designed > for only 3G's of acceleration, what good does the extra power do? Doesn't it > just mean you use your fuel faster? No explanations, just wild-assed speculations: (0) [I assume, without waking up enough to think it through, that lifting capacity is going to be limited by the size of the tanks, hence that is NOT why they are improving to 150%] (1) This much extra power would make one-engine-out an annoyance, rather than something that drastically changes the mission profile. (2) This much extra power would come in real handy for the Shuttle-C, which could be beefed up quite a bit and still save weight over having a crew. -- John Woods, Charles River Data Systems, Framingham MA, (508) 626-1101 ...!decvax!frog!john, john@frog.UUCP, ...!mit-eddie!jfw, jfw@eddie.mit.edu Happiness is Planet Earth in your rear-view mirror. - Sam Hurt
henry@utzoo.uucp (Henry Spencer) (12/09/89)
In article <10631@frog.UUCP> john@frog.UUCP (John Woods) writes: >(0) [I assume, without waking up enough to think it through, that lifting >capacity is going to be limited by the size of the tanks, hence that is NOT >why they are improving to 150%] They'd still reduce gravity losses somewhat by accelerating more rapidly, so there would be some benefit. Also, there are several schemes for getting more fuel into the tank, if it comes to that. (The simplest is to just cool the LOX and LH2 below their boiling points to increase their density.) -- 1233 EST, Dec 7, 1972: | Henry Spencer at U of Toronto Zoology last ship sails for the Moon. | uunet!attcan!utzoo!henry henry@zoo.toronto.edu