brody@eos.UUCP (Adam R. Brody) (09/19/90)
I was reading For All Mankind last night and it claimed that at 2:15 MET, the middle engine of the S-1C first stage goes out while the surrounding four burn until completion. The same thing occurs with the SII second stage at 3:30. Why is this? The book also mentioned that Apollo took 1.5 orbits around the Earth before TLI to gain momentum much like a discus thrower. Can somebody explain this? Can it be like a gravity assist to another planet?
dil@mace.cc.purdue.edu (Perry G Ramsey) (09/20/90)
In article <7285@eos.UUCP>, brody@eos.UUCP (Adam R. Brody) writes: > middle engine of the S-1C first stage goes out while the surrounding four > burn until completion. The same thing occurs with the SII second stage at > 3:30. Why is this? The inboard engines of the Saturn V shut down to reduce acceleration. As the fuel burned, the stack got lighter, so the same thrust resulted in higher acceleration. To keep the loads down, they shut down one engine. The engines also became more efficient as the ambient pressure went down, so the raw thrust increased. Note that the Shuttle solids have the propellant properties tailored to make the thrust go down as the vehicle gets higher. > The book also mentioned that Apollo took 1.5 orbits around the Earth before > TLI to gain momentum much like a discus thrower. Can somebody explain this? > Can it be like a gravity assist to another planet? The parking orbit was just to check out the vehicle before proceeding to the moon. There was no momentum gain. -- Perry G. Ramsey Department of Earth and Atmospheric Sciences perryr@vm.cc.purdue.edu Purdue University dil@mace.cc.purdue.edu We've looked at clouds from ten sides now, And we REALLY don't know clouds, at all.
dsmith@hplabsb.HP.COM (David Smith) (09/20/90)
In article <7285@eos.UUCP> brody@eos.UUCP (Adam R. Brody) writes: >..middle engine of the S-1C first stage goes out while the surrounding four >burn until completion. The same thing occurs with the SII second stage at >3:30. Why is this? To limit the peak acceleration loads. >The book also mentioned that Apollo took 1.5 orbits around the Earth before >TLI to gain momentum much like a discus thrower. Can somebody explain this? >Can it be like a gravity assist to another planet? Not a gravity assist, nor momentum gain. They wanted to go into a parking orbit so they could check out vehicle operation in space before committing to lunar transfer. The orbit was inclined 28.5 degrees to the equator, and if TLI occurred over Canaveral, the spacecraft would climb out toward the opposite place in the sky 28.5 deg. south, where the Moon isn't. Instead, TLI took place in that part of the orbit which was opposite the planned rendezvous point with the Moon. -- "Some fear that Newtonian physics | David R. Smith, HP Labs governs superpower relations: | dsmith@hplabs.hp.com What goes up must come down." | (415) 857-7898 Time Magazine, interviewing Gorbachev, June 4, 1990
roberts@larry.sal.wisc.edu (Tim Roberts) (09/21/90)
>In article <7285@eos.UUCP>, brody@eos.UUCP (Adam R. Brody) writes: >> middle engine of the S-1C first stage goes out while the surrounding four >> burn until completion. The same thing occurs with the SII second stage at >> 3:30. Why is this? > >In article <5556@mace.cc.purdue.edu> dil@mace.cc.purdue.edu (Perry G Ramsey) >writes: >The inboard engines of the Saturn V shut down to reduce acceleration. Sorry, but that is half the story. The first Saturn flights had trouble with oscillations of a compression wave, i.e. the rocket got longer and shorter due to harmonic coupling of the acceleration vs. gravity. To reduce the effect (called the "Pogo effect") they either had to stiffen the rocket longitudinally or break the harmonics. The solution was to maintain wave interference by shutting off the center engine. Apollo 7 rode a Saturn 1b and they had the shorts scared off them by this Pogo stick ride to orbit. I believe the solution was found in time for Apollo 8, which was the first manned Saturn V. -Tim
brody@eos.UUCP (Adam R. Brody) (09/21/90)
>> The book also mentioned that Apollo took 1.5 orbits around the Earth before >> TLI to gain momentum much like a discus thrower. Can somebody explain this? >> Can it be like a gravity assist to another planet? >The parking orbit was just to check out the vehicle before proceeding to >the moon. There was no momentum gain. That is what I thought also but the book very clearly and explicitly mentioned the gain and the analogy to a discus thrower.
jabishop@uokmax.ecn.uoknor.edu (Jonathan A Bishop) (09/21/90)
roberts@larry.sal.wisc.edu (Tim Roberts) writes: >Sorry, but that is half the story. The first Saturn flights had trouble >with oscillations of a compression wave, i.e. the rocket got longer and >shorter due to harmonic coupling of the acceleration vs. gravity. To >reduce the effect (called the "Pogo effect") they either had to stiffen >the rocket longitudinally or break the harmonics. The solution was to >maintain wave interference by shutting off the center engine. Apollo >7 rode a Saturn 1b and they had the shorts scared off them by this Pogo >stick ride to orbit. I believe the solution was found in time for Apollo >8, which was the first manned Saturn V. Seems reasonable, but apparently shutting off the engine wasn't always enough to prevent pogo, since Apollo 10's ascent was quite rough. -- jabishop@uokmax.ecn.uoknor.edu "Ground Control to Major Tom: Your circuit's dead; there's something wrong. Can you hear me, Major Tom?" -- David Bowie
nickw@syma.sussex.ac.uk (Nick Watkins) (09/24/90)
From article <7294@eos.UUCP>, by brody@eos.UUCP (Adam R. Brody): >>> The book also mentioned that Apollo took 1.5 orbits around the Earth before >>> TLI to gain momentum much like a discus thrower. Can somebody explain this? >>> Can it be like a gravity assist to another planet? > >>The parking orbit was just to check out the vehicle before proceeding to >>the moon. There was no momentum gain. > > That is what I thought also but the book very clearly and explicitly > mentioned the gain and the analogy to a discus thrower. Indeed. The book is wrong. The book also says: 1) Chuck Yeager broke the sound barrier in the X15 2) Saturn V first stage uses liquid hydrogen 3) "Direct Ascent" means firing engines all the way to the moon. 4) Saturn V Rockets only accelerate because they are getting lighter (he also seems to think that G force increasing means gravity is increasing). My personal favourite, this. 5) LH2/LOX is hypergolic. etc etc. Book claims to have numerous proof readers & researchers but what they were doing escapes me. Only value of this book is the astronaut stories & even there a lot is borrowed from "Carrying the Fire" etc. Book also acknowledges Larry Hagman ("JR"). I wonder how he helped ? Nick -- Dr. 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
megazone@wpi.WPI.EDU (MEGAZONE 23) (09/25/90)
In article <3498@syma.sussex.ac.uk> nickw@syma.sussex.ac.uk (Nick Watkins) writes: >2) Saturn V first stage uses liquid hydrogen I was under the impression that it DID burn LH2 and LOX. >5) LH2/LOX is hypergolic. Oh boy, you mean it isn't? (This is a joke, the above isn't.) >Book also acknowledges Larry Hagman ("JR"). I wonder how he helped ? He played an astronaut in 'I Dream of Genie' ############################################################################### # "Calling Garland operator 7G," EVE Email megazone@wpi.wpi.edu # # MEGAZONE, aka DAYTONA, aka BRIAN BIKOWICZ Bitnet Use a gateway. Sorry. # ###############################################################################
clj@ksr.com (Chris Jones) (09/25/90)
In article <15953@wpi.WPI.EDU>, megazone@wpi (MEGAZONE 23) writes: >In article <3498@syma.sussex.ac.uk> nickw@syma.sussex.ac.uk (Nick Watkins) writes: >>[someone's book falsely claims that] Saturn V first stage uses liquid hydrogen > >I was under the impression that it DID burn LH2 and LOX. > No, the second and third stages did (they used the same engine design, while the first stage was different). The first stage burned RP-1 (Rocket Propellant 1, which is kerosene with an attitude) and LOX. > >>Book also acknowledges Larry Hagman ("JR"). I wonder how he helped ? > >He played an astronaut in 'I Dream of Genie' He must have made available the scientific advisors for that show. -- Chris Jones clj@ksr.com {world,uunet,harvard}!ksr!clj
henry@zoo.toronto.edu (Henry Spencer) (09/25/90)
In article <15953@wpi.WPI.EDU> megazone@wpi.WPI.EDU (MEGAZONE 23) writes: >>2) Saturn V first stage uses liquid hydrogen > >I was under the impression that it DID burn LH2 and LOX. No; the first stage used kerosene (well, RP-1), not LH2. -- TCP/IP: handling tomorrow's loads today| Henry Spencer at U of Toronto Zoology OSI: handling yesterday's loads someday| henry@zoo.toronto.edu utzoo!henry
lwake@runcible.West.Sun.COM (Larry Wake) (09/26/90)
In article <3498@syma.sussex.ac.uk> nickw@syma.sussex.ac.uk (Nick Watkins) writes: >Book also acknowledges Larry Hagman ("JR"). I wonder how he helped ? Well, he *was* an astronaut before he was an oil baron. Or aren't you blessed with "I Dream of Jeannie" reruns in the UK? -- Larry Wake, Sun Microsystems (larry.wake@west.sun.com) "I've got gadgets and gizmos a-plenty..."
nickw@syma.sussex.ac.uk (Nick Watkins) (09/26/90)
From article <15953@wpi.WPI.EDU>, by megazone@wpi.WPI.EDU (MEGAZONE 23): > In article <3498@syma.sussex.ac.uk> nickw@syma.sussex.ac.uk (Nick Watkins) writes: >>2) Saturn V first stage uses liquid hydrogen > > I was under the impression that it DID burn LH2 and LOX. In case any one else is under same impression, SIC used Kerosene & LOX, upper stages (SII & SIVB) *only* used LOX & LH2. I think shuttle (& Energia core ?) are only cases of LH2 being used in stages which ignite on the ground, please correct me if I'm wrong. Nick -- Dr. 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
andy@syma.sussex.ac.uk (Andy Clews) (09/26/90)
From article <3513@syma.sussex.ac.uk>, by nickw@syma.sussex.ac.uk (Nick Watkins): >> I was under the impression that it DID burn LH2 and LOX. > In case any one else is under same impression, SIC used Kerosene & LOX, Close examination of a colour photograph of a Saturn V liftoff will show the exhaust to have a brown colouration immediately below the S1C nozzles, which is a little longer than the nozzles themselves, and just before the brilliant white flame starts. This "brown"(?) exhaust is also apparent on close-up film footage of the liftoff (good example in the For All Mankind movie) as the rocket nozzles pass the camera. I assume this is the exhaust from the burnt Kerosene, anyone else know better or more? LH2/LOX exhaust would, I assume, be colourless or blue/white (as on Shuttle's SSMEs). -- Andy Clews, Computing Service, Univ. of Sussex, Brighton BN1 9QN, England JANET: andy@syma.sussex.ac.uk BITNET: andy%syma.sussex.ac.uk@uk.ac
gary@ke4zv.UUCP (Gary Coffman) (09/26/90)
In article <3498@syma.sussex.ac.uk> nickw@syma.sussex.ac.uk (Nick Watkins) writes: > >Book also acknowledges Larry Hagman ("JR"). I wonder how he helped ? Why everyone knows that Larry Hagman was one of the original NASA astronauts. They all saw it on "I Dream of Jeannie". :-) Gary
petej@phred.UUCP (Pete Jarvis) (09/26/90)
In article <15953@wpi.WPI.EDU> megazone@wpi.WPI.EDU (MEGAZONE 23) writes: >>2) Saturn V first stage uses liquid hydrogen >I was under the impression that it DID burn LH2 and LOX. > >############################################################################### ># "Calling Garland operator 7G," EVE Email megazone@wpi.wpi.edu # ># MEGAZONE, aka DAYTONA, aka BRIAN BIKOWICZ Bitnet Use a gateway. Sorry. # >############################################################################### The Saturn V first stage burned an aviation-grade kerosene. Peter Jarvis, Physio-Control
petej@phred.UUCP (Pete Jarvis) (09/26/90)
In article <3261@phred.UUCP> petej@phred.UUCP (Pete Jarvis) writes: >> >The Saturn V first stage burned an aviation-grade kerosene. > I should have said "aviation-grade kerosene and LOX". P.J............
davet@tsdiag.ccur.com (Dave Tiller N2KAU) (09/27/90)
In article <15953@wpi.WPI.EDU> megazone@wpi.WPI.EDU (MEGAZONE 23) writes: -In article <3498@syma.sussex.ac.uk> nickw@syma.sussex.ac.uk (Nick Watkins) writes: ->2) Saturn V first stage uses liquid hydrogen - -I was under the impression that it DID burn LH2 and LOX. I'm pretty sure it burned LOX and (hee..hee) Kerosene! Really... -- David E. Tiller davet@tsdiag.ccur.com | Concurrent Computer Corp. FAX: 201-870-5952 Ph: (201) 870-4119 (w) | 2 Crescent Place, M/S 117 UUCP: ucbvax!rutgers!petsd!tsdiag!davet | Oceanport NJ, 07757 ICBM: 40 16' 52" N 73 59' 00" W | N2KAU @ NN2Z
jerry@altos86.Altos.COM (Jerry Gardner) (09/27/90)
In article <15953@wpi.WPI.EDU> megazone@wpi.WPI.EDU (MEGAZONE 23) writes: >In article <3498@syma.sussex.ac.uk> nickw@syma.sussex.ac.uk (Nick Watkins) writes: }}2) Saturn V first stage uses liquid hydrogen } }I was under the impression that it DID burn LH2 and LOX. It does not, rather it burns kerosene and LOX. -- Jerry Gardner, NJ6A Altos Computer Systems UUCP: {sun|pyramid|sco|amdahl|uunet}!altos!jerry 2641 Orchard Parkway Internet: jerry@altos.com San Jose, CA 95134 Guns don't kill people, bullets do. (408) 432-6200
dil@mace.cc.purdue.edu (Perry G Ramsey) (09/27/90)
In article <1096@tsdiag.ccur.com>, davet@tsdiag.ccur.com (Dave Tiller N2KAU) writes: > > I'm pretty sure it burned LOX and (hee..hee) Kerosene! Really... > -- > David E. Tiller davet@tsdiag.ccur.com | Concurrent Computer Corp. RP-1 is nothing to snicker at. Hydrogen is light and has a high Isp, but it has very poor volumetric efficiency (a fancy way to say it takes up a lot of space.) If the Saturn first stage had been hydrogen powered, the fuel tanks would have been a lot larger (I can gen some more reliable numbers if anyone is interested, but 5 or 6 to 1 is about right.) Take a look at a cutaway of the external tank and see how much is for the liquid hydrogen. Or better yet, look at cutaways of the S-IC and S-II. The difference in fuel tank size is very apparent. RP-1 is the booster fuel in the Delta and Atlas, which are still the most reliable launch vehicles around. Hydrogen makes sense for upper stages, but using it to boost from the ground is not so great. There have been proposals to switch the Shuttle to hydrocarbons, usually liquified natural gas (methane), or liquified petroleum gas (propane), both for volumetric efficiency and ease of handling. Imminently sensible proposals, IMHO. -- Perry G. Ramsey Department of Earth and Atmospheric Sciences perryr@vm.cc.purdue.edu Purdue University, W. Lafayette, IN USA dil@mace.cc.purdue.edu We've looked at clouds from ten sides now, And we REALLY don't know clouds, at all.
drudetb@infonode.ingr.com (Ted B. Drude) (09/28/90)
In article <5633@mace.cc.purdue.edu> dil@mace.cc.purdue.edu (Perry G Ramsey) writes: >RP-1 is the booster fuel in the Delta and Atlas, which are still the ^^^^^ Ahem. I beg to differ. The Atlas DOES use LH2 for its booster fuel. In fact, it was the use of hydrogen fuel that made it possible for the Atlas to have such high payload weights for its day (late 50's-early 60's). >Hydrogen makes sense for upper stages, but using it to boost from >the ground is not so great. Until Energia (which also uses hydrogen) the Soviets had used nothing but kerosene/LOX for fuel. They've had huge boosters, but relatively small payloads for their size. BTW, when NASA started to put Mercury capsules on Atlases (instead of Redstones), there was a lot of concern about having humans ride on hydrogen- based boosters. Von Braun was not convinced of the safety of hydrogen fuel. (Which may partly explain why the Saturn V had a kerosene first stage.) Reportedly, when he first heard that one of the astronauts was going to ride an Atlas into orbit (was it Glenn?) his reply was "He ought to get a medal just for sitting on it!" -Ted Drude drudtb@ingr of !ingr!infonode!drudetb
dil@mace.cc.purdue.edu (Perry G Ramsey) (09/30/90)
In article <1990Sep28.151756.3973@infonode.ingr.com>, drudetb@infonode.ingr.com (Ted B. Drude) writes: > In article <5633@mace.cc.purdue.edu> dil@mace.cc.purdue.edu (Perry G Ramsey) writes: > >RP-1 is the booster fuel in the Delta and Atlas, which are still the > ^^^^^ > Ahem. I beg to differ. The Atlas DOES use LH2 for its booster fuel. > In fact, it was the use of hydrogen fuel that made it possible for the Atlas > to have such high payload weights for its day (late 50's-early 60's). GARBAGE! Go look in any reference. The Atlas is RP-1 and LOX. The Centaur upper stage used along with the Atlas now is LH2, but the basic booster uses RP-1. > >Hydrogen makes sense for upper stages, but using it to boost from > >the ground is not so great. > > Until Energia (which also uses hydrogen) the Soviets had used nothing > but kerosene/LOX for fuel. They've had huge boosters, but relatively > small payloads for their size. Because the structures are so heavy. Besides, as I said before, hydrogen does make sense in the upper stages, where weight is at a great premium. For the first stage, though, the volume of fuel consumed tends to override the weight savings. I had my Saturn V flight manual (AS-507) out last night, and I don't remember all the details, but the SII had a fuel tank 50% larger than the S-IC, even though its total impulse was about 1/3 that of the S-IC (410 million pound force-seconds vs. 1440 ) Now, it's true that if LH2 had been used for the booster stage, all that impulse wouldn't have been necessary, due to the lower fuel weight, but the added size of the tankage would have made the stage heavier, and making a clear comparison takes a lot more time than I have. Everything is a trade off. For the upper stages, hydrogen is the clear winner, but for the booster, it isn't so certain. > BTW, when NASA started to put Mercury capsules on Atlases [etc.... based on the incorrect assertion that the Atlas was LH2]i > [von Braun's] reply was "He ought to get a medal just for sitting on it!" Up to that time, there had been a lot of problems with Atlases blowing up or otherwise not making it to orbit. It doesn't change the fact that it was an RP-1 fueled vehicle. (was it Glenn?) Yes, John Glenn was the first American to orbit the earth. (You mean you know all about boosters, but you don't know what every six year old space buff knows? Interesting.) -- Perry G. Ramsey Department of Earth and Atmospheric Sciences perryr@vm.cc.purdue.edu Purdue University, W. Lafayette, IN USA dil@mace.cc.purdue.edu We've looked at clouds from ten sides now, And we REALLY don't know clouds, at all.
henry@zoo.toronto.edu (Henry Spencer) (09/30/90)
In article <1990Sep28.151756.3973@infonode.ingr.com> drudetb@infonode.UUCP (Ted B. Drude) writes: >Ahem. I beg to differ. The Atlas DOES use LH2 for its booster fuel. Sorry, you are misinformed. LOX and kerosene. The Centaur upper stage, when it is used (it wasn't for, e.g., Mercury), does burn hydrogen. >In fact, it was the use of hydrogen fuel that made it possible for the Atlas >to have such high payload weights for its day (late 50's-early 60's). Sorry again. Hydrogen had nothing to do with it. Hydrogen engines were not sufficiently well developed to be used for Atlas; NASA had considerable trouble getting them ready in time for Centaur and Saturn. Atlas's high payload mass with a 1.5-stage launcher was due mostly to the use of "balloon tanks", relying on tank pressurization for most of the structural strength of the rocket. Exploiting the extra strength of pressurized tanks was not novel, but relying on it to the extent that the rocket would collapse unless pressurized was. This gave outstandingly low structural weights, and a plain Atlas (no Centaur) is the closest thing to a single-stage-to-orbit launcher the US has ever built. (For those who are mystified about how you get half a stage: Atlas drops two of its three engines, and some associated structure and equipment, partway up. The third engine burns from launch to orbit.) >Until Energia (which also uses hydrogen) the Soviets had used nothing >but kerosene/LOX for fuel... Well, not strictly true. They also use the UDMH/N2O4 combination in some of their boosters, notably the first stage of Proton as I recall. >BTW, when NASA started to put Mercury capsules on Atlases (instead of >Redstones), there was a lot of concern about having humans ride on hydrogen- >based boosters... No, there was a lot of concern about having humans ride on Atlas in particular. Its reliability record was dismal. NASA lost a lot of lunar and planetary probes to Atlas failures in the early days, and of course it was NASA that got blamed for it. >...(Which may partly explain why the Saturn V had a kerosene first >stage.)... No, the reasons for the kerosene first stage are quite simple and well known. The single biggest reason for hydrogen's high exhaust velocity (which makes it a lightweight fuel for upper stages) is the low molecular weight of the exhaust. This works *against* it in first stages, because low molecular weight also means low thrust for a given engine size, other things being equal. First stages are not too sensitive to weight but care a lot about thrust, and being big they also prefer high-density fuels (which hydrogen isn't). All of this might have meant kerosene in any case for the S-IC stage... but it was academic, because there simply was no prospect of developing a sufficiently large hydrogen engine in time. Getting the J-2 ready for the second and third stages was hard enough. -- Imagine life with OS/360 the standard | Henry Spencer at U of Toronto Zoology operating system. Now think about X. | henry@zoo.toronto.edu utzoo!henry
jabishop@uokmax.ecn.uoknor.edu (Jonathan A Bishop) (10/01/90)
drudetb@infonode.ingr.com (Ted B. Drude) writes: >Until Energia (which also uses hydrogen) the Soviets had used nothing >but kerosene/LOX for fuel. They've had huge boosters, but relatively >small payloads for their size. I don't remember the source (I think it was _The Russian Space Bluff_; I don't remember the author's name either), but I have read that the Proton booster utilized hypergolic propellants. Can anyone confirm or deny this? -- jabishop@uokmax.ecn.uoknor.edu "Ground Control to Major Tom: Your circuit's dead; there's something wrong. Can you hear me, Major Tom?" -- David Bowie
gmk@texhrc.UUCP (Gail Kahle) (10/09/90)
Does anyone know where I can get a list of the universities that have been designated as "Space Grant" universities ? I have heard that there are as many as 25, and the list includes LSU and Univ. of Calif-San Diego. Thanks. Gail Kahle Texaco, Inc. Houston, Tx