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#11
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On 26 Jun 2005 07:11:26 -0700, "Matt" wrote:
I have no doubt the SSME mod is doable. However, given that NASA is preselecting a single source for the heavy-lifter engines, the contractor is likely to hold up the government with cost estimates bordering on extortion. Well, once the Rocketdyne sale to UT/P&W goes through, there will only be one source for heavy-lifter engines in the United States, so it isn't as though NASA has a lot of options. Brian |
#12
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On Sun, 26 Jun 2005 09:09:16 -0500, Herb Schaltegger
wrote: http://www.safesimplesoon.com/media-images.htm Ah, the joys of view-graph engineerning. Makes it look all so damned easy, doesn't it? Kind of like sliding down a snowy slope with your feet on two planks looks easy until the first time you try it. Well, these pretty pictures are all definitely for public relations and politics, not engineering. But you can easily make the same claim about the LockMart Atlas-5 based heavy-lifter in this week's AvLeak. At least for the SDLV, all the essential elements have either been tested or are in service, even the 5-segment SRB. The Atlas 5 Super Heavy seems to require new tooling for a wider core stage and a new pad to launch it from. Brian |
#13
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Brian Thorn wrote:
Well, these pretty pictures are all definitely for public relations and politics, not engineering. But you can easily make the same claim about the LockMart Atlas-5 based heavy-lifter in this week's AvLeak. At least for the SDLV, all the essential elements have either been tested or are in service, even the 5-segment SRB. The Atlas 5 Super Heavy seems to require new tooling for a wider core stage and a new pad to launch it from. That part of that AWST issue that I found most interesting was the statement attributed to Boeing VP Chuck Allen. He said that the Northrop/Boeing's CEV design could be launch by *existing* Delta IV vehicles. That does not jive with pronoucements made by both Griffin and ATK officials that the EELVs would need new upper stages (just like "The Stick") to lift CEV. - Ed Kyle |
#14
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From: Brian Thorn Well, these pretty pictures are all definitely for public relations and politics, not engineering. But you can easily make the same claim about the LockMart Atlas-5 based heavy-lifter in this week's AvLeak. At least for the SDLV, all the essential elements have either been tested or are in service, even the 5-segment SRB. The Atlas 5 Super Heavy seems to require new tooling for a wider core stage and a new pad to launch it from. For the SDLV, you're going to need new tooling: the "core" will be substantially different, as it takes loads through different directions and different attachment points; AFAIK, the 5-segment SRB isn't in service, and finally, I believe it will need a new pad to launch from (as the engines are in a different place on the vehicle, among other things). Phil |
#15
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Ed Kyle wrote:
Brian Thorn wrote: Well, these pretty pictures are all definitely for public relations and politics, not engineering. But you can easily make the same claim about the LockMart Atlas-5 based heavy-lifter in this week's AvLeak. At least for the SDLV, all the essential elements have either been tested or are in service, even the 5-segment SRB. The Atlas 5 Super Heavy seems to require new tooling for a wider core stage and a new pad to launch it from. That part of that AWST issue that I found most interesting was the statement attributed to Boeing VP Chuck Allen. He said that the Northrop/Boeing's CEV design could be launch by *existing* Delta IV vehicles. That does not jive with pronoucements made by both Griffin and ATK officials that the EELVs would need new upper stages (just like "The Stick") to lift CEV. - Ed Kyle Sure, the CEV is not goint to be heavier than 20 t even if they decide and if it will have wings. So it can be lauched by a Delta IV heavy. Sending them to the Moon requires 4 lauches, 1 additional to the lunar module and 2 for the booster stages, which are considerably heavier, than the spacecraft to be boosted. So, at the end of the day, they have to develop new ("upgraded") lauch vehicle for the booster stages AND still use 4 launches to reach the intended destination. Sure, the SRB-based new manned launcher does not seem to be a great idea. Géza Meszéna |
#16
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From: "Ed Kyle" Brian Thorn wrote: Well, these pretty pictures are all definitely for public relations and politics, not engineering. But you can easily make the same claim about the LockMart Atlas-5 based heavy-lifter in this week's AvLeak. At least for the SDLV, all the essential elements have either been tested or are in service, even the 5-segment SRB. The Atlas 5 Super Heavy seems to require new tooling for a wider core stage and a new pad to launch it from. That part of that AWST issue that I found most interesting was the statement attributed to Boeing VP Chuck Allen. He said that the Northrop/Boeing's CEV design could be launch by *existing* Delta IV vehicles. That does not jive with pronoucements made by both Griffin and ATK officials that the EELVs would need new upper stages (just like "The Stick") to lift CEV. It can't be difficult to make a CEV liftable by a Delta-IVH if one so desired. (Heck, I thought they were making a mistake building one so large it required the -H rather than one of the heavier mediums). It sounds like the new upper management at NASA has a direction they want to go in ("The Stick") and will rewrite whatever other requirements they need to to make their decision... stick. pgf |
#17
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Brian Thorn wrote in
: On Sun, 26 Jun 2005 09:09:16 -0500, Herb Schaltegger wrote: http://www.safesimplesoon.com/media-images.htm Ah, the joys of view-graph engineerning. Makes it look all so damned easy, doesn't it? Kind of like sliding down a snowy slope with your feet on two planks looks easy until the first time you try it. Well, these pretty pictures are all definitely for public relations and politics, not engineering. But you can easily make the same claim about the LockMart Atlas-5 based heavy-lifter in this week's AvLeak. At least for the SDLV, all the essential elements have either been tested or are in service, even the 5-segment SRB. Well, except for the ET. The current ET is designed to absorb loads along the side through the intertank (orbiter and SRB forward attach points) and the aft ring (orbiter and SRB aft attach points). The SDLV ET will have to take thrust loads through the bottom of the tank, and to take the weight of the payload from the top (which will also necessitate redesigning the LOX tank ogive). The ET is such a lightweight, optimized structure that you're pretty much going to have to redesign it. And *then* you've got to move the flame trench on the MLP and the pad to match where you just moved the main engines. Possibly add more thermal protection to the SRB aft segments to account for the increased proximity of the main engines. These are all straightforward engineering problems, but to say that they're "tested or are in service" is a bit of a stretch. -- JRF Reply-to address spam-proofed - to reply by E-mail, check "Organization" (I am not assimilated) and think one step ahead of IBM. |
#18
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#19
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"Ed Kyle" wrote in message oups.com... Brian Thorn wrote: Well, these pretty pictures are all definitely for public relations and politics, not engineering. But you can easily make the same claim about the LockMart Atlas-5 based heavy-lifter in this week's AvLeak. At least for the SDLV, all the essential elements have either been tested or are in service, even the 5-segment SRB. The Atlas 5 Super Heavy seems to require new tooling for a wider core stage and a new pad to launch it from. That part of that AWST issue that I found most interesting was the statement attributed to Boeing VP Chuck Allen. He said that the Northrop/Boeing's CEV design could be launch by *existing* Delta IV vehicles. That does not jive with pronoucements made by both Griffin and ATK officials that the EELVs would need new upper stages (just like "The Stick") to lift CEV. - Ed Kyle If it's a 20 ton CEV Delta IV should have no problem, with 25 tons it would probably need twin RL10's and an upper stage with more propellant than the small Delta IV upper stage, but less then the large upper stage. It's the same with the SRB launcher, the 20 ton might get away with a J2 engine, but 25 tons would require an SSME. This is a bait-and-switch type situation, whereby a nonexistent launcher with J2/SSME is proclaimed better than an existing launcher that needs a comparatively minor upgrade to the upper stage - then we learn that only the SSME (with extended nozzle, and altitude start capability) will work, and the lower stage will require a bit of work to make the steering function in a highly unstable design. Murray Anderson |
#20
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In article ,
Brian Thorn wrote: Well, once the Rocketdyne sale to UT/P&W goes through, there will only be one source for heavy-lifter engines in the United States... That's been true for a long time... partly thanks to NASA's long-standing unwritten policy that all its big engines are built by Rocketdyne. (To the point that for the SSME, NASA basically took technology developed by P&W and gave it to Rocketdyne to build an engine with.) I think the only other US company that has ever designed and built big liquid rocket engines -- at least, ones that have made it to full qualification and production -- is Aerojet, and they've been out of that business for decades except for minor upgrades to the Titan engines. -- "Think outside the box -- the box isn't our friend." | Henry Spencer -- George Herbert | |
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