tag:blogger.com,1999:blog-3673435362400368888.post8101640965714469169..comments2023-04-01T13:39:24.156-07:00Comments on RocketsAndSuch: SmokescreenRocket Manhttp://www.blogger.com/profile/05109496878476775729noreply@blogger.comBlogger17125tag:blogger.com,1999:blog-3673435362400368888.post-11831539721191893212009-05-19T14:53:05.466-07:002009-05-19T14:53:05.466-07:00Chuck2200 said...
Why not put the SSME's under the...<I>Chuck2200 said...<br />Why not put the SSME's under the ET and fly it with a pair of 4-segment SRB's? </I>Chuck, that would be DIRECT v3.0.Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-3673435362400368888.post-91370471691009708152009-05-18T22:39:00.000-07:002009-05-18T22:39:00.000-07:00"Dear $5 billion man, you are totally wrong. Testi..."Dear $5 billion man, you are totally wrong. Testing at Stennis Space Center demonstrated SSME start and performance at the upper stage ICD manifold pressures. You are making things up..."<br /><br />Dear Anon.<br /><br />I've worked at Stennis, lots of smart techies but<br />not a single manager capable of finding their way out of paper bag.<br /><br />Okay, I believe you in that they tested the SSME Start at ICD Manifold pressure.<br /><br />But that isn't the hard part, it's not hard to set up manifold pressure to the Upper stage manifolds what's hard to do is do all the spool up of the SSME. Take a trip over to the B stand where they test the SSME's and RS-68s . Look at all the stuff they need to start those engines.<br /><br />That's the hard part, then figure out how much fluid is needed to start the enginesAnonymousnoreply@blogger.comtag:blogger.com,1999:blog-3673435362400368888.post-54835466054866773422009-05-18T07:19:00.000-07:002009-05-18T07:19:00.000-07:00Why not put the SSME's under the ET and fly it wit...<I>Why not put the SSME's under the ET and fly it with a pair of 4-segment SRB's?</I>You mean Direct 3.X.<br /><br />Again, throwing away $100 million dollar SSMEs en mass' is a fools errand. Nobody in their right mind would propose such a thing.Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-3673435362400368888.post-69142855112019765062009-05-18T05:53:00.000-07:002009-05-18T05:53:00.000-07:00anon, better cheeck again. testing was planned, bu...anon, better cheeck again. testing was planned, but never carried out, in flight-like conditions.Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-3673435362400368888.post-48537841833298473222009-05-17T18:44:00.000-07:002009-05-17T18:44:00.000-07:00Dear $5 billion man, you are totally wrong. Testin...Dear $5 billion man, you are totally wrong. Testing at Stennis Space Center demonstrated SSME start and performance at the upper stage ICD manifold pressures. You are making things up...Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-3673435362400368888.post-44869072949623725932009-05-16T16:48:00.000-07:002009-05-16T16:48:00.000-07:00Why not put the SSME's under the ET and fly it wit...Why not put the SSME's under the ET and fly it with a pair of 4-segment SRB's? That's not that much different than what we're actually flying right now. You could put all the safety features back on Orion that Ares-I stripped off and still fly it before the RS-68 is man-rated for the Delta. No new engine development needed. Almost eliminates the gap. Later, when the economy allows, put an upper stage on it and go to the moon flying that same rocket.Unknownhttps://www.blogger.com/profile/13482958353631379312noreply@blogger.comtag:blogger.com,1999:blog-3673435362400368888.post-30497234520001567212009-05-16T12:34:00.000-07:002009-05-16T12:34:00.000-07:00In working on the program, I haven't heard a singl...In working on the program, I haven't heard a single, discouraging word about doing an airstart with J-2x. Not being a rocket engine type, I was not aware, although the evidence was apparently all around, that this could be a problem.<br /><br />That said, I wonder when they planned to try an air start in the test program, other than with a full up flight? Seems that one would want to do a number of runs on the ground to see if the stand-alone second stage can actually start and run as planned. Even that would only give a low level of confidence that the startup could be accomplished in flight with all of the shake, rattle and roll that will be going on. <br /><br />It might be wise to think about more than a couple of test flights to avoid the "random success" syndrome.<br /><br />The truly amazing part is that NASA still thinks they can leap straight to man-rated with the totally inexperienced design staff. The staff is thus able to leap right around the proven records of Delta and Atlas, to produce the magic, man-rated rocket.<br /><br />What's next, spinning straw into gold?Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-3673435362400368888.post-66467733279861723722009-05-16T11:35:00.000-07:002009-05-16T11:35:00.000-07:00"I still fail to see how going back to 4SRB + SSME..."I still fail to see how going back to 4SRB + SSME is going to make much difference. Thrust oscillation is still a problem "<br /><br />The longer the SRB is the lower the TO Frequency.<br />The lower the Frequency, the more amplitude to the wave. The larger the amplitude the harder you are<br />moving around.<br /><br />If you look at a 2000 Hz frequency, while it rattles your teeth, it only throws you around a few Millimeters.<br /><br />if you look at a 2 Hz frequency it's throwing you up a few feet. That is a very big structural challenge.<br />Look at a suspension bridge. the wires sing in the wind, but the deck moves at low frequency. If you ever saw video of the tacoma narrows bridge collapse that's what Low Frequency oscillation look like. The High Frequency stuff is minor.Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-3673435362400368888.post-4899701050956208332009-05-16T11:28:00.000-07:002009-05-16T11:28:00.000-07:00Back in the ESAS days, the combo of 4segSRB and 2x...Back in the ESAS days, the combo of 4segSRB and 2x NK-43 was considered. It would outperform the current Ares I configuration, and it was the only "Shaft" that didn't require any new engine development. It might be the only choice if NASA still wants a Shaft, but it still doesn't solve T.O. and would still take longer to develop than Orion-on-EELV.Mr. Xhttps://www.blogger.com/profile/08537371901494918449noreply@blogger.comtag:blogger.com,1999:blog-3673435362400368888.post-61910433911972144362009-05-16T09:16:00.000-07:002009-05-16T09:16:00.000-07:00Is there any particular reason why new SSMEs canno...<I>Is there any particular reason why new SSMEs cannot be built beyond cost?</I>The only problem I am aware of is the nozzle is hand brazed using good old American labor, and has a four year lead time for ordering.<br /><br /><I>I admit, they are horribly expensive to use as the core stage engine of an ELV.</I>Only if you throw them away. The engine is of an efficiency that any booster augmentation of the core stage virtually guarantees that core stage will make it to orbit.<br /><br />The main problem is terminal acceleration of the lightweight core stage at thrust termination, and the foam insulation on the tank is most definitely not space rated.<br /><br />These are fundamental problems of rocket science. So I see no reason that they should not be pursued since we have a dozen engines to experiment with during the course of development, and the engine line can either be restarted, or more preferably, a second generation engine can be developed, which is more easily removed from the core stage, a more robust channel wall nozzle and hydrostatic bearings, etc., in which case it might be advisable to switch to a new cycle.<br /><br />The clustering of engines obviates many of the acceleration problems.<br /><br /><I>Come on guys the ONLY way to get a US made capsule to ISS is to get rid of the service module and put the CM on an Atlas 402.</I>I can list a dozen or so other rockets capable of doing that job.<br /><br />I am not advocating air starting of these engines, and I am advocating throwing every available rocket at the problem, but I am also honestly advocating using these engines in a fight test development program to develop advanced space flight and reusability options, which can then subsequently be farmed out to every other EELV, or COTS vehicle or international rocket that exists.<br /><br />I can even USE these rockets as prototype boosters for my rocket.Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-3673435362400368888.post-57843072113465297022009-05-15T08:49:00.000-07:002009-05-15T08:49:00.000-07:00Isn't the obvious down side-to using SSME on Ares ...Isn't the obvious down side-to using SSME on Ares I upperstage, that apparently its too hard to air-start the thing? That's why J2x was chosen....or so I'm told.<br />The upshot of this is that the smokescreen won't be very thick ;-)SimonFDhttps://www.blogger.com/profile/08851442820357898296noreply@blogger.comtag:blogger.com,1999:blog-3673435362400368888.post-86683318058287773242009-05-15T08:31:00.000-07:002009-05-15T08:31:00.000-07:00At JANNAF a few years back, NASA decided to roll o...At JANNAF a few years back, NASA decided to roll out the concept of an Air-Started SSME for the Ares 1. The room full of liquid propulsion engineers, over 800 of them openly laughed at that concept. The Presenter then retreated to his fallback position of Air Starting RS-68's and the room started roaring with laughter.<br /><br />After that the J-2X was announced.<br /><br />It takes 6 seconds to get an SSME started and stable. That's a tremendous amount of support power, fluid, monitoring. <br /><br />while much of the electronics can be miniaturized, the demands for helium, nitrogen, steam, water, are enormous. A lot of people looked to try and speed up SSME start, and nobody ever cracked that problem. The teams today will be unable to solve that with their lack of experience.<br /><br /><br />The other thing is the SSME is out of production, restarting the line and requaling production will be $5 Billion. <br /><br />if NASA is trying to sell this concept, it means they have given up hope on making the J-2X work.Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-3673435362400368888.post-1502153253178261712009-05-15T05:40:00.000-07:002009-05-15T05:40:00.000-07:00I still fail to see how going back to 4SRB + SSME ...I still fail to see how going back to 4SRB + SSME is going to make much difference. Thrust oscillation is still a problem (only one SRB, nothing to cancel its "chugging" out.) And how much schedule is required to develop the air-start mods to SSME? <br /><br />As an astronaut, I'd have a pretty high pucker-factor riding a rocket with a staged-combustion upper stage. If we're going to put air-start SSME's back on the table, then air-start RS-68's should be fair game too. Both are equally fantasy as far as I'm concerned.Mr. Xhttps://www.blogger.com/profile/08537371901494918449noreply@blogger.comtag:blogger.com,1999:blog-3673435362400368888.post-47179703730022224552009-05-15T04:46:00.000-07:002009-05-15T04:46:00.000-07:00A dozen? Excellent- just enough for every credibl...A dozen? Excellent- just enough for every credible museum to get one. <br /><br />Come on guys the ONLY way to get a US made capsule to ISS is to get rid of the service module and put the CM on an Atlas 402. That is the simplest approach and by far the cheapest and least risky. Put the puny ECLSS and orbital manuever thrusters in a small module or mission peculiar kit between Centaur and Orion CM. Done. There is no need for a large SM engine. You can even keep the over-done escape system. <br /><br />The biggest effort will be to put crew access at the pad. Build a separate VIF for NASA and call it done.<br /><br />The costs for this task, assuming that NASA does not insist on redesigning the Atlas in a half-assed attempt to "make it better" are round off error compared to the present ARES I go-forward spend plan.Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-3673435362400368888.post-34475616713348491932009-05-15T03:16:00.000-07:002009-05-15T03:16:00.000-07:00@ kT
Is there any particular reason why new SSMEs...@ kT<br /><br />Is there any particular reason why new SSMEs cannot be built beyond cost? I admit, they are horribly expensive to use as the core stage engine of an ELV. However, if they are the only game in town when it comes to minimising the capability gap...?<br /><br />I'm pretty sure that NASA is happy to wait for the regen version of RS-68 (RS-68B?) for its HLLV. However, going with SSME, for all its cost, could pull return to the Moon back to this side of 2020, which would be a considerable feat.<br /><br />With all due respect, recoverable core stages (even just the engines) is a 'long gap' objective. Let's be incremental: Use and lose the SSMEs for now and work towards a recoverable core in the medium-term rather than let it get in the way of the short-term objectives like return to the Moon and beyond-Earth/Moon.<br /><br />~<br /><br />Ben the Space BritAnonymousnoreply@blogger.comtag:blogger.com,1999:blog-3673435362400368888.post-10693210134385001082009-05-14T20:30:00.000-07:002009-05-14T20:30:00.000-07:00So are we talking about an air startable SSME, or ...So are we talking about an air startable SSME, or the current one? knowing which version would clarify which rocket design is being chewed over, however I am pretty sure that it is the later which indeed means a decades old phoenix is rising.thatguyfromNSFnoreply@blogger.comtag:blogger.com,1999:blog-3673435362400368888.post-26254829069413502262009-05-13T20:45:00.000-07:002009-05-13T20:45:00.000-07:00Loose cannon alert.
The SSMEs are pretty much sel...Loose cannon alert.<br /><br />The SSMEs are pretty much selling themselves right about now, but anything other than a reusable orbital test flight program is just plain nutty thinking - IMHO. <br /><br />There are only a dozen of them. If I were Obama I'd say something like 'before my first term is out we'll send an SSME to low Earth orbit and return it safely to Earth.' That's what the shuttle does, we should demand nothing less than that, except defer the passengers until we sort out the recovery methods. Recovering LRBs via parachute or flyback should be high on the priority list right now as well.<br /><br />Plus we'll use a bunch of those other EELVs and COTS rockets too. If there is anything else that can be done in three and a half years flat, let me know about it, ok?<br /><br />I'd love to see a cluster of about seven 125 klb hydrogen engines on that center core, shut down sequentially, with a nozzle extension on the center engine - engines that would be extremely useful in deep space, but right now all we have is a dozen SSMEs and a bunch of two stage to orbit launch vehicles. We can start right now with the upper stages of those launch vehicles and their payloads.Anonymousnoreply@blogger.com