LRB's and Ares1

[pmn1]

If the LRB's of say the 1984 study had been developed, what would the use of these have done to the Ares1 design? <div class="Discussion_UserSignature"> </div>

 

[jimfromnsf]

What study? there have be dozens <br /><br />Anyways, maybe nothing. There might not have been an Ares I

 

[vulture2]

An interesting question. [There have been various studies, but the most detailed was probably the 1987 Martin-Marietta study,<br />http://www.stormingmedia.us/71/7168/A716833.html ]<br /><br />I read the LRB study and met (after his retirement) one of the engineers who worked on it. I believe the proposal was doomed by the fact that additional money would have been needed to develop the LRBs, and no one had extra money. Moreover the study simply looked at all the possibilities (MMH/N2O4 vs LOX/RP-7, pressure-fed vs pump-fed, even LRB vs SRB) and left "decisions" up to management without making a strong recommendation. While they might have been an improvement, with the redesigned solids already in the pipeline, there was no way to actually prove LRBs were essential to keep the Shuttle flying. And of course, there was politics; the SRB lobby would have been hard to overcome. <br /><br />That said, had the LRBs been built, then no one would have suggested going back to SRBs now for a shuttle successor.

 

[j05h]

I've only seen media references to LRBs, but my favorite almost-flown is definitely the Baikal LFBB. Not flown yet, but designed as a drop-in replacement for the eternally-delayed Angara's booster stages, complete with rotate-out wing and jet engines for return to site. <br /><br />http://www.russianspaceweb.com/baikal.html<br /><br />Solid boosters are still a bad idea, especially for crew launch. Shouldn't we be moving away from the most dangerous components of our launch infrastructure? Jim and Shuttle_guy are comfortable with the SRB from a launch-loading standpoint. To me, the best argument is that a liquid rocket can have a full test run before flight, whereas the solids are one-shot. <br /><br />Josh <div class="Discussion_UserSignature"> <div align="center"><em>We need a first generation of pioneers.</em><br /></div> </div>

 

[edkyle98]

An LRB developed during the 1980s (Cold War era) would have meant that a powerful U.S. hydrocarbon booster engine would have been developed that does not now exist. That would have changed not only how the CEV launcher was designed but also how the EELV designs turned out. Ares I would almost certainly have used the LRB booster engine rather than an Ares I five segment solid booster. A more powerful first stage liquid engine might also have eliminated the need to re-develop J-2 for the second stage. A cluster of evolved RL10s might have sufficed. <br /><br /> - Ed Kyle

 

[jimfromnsf]

"Shouldn't we be moving away from the most dangerous components of our launch infrastructure?"<br /><br />The stick proponenets say it is the opposite. since 51-L, SRB's have the best success rate, almost 200 launches

 

[j05h]

<i>> The stick proponenets say it is the opposite. since 51-L, SRB's have the best success rate, almost 200 launches</i><br /><br />Segmented SRBs were the direct cause of 51-L, one of two loss of vehicle/crew with STS. When considering the overall STS project, the SRBs and weak composites are major failings. Mature liquid booster designs generally have more benign failure modes before catastrophic detonation. I believe a strong case can be made for no SRBs for crew launch, be that ARES, Atlas, Delta-derived. Another factor, per recent mishap, is that liquid rockets (and to lesser degree hybrids) are safely shelf-storable, while solids have an ignition danger while on the ground and rail. No more hazardous than other rail-cargo, but it should be a consideration. If they are so gung-ho about a solids, why not revise the 260" monolithic solid that was tested for Saturn? With the current segment addition, ATK is already talking about a new design, essentially. If it has to be their pork product, at least push the state of the art a little bit. Hopefully it will produce a safer product. Better yet, cancel it and announce crewed-K1s with RpK. <br /><br />Orion should go up on Atlas, all things being equal. EDS via Boeing (if they want it), all other hardware and propellant by bid to LEO. Modular components work great in computers, they should work great with rockets (and yes this relates to Liquids), because clustering is necessary and common components reduce costs, increase group knowledge allow for known factors in planning. Why should <br /><br />Clusters of liquid rockets as common cores/boosters make the most sense, or single monolithic liquid stages. We know this approach works, have the capacity now and already have the rockets (Delta and/or Atlas). The ideal situation for a well-heeled investor/entrepreneur to bring Soyuz to Texas or Florida. Alternatively develop "Space Adventures"-style services with Kourou, perhaps lessoning some of the 6-month study time for bu <div class="Discussion_UserSignature"> <div align="center"><em>We need a first generation of pioneers.</em><br /></div> </div>

 

[pmn1]

I had this one in mind.<br /><br />http://www.astronautix.com/lvs/shulelrb.htm <div class="Discussion_UserSignature"> </div>

 

[j05h]

That would have been a great upgrade.<br /> <div class="Discussion_UserSignature"> <div align="center"><em>We need a first generation of pioneers.</em><br /></div> </div>

 

[jimfromnsf]

"Segmented SRBs were the direct cause of 51-L, one of two loss of vehicle/crew with STS"<br /><br />Just being devil's advocate.<br />The stick proponents would say that was with an old SRM and the RSRM has the 200 plus flights. Also they would say, it was a configuration flaw* (proximity to the ET) and if this were to happen on the stick, it would had kept flying. <br /><br />"believe a strong case can be made for no SRBs for crew launch," the stick is basicall an astronaut office design<br /><br />Cluster boosters are not a good idea for a manned launcher, reliability is lower and more failure modes. A bigger booster would be bigger (Atlas 5 phase II 5.4 core vs Atlas V Heavy)<br /><br />* as for configuration flaws, Columbia was a TPS failure vs foam problem. All launch vehicles are known to have debris liberated during flight. Shuttle's flaw is using fragile orbiter TPS in this environment<br /><br />

 

[edkyle98]

>> The stick proponenets say it is the opposite. since 51-L, SRB's have the best success rate, almost 200 launches<<<br /><br /> />Segmented SRBs were the direct cause of 51-L, one of two loss of vehicle/crew with STS. <<br /><br />Yes, but how many shuttle orbiters, and crews, would have been lost to LRB failures? Big liquid booster stages fail more often than big solid stages. The Zenit/Energia boosters, which were designed to launch Soviet space shuttles, have failed three times in 68 uses (including two Energia flights). Proton first stages have a failure rate exceeding 2%. Ariane 4 was wildly successful, but it suffered a first stage failure in 116 flights. The U.S. Titan core stage had about the same failure rate as the Ariane 4 core stage - as has the R-7 booster during the past 10 years or so. Shuttle SRBs have failed half as often as the best liquid booster stage.<br /><br /> - Ed Kyle

 

[qso1]

Can you post links?<br /><br />I began looking into that very question and so far have turned up no evidence that LRBs are more dangerous than SRBs. Fact is, NASA publications dating from the 1960s mentioned SRBs as not being safe enough for manrating. They changed that view when forced to use SRBs for shuttle once the shuttle budget was such that development of LRBs, much less FBBs were no longer practical.<br /><br />Energia was launched twice...both successes. The first mission failure was due to the payload or an upper stage propulsion system failure which caused the payload to plunge into the pacific IIRC.<br /><br />http://en.wikipedia.org/wiki/Energia excerpt:<br />The Energia was first test-launched 15 May 1987 21:30 with Polyus (UKSS military payload), where the Energia itself functioned well, but the Polyus did not reach orbit due to a mishap of its own attitude control system after separation from Energia.<br />End excerpt.<br /><br />Energia number two launched the Buran which was a success according to the same link.<br /><br />The only other flight to orbit has been the successful mission in which the unmanned Shuttle Buran was brought to orbit, in 1988. Both the Energia and Buran programs were designed to maintain strategic parity between the two superpowers.<br />End excerpt.<br /><br />As for the Energia LRB derived SL-16 or Zenit, 8 have been failures according to the wiki link:<br /><br />http://en.wikipedia.org/wiki/Zenit_rocket<br /><br />This might be simply an inferior LRB system, or may point to LRBs having an equal or maybe worse record than SRBs. I won't know the answer to that until I can run down a statistical analysis of all or most major LRB systems flight records. Having said that, SRBs and LRB failures have been responsible for failed launches of Titans, Atlas, and Delta rockets and based on these rockets success rates, <div class="Discussion_UserSignature"> <p><strong>My borrowed quote for the time being:</strong></p><p><em>There are three kinds of people in life. Those who make it happen, those who watch it happen...and those who do not know what happened.</em></p> </div>

 

[josh_simonson]

The SRBs are very safe and reliable, but they are also a major expense for handling because of their mass. If they were free, nobody would be complaining. As it is, ATK gets less for them than a comparable liquid booster would cost, but the shipping, handling and integration snowball the costs dramatically. The smaller solids used on Atlas and Delta are relatively cost effective because they're small enough that they don't need custom mega-machines to handle them.<br /><br />The 260" motors are out of the question because SRBs need to be transported by rail. They're too heavy to fly and have no other transportation options from Utah. A 260" motor would also require even more expensive handling than the current SRBs do.<br /><br />Without some significant new development, high performance liquid engines will continue to have a reliability disadvantage to solids. SpaceX's rundant approach and high-performance pressure fed systems are probably the best contenders to unseat SRBs in reliability.

 

[jimfromnsf]

It isn't the mass, cranes are easy to build, it is the labor needed to assemble them. It is the part count. Atlas and Delta have less parts.<br /><br />Spacex uses turbopump engines everywhere, except for the Falcon 1 second stage.

 

[edkyle98]

>"Can you post links? "<<br /><br />http://www.geocities.com/launchreport/lvsum.html<br />http://www.skyrocket.de/space/<br />http://www.planet4589.org/space/lvdb/list.html<br />http://www.astronautix.com/<br /><br />Etc.<br /><br />Liquid boosters with turbopump engines have <br />a demonstrated failure rate that is at least two <br />times worse than that of large solid boosters.<br /><br /> - Ed Kyle

 

[josh_simonson]

The mass of the SRBs eliminates the possibility of horizontal integration, requiring the huge VAB and transporters. They are also hazardous to some degree - an accident could destroy the VAB. <br /><br />I was refering to redundant clusters and high performance pressure-fed systems as separate entities, not both SpaceX approaches. Microcosm is probably the best example of the advanced pressure fed approach, I'm disapointed that they aren't getting much traction in applying their technologies.

 

[jimfromnsf]

"The mass of the SRBs eliminates the possibility of horizontal integration, requiring the huge VAB and transporters. ."<br /><br />What did the N-1 and Energia use? horizontal integration with a huge VAB and transporter/erector.<br /><br />Horizontal integration isn't the end all<br />

 

[jimfromnsf]

"Microcosm is probably the best example of the advanced pressure fed approach, I'm disapointed that they aren't getting much traction in applying their technologies."<br /><br />Maybe because they weren't viable?

 

[j05h]

<i>> The 260" motors are out of the question because SRBs need to be transported by rail. They're too heavy to fly and have no other transportation options from Utah. A 260" motor would also require even more expensive handling than the current SRBs do. </i><br /><br />The 260" SRB was poured and fired in Florida. Ground handling involved pulling it out of the mold and trailering it to the test stand. Something that large doesn't really fit US ground transportation systems.<br /><br />Josh <div class="Discussion_UserSignature"> <div align="center"><em>We need a first generation of pioneers.</em><br /></div> </div>

 

[qso1]

Thanks for the links.<br /><br />Good list, especially the first link. The N1 was built and failed as shown on the list from 1969 to 1972 I'd forgotten. You made a good case but to complete the task, I will have to gather SRB failures and compare them to LRB failures. I'm left wondering why the SRB was considered more dangerous (Beyond the fact they cannot be shut off) than LRBs before the shuttle became operational. <div class="Discussion_UserSignature"> <p><strong>My borrowed quote for the time being:</strong></p><p><em>There are three kinds of people in life. Those who make it happen, those who watch it happen...and those who do not know what happened.</em></p> </div>

 

[qso1]

jimfromnsf:<br />"The mass of the SRBs eliminates the possibility of horizontal integration, requiring the huge VAB and transporters. ." <br /><br />Me:<br />Thats part of the reason for vertical transport, the SRBs are indeed quite a bit of mass which would probably have a slumping effect on the propellant grain. The other reason is that complex 39 was not intended for space shuttle missions as it was originally intended, developed, and utilized for Apollo.<br /><br />Either method of integration certainly works as you mentioned more or less with horizontal integration isn't the end all. <div class="Discussion_UserSignature"> <p><strong>My borrowed quote for the time being:</strong></p><p><em>There are three kinds of people in life. Those who make it happen, those who watch it happen...and those who do not know what happened.</em></p> </div>

 

[frodo1008]

If there have been 200 successful flights of the SRB's since 51L, with two SRB's per shuttle flight (as the advocates of SRB's like to point out), then there have also been 300 flights of the SSME (with 3 SSME's per shuttle flight) in the same time period, and as 51L itself and all such shuttle flights before were also successful as far as the SSME was concerned, then you could take the total number of shuttle flights and multiply by three and you then find the total number of successful SSME flights! (NOTE: according to wikpedia there have been 117 flights of the space shuttle, which would give 351 successful flights of the SSME)<br /><br />Further, the SRB's of the shuttle are to my knowledge the ONLY exclusive use of such large SRB's in the inventory of ANY country that has a civilian space launch program that launches to LEO. So somebody must think that LRB's are safer, cheaper and more useful than SRB's. <br /><br />And this is beside the argument for greater safety of liquid engines that I have presented on these boards at least three times. In short that you can not both test and then use the same SRB, which you can do with the engines of an LRB!<br /><br />When you take the history of such vehicles, please note that they generally include the early years of such launches, in which the safety of such flights were indeed in question! It is called a learning curve, and at the beginning it is very bad as far as safety is concerned!<br /><br />Besides the ONLY rocket to have previously lofted human beings beyond LEO (the truly magnificent Saturn V) had only one solid rocket engine among its 28 other liquid engines, and that was the escape tower engine, and it was hoped that it would NEVER have to be used!! <br /><br />So some at least the point for using SRB's is very shaky at best! Even the argument by ATK for cost is bogus (and admittedly I accepted that argument myself in the early development of the VSE system) as they have already given a cost estimate to NASA of

 

[jimfromnsf]

HUH?<br /><br />SSME's don't count since they are reusable.<br /><br />ELV propulsion failures in the last 15 years:<br />Zenit, Ariane V, Delta-IV, Protons, Soyuz, etc. <br /><br />Titan-IV is not listed since it hadn't had a liquid propulsion failure <br /><br />Saturn V had many more solid motors for retro and ullage rockets<br /><br />The Saturn V was designed as man rated. The others were used because of the space race and more risks were accepted<br /><br />I am against the stick but based on cost, underperformace and lack of utility. You will lose the manrating argument

 

[edkyle98]

>"I'm left wondering why the SRB was considered more dangerous (Beyond the fact they cannot be shut off) than LRBs before the shuttle became operational."<<br /><br />Solids were (and in some quarters still are) considered too hazardous for crews because they cannot be shut off easily and because they have instantaneous catastrophic failure modes. These hazards are substantially offset by their lower failure rates compared to liquid boosters. Escape systems can mitigate most hazards for both solid and liquid boosters, but it is a myth that all liquid (or solid) booster failure modes can be made survivable. <br /><br />NASA's ESAS report said that a crew launcher with a big solid motor first stage would be safer than one with a cluster of big liquid stages, or with a big liquid stage with a cluster of engines. This finding is considered debatable by more than a few. My guess is that both designs, if properly executed, would present about the same amount of risk in the end. Any new design with a launch escape system should be safer than shuttle. <br /><br /> - Ed Kyle

 

[frodo1008]

In a way that is even worse for the big SRB solids! It means that each of the reusable SSME's not only does far more firing time per each flight, but does more than one flight! <br /><br />I will once again give my own argument for the relative safety of liquid engines.<br /><br />When you test any solid, that solid is used up and can no longer be used on the actual vehicle (I know that the casings for the shuttle SRB's are themselves reusable, but the hugh amount of solid fuel is not), this means that you have to have extremely good quality control of every step in the manufacturing and loading of these large rockets, this is both a very exacting and expensive procedure! It is indeed to the credit of ATK that they have done such a superb job of this quality control with the shuttle SRB's.<br /><br />Whereas, with a liquid engine (at the very least with Rocketdyne where I worked for most of my 37.5 years in aerospace) you run what is referred to as a "Green Run" with the actual engine that you are going to use on your final flight vehicle. This not only gives you a chance to make sure that all of the many parameters used are in the green zone (hence the name Green Run) of the safety factors of the particular engine, but you can even make sure that the engine is maximized for performance!<br /><br />In the case of the RS27A engines used on the Delta II there has never been a failure of the main sustainer liquid engine itself, although there was at least one spectacular failure of the solid boosters. Why do you think that NASA uses the venerable Delta II as its main launch vehicle for almost all of its Mars and deep space probes? After all, NASA has enough problems in deep space millions of miles from earth, they certainly want to make sure that the spacecraft at the very least gets a correct start on its journey (and yes, there are sometimes large solids as a booster on the Delta II system, but they are not nearly as large as the SRB’s on the Shuttle, and that is the