6 Segment SRB?

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space_dreamer

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I was thinking about the weight issues with Orion/Ares 1 which are partly coursed by the 5 segment SRB first stage. And the need to land as large Luna base modules as possible with the Ares 5<br /><br />Is it possible to make a 6 segment SRB?<br />
 
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jimfromnsf

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That wouldn't help, it would only increase the thrust. The SRB needs to burn longer, which means it needs to be wider
 
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space_dreamer

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The SRB needs to burn longer, which means it needs to be wider -<br /><br />Would it cost too much to design a wider SRB?<br /> <br />I know that originally the shuttle engineers wanted the SRBs to be wider but transporting them was a problem. But as the SRBs are going to be used for the next 40 years on all the Ares rockets, then surely getting it right now makes sense.<br />
 
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jimfromnsf

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"Would it cost too much to design a wider SRB?'<br /><br />The point of using the SRB's was to reuse the existing hardware and a system that has worked successfully for over a 200 "flights" <br /><br />There is no sense in just using "any" solid motor for the first stage, Ares I is a specific case. If the shuttle SRM's can't be used then there are better options out there<br /><br />f
 
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thereiwas

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If ATK built an SRB factory in a different location, where the segments could be transported to KSC by sea instead of by train, it would be physically possible to make them larger. But that would not keep all those Utah employees busy (an important goal of NASA'a manned spaceflight program, as ordained by Congress). It would also be very expensive. That is all in addition to not meeting the goal of using existing designs.
 
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josh_simonson

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Wasn't Atlas V production moved from CA to Decatur, AL? Moving SRB production may not be unprecedented. <br /><br />However, making the SRB larger probably doesn't make sense. As it is the SRB gets the Ares second stage high enough that it's vac optimized engine can run outside the atmosphere, adding burn time to the first stage would just keep using the sea level optimized motor in space, running at a much, much, lower efficiency. A first stage with more thrust and the same burn time could lob a heavier second stage on the same trajectory, resulting in larger payloads.<br /><br />Just from a design perspective, the SRB exists, but the second stage is a completely new clean sheet design. From a cost perspective it makes the most sense to make minimal changes to the SRB, then design the second stage to finish the job. Then only one of the stages requires a full development cycle.
 
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frodo1008

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If we are talking about using existing designs, then it makes even more sense to use either the Delta IV Heavy or the Atlas V Heavy of ULA (of course, the Atlas V is probably out of contention here as it uses Russian engines) than redesigning the existing four segment SRB's at a design cost of over $3 billion dollars. <br /><br />At its current capabilities the Delta IV Heavy (and as the Atlas V uses Russian Engines, I don't think congress would allow that) can place up to some 53,000 lbs into LEO (which is all that NASA needs from a first stage anyway). It would be relatively simple for ULA to redesign the Delta IV Heavy with two more attach points for a five Common Booster Core launch system, which would place as much as some 90,000 lbs into LEO, and totally eliminate NASA's weight problem with almost ANY capsule it desired! <br /><br />The EELV program was designed by the Air Force to be far cheaper than either the shuttle or the Titan IV to place very heavy military satellites into GEO. Just as an example, an SSME currently costs about $60 million each, and the shuttle requires three of them, on the other hand the RS68 of the Delta IV costs about $10 million each, and the Delta IV Heavy also requires three such engines. Of course the reuseablility of the SSME brings the over all costs down somewhat in itself, but not enough to overcome the cost difference of the RS68. <br /><br />This is because when the SSME was being designed and built by Rocketdyne, performance and weight were the prime considerations and cost was a secondary consideration, but when the RS68 was being designed and built, cost was the primary consideration and performance and weight (which is still very good for the RS68) were a secondary consideration.<br /><br />Also, the Common Booster Cores used for the Delta IV and the Atlas V are built in a far more assembly minded plant that the earlier rockets were. The only thing stopping these excellent (and already established) rockets from being as
 
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cdr6

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Frodo-<br /><br />I've had a thought bubbling around in my head for a while about the SRBs. Could we mount 4 SBS to the ET (ala the Russians) and get more "lifting power" that way? Or have we passed the point of deminishing returns with the curret design of the 2 SRB configuration. (What with structural changes to the ET and all)?<br /><br />Regards,<br />Chuck
 
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frodo1008

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There have been many such proposals put forth. I think the first such change would have been the Shuttle C (for shuttle cargo). Which would have retained the basic design of the shuttle with a much larger shuttle bay, capable of about 65,000 kgs (143,000 lbs) to LEO (the orbiter would have been replaced without wings, but the three SSME's would have had a separate returnable pod). <br /><br />This and the next steps that I am about to give are delineated in both one of the best of the few space colony books "Colonies in Space" by T. A. Heppenheimer, and NASA's excellent report "SP-413 Space Colonization: A Design Study". Both of these were issued in 1977, four years before the shuttle even had its first launch! <br /><br />The next step would have indeed been a baseline lift Heavy Vehicle with four SSME's on a central vehicle with four SRB's placed around it symmetrically. This vehicle would have been capable of placing 120,000 kgs (264,000 lbs), almost exactly the capacity of the legendary Saturn V!<br /><br />Now as the RS68 engines are both far cheaper and expendable, (eliminating the need for a pod to bring them back) the over all price of such vehicles would be far less, plus the additional 200k+ thrust of each of the RS68's would give even more weight to LEO.<br /><br />Note that this configuration (from 1977 no less) is almost exactly what NASA now proposes for the Ares V.<br /><br />T. A. Heppenheimer went even one step further, he also proposed a third vehicle that would have had F1 engines in a fly back maned configuration, which would have been capable of some 400,000 kgs to LEO (or 880,000 lbs) to LEO. Such a vehicle could lift more than the entire weight of the ISS into space in less than two loads!<br /><br />Alas, NASA is only now only considering the middle vehicle (and even design and construction of that would not even start for the next five years or so).<br /><br />So what we are now discussing here is the reality of either the single stick (which seems
 
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frodo1008

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But Jim, such a vehicle is almost what NASA is already proposing for the Ares V to take us back to the moon, and eventually for even greater space needs!<br /><br />Space power satellites beaming down an almost unlimited electrical power to the Earth's surface. And the very necessary space colonies to support a true space faring civilization, even with the use of the materials and energies of space itself are going to easily require such vehicles to be built eventually.<br /><br />As stated even going back to the moon, and certainly any kind of reasonable manned expedition to Mars are absolutely going to require the use of a vehicle with at the very least the capacity of the Ares V. So such a discussion of vehicles with such capacities is not inappropriate here .<br /><br />However, I do agree that the Ares I is the immediate concern here.
 
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pmn1

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If ATK's plant was such it could have sea transport, how many segments (if any??) could you reduce the booster to and what width would be possible? <br /><br />Edit - assuming you now need the support of the state the plant is now in. <div class="Discussion_UserSignature"> </div>
 
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jimfromnsf

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anything. A 260 inch wide motor was tested in south Florida. But again, why the fixation on solid motors? <br /> A liquid could do the job. Ares 1 is only reusing the shuttle boosters because the hardware and ground infrastructure exists and it has a good flight record. This is not applicable to any other solid motor. A clean sheet design would not use solid motors.<br /><br />Ares I is having problems because it is only constrained to shuttle SRB's and the lack of ability to change it. If it were a liquid booster, the combination of increasing the following would fix the problems: engines, stage width or height.
 
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pmn1

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I wasn't thinking now, more a case of if at the time of the STS design process. <div class="Discussion_UserSignature"> </div>
 
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