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GRIFFIN'S DRIVE FOR SHUTTLE-DERIVED
GRIFFIN'S DRIVE FOR SHUTTLE-DERIVED
In recent weeks it has become clear that Michael Griffin, NASA's new Administrator, is maneuvering to win support for development of a new series of "shuttle-derived" launchers. By stating that he expected the Crew Exploration Vehicle (CEV) launch mass to grow beyond the capabilities of any existing launch vehicle, Griffin effectively leveled the playing field between shuttle-derived and Evolved Expendable Launch Vehicle (EELV) options. In early May, in a speech at a meeting of Women in Aerospace, Griffin said that the Project Constellation CEV should weigh no less than about 30 metric tons, more weight than could be carried by any vehicle available to launch it today. Previously, NASA's CEV requirements had called for a launch mass not to exceed 20 metric tons, a weight that could be launched by current EELV (Boeing Delta IV and Lockheed Martin Atlas V) designs. On May 18, in a statement before a U.S. Senate subcommittee, Griffin mentioned two possible paths toward development of a CEV launch vehicle. The first path would be to develop a launch system derived from the Shuttle components, specifically a single Solid Rocket Booster (SRB) topped by a new upper stage. The second option would be to upgrade the EELV heavy-lift designs, an effort that he said would also require development of a new upper stage. During the same presentation, Griffin reiterated his previous commitments to both retire Shuttle in 2010 and to revise the CEV program to make the new spacecraft available soon after the Shuttle retires so that it could perform International Space Station (ISS) support missions. With these commitments, Griffin deftly added a sense of urgency to the CEV program - an urgency that seems intended to leverage Congressional support for shuttle-derived launch vehicle development. Griffin told the subcommittee that, "a key aspect of the Agency's analysis of alternatives will be to capitalize on existing technical and workforce assets in a cost-effective and efficient way. NASA's goal is to develop a CEV capable of operating safely soon after the retirement of the Space Shuttle .... The existing Space Shuttle infrastructure and workforce will be carefully evaluated, as their use may enable more rapid development of crew and heavy lift capability than other alternatives like Evolved Expendable Launch Vehicles". After reading the Griffin's statement, Boeing managers might be clambering for a rebuttal hearing. While NASA is years away from fielding a shuttle-derived launcher, Boeing has already launched Delta IV Heavy. Able to boost 25 metric tons to low earth orbit (LEO), Boeing's triple-barrel rocket is already the world's most powerful expendable launch vehicle and would easily be able to launch a reasonably-sized CEV. And contrary to Griffin's statement, Delta IV Heavy could do it without needing a new upper stage. Contemporary ballistic reentry manned spacecraft (Russia's Soyuz and China's Shenzhou) weigh 7 to 8 tons. A new Russian lifting body concept named Kliper, designed to haul up to six passengers with much more internal space than Soyuz, would weigh 15 tons. The Apollo spacecraft that were used to perform earth orbital missions weighed roughly 15-20 tons. But Griffin's heavy 30 ton CEV has moved the bar up beyond what the current Delta IV or Atlas V designs, or any other rocket in the world for that matter, can carry, sending a clear message both to the EELV manufacturers and to the U.S. Air Force, who funded much of the EELV development effort. What is the message? The message is that Griffin isn't planning on using their rockets. - Ed Kyle "www.geocities.com/launchreport/weblog.html" |
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Ed Kyle wrote: On May 18, in a statement before a U.S. Senate subcommittee, Griffin mentioned two possible paths toward development of a CEV launch vehicle. The first path would be to develop a launch system derived from the Shuttle components, specifically a single Solid Rocket Booster (SRB) topped by a new upper stage. That's a very interesting idea; it gets rid of a lot of the time problems associated with building a new booster (assuming they exceed the Delta IV Heavy/Atlas V payload capability with CEV's weight), and would be fairly simple and reliable to use... plus, the first stage now becomes reusable. Pat |
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Considering the likes of the Bigelow prize? What odds would people give
of a commercial manned capsule design getting to LEO first? If this does happen, what are the odds of the NASA effort dieing a quiet death? With the requirement to also develop a new heavy launch vehicle, they seem to be dealing themselves out of the race. Pete. |
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"Pete Lynn" wrote in
: Considering the likes of the Bigelow prize? What odds would people give of a commercial manned capsule design getting to LEO first? Not too likely. It's more than an order of magnitude greater in difficulty of development and execution over a SpaceShipOne suborbital hopper. If this does happen, what are the odds of the NASA effort dieing a quiet death? If it's nothing more than three or four people up and down, with no rendevouz/docking capability and no cargo capability, none. With the requirement to also develop a new heavy launch vehicle, they seem to be dealing themselves out of the race. I do get the feeling Griffin's shooting himself in the foot. --Damon |
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Pete Lynn wrote:
Considering the likes of the Bigelow prize? What odds would people give of a commercial manned capsule design getting to LEO first? A capsule capable of re-entry from an interplanetary trajectory... seems the odds would be low. |
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"Pat Flannery" wrote in message ... That's a very interesting idea; it gets rid of a lot of the time problems associated with building a new booster (assuming they exceed the Delta IV Heavy/Atlas V payload capability with CEV's weight), and would be fairly simple and reliable to use... plus, the first stage now becomes reusable. The assumption that NASA needs a launch vehicle bigger than a Delta IV Heavy/Atlas V Heavy is a terribly bad assumption. Launching components to LEO and docking them together should allow the building of vehicles large enough to return to the moon and go on to Mars. Furthermore, NASA is supposed to be bound by law to buy commercial launches whenever it is possible. Considering how hard of a time Atlas and Delta are having, I'd hate to see NASA turn their backs on commercial launch vehicles and build their own. Lastly, any sort of shuttle derived vehicle is going to necessarily require the retention of much of the shuttle ground infrastructure and "standing army". Because of this, it also would retain the high cost of shuttle launches. This is something that even NASA ought to be against. The low flight rate and high cost of the shuttle should not be repeated by creating a shuttle derived vehicle. I hope that Congress realizes this and puts a stop to it now. They certainly don't want a repeat of the shuttle/ISS experience (e.g. repeated redesigns due to mounting costs). Jeff -- Remove icky phrase from email address to get a valid address. |
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Jeff Findley wrote: The assumption that NASA needs a launch vehicle bigger than a Delta IV Heavy/Atlas V Heavy is a terribly bad assumption. Launching components to LEO and docking them together should allow the building of vehicles large enough to return to the moon and go on to Mars. But that way you end up with the parasitic weight of the rendezvous and docking gear on each of the modules, plus the necessity of interconnecting their control systems so that they function as one. Furthermore, NASA is supposed to be bound by law to buy commercial launches whenever it is possible. NASA may have taken a dim view of the proposed LockMart-Boeing space services merger and what it would mean in regard to pricing of commercially bought boosters. If you are required to buy commercially, and you have a sole-source supplier, then you have a situation where that sole-source supplier can charge whatever it wants. Other firms may get a slice of the action in the small booster field, but the 500 pound gorilla that the merger will create is going to be awfully hard to beat in the medium/heavy lift category unless one is willing to to look to foreign manufacturers as able to bid on a launch on equal terms with American companies. Considering how hard of a time Atlas and Delta are having, I'd hate to see NASA turn their backs on commercial launch vehicles and build their own. Lastly, any sort of shuttle derived vehicle is going to necessarily require the retention of much of the shuttle ground infrastructure and "standing army". Because of this, it also would retain the high cost of shuttle launches. This is something that even NASA ought to be against. The low flight rate and high cost of the shuttle should not be repeated by creating a shuttle derived vehicle. The SRB is a fairly low tech piece of machinery, and it could be stacked right at the launch site from its component sections, eliminating the need for the VAB and the crawler transporter, and then have the upper stage and CEV put on it after it was assembled. That would cut down on the manpower requirerments. It also has the fact that it is a proven design going for it- if considered separately, we've had 216 SRB flights with one failure; that makes it hands-down the single most reliable large booster rocket ever built, with a failure rate of better than .5%. I hope that Congress realizes this and puts a stop to it now. They certainly don't want a repeat of the shuttle/ISS experience (e.g. repeated redesigns due to mounting costs). Unfortunately, one can see that being exactly what happens based on recent NASA experience in regards to new spacecraft design. The project gets started, then around half way through, we decide that we don't need what we are designing or run into a technical snag, and start all over again from scratch. They should have a real sit-down discussion and figure out exactly what they want and what it's designed to specifically do before they go rushing ahead with the design, like they seem to be doing now. The Soviets carefully thought out Soyuz before they built it, and the fact that they made the right decisions gave them a quite versatile spacecraft that could be kept in use at a economical price for decades to come. Pat |
#8
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"Pat Flannery" wrote in message ... Jeff Findley wrote: The assumption that NASA needs a launch vehicle bigger than a Delta IV Heavy/Atlas V Heavy is a terribly bad assumption. Launching components to LEO and docking them together should allow the building of vehicles large enough to return to the moon and go on to Mars. But that way you end up with the parasitic weight of the rendezvous and docking gear on each of the modules, plus the necessity of interconnecting their control systems so that they function as one. This is true, but you're assuming that the parasitic weight matters. It doesn't matter so much if you're saving money by using commercial launch vehicles instead of maintaining the shuttle launch facilities and paying the standing army for a handfull of shuttle derived vehicle launches each year. Also, some of the systems can be pared down to a bare minimum if you work on *real* space infrastructure like a reusable LEO space tug. Many "modules" would be very passive, like LOX or fuel tanks, and would be picked up by the tug. The tug would then "dock" the module to the vehicle being assembled. This way, the docking mechanism and control systems on a fuel tank would be minimal. Furthermore, NASA is supposed to be bound by law to buy commercial launches whenever it is possible. NASA may have taken a dim view of the proposed LockMart-Boeing space services merger and what it would mean in regard to pricing of commercially bought boosters. If you are required to buy commercially, and you have a sole-source supplier, then you have a situation where that sole-source supplier can charge whatever it wants. Other firms may get a slice of the action in the small booster field, but the 500 pound gorilla that the merger will create is going to be awfully hard to beat in the medium/heavy lift category unless one is willing to to look to foreign manufacturers as able to bid on a launch on equal terms with American companies. If NASA build its own shuttle derived vehicle, it will own its own 500 pound gorilla. From NASA's point of view, it would at least have some control over its own gorilla. From the nation's point of view, that's one gorilla too many. Considering how hard of a time Atlas and Delta are having, I'd hate to see NASA turn their backs on commercial launch vehicles and build their own. Lastly, any sort of shuttle derived vehicle is going to necessarily require the retention of much of the shuttle ground infrastructure and "standing army". Because of this, it also would retain the high cost of shuttle launches. This is something that even NASA ought to be against. The low flight rate and high cost of the shuttle should not be repeated by creating a shuttle derived vehicle. The SRB is a fairly low tech piece of machinery Surely you jest. It's got to the the most complex SRB ever built. The thrust vector control system is pretty complex. You've even got a flexible joint for the nozzle, which is very complex compared to your "typical" strap-on SRB on the side of an ELV. There is also the recovery system, which you don't have on other SRB's. Remember the joints aren't simple either, and I'm talking not only about the casings, but the fuel itself. Simple SRB's don't have segments and have their fuel cast in one piece to eliminate joints, which are a possible point for burn through issues. , and it could be stacked right at the launch site from its component sections, eliminating the need for the VAB and the crawler transporter, and then have the upper stage and CEV put on it after it was assembled. That would cut down on the manpower requirerments. It also has the fact that it is a proven design going for it- if considered separately, we've had 216 SRB flights with one failure; that makes it hands-down the single most reliable large booster rocket ever built, with a failure rate of better than .5%. My gut feel is that if *any* shuttle derived vehicle is built, it will use the VAB, MLP's, crawlers, and the shuttle pads. Are any other large, segmented solids stacked at the pads? I hope that Congress realizes this and puts a stop to it now. They certainly don't want a repeat of the shuttle/ISS experience (e.g. repeated redesigns due to mounting costs). Unfortunately, one can see that being exactly what happens based on recent NASA experience in regards to new spacecraft design. The project gets started, then around half way through, we decide that we don't need what we are designing or run into a technical snag, and start all over again from scratch. For the station program, this was most often (always?) usually due to cost overruns. Remember the year that NASA "discovered" $4 billion in overruns? They should have a real sit-down discussion and figure out exactly what they want and what it's designed to specifically do before they go rushing ahead with the design, like they seem to be doing now. The Soviets carefully thought out Soyuz before they built it, and the fact that they made the right decisions gave them a quite versatile spacecraft that could be kept in use at a economical price for decades to come. Now you're going to have Derek after you. ;-) Part of the success of the Soyuz launcher is the fact that the Soviets/Russians have figured out ways to use it without requiring it to grow much, as US launchers seem to do over the years. You don't see the latest Soyuz launchers sporting large segmented solid rocket boosters like Titan III/IV. Delta IV Heavy and Atlas V Heavy are plenty big enough. A real spacefaring nation would figure out a sustainable LEO architecture capable of flying missions with these vehicles rather than resorting to a shuttle derived launch vehicle. Firstly, an assembly space station at KSC's inclination would go a long way towards this goal. It would provide power, cooling, consumables, airlocks, robotic arms, and a reusable space tug to support assembly of interplanetary craft in LEO. It would enable possible (eventual) reuse of components returning from the moon (using tricks like aerobraking). Such a station need not be as complex as ISS. After all, who cares about the microgravity environment aboard an assembly station? Make it gravity gradient stabilized and be done with nasty issues like active three axis stabilization. If you're not doing science aboard it, who cares that you dump your waste fluids and gasses overboard? The interplanetary craft can keep its instruments behind protective covers until it leaves LEO. Jeff -- Remove icky phrase from email address to get a valid address. |
#9
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It doesn't matter so much if you're saving money by using commercial
launch vehicles instead of maintaining the shuttle launch facilities and paying the standing army for a handfull of shuttle derived vehicle launches each year. Assumign you're using actual commercial vehicles with low cost, sure. But we're talkign about EELV. Neither truly commercial, nor low cost. If NASA build its own shuttle derived vehicle NASA is not really in the business of building *any* vehicles. It's got to the the most complex SRB ever built. And even so it's vastly cheaper than an EELV core. |
#10
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Jeff Findley wrote: My gut feel is that if *any* shuttle derived vehicle is built, it will use the VAB, MLP's, crawlers, and the shuttle pads. Are any other large, segmented solids stacked at the pads? There were, but the last one may be on the pad now. That would be the Titan IV stacked on Vandenberg SLC 4E. India's PSLV and GSLV launchers, which have a core segmented solid rocket stage that is about 1/3rd the mass of Titan's SRMU (augmented by *liquid* strap-on boosters in the GSLV configuration) were also stacked on a fixed pad, but this practice also ended this year with the opening of a new pad that features a rail-mobile launch platform. Ariane 5 rolls on rails, of course, as does Japan's H-IIA (which now uses single-segment SRBs). Delta IV and Delta IIH may be the biggest SRBs (nonsegmented tho) that are actually still attached to the vehicle while it stands on a launch pad. (Atlas V's SRBs are attached in the VIF). I can't think of any others. - Ed Kyle |
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