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Version of the Atlas II with no sustainer?
I vaguely recall that in the long era of the 1990s, there were a few
Atlas II launches did not carry the small sustainer engines, but rather just the two booster engines, which fired until all propellant was consumed. Was this just a dream, or did Lockheed build a few of these? Or am I simply confusing Atlas III with Atlas II? |
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Explorer8939 wrote:
I vaguely recall that in the long era of the 1990s, there were a few Atlas II launches did not carry the small sustainer engines, but rather just the two booster engines, which fired until all propellant was consumed. Was this just a dream, or did Lockheed build a few of these? Or am I simply confusing Atlas III with Atlas II? The Atlas II had the 3 chamber (2 booster, 1 sustainer) Rocketdyne MA-5A engine. The Atlas III has the 2 chamber RD-180. The MA-5A did not have the two small vernier engines that previous Atlas engines had. Could that be what you are thinking of? Jim Davis |
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I vaguely recall that in the long era of the 1990s, there were a
few Atlas II launches did not carry the small sustainer engines, pcrecycling1 this is true |
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It seems that this question has two possible replies but to get the
answers is going to take someone who has access to their resources. I was not entirely clear on the original question so I will take a shot, hoping folks remember that I am doing this from memory with NO references. At liftoff, the sixties-era Atlas (such as the types that served as ICBM's and as the Mercury booster) had five engines running. At the base were two outboard booster engines, and a centerboard sustainer engine. In addition, two vernier engines were on the side of the vehicle. If the question asks about an Atlas configuration without the centerboard sustainer, I believe that only early test versions of Atlas flew this way while the vehicle was under initial development and no operational versions of Atlas flew this way. If on the other hand, the question refers to the two vernier engines, later versions of Atlas (Atlas III or V) deleted the two vernier engines. I am hoping others will correct my mistakes and provide either corrections or amplifications. Take care . . . John M. Pelchat |
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Jim is correct. No Atlas II ever flew without a sustainer engine, but
Atlas II did delete the two small side-mounted vernier engines that were on earlier Atlas vehicles. General Dynamics was working on a new design called Atlas IIAR, that would have replaced the booster/sustainer MA-5A engine with a straight two-chamber design. Rocketdyne bid an engine design. So did Russia's Energomash (in combo with Pratt). Energomash won when Rocketdyne pulled out of the competition. Eventually, General Dynamics space division was sold to Martin Marietta, which was later merged into Lockheed Martin - and the new Atlas IIAR was renamed "Atlas III". Lockheed used the new Atlas as the starting point for its EELV design - which it called "Atlas V". Next year, the last Atlas III will fly and Lockheed will shut down the last remnants of the long-running Convair/General Dynamics heritage Atlas program at the Cape. - Ed Kyle |
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"Explorer8939" wrote in message om... I vaguely recall that in the long era of the 1990s, there were a few Atlas II launches did not carry the small sustainer engines, but rather just the two booster engines, which fired until all propellant was consumed. Was this just a dream, or did Lockheed build a few of these? Or am I simply confusing Atlas III with Atlas II? Back when the first Atlas missiles were flown the first test vehicles had only the two booster engines and the propulsion system was not separated. This was back in 1957-58. I don't know of any later Atlas missiles that didn't have the sustainer engine until the Atlas III. Mike Walsh |
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ed kyle wrote: ... it must have taken a lot of engineering to design it such that when the booster skirt was jettisoned, that the shared equipment came a part in such a way that the sustainer had what ever it needed to continue to operate. You betcha. Atlas development was part of one of the largest military-industrial efforts ever marshalled by the United States. Atlas was a troubled bird for quite a few years. Go see a real Atlas at Cape Canaveral (not Kennedy Space Center) or the one in Huntsville to get an idea of how complicated the engine section was. It's fairly involved back the http://www.siloworld.com/ICBM/ATLAS/ATE/TRANS13.jpg http://www.geocities.com/atlas_missile/diagrams.html http://www.geocities.com/atlas_missi...tdyne_ma5a.jpg Speaking of involved Atlas's, did anyone have this model when they were a kid? I had it at least three times: http://www.geocities.com/atlas_missi...r_missions.htm Is that supposed to be a four-engined variant of the Centaur on the Atlas Cargo Vehicle? Or has somebody started clustering Agena motors? According to the U.S. Air Force: "Titan II was boosted by an Aerojet LR87-AJ-5 two chamber liquid propellant rocket engine of 430,000 lbs. thrust" Don't ever get Henry Spencer started on this one... trust me. ;-) Pat |
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