Posted on 03/20/2006 4:52:26 PM PST by KevinDavis
NASA is considering dropping the Space Shuttle Main Engine (SSME) from its heavy-lift launch vehicle plans and using the cheaper-to-manufacture RS-68 engine instead.
Daniel Dumbacher, deputy director of the Exploration Launch Office at NASA’s Marshall Space Flight Center, Huntsville, Ala., told reporters following his presentation at the Goddard Memorial Symposium here March 14 that a formal trade study is under way to examine the cost, schedule and performance merits of the SSME and RS-68. At present those two engines are NASA’s first choice for the main stage engines that would power the planned heavy-lift cargo launcher NASA intends to build to boost payloads on their way to the Moon.
Dumbacher said the trade study would be completed this spring. "It’s got to be done in the next month or so because it plays a factor in how we do our budget planning," he said.
If NASA goes with the RS-68, then the SSME would have no obvious future beyond the space shuttle program, which is slated to end in 2010.
(Excerpt) Read more at space.com ...
Have you ever watched any of the Spacecreaft series DVD's that are out? I rent them from Netflix and have seen Apollo 8, 11, {and I'm currently watching} 15, also Gemini and Saturn I and Saturn V. These dvd's pack a lot of information on them. I might eventually buy them because they are great for space buffs.
SSME's: one of the greatest technical successes in history.
Disposable RS-68 vs. reusable SSME. Will the Heavy Lift Vehicle have a recoverable first stage?
SSME is needlessly complex, but, its tested and it works, and we will have 9 spare ones soon.
That is one hell of a lot of work and money for a throwaway engine.
BTW, read "Riding Rockets" by astronaut Mike Mullane. True and pretty salacious stories from the first class of Space Shuttle astronauts, its a great read.
Thank you for the tip; I hadn't known of them.
It's a shame that it really isn't needed any more. The SSME is needlessly robust for a disposable launch system. The throttling capability is probably unnecessary too.
Since these are to be unmanned rockets, why are they bothering with liquid fueled engines for the boost stage? Aren't solid fuel engines a heck of a lot cheaper?
The primary reason for liquid over solid is the ability to shut down the engine. I'm not sure the launch system is strictly unmanned. I think NASA is intending to use the same launch vehicle for the CEV and cargo, but I'm not certain.
According to Wikipedia, the real cost of solid vs. liquid is a wash. The handling requirements for the volatile solid fuel runs the cost up.
The first SSME's blew up on Rocketdyne's test stands because nobody had ever built dual LOX and hydrogen pre-burners AND turbopumps in an engine before, and many scientists considered it impossible. The achievement demarcated rocketry before the SSME and after the SSME. It is definitely one of the greatest achievements in rocket science, which is about as "technical" as one can get.
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