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NASA Eyes Shuttle Replacements

Posted by chrisd on from the big-rubber-bands-are-not-under-consideration dept.

jonerik writes "According to this article at Space.com, NASA yesterday released a status report on the first year of NASA's Space Launch Initiative; the search for a space shuttle replacement, currently planned to begin operating ten years from now. The competing contractors - Boeing, Lockheed Martin, and a team consisting of Northrop Grumman and Orbital Sciences Corp. - have their work cut out for them. NASA is looking for both a ten-fold improvement in per-pound launch costs (from $10,000 per pound to $1,000) and massive improvements in crew survivability." In related news, Rubyflame writes: "Aviation Now has a story about four new kerosene-fueled rocket engines being developed by Aerojet, Pratt & Whitney, Rocketdyne, and TRW. These are engines that will produce a million pounds of thrust, intended to outdo Russian designs in reliability and launch cost, and one of them may power a new reusable launch vehicle. Kerosene has the advantage that it's denser than hydrogen, so the fuel tanks can be smaller."

2 of 314 comments (clear)

  1. Multi-stage Launch by jchawk · · Score: 5, Informative

    This article is light on details but does mention that all of these systems that they are working on are two-staged.

    At first you may think that two-staged launches are a waste of money, but some of it does at least look promising.

    The design from Boeing is an interesting one. It looks like a smaller shuttle attached to a jumbo jet. It's then flown near the limits of space where the top ship would then come apart and finish it's journey into space on it's own.

    The jumbo jet would then return to the launch site.

    I must admit that I would love to see a 1 stage space craft. :-)

  2. Re:Kerosene? by Waffle+Iron · · Score: 5, Informative
    I understand the space savings advantages of kerosene, but how does the thrust produced per unit weight compare to that of the current SRB/LRB compare? Having to (hypothetically) double the fuel weight to double the thrust seems like a waste of money to me.

    On another article a few weeks back, someone posted an answer that cleared this up for me. (I'm too lazy to track down the posting now.)

    Bottom line is: hydrogen is like a high-horsepower, high-RPM turbo racing engine; it's best for driving light vehicles at high speeds (upper stages). Kerosene is like a high-torque diesel truck engine, good for getting a lot of weight moving from a dead stop.

    The difference has to do with the physics of exhaust density, speed, momentum, etc.