Want to read Slashdot from your mobile device? Point it at m.slashdot.org and keep reading!


Forgot your password?
The Military NASA Space Transportation Science Technology

Air Force Wants Reusable Fly-Back Rockets 94

FleaPlus writes "The Air Force is initiating a pathfinder program to develop a first-stage rocket booster capable of gliding back to a runway so it can be easily reused. Lockheed Martin has already launched a secretive prototype, and a Cal Poly team has a prototype based on Buzz Aldrin's Starcraft/StarBooster design (video). The Air Force estimates such a booster could cut launch costs by 50% over the current Atlas 5 and Delta 4 rockets, and could also offer a rapid surge/replacement capability if combined with reusable spacecraft like the recently launched X-37B. Initial test flights are planned for 2013."
This discussion has been archived. No new comments can be posted.

Air Force Wants Reusable Fly-Back Rockets

Comments Filter:
  • Shuttle (Score:4, Insightful)

    by IdahoEv ( 195056 ) on Friday May 21, 2010 @09:17PM (#32301572) Homepage

    Fifteen years of development by committee, and they'll start construction on something that looks exactly like the Shuttle.

    Because this is pretty much exactly where the Shuttle started.

  • by fustakrakich ( 1673220 ) on Friday May 21, 2010 @09:22PM (#32301600) Journal

    We are using 2,300 year old technology... It's time to quit teaching what can't be done, so we can open up to what can be... The subject of propulsion, or mass and inertia would be a good place to start.. Right now our systems are as comical as the old Flash Gordon pointy tin can with sparks(ions?) coming out the back.

    You can't do that, it's impossible!
    Well, nobody told me...

  • by RsG ( 809189 ) on Friday May 21, 2010 @09:35PM (#32301688)

    If flying cars could be made to blow up the enemy, or even just humiliate them, we'd have flying cars. Not to take anything away from the folks at Cal Poly, but I'm still waiting for the next Teflon.

    Helicopters fly, can land or take off from a pad not much bigger than your average driveway, and can be less massive than most trucks. For most values of the word, they are "flying cars". Granted, they don't look like a sedan with jump jets (which is what most people think when they hear the phrase), but it's silly to expect a flying car to resemble a ground car in basic shape. And yes, the military does spend loads on designing, testing, building and fielding choppers for use in war.

    The problem with the '50s vision of flying cars has never been technological. It's been a host of practical issues, from safety, to cost, to fuel consumption, to piloting versus driving skills, to simple common sense that's kept the flying car fictional.

  • by 0123456 ( 636235 ) on Friday May 21, 2010 @10:04PM (#32301828)

    Every Kilo counts - there are no tricks, or move closer to the equator.

    First stage mass makes little difference to overall performance because it doesn't have to be carried into space... if the first stage is heavier you typically just load more fuel to compensate, and fuel is generally cheap compared to the hardware in the first stage (obviously that's not true for the shuttle SRBs, which is another reason why they were a really dumb idea).

  • by SEWilco ( 27983 ) on Friday May 21, 2010 @10:25PM (#32301966) Journal
    If we had flying cars, we'd be humiliating various countries constantly by thousands of tourists flying over or past them on the way to all the good tourist destinations. Because a flying car probably won't have the range to cross the Atlantic easily, but it will be able to fly from Alaska to Russia. Tourists going all over the place. Oh.. sorry about that, Hawaii.
  • Re:Sensible (Score:3, Insightful)

    by tsotha ( 720379 ) on Friday May 21, 2010 @10:27PM (#32301974)
    It wouldn't surprise me either, because Congress is far more focused on how many jobs are maintained by the program than they are on efficiency. Creating a vehicle that can be maintained by 20 people instead of 20,000 is really at odds with Congress's interest in the endeavor.
  • Re:Simple (Score:3, Insightful)

    by AJWM ( 19027 ) on Friday May 21, 2010 @10:45PM (#32302082) Homepage

    1) You shouldn't reuse rockets.

    Yeah, you should, because if you use it once and it works, you know it will work again and again (see DC-X). If you build a new one, you won't know until you've flown it.

    This of course assumes that the thing is designed to be flown and re-flown without a complete overhaul between each flight -- i.e. like airplanes not like current Shuttle technology. Or you build a new one for each flight, spend a fortune trying to inspect-in quality, and blow up one in thirty or so anyway. The latter is how missiles are designed, not a rational transportation system.

  • by Ungrounded Lightning ( 62228 ) on Friday May 21, 2010 @11:05PM (#32302200) Journal

    Isn't the shuttle such an albatross precisely because reusability is so impractical?

    Nope. It's because somebody goofed and they made the wings too big. As I heard it back then (caveat: didn't check it myself):

    The shuttle was supposed to be a combined civilian and military vehicle, so the design budgets could be combined and the cost per unit could be brought down by building a bunch of 'em.

    Civilian stuff mostly orbits equatorial and near-equatorial, launching eastward to get a boost from the Earth's rotation. This would be launched east from Canaveral, so crashes would be into the Atlantic. A lot of military stuff orbits polar or near polar, and doesn't get the boost. This would be launched south from Vandenberg, so crashes would be into the Pacific.

    Without the boost from the Earth's rotation you get a significant reduction in payload capacity. There's a rule of thumb for computing this.

    The shuttle lands as a glider. The wings are partly for steering it for cross-track on the way down. The farther the worst-case sideways distance from your orbital track to the landing site is, the bigger the wings you need.

    For typical missions the Shuttle doesn't need much cross-range capability: You just wait for the orbit closest to going right over the landing site and go down then. This happens twice per day. You could get away with little stubby wings like the X-15.

    But the military wanted to be able to run another mission profile: A polar, pop-up, once-around shot, landing back at the launch site. This would be for things like spying in a war or near-war situation, when you'd want to get the shuttle down with the info right away and also before the enemy could shoot it down. Problem with this is that the earth moves the landing zone out from under the orbit and you need a lot of cross-range capability to do it. So you need big wings.

    So they ran a sanity check on whether the polar orbit was still doable with the big, heavy wings needed for this mission. They're heavy, and that weight comes right out of payload, so the payload capacity would be reduced and the cost-per-pound to low orbit raised a bunch. But it looked like the polar orbit could still launch a decent-sized cargo. So they went with the big wings.

    But when they'd run the sanity check they'd applied the rule-of-thumb to the CARGO weight. Somebody had forgotten that, since it also ended up in orbit, the orbiter itself, along with the crew and their consumables, WAS ALSO PART OF THE PAYLOAD. So you have to apply the rule of thumb to the TOTAL weight: Payload, orbiter, consumables, reentry fuel, yadda-yadda-yadda.

    Once they did the computation right it turns out that the shuttle would only have a couple hundred pounds of payload to polar orbit. No launching spy satellites for you! Oops!

    So the military didn't end up using the shuttle (except for a couple equatorial shots testing some gear). They built their own big boosters and went their separate way. The Vandenberg shuttle launch site was demoted to an emergency landing site (so the shuttle could be landed if Canaveral had bad weather and then piggybacked to Canaveral rather than relaunched from Vandenberg). The military didn't buy any craft and the whole cost of construction and operation fell on the civilian projects, raising the cost-per-pound still further.

  • Re:Sensible (Score:3, Insightful)

    by tsotha ( 720379 ) on Saturday May 22, 2010 @12:24AM (#32302566)

    Not right now. SSTO with chemical rockets is just plain impossible. Weight-to-payload ratio is murderous.

    I don't think that's been established at all. It's definitely doable if you build a really large rocket. It's not doable for a really small rocket. I think you could probably make it work for a medium-sized vehicle if you didn't have high expectations on payload side. But that's okay, since the point of a rocket like that is to fly often.

    Let me echo the AC that replied mentioning Pournelle. I can't recommend How To Get To Space [jerrypournelle.com] and also The SSX Concept [jerrypournelle.com] highly enough.

    2STO should be possible, but how would it be different from Shuttle?

    It would only be beneficial if you got rid of the wings on the upper stage. IMO powered landing is crucial to reducing operational costs because you don't have the enormous heat stress on reentry. If they build a 2STO and use a shuttle-style vehicle for the second stage... well, it's a waste of money.

    Were I king I'd restart DC-X and build DC-Y. I'd find out, through experimentation, exactly how much payload we can get to LEO using a VTVL SSTO, realizing the answer might be a negative number.

    If that didn't work out I'd pursue a 2STO solution with the upper stage being a VTVL craft lifted from my SSTO program and the lower stage being some kind of flyback (either VTVL or VTHL).

  • Re:Simple (Score:2, Insightful)

    by strack ( 1051390 ) on Saturday May 22, 2010 @02:24AM (#32303176)
    maybe if you engineer it to the bleeding edge specifications that the space shuttle main engines were built to, but the thing is, you dont need to build them like that, you can build them to be reusable, and still get large amounts of payload into space.
  • Re:Sensible (Score:4, Insightful)

    by BJ_Covert_Action ( 1499847 ) on Saturday May 22, 2010 @05:15AM (#32303968) Homepage Journal

    It wouldn't surprise me if Congress and the White House doesn't manage to repeat the same mistakes made almost 40 years ago.

    I think that's why the Air Force wants control of this development project. As long as they can claim the system to be a weapons/national defense platform, they can pretty much tell the rest of the government to keep their hands off the design. This gives them the freedom to develop the booster for whatever mission profiles they want. Of course, that's assuming that the Air Force is funding this with money they already have, rather than asking Congress for more. If they are asking Congress for more money then, yes, the politicos will control this particular project as well.

Due to lack of disk space, this fortune database has been discontinued.