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Space

X-43 Scramjet Rollout 121

Posted by michael from the just-enough-time-to-roll-out-the-beverage-cart dept.
PenguinRadio writes: "The Washington Post is reporting that NASA is readying the X-43 space plane for a 10 second test flight, after which is will plunge into the ocean and not be recovered. The X-43 is an unmanned aircraft (there are three of them) that is used as a testing bed for hypersonic aircraft and may lead to a commercial version in about 20 years or so. Anybody got an extra wet suit?" See also the Reuters article on the same subject, and our previous story about an Australian version.
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X-43 Scramjet Rollout More

X-43 Scramjet Rollout

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  • Re:Submarine (Score:1)

    by Anonymous Coward
    It's just that Yanks can't keep up with world politics and news. With two major US fuck ups in the Asian-Pacific region this year so far, they've gone into Non-US-Incident overload. The symptoms include the inability to distinguish between major world powers, dates, times, and wether an object is Sea, Air or Land borne.

    Provided that the US people are not subjected to any further news from outside of the United States of America for the next eight months, they should recover fully. We can only pray that the recent news of the Russian State owned company taking control of Russias last independent media company NTV does not reach their shores, or they may go into total World-Isolationist-Meltdown, and possibly end up starting a war in Mexico to make up for it.

    Hope that helps.
    Dr. Fred

  • Re:Why no Post-crash analysis? (Score:1)

    by Anonymous Coward
    During early part of the contract, Rockwell/MicroCraft proposed to make the vehicle a reusable vehicle and land it on a remote strip on an island. NASA felt the technical and financial risk it too high to add this capability (Landing at over 350 knots without wheels). So the decision was made to just splash it. Granted, it would have been invaluable to be able to look at the engine structure after the high speed run. But given the budget and time constraint, that was sacrificed. Besides, the vehicle, as it's currently sized, has no room for landing gears!! Don't worry about foreign country recovering the parts. First, at Mach 2+ impact speed, the vehicle (only 12 ft long and 4 ft wingspan) will be in tiny pieces, and the impact area is over 12000 ft deep. Not practical for anyone to try to recover bits and pieces of scrap.

  • Re:Why no Post-crash analysis? (Score:1)

    by Anonymous Coward
    The airspace will be cleared of all non-test related traffic. This including commercial airliners flying to US from Asia. They are being rerouted around the Navy test range during this test. The test won't occur if any other air traffic is detected. By the way, the descent won't be a freefall at all. There is an imaginenary landing area that the vehicle will hit in a controlled flight, just as if it is landing on an airstrip.
  • you mean Japanese.
  • if it existed, it could easily fly along at Mach 5, using all it's elint equipment to monitor the X-43.

    But they probably don't exist.
  • than space shuttles, though the overall energy efficiency of SSTO is still a little dicey.
  • You're just a bit off on your prediction ...

    My prediction: the scramjet will successfully accelerate to Mach 5, plowing into a Chinese observation plane and obliterating it.

    More likely, it'll be "A Chinese fighter pilot will plow into the scramjet by stupidly flying too close while trying to show the unmaned aircraft his email adress".
  • Ok, so instead of working on this scramjet, you would rather NASA do... what? A project like this is one of the best things they can do for making space cheap. Maybe it'll be used as a weapon, but so what? Everything does. ICBMs were built before we sent anybody into orbit. You can't get away from it, you can only live with it.

    Oh, and by the way, Pan Am went away many, many years ago. ;-)
  • Jet fuel prices have been rising a lot for the past few years. According to Southwest Airlines' financial statements [yahoo.com] they spent 39 cents per gallon in 1999, and 82 cents per gallon in 2000. It probably is higher now.

    Of course, as a high-volume carrier, Southwest is probably paying less than people or companies without high-volume contracts.

    Kevin Fox
    --
  • I seem to recall reading this before [slashdot.org]..
  • Dryden's photo archive is supremely bad ass. When I first stumbled across it six years ago, I had no idea what anybody could ever do with a 3000x1800 pixel JPEG. Now I can get one out of a digicam the size of a pack of smokes. I love technology!
  • You're just bitter that you'd have lost World War II. Damn foreigners.

  • I really think NASA should focus on the 'S' and stick with space exploration. But what about the poor A?

    2001 is almost behind us and their still aren't any PAN AM destinations in our solar system. Unless you count the ones on Earth. Shouldn't Pan Am focus on the 'Am'? :)

  • ...besides, if you remove the first "A" from "NASA", you get an acronym that's already in use.
  • If you do, take a sieve. You're going to need to to recover any pieces of an object that hits the water at hypersonic speed.
  • Does anyone know where to rent a small submarine? I think we should get some people together and go down and get this puppy.
  • Will Taco Bell float another target and offer everyone free Tacos if it hits it?
  • I wonder if there is any coincidence to the China event? Never hurts to demonstrate your ability to get anywhere 10 times faster than sound...
  • I'd use a railgun as a launching pad for these things.
  • It's not going to have anything to salvage once it hits the water anyway... The entire design is built to survive mach 7 enthalpies (5000 deg R) for about 30 seconds. The cooling mechanism involves passing liquid hydrogen beneath the skin of the craft, heating it to about 4000 degrees, then pumping it to the engines to burn. Once the fuel runs out, the unprotected airframe will do 2 things: 1) turn to slag from the incredibly high stagnation temperatures, 2) tear to pieces from the sudden deceleration.

    Remember, Tt and D are f(M^2)... when M gets large, both become dangerous.
  • Umm....the x is roman numeral X (as in 10)

  • An article from NASA (http://www.dfrc.nasa.gov/gallery/photo/X-43A/ [nasa.gov]) says three seperate tests at mach 5, 7 and 10.

  • Yeah, I was kinda hoping they'd run it into a highrise

    Sorry guys - just testing structural integrity!

    somebody is gonna take me seriously here... sad sick little puppies!

  • Traditional rockets are inefficient fuel wise as compared to space planes. Space planes create lower G forces in getting to and leaving orbit, which will allow more rich old men to go up. Most designs for space planes also don't require booster rockets to get them into orbit, so they are reusable almost immediately, unlike rockets or the space shuttle. Space planes can carry more payload for their size. What more can you ask?

    In essence, any step towards space planes will be a step towards space colonization which (I feel) is a step in the right direction. What else do planets exist for if not for our amusement (look ma - I'm walking on Mars! :)

  • The only advancement to Commecial air travel in the last 20 years has been Delta Airlines' get-it-yourself, bottled water and banana "Sky Deli".
  • What makes you think that the governments are holding anyone back? As far as i know, if you had 10 billion dollars, and you wanted to fund your own space flight company, nobody would stop you.

    Malcolm solves his problems with a chainsaw,
  • I wonder what terminal velocity is for a highly aerodynamic mach capable plane? Probably pretty high. I suppose it would depend if it tumbles, or dives.

    I'm going to go drop a penny off a tall building into a jug of water, see what happens.

  • "If Pan Am were flying space shuttles, there would be a lot more activity above the atmosphere."

    True, but we'd be crammed like sardines and be 3 hours late!

  • It's just like NASA to crash it into the ocean.

  • You keep your "flat" clean? I dunno about you, but my place is a shithole...

    (Do I get modded up for "Informative" or modded down for "Too Much Info, Ya Friggin Slob"?)


    ----------------------------------------
    Yo soy El Fontosaurus Grande!
  • True that their X is for 10, but the article says they are heading for 6+ (its not very precise), so I just wanted to say that its going to be fast
  • high framerate good, low ping better.

    Of course, real railguns wouldn't be any good, as magnetically accellerating something this big up to mach 5+ is going to need a really _long_ rail. Shall we get back to Q2 jokes then?
  • Its not 0 to Mach 5 in 10 seconds; they are launching it up to some significant speed already on a booster.

    From the article: "A booster rocket will ignite to accelerate the X-43A to its test speed and altitude of about 100,000 feet"

    Since its a scramjet, that starting speed has got to be above mach 1 (the point of a scramjet is that the fuel is injected into the airflow at supersonic speed). It says 10 seconds and 17 miles at the start of the article, which is a mean speed of 6120 miles per hour. As it also says speeds up to 7200 miles per hour thats a first approximation of a roughly 5000 mph start speed (yes, I know that a linear velocity increase is a massive approximation, but it'll do for now.)
  • after which is will plunge into the ocean and not be recovered.

    Manager: What do you mean it can't land?
    Developer: Land? That was not included in the spec.
    Manager: So we have a jet that can take off, but can't land.
    Developer: Correct. Should we add a landing feature?
    Manager: No, we are already over budget and behind schedule even by NASA standards. Any ideas?
    Developer: Our team recently discovered a new "feature." Ocean-floor data repository.
    Manager: Great. Forward that to marketing and lets start shipping it. It doesn't matter if it crashes, it only has to start running.
  • >after which IS will plunge into the ocean >Could you guys ever use an spell checker? :-) Yeah.. because a spell checker would catch "is".. gosh that is so horribly misspelled.
  • We really do need to start getting our butt in gear and getting off the planet.. 2001 is almost behind us and their still aren't any PAN AM destinations in our solar system.

    Um, even if there were extraterestrial flights, where exactly would you go? Pitch a tent outside the ISS? Hope you remember your sun screen.


    --
  • This is probably a troll, but I'll bite. There are many reasons space travel is much more expensive than travel on land.

    1. Radiation. There is a lot of radiation out there that wreaks havoc on electonics not to mention our bodies. Down here it's mostly filtered out by the atmosphere and jets don't have to deal with it.
    2. Heat. The tiles on the shuttle must be hand-mounted and checked very carefully so the shuttle doesn't burn up on reentry. Do you know how long that takes?
    3. Risk. There are no rescue missions in space. Either you return safely or you never return.
    4. Insurance. Insurance costs enough already. Do YOU want to foot the bill for space travel?
    5. 175,982.7 other reasons.

    Of course some of this could change if space travel were more widespread, but the major challenges still remain. Our day will come, but it'll be a while.


    --
  • What exactly does everyone think is going to be left of this plane after it slams into the ocean at Mach X?
    BINGO! The only intelligent comment in this thread. Let's recap. It'll be flying at 100,000 feet. When it runs out of fuel and FALLS 100,000 FEET, what will be left when it impacts the ocean? Debris.
  • if we only would learn to leave nature as clean, as we leave our flat.

    If that's the standard, I'm packing my bags tomorrow and moving off-planet quick.

    At best, one's flat is a near-sterile surface nearly devoid of life and populated wholly by artificial stuff.
    At worst, one's flat is little different from a landfill.

  • Judging from the photos, that thing is amazingly small! It looks roughly 10 feet long, 3 feet wide and 1 foot high.

  • If that. :(
  • If it hits it, everyone at NASA gets a free Chalupa....

    heh, first time i read that i saw "everyone at NASA gets a free Chihuahua"....
  • plowing into a Chinese observation plane and obliterating it

    or even a Chinese fighter plane.
  • Seeing that the illuminati controls the world, especially the government, its using NASA to work on some secret project, probably having to do with aliens. Once this is complete, they will discover ways to conceal it, they will figure out ways to control the corporations as they start building in space. Taxes and laws that are difficult to understand is the usual tactic.
    You must wait for the illuminati to be ready before any of that will be ready.

    FNORD!!!
  • Dude... last time civilians got behind the wheel of a submarine, there were Chinese civilian casualties.
  • Can I win one of these with a couple million Pepsi points??

    (Nobody give me the snopes addy, I know its fake) :-P
  • This is the world as i like it: everyone's throwing its waste into the sea ...
    Damn, if we only would learn to leave nature as clean, as we leave our flat.

  • I always see that Mach 6.7 record for the X-15.

    In a german book on experimental planes, I've read the claim that the X-15 was tested with auxiliary fuel tanks fixed to its underside, and that with that additional burn time for its rocket engine, it reached Mach 8. Does anyone have any insights on this?

    The WP article also claims that the SR-71 Blackbird is the fastest air-breathing plane. If memory serves, the XB-70 Valkyrie had a better design for high speeds, and could maintain them more efficiently than the Blackbird. I wonder where aviation'd be if they had continued testing and improving the XB-70...

  • I really think NASA should focus on the 'S' and stick with space exploration. An air sucking hypermach jet that can get around the world in little time sounds like a usefull delivery platform for weapons of mass destruction and not much else. I suppose they could use it as a launch platform to get things into space but doubt that's why they are spending billions on it. We really do need to start getting our butt in gear and getting off the planet.. 2001 is almost behind us and their still aren't any PAN AM destinations in our solar system.
  • Exactly, you're hi-lighting my point. We are a generation of failures who have quit the dreams of their forebearers. We don't even have a Martian Jack-Tar yet! Let alone a moonbase alpha, or mining interests on IO! what of longing for those cool green hills of Earth? what of getting off the planet and cruising? Where are our HOMES?
  • Dear Anonymous Dickhead,
    I already said it would be great if they planned on using it as a launchpoint to space, which you would know if you could read. At least I wasn't rated at 0 because I'm too chickenshit to identify myself.
    Regards, Ima Clueless Moron
  • How do you think an 'air' sucking scramjet will make space cheap. Like I said maybe it will be useful for launching things into space.. but getting things around once they're in space and building things off planet should be where they focus.

    >You can't get away from it, you can only live with it.
    Says who? Thats the kinda cop-out attitude that would make Thomas Jefferson roll over in his grave and choke on his own vomit.

    I know PanAm went away.. it was purely a 2001 reference.

    Sic Semper Tyrannis
  • Anyone who believes in a 'peaceful weapons system' is an idiot. WTF! are you serious? Go get a dictionary... look up peaceful, then look up weapon, then look up oxymoron.
    Sic Semper Tyrannis
  • I hope someone mod's you up one for that comeback. I know what the A stands for, and yes there are many useful 'Space' applications that rely on the 'Aeronautics' side of things; I agree. Like I said.. if it's being developed to make space more accessible, that's fine by me.
  • re: "I'm pretty sure Kubrick knew he was writing fiction, and I'm not sure how you came to believe that 2001 was some sort of Nostradamus-sanctioned prediction of the future. "

    Lets not forget Arthur C. Clarke!
    But I sure hope it isn't prophecy.. those monolith thingys really creeped me out ;)
  • It is perfectly legal for private or public corporations to get involved in their own space exploration programs. As a matter of fact, there are many companies and corporations that have been developing their own technologies. You don't hear about them for a damn good reason... they don't want you to hear about it until they think you are ready to shell out the bucks.
    I can't explain why NASA has decided to stick to the older technologies, because there is no understaning their logic(if there be any). But, I do like the fact that we, as citizens of the USA, get to hear about what they are doing, and what they are planning(even if it is mangled by the media and nameless others).
    I say here here to those working at NASA. I am glad to see that even though the ColdWar is over, they haven't taken their eyes off of the pentultimate goal: Space.
  • Technically, coasting is movement without a driving force, no acceleration. Once you reach high high upper atmosphere, where there's not enough there to stop you due to friction, you can use what speed you've built up (provided it's enough for the orbit you're shooting for) and coast your way into it. Orbits are actually the ship trying to fall back to earth, just constantly missing ;)

    Besides, you coast to different orbits, while only giving yourself a quick boost or braking force. Once you achieve the speed you need for your new orbit, you will 'fall' into that new orbit. You don't do so under power (ie, running your engines til you're in your new orbit), or at least, it's not required.
  • This is important aerospace research, and if you read the article, it's pretty easy to see why. The ability to fly at such speeds for intercontinental, oceanic flights is of great societal benefit. Speed of transport will make this work commercially.

    The military aspects are a bit more challenging, though. If you're going to build a bomber so fast it can't be shot down, fine--but then you have to either slow down the craft so that the munitions can exit the slipstream, or you have to come up with some design that will allow you to drop iron at high speeds--such as the Valkyrie, which dropped munitions out the tail.

    Either is a huge design problem. If you slow the craft down, you have to design a craft that performs at all speed ranges with in-theater fidelity. If you kick the munitions out of the back, you have to compensate for the mass changes with aerodynamics, because you change the center of gravity all the way through the release profile, and you better hold the craft steady during release, lest you hit the bomb on the way out. "Somebody set us up the bomb," indeed!

    But this won't replace STS. Yes, a scramjet is nice. Yes, this is similar to rocket-based combined cycle. But we could more cheaply build a reliable, two-stage system to get into orbit. Mass fractions are all you have to look at to wonder why Single Stage To Orbit [SSTO] is some perverted NASA priority. As a NASA sub, I know they don't live in reality, but damn...

    But this is, for once, a positive example of your tax dollars at work.

    --
    Geof F. Morris TOTK.com Sports--Sports for Geeks, Commentary that Matters
  • The VCs will only go for it if $Commercial_Scramjet_Entity sets up a website named eScramjet.com, and sells tickets and Snap-Tite models at a loss, but intends to make up the profit in volume.

    --
  • Probably, but it won't work as shown on TV. It'll only sit dead on your lawn.

    --
  • My favorite parts of the article:

    "Two other X-43As will fly after the initial test at six-month intervals. If successful, the 12-foot-long, surfboard-shaped planes will smash the speed record of Mach 6.7, set by an X-15 in October 1967."

    followed shortly by:

    "The X-43A, or Hyper-X, will probably never carry commercial passengers because of the high acceleration, heat generated by friction with the atmosphere and the difficulty of turning a plane at such high speeds."

    Something tells me that a 12 foot long commercial aircraft is going to have other problems besides heat/acceleration with enticing passengers onboard.

    Well, that is unless they use footage from Dr. Strangelove as an advertisement. (Cue Slim Pickens' product endorsement - "YEEEEHAAAA!!!")

    Sheesh. Do these writers ever run a brain-check on their articles?

    zeke
  • Good thing it's stuffed to the gills with telemetry. It's a one-shot drone...that's one reason they didn't put people in it. Or landing gear.

    Not needing to figure out how to land an aircraft dramatically simplifies your design.
  • I also find it hilarious that is a NASA project manager talking...

    NASA project managers are just as prone to say hilarious things as anyone else. They are managers, after all.

    A hypersonic cruise missile, however, actually would be pretty darn hard to intercept. With ballistic missiles you can usually detect them about 10 minutes or so before they reach their target. A hypersonic cruise missle at only 100000 feet altitude is both harder to detect and harder to intercept.

    ...One is, yes, adequate even enough to induce some fun and pleasure for an instant, miserably brief.

  • I really think NASA should focus on the 'S' and stick with space exploration.

    So then we'd be the "National Space Administration". Cool! I always wanted a super-l33t firstname.lastname@nsa.gov email address ;-)

  • Everyone knows that anything fired from a railgun reaches its target *instantly*. With that kind of technology there would be no need for a scramjet as well.

    Unfortunately, everyone also knows that in order to get any kind of accuracy with a railgun, you need a really high framerate and fast reflexes.

  • Sure it's fast, but I wonder what kind of mileage this thing gets for its 17 mile flight

    And if you look at the whole flight, with the lift from the B-52 and then a booster rocket, I'll bet that mileage goes way down.

  • Also parts from all three will appear on Ebay within days.

    Bob.
  • Moderators!!! up! Up! UP!

    Those are cool photos. Better than the few on CNN and other news sites. These photos show the scale of this model, which is really tiny.

    I can understand why they aren't salvaging these 3 craft, they are nothing more than large model airplanes. If they can get some good telemetry data from them, it will keep the scientists and aerospace engineers happy for years.

    I'd like one in my bathroom =)
    Which, a photo or one of these scale planes? It looks like one plane would fit in my bathroom, and would certainly make for interesting conversations :-)

    the AC
  • see if I got this right:

    The cooling device and the fuel preheater are the same? SWEET!

    Just out of curiosity: if a manned plane were to lose power while hypersonic, would it be able to passively slow down to subsonic without melting, or 1) is this effectively impossible due to scramjet design or 2) a powered slowdown is absoultely required, so don't fail.
  • .77 cents a gallon? I was at the airport last week and jet fuel cost 2.71 dollars per gallon.

    Oddly enough, fuel for piston engines cost 2.70$
  • What exactly does everyone think is going to be left of this plane
    after it slams into the ocean at Mach X?
    <surrealism> Apples. </surrealism>

    ;)

  • It really depends on the size of the airplane. A tiny (~12 ft) plane like the X-43 will have very little inertial energy compared to the size of the wave drag force that it will see, meaning that it will have a massive deceleration. A manned plane would be more like 90-250 ft long, weighing upwards of 2 million pounds fully fueled. Inertia and drag would be much less disparate in that case.

    A better way to think about the fuel is as a heat sink. It takes a lot of energy to go from 70K to 2900K, especially since there is a phase change involved. A manned plane would also probably have much more complex cooling system, and would probably be made of materials that could support hypersonic cooling. The X-43 is so tiny that there is little effective internal mass to use as a heat sink, so the engineers were forced to improvise. I do think their method is ingenious, as long as it works...

  • turn radius r=(v^2)/g(sqrt(n^2-1)) where g = 32.2 and n = load factor.

    At mach 10, a vehicle pulling 3 g's would have a turn radius of ~260 miles. That means that a plane flying due west over Atlanta would enter a 3g turn, pass over Little Rock, AK, St Louis MO, and Cincinatti OH before it pointed east. (It would take 4 minutes and 12 seconds to perform the maneuver). At 2 g's it would overfly Topeka KS, Des Moines, and Milwuakee... and would take 7m 14s.

    That's at sea level (a=1116 ft/s).

    Neh
    aero geek
  • How do you think an 'air' sucking scramjet will make space cheap. Like I said maybe it will be useful for launching things into space.. but getting things around once they're in space and building things off planet should be where they focus.

    Well, like you said, it is useful for launching things into space. Getting into orbit currently uses much, much more fuel than moving around once you're in orbit, and is therefore much, much more expensive. If you only need hydrogen to burn in the atmosphere, you save a lot of weight (the oxygen weighs 8 times as much as the hydrogen), and therefore a whole hell of a lot of money.

    Being able to move things around in space won't do us much good if we can't get them to orbit cheaply. That's what the scramjet's good for.
    --

  • At the risk of sounding ironically redundant; didn't we already read this article?
    Perhaps here? [slashdot.org]
    Slashdot: News for Nerds. Over and Over and Over and Over....
  • 0 to Mach 5 in 10 seconds. Future commercial flight? At that rate of acceleration wouldn't the passengers become lethal object within the cabin? They better get a strong hull to contain all that goo that paid to climb aboard!

    Cynically yours,
    Trevor.

  • If you'd bother look at the acronym, you'd notice that it stands for National Aeronautics and Space Administration.

    Yeah, NASA should stick to space and not develop aircraft systems like wind shear detectors, safer emergency fuel-cutoff systems, LIDAR, or computer-assisted flight systems.

    Yeah, we should just make NASA stick to space...thereby widening the gap between aviationa and space, keeping space a horribly expensive venture.


    ----------------------------------------
    Yo soy El Fontosaurus Grande!
  • Given that its travelling at over a mile a _second_ I'll not be volunteering for being hit by the pointy end even if it doesn't have a warhead attached! Simply crashing one of these into the building of your choice is going to disperse a pretty large quantity of kinetic energy into it with no muss, fuss or radiation to worry about.
  • As another post has already mentioned, this thing is going up to 100 000 feet, speeding up to mach x (where x is large) and then freefalling down into the ocean. What exactly are you planning on salvaging?
  • Let's be honest here...a plane hurtling into the ocean at Mach X is going to go straight to the bottom. Depending on where in the ocean it hits, this could be MILES deep.

    Point two: a plane hurtling straight down at Mach X is going to get VERY hot...anyone who's ever put an ice cube in a glass that just came from the dishwasher knows what might happen to that plane once it hits the water. Also, if you've ever done a bellyflop into a pool, you know how hard water can be...

    It would seem an absurd waste of taxpayer money to salvage the craft since 1.) it would probably break into a gazillion pieces and 2.) it would probably reside at unsalvageable depths.
  • I'm a space policy grad student, and we hear about McCurdy a lot. He might not be an engineer, but he knows the space business. I don't think there was too much dilution for him. B
  • One of the thoughts that has come up in relation to this story has been the speedy delivery (Thanks, Mr. McFeely) of warheads to strategic targets (like Chinese Embassies and the such.)

    Now, obviously, we can't exactly send a traditional fighter out to shoot this thing down, but would it be possible to detonate something in front of the craft, which would pepper the area with oversized buckshot, and let the craft fly through it?

    I'm not well versed in the mechanics of air travel, and I know that at supersonic speeds, it becomes harder to maneuver (jumping into hyperspace ain't like dusting crops, boy!), but at the speeds this thing moves, would it be pretty much limited to a straight line, or could it "go around" the danger zone?

    Also, if this can go from one end of the globe to another in 30 min, would anybody be able to detect it, track it, and send up a countermeasure in enough time?

  • Er, no.

    Orbital altitude is determined solely by final speed.

    I.e., once you shut off the thrust, you are in the highest orbit you will ever have.

    If you think you will "coast" to a higher orbit after an impulse of thrust, you need to think about adding wings to your coaster, because you're gonna need them to help you miss the Earth on the way down.

    To change a circular orbit, you do not push up, and you do not push down, you push with or against the direction of travel, tangential to your orbit. And you do so constantly, and constantly adjusting your attitude to keep the thrust purely tangential, because, again, once you shut off the thrust, you are in your new orbit, and if you add any radial thrust, you're in an elliptical orbit. And we're back to needing those wings.

    --Blair
  • What do wings have to do with eliptical orbits?

    If you're miscalculating your orbit as badly as implied here, they and a few seconds of panicky stickhandling when you re-enter the atmosphere are what keeps you from hitting the planet, splat, we can rebuild him, etc., etc.

    Any orbit that gains significant altitude (radial distance) is elliptical, and turning elliptical orbits into circular ones takes more than just a little "maneuvering", unless they're only slightly eccentric.

    You're not going to go hell-bent up to 180 miles and then just sort of float and puff-puff steer to 220 miles. Not unless you want to go back down to 140 miles a few minutes later. You need to fire main engines and reduce your radial momentum and acceleration both to zero. Maneuvering thrust is only for fifth-decimal-place stuff like attitude control and easing up to a space station for docking.

    And thanks for the pointer to the Niven book. There's so much cloying fantasty and ersatz science in SF these days that I've given up everything in the written forms but collecting signed copies of books I've read.

    --Blair

  • Re:Correction (Score:3)

    by sharkey ( 16670 ) on Thursday April 19, 2001 @06:29AM (#280335)
    unmaned aircraft

    I should hope the aircraft is unmaned. Putting a big mane on it would seem to serve no purpose other than decoration, and would increase drag a great deal.

    --

  • Great... (Score:3)

    by Neon Spiral Injector ( 21234 ) on Thursday April 19, 2001 @05:02AM (#280336)
    Great, the Chinese will probally end up with this one too.
  • Sorry. You're very mistaken.

    Air breathing engines have one killer drawback: the air intake. It needs to be very large, which drives up the cross-sectional area of the craft, which drives up the wave drag of the airframe. The air breathing engine has a very low impulse (thrust per unit drag) because its cross-sectional area is huge relative to that of a similar-thrust rocket.

    I've said it before, and I'll say it again: Air breathing engines are a bad way to get into orbit. Full stop. The math just doesn't work. It's a pretty idea, but it's impractical with anything like today's technology. We can make MUCH better rockets (aerospike engines have potential) but air-breathers are not the way to go.

    And yes, I am a rocket scientist. Thanks for askin'. : )

  • Re:Scramjets are wasteful, and the wrong direction (Score:3)

    by SEWilco ( 27983 ) on Thursday April 19, 2001 @05:14AM (#280338) Journal
    No, scramjets are more fuel efficient than rockets because the former does not have to carry oxygen along.

    Yes, scramjets are less fuel efficient than a 747 because they accelerate faster to a higher speed.

    If you want fuel efficiency, take a slow boat to China. If you want to get to Tokyo quickly or the edge of space, you'll need something that gives a kick in the pants.

    Yes, the reason we don't have a real hotel in orbit in 2001 is because space development is moving at the speed of governments. If Pan Am had been flying space shuttles there would be a lot more activity above the atmosphere.

  • What exactly does everyone think is going to be left of this plane after it slams into the ocean at Mach X?

  • best quote: (Score:3)

    by wunderhorn1 ( 114559 ) on Thursday April 19, 2001 @05:28AM (#280340)

    ``I wouldn't want to be on the pointy end of one of these things if its got a bomb on it,'' Sitz said. ``We could call someone up and say: 'We're gonna bomb you,' and there would be nothing they could do about it.''

    Since this is basically what the US does anyway, it's good to know that we'll have some stability in our foreign policy during the coming decades!

    I also find it hilarious that is a NASA project manager talking...

  • The concept is pretty simple (Score:3)

    by Alien54 ( 180860 ) on Thursday April 19, 2001 @05:18AM (#280341) Journal
    "The concept is pretty simple, it's just that no one can seem to make it work," said Howard McCurdy, a professor of public affairs at American University.

    Sounds like Nasa.

    Seriously, the idea is based on the observation that alot of the time you spend going into orbit you are simply coasting. And you are also bringing along alot of oxygen for the fuel. So if you could get your oxygen for the ascent from the atmosphere, and then coast to orbit, you could save a lot of weight. You would still have enough on board for manuevering jets, etc. But this requires something that can operate in the middle range of speeds of Mach 2 to Mach 10 (and higher)

    Check out the Vinny the Vampire [eplugz.com] comic strip

  • Why no Post-crash analysis? (Score:3)

    by Bonker ( 243350 ) on Thursday April 19, 2001 @05:08AM (#280342)
    I can't beleive that they're not going to recover the jet after it crashes. While I understand that this is a test of the engine only, it seems like there would be a wealth of data to be had from examining the structure of the device, even after it crashed.

    While I'm no engineer, don't crash investigators for regular airplanes often look for things as minor as cracks in the substructure to indicate possible areas of improvement for future planes?

    I think it's a horrible waste of information and effort to let this thing sink to the bottom of the ocean. Worse, they're putting information in the hands of the other few countries with the resources to salvage this guy, and you can sure bet that they won't share the results with us.

    C'mon guys. Fish it out!

  • Commercial version (Score:3)

    by Hilary Rosen ( 415151 ) on Thursday April 19, 2001 @05:48AM (#280343) Homepage Journal
    Isn't there a very limited market of people who want to plunge into the ocean at Mach 5?

    Should have no problem getting venture capital, though.
    --

  • That post is wasteful, and the wrong direction. (Score:4)

    by KFury ( 19522 ) on Thursday April 19, 2001 @06:24AM (#280344) Homepage
    I'll bite:

    "A space plane like the space shuttle costs the same amount of money in terms of fuel as a jumbo jet from London to New York does."

    How do you figure that? Mile-per-mile? Did you not notice the external fuel tank needed to get the Shuttle to orbit? Do you think LOX and LH are so much less expensive than jet fuel? The External Tank alone uses 526,000 gallons of fuel in the 8.5 minutes before it's jettisoned (That's 1031 gallons per second (g/s). A 747 on the other hand, has a maximum fuel capacity of 57,285 gallons, which it sips at 1.06 g/s.

    Jet fuel currently costs about 77 cents/gallon, while LH costs about 75 cents and LOX costs about 35 cents, but that kind of logic is like saying it would be more economically efficient to walk to the moon.

    "Wall Street would be the new mission control, and you can bet that the analysts of that city would make space trave as cheap as boarding a jumbo jet - there is no reason why it should not be."

    I'd suggest you take a look at this economic analysis [princeton.edu] of the $/lb costs for the Space Shuttle under various scenarios, including daily launches. It'll never get beneath $640/lb, which is significantly more expensive than boarding a jumbo jet, unless you're a mouse. but then, mice fly free...

    It would be more accurate to say that Wall Street would be able to raise enough money in an IPO to send the company's founders into space, but Wall Street itself doesn't have as much to do with the creation of economical solutions as they do the speculation of profitability of said systems.

    Kevin Fox
    --

  • Free Chalupas if it hits 'Taco bell' barge (Score:4)

    by malacai ( 22076 ) on Thursday April 19, 2001 @05:08AM (#280345)
    I hear they're moving the 'Taco Bell' sign
    that MIR missed into the area where this
    is supposed to land. If it hits it, everyone
    at NASA gets a free Chalupa....

  • More on the X-43A (Score:4)

    by Daath ( 225404 ) <lp@code r . dk> on Thursday April 19, 2001 @05:49AM (#280346) Homepage Journal
    Check out these cool photos [nasa.gov]!
    I'd like one in my bathroom =)

  • The previous story (Score:5)

    by Pulzar ( 81031 ) on Thursday April 19, 2001 @05:22AM (#280347)

    See also the Reuters article on the same subject, and our previous story about an Australian version.

    Or, see the exact same previous story [slashdot.org] from the last week.


    ----------

  • Re:Scramjets are wasteful, and the wrong direction (Score:5)

    by Twanfox ( 185252 ) on Thursday April 19, 2001 @05:34AM (#280348)
    I hate to play devil's advocate on this, but you stated that 'Scramjets are wasteful, and in the wrong direction' then.. do not go anywhere near that topic in the body of your message. Any particular reason you made this omission?

    As for the government retarding space exploration, of course they have. You see how corperations act on planet Earth, right? Imagine that up in space, where things like a misplaced bolt traveling at orbital speeds can take out satellites. NASA tends to be very exacting about how and when they do things. Corperations go for the bottom line. Does it make them profit? If so, they don't care about the little details like debris. Can you imagine the difficulty we'd face in even getting out of the atmosphere if our entire LEO sphere was a mass of garbage and debris left from satallite leavings? (well, at least til they managed to drift back to the atmosphere)

    I've been following this project for years since I heard it announced. While I'm not the utmost on what they're current plans are, there are reasons for doing things this way. The more disposable pieces they take to orbit (fuel tanks on the shuttle), the more explosive bolts they fire, the more garbage there is. If they can make a SSTO craft (Single Stage to Orbit for those that need it explained), then they cut down on the ammount of crap left in space.

    Problem number one is getting the speed involved to reach orbit without booster rockets. Scramjets are the answer to this. They operate at high speeds only (well into the Mach range) and are ideal for use in situations where you don't need the compression of turbo fan blades in other jet engines. Read: A Scramjet is a ramjet only for use at higher speeds.

    Problem number two is that, if they really want to make a SSTO craft, they have to carry Everything they need within that craft, all fuel to break escape velocity, everything. The current shuttles carry just enough fuel for maneuvering in space, and dropping back to earth. They do not and cannot (without external fuel tanks) have the reserves within to break out of the atmosphere. The only reason why this new space plane will be able to do it is because it will carry only half it's fuel. The other half (the bulk of the oxygen needed) will be gathered from the atmosphere itself as it flies.

    Now, saying this is wasteful is frankly trolling and misinformation unless you can prove that it is wasteful. This plane will be lighter than it must be if it were to burn LOX and Liquid Hydrogen, and will therefor require less power to get the speed necessary to reach orbit. How is this more wasteful than before? What other methods would you use to get to space? A space elevator? Linear accelerator based on the ground? (Check out your Sci Fi book stores for what I mean by these). These ideas are nice and far more efficient, but are a little out of our league at the moment.

    Until we can manage to build some of these things and overcome the technical hurdles involved in their creation and use, we still have to use rockets and jets to reach orbit. I'm all for a SSTO craft. They are more cost effective, they are more easily maintanable (The shuttle takes months on the ground for refits of lost tiles, damage from orbital debris, and other maintenance). If they can do this right, they can make this space plane more usefull by making it able to fly more often. Get a small fleet of them, and you could have daily flights to orbit. Tourism anyone?

    Oh, and as for why NASA only bought 6 shuttles, several month downtimes, and single missions to orbit. At the moment, I doubt you'll see several shuttles in orbit at the same time. With all the monitoring tools they have, I don't think Nasa has the manpower to handle 2 or 3 in orbit at once. With those factors in mind, and a price tag in the billions (IIRC), they don't need more, they can't handle more, they're certainly not going to spend that much money on something they can't utilize effectively. Would you?

  • Prediction (Score:5)

    by sllort ( 442574 ) on Thursday April 19, 2001 @05:05AM (#280349) Homepage Journal
    My prediction: the scramjet will successfully accelerate to Mach 5, plowing into a Chinese observation plane and obliterating it. The flaming wreckage will fall from the sky and land on a Japanese pleasure cruiser, sinking it.

    George Bush will blame the Russians.

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