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Science Technology

NASA 'Hyper-X' Series Scramjets 58

Posted by michael from the ginger-ale-peanuts-and-oxygen-mask dept.
swight1701 writes "Sciencedaily.com is reporting that NASA has revealed its plans for developing Hypersonic aircraft within 2 decades. These plans include planes that could routinely go Mach 5+ and capable of taking off from an airport and visiting the IIS, or for you earthbound folk, from one airport to any other within 2 hours. And you thought your luggage gets lost NOW.:)" NASA's release includes some graphics showing what the test vehicles look like.
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NASA 'Hyper-X' Series Scramjets More

NASA 'Hyper-X' Series Scramjets

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  • Has anyone else noticed the lack of windows (as in glass) for the pilots?

    • Re:How do they see? (Score:5, Informative)

      by TamMan2000 ( 578899 ) on Thursday July 25, 2002 @08:27AM (#3950461) Journal
      I am going out on a limb here, but I think they have to use remote sensing because of the aerodynamics involved.

      Any useful window has to have a large area projected to a plane perpendicular to the direction of travel. This would mean an extremely large window because of the wedge angle at the front of the plane. And this angle is required to be very small to keep the losses associated with the bow shock from becoming astronomical. The faster you are going (relative to the speed of sound) the smaller that angle must be to keep the shock attached and oblique.

      The really interesting stuff on this craft is the engine inlets, the entire plane is designed to minimize engine inlet losses, due to shocks. Cool stuff
    • Lack of windows??
      They said they may be able to visit the _IIS_...
    • These craft will be piloted only by navigators, members of the Space Guild, who, due to their heavy use of spice melange, can perceive the present and future without windows, and can fold space.
      • Um didn't the guild navigators see the present/future/and _navigate_. All they did was know where all the stuff(planets/astroids/suns/ships/ et cetera) was on the route, and just piloted their ultra fast ships around it?
      • Guild Navigators can't fold space. They can only see the future and guide their ships appropriately. The spice doesn't allow people to fold space, or else Muad'dib would just be flat out God, and that would go against the Orange Catholic Bible. Yeah.
  • Perhaps since they are developing hypersonic aircraft, they will scrap the X-4000 Launch Aparatus. [uncoveror.com] I hope they have better luck with these these aircraft than they do with Mars probes. [uncoveror.com]

  • Visiting the IIS... (Score:4, Funny)

    by Muad'Dave ( 255648 ) on Thursday July 25, 2002 @08:49AM (#3950570) Homepage
    and visiting the IIS...

    If I want to visit the IIS, I'll just go into the computer room, thank you. Oh, you mean the ISS...

    • I am currently still continuously visited by IIS, why go there:

      12.34.56.789 - - [28/Feb/2002:05:44:58 -0500] "GET /scripts/..%c1%1c../winnt/system32/cmd.exe?/c+dir HTTP/1.0" 404 224

      >:)
  • My GOD! That thing is HUGE! In that first picture, you can see the artist's concept of the thing about to swallow a B-52!
    • The first time I looked at that picture I thought it was some sort of joke. I wondered how sticking a B-52 on the front of the plane would make it faster.
      • I don't know. To me it looks like the B-52 may be beneath the X. It just doesn't look like a scale picture to me. It's probably not quite that big.
    • I know you are trying to be funny, but some people took you seriously, so I will clarify: The X-43 in that picture is designed to be dropped from beneath the wing of a b-52. The X-43A, which tried to fly last june and failed, is only 12 feet long. It is fitted [orbital.com] to the front of a pegasus rocket, carried to altitude, and dropped. Once it falls free of the aircraft the pegasus ignites, pushing the vehicle to a speed at which the scramjet engine can work; there the pegasus releases and the airbreathing engines take over.

      The X-43B is much larger, for sure, and is not powered by a pegasus, but it is still going to be dropped from either a B-52H or an L-1011. Probably the B-52H which Nasa just acquired from the USAF.

      Now, when you start talking about single stage to orbit vehicles with combined cycle engines designed to carry freight cheaply,you will be talking about aircraft 200 feet long weighing upwards of 1.5 million pounds. Anything less and the incredible inefficiencies of fixed structure cause your useful cargo load to be negative (I could write a whole lot more about this, and may, later, but it is going-home-time now :) If you really care, there are plenty of references on the net).

      Neh
      aero geek
  • ...how on of those can travel to the space station IIS and back when it's using an air breathing engine?

    • Re:May I ask... (Score:4, Informative)

      by Mt._Honkey ( 514673 ) on Thursday July 25, 2002 @10:29AM (#3951075)
      Read the article:
      Once a hypersonic vehicle has accelerated to more than twice the speed of sound, the turbine or rockets are turned off, and the engine relies solely on oxygen in the atmosphere to burn fuel. When the vehicle has accelerated to more than 10 to 15 times the speed of sound, the engine converts to a conventional rocket-powered system to propel the craft into orbit or sustain its top suborbital flight speed.
      Also notice this:
      NASA's Space Launch Initiative, managed by the Marshall Center, is working to develop the technology for a second-generation vehicle that could lead to a replacement for the first-generation Space Shuttle by 2012 --
      I don't think that the shuttles are going to last 10 more years... they're already cracking, who knows what else might happen by then. This project should have started a long time ago. The budget is $700,000,000, which is cheap compared to the repeated launch cost of the overly expensive shuttle fleet. I'd say that it's a worthy investment.
    • Most of the fuel burnt to get a space craft into space is burnt in the first 100,000 feet of altitude. If you could fly to this altitude (and get to Mach 5+) and then use a small rocket engine to take you the rest of the way you are going to save *a lot* of money.

      Another way is to build the rocket engine into the Scramjet but that's much more difficult.

      • Most of the fuel burnt to get a space craft into space is burnt in the first 100,000 feet of altitude. If you could fly to this altitude (and get to Mach 5+) and then use a small rocket engine to take you the rest of the way you are going to save *a lot* of money.

        Probably not. The problem is you need extra equipment to breath the air- and you carry that all the way to orbit. It turns out that's really critical- you gain most of your speed as the tank is running out (because your fuel level is low and the vehicle is really light then, so you get better acceleration per unit of fuel at that point). And you're in a vacuum, so this equipment doesn't help at all at that point.

        Adding in extra mass for airbreathing means that the latter part of the launch is messed up- and so the designs to do this have not succeeded well- they end up using more fuel not less, and/or the payload ends up being really tiny.

        Also, you're probably solving the wrong problem- the fuel is less than 1% of the cost of building and launching a space vehicle.

        • Also, you're probably solving the wrong problem- the fuel is less than 1% of the cost of building and launching a space vehicle. Where did you get that information? I am no expert so I am not necessarily trying to refute you, but it has been my understanding that fuel is the major cost of launching a space vehicle. Or at least the root of the problem. The shuttle itself is reusable, so a minimal amount of money is used to get it flight ready again. The SRB's are reuseable, but must be refueled with solid rocket fuel. However a new External Tank must be constructed for each launch. That is the biggest part of the assembly. This then must be filled with fuel. I might be able to see where you are comeing from if you are referring to the R&D, construction, and man-hours involved in getting the space shuttle program running and building the shuttle, but if you are talking about an individual launch, then I would have to disagree. By the way, for anyone who doesn't know. The NASA Space Launch Initiative is attempting to reduce the cost of a launching vehicles into space. Currently, it costs $100,000.00 to send 1 pound into space. So a 200 pound man would cost $20,000,000 to send into space. The Space Launch Initiative hopes to find a way to reduce that cost to only $10,000.00 per pound.
          • it has been my understanding that fuel is the major cost of launching a space vehicle. Or at least the root of the problem. The shuttle itself is reusable, so a minimal amount of money is used to get it flight ready again. The SRB's are reuseable, but must be refueled with solid rocket fuel. However a new External Tank must be constructed for each launch. That is the biggest part of the assembly.

            The problem is that because the shuttle is man-rated, they basically have to take it apart and put it back together again to make sure everything still works. This costs a _lot_. Fuel is cheap, but shuttle parts and skilled engineer time are not.

            A secondary problem is that the cost of maintaining all of the facilities for servicing the shuttle must be amortized over the (relatively few) shuttle launches. This too is very expensive.

            The main reason why finding more effective fuels is important is that they let you reduce the total craft size and weight for a given payload weight. This makes the craft much cheaper to build and maintain, reducing the cost of lifting the fixed-weight payload.
          • Well, liquid hydrogen costs about $5/kg. You need much less than 30 kg to launch 1kg of payload. (2.2 pounds to the kg btw). You do the maths. And incidentally, hydrogen is pretty expensive. LOX is under 4c per kg, and kerosene is not much more than LOX. The fuel is totally negligable.

            Your numbers are a bit off BTW. The cost to launch a man is generally reckoned to be about $10,000 per kg. The russians charge less than $20 million, basically because they can. Their whole rocket costs about $5 million. There's a big difference between cost and price...

            The real cost goes into the salaries of the employees. There's about 10,000 or more involved with the Space Shuttle. But don't get the impression that the Russian rockets are cheaper just because the Russians are paid a lot less- they are, that's a big factor, but the way they put their rockets together is more efficient as well. NASA don't seem to care about low cost in quite the same way.

            Please don't mention the external tank... it gives me a headache just thinking about that much waste.

            SLI? Hah!

            • Thats all very fine to say, but where is your proof? Do you have any? And no, I didn't provide any either, but I stated that I was just going on what I had been told by certain members of the NASA community. I happen to live near Marshal Space Flight center and know many people that work there, so I feel that I am pretty well informed.
              • Check out:

                google cache [216.239.35.100] You'll see the cost per kg of liquid hydrogen was $2.60 in 1980. I expect it has gone up since then, but not so very much; and it does vary a bit- e.g. if you order enough hydrogen the price goes down.

                The Space Shuttle's main tank contains 101 tonnes of liquid hydrogen. Assuming a price of $5/kg, that's $505,000 worth of hydrogen (since there are 1000kg to the tonne). Right?

                The cost of adding an extra Space Shuttle to the yearly launch manifest is about $200 million.

                Congratulations, you have just learnt something!

                Oh yeah the Space Shuttle also burns 606 tonnes of LOX. LOX costs vary, but they are typically a few cents per kg. You can multiply that up if you wish, but the costs are more than 10x less than the hydrogen.

        • Good point. An air-breathing launch vehicle is going to have a fairly high dry weight. It could be compensated for by not trying to get to orbit in one stage. The scramjet powered plane would just carry a rocket up to launch altitude and then fly home. The rocket alone would achieve orbit.

          About your cheap fuel point, you're missing the problem of weight. Yes, the fuel is cheap. Getting the fuel to 100,000 feet with a rocket is not cheap. Rockets are not the most efficient propulsion system. They are needed in space because nothing else works.

          I'm not an expert. If you are, I'll concede the point.

          • Good point. An air-breathing launch vehicle is going to have a fairly high dry weight. It could be compensated for by not trying to get to orbit in one stage. The scramjet powered plane would just carry a rocket up to launch altitude and then fly home. The rocket alone would achieve orbit.

            Yeah, that can work. But then you've got a two stage rocket; which is messier. Anyway they already do that- with a normal jet- the Pegasus launch vehicle carries a rocket up and then fires it from there.

            About your cheap fuel point, you're missing the problem of weight.

            That's mainly an issue with ground handling I think.

            Yes, the fuel is cheap. Getting the fuel to 100,000 feet with a rocket is not cheap.

            Actually it probably is, it mostly just costs fuel, but fuel is cheap.

            Rockets are not the most efficient propulsion system.

            Thermodynamically a rocket is the most efficient propulsion system. It can turn practically all of the energy in the fuel into fast moving fluid flow. It's more efficient than jets because it runs at incredibly high temperatures. However, jet engines can get more total thrust ('impulse') per unit of fuel because they suck in the oxygen from the atmosphere. If you count that in; Jets are less efficient in fact.

            I'm not an expert. If you are, I'll concede the point.

            It's not that the idea is silly, it's just that the constraints on it are tight enough that nobody has managed to get it to work well.

  • Stupid designs. (Score:2, Insightful)

    by Mordant ( 138460 )
    At those speeds, wings are a hindrance. One finds that the leading surfaces must be made of unobtanium.

    The correct model for spacecraft is to take off and land on a tail of fire, as God and Robert Heinlein intended. The DC/X proved that; 11 successful test flights, including an 11-degree 'walking tilt', before NASA took over that program and (deliberately?) crashed the prototype on their first try with it.

    • Re:Stupid designs. (Score:3, Interesting)

      by spike hay ( 534165 )
      At those speeds, wings are a hindrance. One finds that the leading surfaces must be made of unobtanium.

      One of the ways around this is to use plasma. If you generate plasma ahead of an aircraft with a welding-torch type of thing, you can reduce the drag by as much as 30%. The Russians are using plasma in their next generation of MiGs. (BTW, plasma also absorbs radar)

      Another thing is to use carbon-carbon composites. C-C's are very expensive but can withstand many thousands of degrees. They are used in rocket nozzles.
      • CCs are indeed very expensive, and have their own issues (brittleness/cracking after a few dozen reuses, etc.). They aren't suitable for craft intended to be flown constantly, with the regularity of normal aircraft.

        The plasma thing sounds really cool, until you think about it. After the first couple of MiGs come apart in mid-air, I'm sure the Russians will scrap that idea.
      • One of the ways around this is to use plasma. If you generate plasma ahead of an aircraft with a welding-torch type of thing, you can reduce the drag by as much as 30%. The Russians are using plasma in their next generation of MiGs. (BTW, plasma also absorbs radar)

        You get the same effect with a gas blanket, which is a lot easier to produce than plasma. However, this is still a pain in the neck, making your craft vastly more complicated and requiring considerable fuel if the wings have any significant cross-sectional area at all (to spray the gas blanket [most likely an exhaust stream] forward fast enough to move the shockwave off the wing edge).

        A better approach would be a) making the wing angle very small, so that you have a lot of leading-edge area per unit cross-sectional area, and b) only going at hypersonic speeds when you're in very thin atmosphere, reducing the amount of heating.

        As for carbon composites, while graphite won't vapourize until about 4000 degrees C, it'll be rapidly etched away unless you coat it with something. "Something" is tungsten carbide, for the shuttle, at least. That has a melting point of around 3000 degrees C, and may or may not start degrading at a lower temperature (ask an aerospace engineer). Carbon composite shielding can take a lot of punishment, but _gliding_ at orbital velocity in an atmosphere overwhelms it unless you have a very light craft. (Important number is effective pressure exerted by the air you're plowing through, which is proportional to the craft mass, and which rate of heating is directly proportional to. You can play with the proportionality constants [by altering craft geometry and materials] to make the problem less severe, but a lighter craft will always help and the problem is always bad at high speeds).
  • 1) What sort of damage could one do if it crashed into a target on the ground?

    2) How do you intercept one that has been hijacked?

  • Wow, new airplane designs! (Score:3, Interesting)

    by bill_mcgonigle ( 4333 ) on Thursday July 25, 2002 @01:08PM (#3952185) Homepage Journal
    The flying tube really hasn't had much design change for the past 50 years. Oh, I forgot, "Winglets, yay!"

  • Ozone Layer? (Score:2, Interesting)

    by EvilBudMan ( 588716 )
    How is this going to affect the ozone layer in the future, if hundreds of these things are flying through it every day?

  • Vapourware (Score:1, Informative)

    by Anonymous Coward
    This whole scramjet business is a joke. A scramjet only really comes into its own at about mach 5 to mach 6. How are you going to get the craft up to that speed? There are half a dozen answers to this question, here are a few of the best options:
    • use a turbojet to get to mach 2 or so, then turn on a ramjet to get to mach 5 or so and then light up your scramjet. This plane will never fly carrying two engines which are dead weight at any point in its flight.
    • Launch it off of a rocket. Well, then we are back to a 2 stage to orbit vehicle which defeats the purpose of developing such a craft.
    • Crazier options: Catapult launches and all sorts of other crazy stuff.
    IMO NASA is wasting your tax payer dollars again.

  • PULSEJET: Combines Air Breathing and Rocket (Score:5, Interesting)

    by justanyone ( 308934 ) on Thursday July 25, 2002 @03:12PM (#3952972) Homepage Journal
    Pulse jets (like the WWII German V-1 "cruise missle") could transition between air-scoop and rocket. Features:
    • using atmospheric oxygen as oxidizer at low altitude & speed
    • use onboard oxygen as oxidizer at higher altitudes and speeds;
    • climb to 50-60 K feet altitude and refuel conventionally (subsonic of course);
    • change air scoop / inlet geometry with increasing speed / air density (model this in wind tunnel);
    • Add oxidizer as needed to optimize fuel efficiency;
    • Fuel/oxidizer drop-tanks if necessary (cheap, conventional);
    • pulsejets are non-continuous burn, can shut them down easeier than turbine / rocket engines;
    • Can use variable-sweep wings for different mach numbers and to optimize wing loading;

    Just some ideas.

    ALSO: How come we don't see postings on Nasa websites with "what we've considered and why it didn't work" so outside engineers can solve their problems for them...

  • So they want to build a plane that files in atmostphere at mach 5+?

    Lets think about the plane that closest fit the bill, the SR-71.

    It was capable of mach 3+ and flew at an altitude of ~120,000 ft.

    It was made completely out of titanium and the body of the plane got so hot that the pilot had to wear a space suit and couldn't touch the cockpit glass. The plane leaked fuel on the tarmac because it had to be designed with gaps that would close once the frame expanded from the extreme heat. In order to maintain mach 3, it had to run at full afterburners, burning a special fuel that had a super high temperature of ignition. And this was so it could carry 2 guys and a camera.

    See the problems I have with this? Now granted, I'm not an airanotical engineer by any stretch of the imagination (or literate for that matter, based on my inability to spell...)

    It was hard enough to get a moderately large plane going mach 3, now imagine what kind of energy you'd have to exert to get something the size of a 737 going?

    Just my thoughts...

    • We've come a long way since the late 1950's. :-)
    • You should be thinking instead about the X-15.

      http://www.x15.com/program.html

      "The X-15 was carried to an altitude of 12,000 meters (40,000 feet) under the wing of a Boeing B-52 bomber. During one test, it attained an altitude of over 108 kilometers (67 miles), flying so high that it functioned more as a spacecraft than an airplane. In 1967 it reached Mach 6.72 (7,297 kilometers or 4,534 miles per hour). "

      http://www.hq.nasa.gov/office/pao/History/SP-60/ co ver.html

      http://www.wpafb.af.mil/museum/modern_flight/mf5 7. htm

      http://www.astronautix.com/craft/x15a2.htm

  • This looks like an even grander attempt than the X-33 [nasa.gov] and the now-defunct Venturestar project. Venturestar was cancelled because it was too ambitious, wasn't it? Looks like some NASA vaporware...er vaporplane.
    • Agreed...although it looks like something they did in the 70's called "The Lifting Body" Program. Basically no wings, just a fuselage to create the appropriate airfoil. Now they just crammed a big f*cking engine up its ass...
  • I looked at those pictures on the NASA website and it doesn't look like those things have a very big gas tank to run off of. Especially if it were to use the amount of gas to get it to mach5, then keeping all that deadweight gas going that fast.

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