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X-43A Hits Mach 7

Posted by CowboyNeal on from the doing-it-and-doing-it-well dept.

quiggy writes "As previously reported, NASA tested the X-43A yesterday. The results are in, and the scramjet hit Mach 7, setting a new speed record. CNN is also reporting the story, with a note that a similar jet could be tested by the end of the year, hopefully reaching Mach 10."

23 of 405 comments (clear)

  1. sublight speed ;) by Janek+Kozicki · · Score: 5, Interesting

    1 mach = 334 m/s ,
    10 mach = 3340 m/s = 3.3 km/s ,
    speed of light c = 300 000 km/s ,
    (3 km/s)/(300 000 km/s) = 1/100 000 of c

    this engine travelled at aprox 0.00001c !

    good work scientists :)

    --
    #
    #\ @ ? Colonize Mars
    #
    1. Re:sublight speed ;) by Anonymous Coward · · Score: 1, Interesting

      Right, but once it is in space the game is different entirely. Speed is the name of the game if you want to get anywhere before your dead. I think that it is the speed in space that he is referencing.

    2. Re:sublight speed ;) by Maimun · · Score: 2, Interesting
      Escape velocity is necessary only when you want to, well, escape the Earth :)). If you want to go into Earth's orbit, the velocity is 7.8km/s. In fact, this is the minimum velocity you need, given that the direction of the movement is perpendicular to the line that connects you with the center of the Earth, never to fall down. AFAIR, 7.8km/s is that velocity at the Earth's surface. Since there is air friction at the surface, it makes sense to consider that velocity at, say, 250km or more above the surface -- it is surely smaller there, of course, and grows smaller as you go up, because the Earth's gravitational pull grows weaker.

      When I studied these things in secondary school, we called 7.8km/s, "first space velocity", and 11.2km/s, "second space velocity". I think the terms are Russian (pervaya kosmicheskaya skorosty, vtoraya kosmicheskaya skorosty).

    3. Re:sublight speed ;) by slim-t · · Score: 5, Interesting
      Then how did that original post get modded informative? I thought physics was pre-requisite for reading slashdot.

      Seriously, there's a need for a "wrong" modifier, so people can mod such posts down without fear of recourse from meta-moderators who think the post is correct.

    4. Re:sublight speed ;) by Anonymous Coward · · Score: 2, Interesting

      There is a free (beer) space shuttle simulator called Orbiter. I would recommend everyone to try it, in a few hours of experimenting you will learn so much information about space flight you will for example never post nonsense like that again *grin*.

      Orbiter features more then just the shuttle, there is a slightly more powerful Delta Glider which you can in fact use to fly to Mars. And don't think it is easy, just getting to the orbit with the space shuttle will require a lot of training and reading the manual.

      After two hours of so (of accelerated time of course) when I got near Mars, I was actually unable to land because of lack of fuel :(. It's a really strange feeling you get when flying on a hyperbolic curve, with no fuel, getting further and further from Mars and knowing that nothing can save you from dying in this damn spacecraft except from it being a simulation :). And yet another strange feeling is when you are descending to the Earth atmosphere with a wrong angle of attack and suddenly you just bounce of the atmosphere and Earth, there you go, hyperbolic curve again and our planet getting smaller and smaller... is that small thing Africa?

      Just try it, it's a great game!

  2. Mach10?! by DigiShaman · · Score: 5, Interesting

    And just how do you keep something going that fast from burning up in the atmosphere?

    --
    Life is not for the lazy.
    1. Re:Mach10?! by Phosphor3k · · Score: 2, Interesting

      As a previous poster stated, any vehicles that we launch into orbit need to attain a speed of 11.18 km/s, which is about mach 36, for escape velocity. I imagine they've got more than a few ways to protect this vehicle traveling at a paltry mach 7.

  3. CNN slipping,... by epicstruggle · · Score: 4, Interesting

    CNN in a poor programming decision IMHO, did not carry any news of this while it was happening. OTOH FoxNews did!! Which supprised the hell out of me. They did ask some expert a few times how this would mean that missiles (in the future) could hit Osama in 15-30 minutes instead of the 4+hours it takes today. But at least they did have someone talking about the technolodgy/science behind this, and actually showed the takeoff, and launch of the plane. Quite nice of them.

    Kudos to Fox, to CNN: do a better job, or you will fall further behind FoxNews.

    later,
    epic

    --
    "Im drowning here, and you're describing the water!"
    1. Re:CNN slipping,... by dealsites · · Score: 4, Interesting

      Might be slightly off-topic, but I agree with this. I have enjoyed Fox's coverage much more than CNN's. Not only in this news event but also others. I have noticed that CNN is quite a bit more PC, while FOX news seems to give your the direct information.

      --
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    2. Re:CNN slipping,... by bombadillo · · Score: 3, Interesting

      News is supposed to be "PC". We don't need a TV network telling us what to think. After all how many times last year did Fox news anounce that WMD were found in Iraq?

  4. 10 seconds by henryhbk · · Score: 3, Interesting

    Did anyone notice that the length of flight was 10 seconds? If it carried enough fuel for a sustained flight, it would be more impressive for a mach 7 flight. I realize this is a proof of concept flight.

    1. Re:10 seconds by Anonymous Coward · · Score: 1, Interesting

      There were discussions about making the vehicle a recoverable and reusable test system. However, with the increase in complexity, cost, and the need to fly in the area with heavy commercial air traffic (near LA) in order to land the X-43A, program official ultimately decided to make this version a single use engine test bed.
      There were plans to build larger follow-on vehicles that are re-useable. I believe those plans are now are hold indefinitely as NASA shifts its focus to the moon and Mars missions.

  5. Re:CNN gets it wrong by the_2nd_coming · · Score: 2, Interesting

    the trip to london is to short to benefit from a scramjet..

    --



    I am the Alpha and the Omega-3
  6. THE PROGRAM IS BEING HALTED! by wisebabo · · Score: 5, Interesting

    There's an old Airforce saying:
    A new plane doesn't make a new engine possible: A new engine makes a new plane possible.

    That's why when NASA went for the moon a critical development was the F-1 first stage rocket engine. Capable of 1.5M lbs. of thrust it allowed the Saturn V first stage to be built with only 5 engines. Compare this with the Russian failed manned lunar rocket the N-1 which had 20 engines. They never were able to work all together (vibrational problems) and abandoned it after several launch disasters.

    So why is NASA stopping development? (The successor the X-43C will not be flown). Why are we freezing this enabling technology? Are we (under Bush's program) sacrificing everything to plant a flag on Mars and not making space flight practical? It might be worth it if we ever got to Mars but it looks highly doubtful that his proposal is a serious attempt at anything but votes!

    Sorry for the (mostly) repost but I really wish we would move "faster" towards developing the technologies towards practical* spaceflight.

    *As noted in previous posts, by not carrying the oxygen on board you save a LOT of weight. Remember the reaction is H2 + O = H2O (and energy) and since the atomic weight of oxygen is 16 compared to hydrogen for every kilo of hydrogen you carry you carry EIGHT of oxygen. The weight savings (could be in the millions of pounds) makes up for the turbo-fans/rocket engines you must carry for the takeoff/orbital transition parts of the flight.

    1. Re:THE PROGRAM IS BEING HALTED! by demachina · · Score: 3, Interesting

      "So why is NASA stopping development?"

      I'd rather doubt they are. If it can be made to work and there is a need, either the NASA program will be funded or it will disappear in to an Air Force black program and will just appear to have been killed.

      It does appear it can be made to work and it would presumably add a new top end to Aurora or whatever the Air Force's current black program is.

      Its use for civilian transportation is dubious. Its pretty dangerous and would take a LONG time to be made safe, cheap and comfortable. I'm also doubtful it will prove to be a great launch vehicle though you never know.

      Its military applications are obvious. The DOD has a pretty desperate need to drop bombs on targets of interest that arise quickly and move around like Bin Laden. When they get intelligence he is at a place they need to drop ordinance there as quickly as possible before he moves and with some targeting flexibility. A manned or remotely controlled Mach 11 bomber would seem ideal. An RPV version of this could come to fruition a lot faster than a manned version, Cruise missiles, the stealth bomber etc are to slow to get to the target in time. Using ballistic missiles tends to set of alarm bells in Russia, China and everyplace else where governments have satellites watching for launch signatures. Targeting for ballistic missiles also can't be redirected at or stopped at the last minute.

      It would also be priceless for strategic and tactical reconnisance. Spy satellites are to predictable and inflexible since they are locked in to orbits with limited manueverability. Most countries know the schedule and hide stuff when they are overhead. A Scramjet would be flying fast and high enough it would be hard to shoot down, or even detect until after its done the job.

      NASA Dryden deserves a huge pat on the back for finally bending metal and flying something. They've been wasting money on computer generated fantasies for this concept for more than a decade and haven't done much to realize it. It would be fantastic if it lead to a better launch vehicle and civilian transport, I just doubt that it will.

      --
      @de_machina
    2. Re:THE PROGRAM IS BEING HALTED! by DerekLyons · · Score: 2, Interesting
      The weight savings (could be in the millions of pounds) makes up for the turbo-fans/rocket engines you must carry for the takeoff/orbital transition parts of the flight.
      Actually, the weight savings is non-existent. Sure, you save about 25% of the LOX in your first stage, but that's more than made up by the increased structural weight and thermal protection. Fact is, when the numbers are added up, you frequently come out worse in both weight and cost.

      Using a re-useable airbreathing first 'stage' is a powerfully seductive theory, but it simply doesn't work in reality. (Ever wonder why those stages appear now largely only in fiction, and have mostly dissapeared from serious proposals?)

  7. Re:Mach 10 enough to sail into orbit? by TheRaven64 · · Score: 3, Interesting
    Even if it can't get all of the way into orbit, it could go some of the way. Imagine this:
    1. First stage, accelerate vehicle on a long maglev runway. 100% reusable, no fuel carried, speed of about Mach 1 reached.
    2. Second stage, SCRAM Jet. Reaches about Mach 10. Then detaches and glides back to Earth on automatic. No oxygen carried, only fuel. Efficient and (apart from the fuel) reusable.
    3. Third stage, rocket. Takes the plane the rest of the way into orbit.
    4. Fourth stage, ion drive, takes the payload to a different planet (Mars anyone?). This would probably carry the payloads of several launches of a space plane.
    Of course, you'll need to build a launcher on the destination planet, if you want to get back. And the SCRAM Jet is not going to be very useful on a planet with a thin atmosphere (but fortunately most such planets have low gravity, so it's less of an issue).
    --
    I am TheRaven on Soylent News
  8. Re:But at that speed... by xs650 · · Score: 3, Interesting

    The artilce that you linked to said

    "Paul said although signs so far are positive, it still is too early to say the scramjet experiment succeeded. The scramjet experiment took place during the final few seconds of the flight, which lasted almost 10 minutes."

    A quick search with google also did not turn up any reports of confirmed success. Do you have any?

  9. Re:Uhh guys...this has been done before by Anonymous Coward · · Score: 1, Interesting

    Check this article for details, but apparently they used a 2 stage solid fuel rocket to accelerate the engine to Mach 7.6. Then they did a 6 second test of the scramjet.

  10. Doubt it Re:10 seconds by WolfWithoutAClause · · Score: 2, Interesting
    I've a sneaking suspicion that it would only work for 10 seconds- 'strapping on a bigger tank' would probably result in it melting. They've probably used heatsink materials to soak up some of the awesome heating effects you get at mach 7.

    Besides, where would they put the bigger tanks? The thing is tiny; and hydrogen is seriously not dense; meaning very little fits into the vehicle.

    --

    -WolfWithoutAClause

    "Gravity is only a theory, not a fact!"
  11. Re:Stupid, Slightly OT Question by pfdietz · · Score: 2, Interesting

    Unfortunately, the drawbacks of airbreathing appear to outweigh the advantages, at least for vehicles intended to put objects into orbit.

    The problem is that a scramjet trades a dense propellant (LOX) for more of a low density propellant (LH2). As a result, the propellant tanks on a scramjet vehicle would end up being larger (and heavier) than those on an SSTO rocket with similar payload. LH2 is also much more expensive than LOX, so your propellant costs go up (not that propellant cost is currently important, but your vehicle is also in a more aggressive thermal environment so it to will be more expensive.)

    Worse, the effective Isp of a scramjet (after you take into account drag and gravity losses due to its lower acceleration) ends up being little better than the rocket. See Henry Spencer's comment on this.

    About the only place scramjets may make sense is in hypersonic cruise missiles. The US military has a scheme for using hydrocarbon fuels, converting these fuels into hydrogen + CO in flight by partial combustion with a portion of the incoming air (that portion is slowed to a stop by a conventional ramjet inlet, with the fuel being used to keep the air relatively cool and the inlet from melting.) The H2 + CO + nitrogen is then injected into a scramjet for complete combustion.

  12. Re:Throwing away information by No.+24601 · · Score: 2, Interesting
    The airframe could yield an awful lot of information

    The simulations are probably more precise than getting your hands on the aircraft after flight. In fact, the simulations would not take into account other non-flight stress like hitting the water from that altitude ;)

  13. Re:What about the nitrogen? by Anonymous Coward · · Score: 1, Interesting

    Nitrogen is far more difficult to dissciate (i.e. seperate the atoms), remember it's a triple bond, while oxygen is only a double bond. You need approximately twice as much energy to seperate a N2 molecule compared to O2.