X-43A reaches Mach 10, Airborne Laser achieves first light, and other aerospace news

Discussion in 'General Science & Technology' started by Stokes Pennwalt, Nov 17, 2004.

Thread Status:
Not open for further replies.
  1. Stokes Pennwalt Nuke them from orbit. Registered Senior Member

    Messages:
    1,503
    http://www.nasa.gov/missions/research/x43-main.html
    The X-43A is a tiny unmanned skimmer about ten feet long but the SCRAMjet concept needed further validation, and the X-43A was the craft with that mission. Here is a short description of the differences between RAMjet and SCRAMjet engines, the former of which has been around since World War Two.

    Basically, the ability of a SCRAMjet to achieve combustion above the speed of sound means that its exhaust can move a lot faster, and thanks to Newton's second law of motion, that means the craft it's propelling can too. This technology has AMAZING implications:

    http://apnews.myway.com/article/20041117/D86DA1MG0.html
    This same advantage will also apply to a new generation of SSTs that will make the Concorde a slug, and cheap, reuseable, SSTO launch vehicles for satellites and spacecraft.

    The X-43A has finally dethroned the X-15, which held the atmospheric speed record of Mach 6.7 since 1967.

    In other news:

    Europe's SMART-1 probe has nudged itself into Lunar orbit. This is special, because SMART-1 uses an ion engine for propulsion, rather than chemical thrusters. Ion drives are low-thrust electric engines and have been used on communication satellites for orbital station keeping since the 1970s, but propulsion is another matter entirely. Once we get nuclear reactors in space (thank you Project Prometheus), we'll have enough power to make one with enough thrust to move a spacecraft of substantial size. This is what could ultimately get us to Mars in three months via direct flight, rather than a nine month slingshot around Venus for a gravity-assist.

    Airborne Laser achieves First Light. In case you don't know, the Airborne Laser is a Boeing 747-400 freighter that will be outfitted with a chemical laser with an output of around five million watts. It will orbit around a ballistic missile threat like North Korea at high altitude (40,000 feet or so) above roughly 90% of the Earth's atmospheric contaminants that normally occlude the beam path. When a ballistic missile launch is detected, the ABL tracks and engages the missile during its boost phase when it's slow-moving, throwing out lots of heat, and largest due to all its engine stages still being attached. A few seconds of lasing later, the missile is rendered functionally dead. One ABL aircraft will have a lateral engagement radius of around 300 nautical miles.

    As far as this "First Light" is concerned, that means that the laser and directing optics have been operated while connected for the first time. The laser itself had been tested but never while connected to the beam shaping optics that will be used to direct it against a target. The optics are pretty complex - gasdynamic lenses that shape the beam using a few layers of Helium moving at supersonic velocity to keep from overheating, and a directing mirror composed of 768 parasitic subreflectors, each capable of changing shape at 1,000 times per second to continually adjust the beam on the target for the few seconds of illumination necessary to kill it. The COIL laser used in the ABL has been around since the mid-1980s (it was originally conceived for use in the SDI) but beam direction is a much finer art than that, and is by far the most technically daunting aspect of any laser weapon system.
     
  2. Google AdSense Guest Advertisement



    to hide all adverts.
  3. ElectricFetus Sanity going, going, gone Valued Senior Member

    Messages:
    18,140
    Last edited: Nov 17, 2004
  4. Google AdSense Guest Advertisement



    to hide all adverts.
  5. phlogistician Banned Banned

    Messages:
    10,342
    X-43, what a fantastic vehicle. This is the future of space flight, flying most of the way, using fairly conventional technology, and saving the clever bit until last. It's the only way to keep the cost down.

    What I really want to know though, is how much thrust the scramjet provided.
     
  6. Google AdSense Guest Advertisement



    to hide all adverts.
  7. slotty Colostomy-its not my bag Registered Senior Member

    Messages:
    885
    The X15 still holds the record for manned flight, its going to be a few years before the manned version of the X43 beats it.
     
  8. ElectricFetus Sanity going, going, gone Valued Senior Member

    Messages:
    18,140
    There won't be a manned version of the X43, NASA is cutting funding for scram jet technology because it has to invest in manned missions to the moon and mars using conventional rockets that are cheaper to develop but more expensive in the long run.
     
  9. slotty Colostomy-its not my bag Registered Senior Member

    Messages:
    885
    What ever happened to the NASA of the 60's? To many accountants i suppose. Mind you they should of stuck with the X15 programme ( it did loads of the donkey work for the shuttle programme) we would have a earth to orbit by flight if they had allowed it to blossom.
     
Thread Status:
Not open for further replies.

Share This Page