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More on JSF Laser System

Posted by michael on from the huh-huh-fire-huh-huh dept.

An anonymous reader writes "Seems Lockheed Martin has won a contract to equip future versions of the Joint Strike Fighter with a 100-kW laser. Housed in a dome within the aircraft, the laser's turret would emerge for firing [sound familiar?], and the laser itself is spec'ed to achieve airborne and ground kills at a distance of more than six miles. The problem? According to this Aviation Week article, Lockheed Martin has to figure out how to dissipate 900 kilowatts of heat. Maybe the Finnish airforce could value-add to the OEM model." We mentioned this earlier.

9 of 419 comments (clear)

  1. sounds more like by graveyhead · · Score: 5, Interesting

    the plot of Real Genius than a star trek episode...

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  2. Dissipating the heat into the fuel... by richard-parker · · Score: 3, Interesting

    To dissipate the heat, cooling loops will be employed to take heat from the laser system and transfer it into the aircraft's fuel tank, where it can be burned away.
    ...
    "If you think about the amount of fuel onboard a jet aircraft, if you put all that heat in the fuel, you might raise it by a degree, something on that order," he said.
    Unless, of course, the aircraft has expended 99% of its fuel - in which case the temperature of the remaining 1% of the fuel would raise by 100 degrees. Ouch.
  3. where do you get the power from? by Anonymous Coward · · Score: 1, Interesting
    How in the world do you get a megawatt of available power in an aircraft? Charge banks of capacitors?



    Can anyone here shed some light on such a compact yet powerfull system?

  4. Not the first time fuel has been used to cool by xmnemonic · · Score: 3, Interesting

    The legendary SR-71 (high altitude mach 3 spyplane) kept the fuel stored at an extremely low temperature in the tanks (sub zero initially I believe), then pumped it through fuel lines running throughout the aircraft. The fuel would absorb the heat from the various internal components of the plane before arriving at the engines.

  5. Re:Thats a lot of heat! by brokenbeaker · · Score: 2, Interesting

    If you read the article, you'll see that the heat will get transferred to the fuel. Although this sounds crazy, apparently there will be enough mass so that the temperature change will be only a few degrees.

  6. Re:hmmm... another approach? by Flamerule · · Score: 3, Interesting
    From the article:
    Lockheed Martin believes that a 100-kilowatt laser is the minimum power level needed to be an effective weapon for a fighter.

    However, "to get 100 kilowatts of light out, you've got to put a megawatt of electrical power in, so somewhere along the way you've got to deal with 900 kilowatts of cooling," Tom Burris, lead for directed energy at Lockheed Martin Aeronautics, told The DAILY. "That's a ton, for a fighter that normally does tens of kilowatts of cooling."

    It's a 100KW laser; that requires 1MW of energy. The energy that didn't go into the laser is lost as waste heat, hence 900KW of heat need to be dissipated. The only way to reduce the amount of heat would be increasing the laser's efficiency, and as other posters have already pointed out, 10% is excellent efficiency for this kind of system.
  7. A sophisticated way of relating to others? by Futurepower(R) · · Score: 5, Interesting


    For some people, this is an acceptable way to relate to other people. If you don't like other people, just kill them. Preferably from a long way away.

    It's profitable, too, for a small number of people, because the weapons are secret and therefore the profits can be kept secret.

    It's an adult video game. Except that you don't get to play. You, if you are an American taxpayer, only get to pay.

    There are a lot of people who would like to kill other people if it is free and they don't have to go to prison. It's a kind of mental illness. For more about this, see What should be the Response to Violence?

    Violence tends to cause other violence. Mostly hidden elements of the U.S. government are causing the U.S. to be a target of violence. For example, the U.S. government (taxpayers) spend more than $900 every year for every man, woman, and child in Israel so that Israelis can buy U.S.-made weapons to kill Arabs. It's a way of transferring money from the taxpayers to the weapons makers. It seems likely that this will result in another holocaust; I doubt the Arabs are kidding when they say they will never surrender.

    Every day in the U.S., it is possible to see American leaders on television calmly discussing the killing of other people. Of course, they have come to believe that they will never be the target.

    I accidentally posted this anonymously before, so here it is now, with my name on it.

  8. Ohohohoh yes... by silvaran · · Score: 3, Interesting

    Star Trek, here we come... Mr Worf, arm phasers!

    I think the best part about a country having powerful weapons is their ability to NOT use them. Keeps evil powers in check (of course, evil is a subjective term, but anyways...). Same with nuclear weapons. Einstein basically told U.S. representatives, "yes, splitting atoms will work, but don't do it. It has disasterous consequences." Well, they didn't exactly listen. But I hope the ability to develop new weapons comes with the mindset to not use them.

    I would prefer to see these laser weapons go from fighter jets to medical surgery. Imagine the medical uses for this. Small, precise cuts, no sterilization necessary.

  9. 900kw of heat? by Perdo · · Score: 3, Interesting

    On a vehicle that uses heated gas expansion for propulsion (fancy name for a jet), It seems like 900kw of extra heat could be used in place of an afterburner.

    Just find a fluid that does a phase change efficiently between the melting temperature of the laser's mechanism and say just a little hotter than the jet's exaust plume.

    Liquid boron or sulfer ought to do the trick.

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