Photon Propulsion Breakthrough

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nuaetius

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TUSTIN, Calif., Sept. 6 /PRNewswire/ -- The aerospace industry has taken notice of a California researcher who, using off-the-shelf components, built and successfully demonstrated the world's first successful amplified photon thruster. Dr. Young Bae of the Bae Institute first demonstrated his Photonic Laser Thruster (PLT) with an amplification factor of 3,000 in December, 2006.<br /><br />Major aerospace agencies and primary contractors have since invited Bae to present his work, including NASA JPL, DARPA (Defense Advanced Research Projects Agency), and AFRL (Air Force Research Laboratory). Senior Aerospace Engineer at AFRL, Dr. Franklin Mead, "Dr. Bae's PLT demonstration and measurement of photon thrust (is) pretty incredible. I don't think anyone has done this before. It has generated a lot of interest."<br /><br />Recently, the Journal of Spacecraft and Rockets, a peer-reviewed AIAA (American Institute of Aeronautics and Astronautics) (http://www.aiaa.org) Journal, accepted Dr. Bae's PLT demonstration paper, "Photonic Laser Propulsion: Proof-of-Concept Demonstration" for publication this year. In his paper Bae documents in explicit detail how he overcame the inherent inefficiencies of traditional photon thrusters in generating thrust by amplification with the use of an innovative optical cavity concept. For decades rocket scientists have tried to overcome the inefficiency of photon thrusters by amplification based on optical cavities separated from laser sources, but failed. In contrast, Bae's patent-pending PLT breakthrough places the laser medium within a resonant optical cavity between two platforms to produce a very stable and reliable thrust that is unaffected by mirror movement and vibration -- ideal for spacecraft control or propulsion.<br /><br />Dr. Bae will be presenting his PLT concepts, demonstration, and applications at the AIAA Space 2007 Conference 18-19 September 2007 in Long Beach, CA, in four sessions: Space Transportation Systems, Promising Space Co
 
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crix

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High thrust propellantless propulsion??<br /><br />Wow, this sounds very interesting!
 
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thereiwas

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Not propellant in the traditional sense, but to get any useful thrust you need an awful lot of energy from <i>somewhere</i>. TANSTAAFL.
 
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crix

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<img src="/images/icons/smile.gif" /> I recognize that acronym from the back of the Heinlein book I just picked up. I'm itching to start it... <br /><br />I'm pretty sure this would be considered propellantless... as long as only photon mass is responsible for momentum transfer.
 
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j05h

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It's hugely inefficient if it uses solar panels to create laser light. I'd think a solar-pumped laser would make more sense, plus it can be used otherwise with ground or orbital lasers. Did I misread it, or is this thing really just an efficient green laser?<br /><br />Josh <div class="Discussion_UserSignature"> <div align="center"><em>We need a first generation of pioneers.</em><br /></div> </div>
 
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crix

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Well it produces non-negligible levels of thrust supposedly, so no, this would be much more than a 'green' laser. I assume you would need gigawatts to get to Mars in a week as the paper claims it could do.
 
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MeteorWayne

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That seems to be a big point.<br /><br />If you are going to shoot energy (photons) out the business end, you have to insert more than the same amount of energy in the front end. <br />Where does that amount come from?<br />How much is it? (i.e.what is the efficiency)<br /><br />If you need a 100 square kilometer solar array to get the power, what's the point? <div class="Discussion_UserSignature"> <p><font color="#000080"><em><font color="#000000">But the Krell forgot one thing John. Monsters. Monsters from the Id.</font></em> </font></p><p><font color="#000080">I really, really, really, really miss the "first unread post" function</font><font color="#000080"> </font></p> </div>
 
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crix

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Yeah, that would be impracticle. Fission powersource most likely. Imagine not having to carry propellant!!
 
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no_way

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Er, with fission powersource, you could move around a lot more efficiently than shooting light at the rear end.<br /><br />Shoot pellets with railguns, or just shoot steam. Hell, even xenon ions would do nicely.
 
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crix

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It's hard to say without having any details on this light 'nozzle.' If I could thrust with photons that's the way I'd want to go.
 
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MeteorWayne

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But you have to carry the fission powersource, which is more mass than the average science payload.<br /><br />If you can get a craft somewhere, but there's no weight for science, what's the point?? <div class="Discussion_UserSignature"> <p><font color="#000080"><em><font color="#000000">But the Krell forgot one thing John. Monsters. Monsters from the Id.</font></em> </font></p><p><font color="#000080">I really, really, really, really miss the "first unread post" function</font><font color="#000080"> </font></p> </div>
 
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crix

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Why are you comparing the reactor's mass to that of the science payload? The mass of the propellant you'd use for chemical propulsion is the thing to compare to.<br /><br />I remember asking in highschool physics how much thrust a handheld flashlight would create. .... I can't wait to learn more about how this assembly of parts creates useable thrust.
 
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kelvinzero

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Im too lazy to do the physics. Could someone look up how much energy is required to get something to mars in a week <i>if using photons for propellent mass?</i>.. I know vastly more energy will go into the photons than the craft.<br /><br />No one has given me a reason to take this mars claim seriously yet. There are fundamental issues with photon propulsion that have nothing to do with details of how the light is produced. These issues seem garunteed to restrict photon propellent for minute adjustments or building up vast speeds over very long periods of time, such as interstellar flight. <br /><br />(edit: <b> oops, I had missed the point. See my later two posts. Very cool if they have those magic mirrors <b> <img src="/images/icons/smile.gif" /> )<br /><br /></b></b>
 
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thereiwas

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This thing is crying out for a Bussard inertial containment fusion reactor. Much less mass than a fission reactor as it does not need radiation shielding.<br /><br />But recall from one of Larry Niven's short stories, taking place just before the Man-Kzin wars, a photon beam that powerful is a considerable weapon at close range. The warlike Kzin thought a human ship propelled by light beams was no threat to them. Until the human ship turned its tail toward the Kzin and turned on the beam.
 
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spacefire

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ok, I have no idea how this works, but why would the guy shoot himself in the foot by making that claim of Mars in 2 weeks if it were that obvious that the amount of power needed to generate this thrust involves impractically large generators?!?!?!<br />I mean, he seems legit, likely looking to get more funding....not be labelled as a quack! <div class="Discussion_UserSignature"> <p>http://asteroid-invasion.blogspot.com</p><p>http://www.solvengineer.com/asteroid-invasion.html </p><p> </p> </div>
 
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strandedonearth

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Please please puh-lease use the code <br /> Click Here! <br />for long links. Otherwise people end up having to scroll sideways back and forth to read the thread. Thanks!<br /><br />This does sound very promising, like the next best thing to a reactionless drive. Now I have a hankering for flash-fried Kzin!
 
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kelvinzero

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Ah, ok.. interesting. I had missed the point.<br /><br />So they are suggesting bouncing light between two satellites. Thats the cavity. If for some reason you can have light trapped between the mirrors in a perfect lossless way, and one of the satellites is trapped in orbit (or better yet on the moon etc) then the photons bounce back and forward many times, imparting a tiny momentum with each collision, and I guess becoming slightly lower wavelength (to conserve energy)<br /><br />If you can produce those perfect mirrors, 100% of your power goes into your craft and NONE into your propellent.<br /><br />Erm.. this is actually an idea I had in the past.. honest! <img src="/images/icons/blush.gif" /> though the clever bit is in the magic mirrors of course. <br /><br />I was also thinking there must be a world destroying amount of energy trapped between the mirrors to give that much push.. but I guess that is wrong too. If a photon surives a million bounces, then an object straying into the beams path will only absorb a millionth of the energy bouncing off the mirror, since every photon it absorbs or deflects is not going to return a million more times.
 
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baktothemoon

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But are we sill going to be able to aim precisely when there is a delay of seconds or minutes from when the photons hit each mirror?
 
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crix

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Why are the generators impractically large? Huge containers full of LOX and LH2 seem pretty damn cumbersome to me too. <br /><br />This system is far from proven at the high power that could do these outrageous Mars runs but they seem to be theoretically possible. Can we get a spacebased 10MW nuclear reactor on an Ares V? I don't know either.<br /><br />I want some government entity to go ahead and begin testing a large scale version of this thruster while simultaneously ordering a compact, low weight megawatt nuke plant. Forget science payloads, I want to establish whether or not it is possible to get something back and forth from Mars in under a month. That would be huge.
 
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kelvinzero

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<blockquote><font class="small">In reply to:</font><hr /><p>Why are the generators impractically large? Huge containers full of LOX and LH2 seem pretty damn cumbersome to me too. <p><hr /></p></p></blockquote><br /><br />If I am right in my last post, this also means the power plant can be as heavy as you like since we are talking about beamed power. A big stinking concrete monstrosity on the moon for example, weighing a zillion times more than the craft.<br /><br />Yes I guess this is very promising if someone has unexpectedly come up with a way of producing these magic mirrors.
 
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billslugg

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Crix<br /><br />I'm confused by your prefixes. Is "m" milli or "micro"? Reading the paper, I think it is micro. You can get a mu (μ) from the character map.<br /><br />Is M a million?<br />If so why would a craft weigh 100 million tons? <div class="Discussion_UserSignature"> <p> </p><p> </p> </div>
 
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kelvinzero

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Yeah there were actually a couple. I've only just figured out what they were actually talking about though.
 
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crix

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MT was metric tons. I updated it. MT is often used when talking about launchers... apologies.<br /><br />So this really is beamed power. /:mad:<br />I am much less excited now. It's still cool but I just don't like that you need a massive object on one side of the equation. Plus, how do you get back from Mars?? Seems like it's only out bound propulsion.
 
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