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Photonic Laser Thruster Promises Earth to Mars in a Week
serutan writes "Using lasers to drive spaceships has been a subject of interest for many years, but making a photonic engine powerful enough for practical use has been elusive. Dr. Young Bae, a California physicist, has built a demonstration photonic laser thruster that produces enough thrust to micro-maneuver a satellite. This would be useful in high-precision formation flying, such as using a fleet of satellites to form a space telescope with a large virtual aperture. Scaled up, a similar engine could speed a spacecraft to Mars in less than a week."
What sort of acceleration would that be? Would it be multi G-force worth, that might be impractical for humans.
“Common sense is not so common.” — Voltaire
And if scaled up, cockroaches run at 800mph and fleas could jump over a mile. However, the increase in mass and energy requirements would make it impossible.
Small scale thrusters using only lasers is a good start, but we'll have to see what else gets bigger with scale, other than just the thrust.
I would think that scaling wouldn't make the laser bigger but would instead use multiple lasers like they do with ion engines. Of course, IANARS (I am not a rocket scientist) so take what I say with a big grain of NaCl.
"Some fight for law. Some fight for justice. What will you fight for? One day, you will see."
Where is the energy coming from to create those photons?
Since you're dealing with a photon drive, the reaction mass usage (as determined by the classic rocket equation) is going to be negligible for the speeds required for interplanetary travel.
In fact, I'm not sure what the reaction mass would be in this case.
But in any case, you're going to need a lot of energy to create that photon thrust. Great phrigging big reactors, which means great, great, phrigging big radiators since you don't have the luxury of a river to carry away your waste heat.
Antimatter might be a compact way to store the required energy, but converting the gamma rays from matter/antimatter reactions to electricity is going to require heat exchangers and great big radiators as well.
Well, anyway, scaling this up is going to involve several bears of a problem.
Also, please note that this "article" is a press release from the guy who made the invention.
To send a ship to Mars in a week, Thrust should be roughly 10m/s^2 times the ship's weight, which we'll say is only ten metric tons. (Because we're getting there in a week, we can pack light... pack light, get it? I slay me.) That gives us 10^5 Newtons of thrust.
Exhaust Velocity is the speed of light, or about 3*10^8 m/s.
So our power consumption is 3*10^13 Watts.
By comparison, the USA is currently consuming less than 1*10^13 Watts on average.
In other words, if think you think it costs too much to refuel an RV now...
It's not completely implausible to use light to propel a spacecraft, but either that propulsion will be ridiculously slow (e.g. solar sails, laser sails, or the "precisely tweak your satellite's orbit a tiny bit" applications mentioned in the article), or it's going to require ridiculous "cheap antimatter" amounts of energy.
Twice the average speed if you want constant acceleration.
To get to Mars in a week, only about 5m/s^2 is necessary. ( Mars at 1G is about 3.5 days, so a week is 1/2 G, turnaround halfway )
So call it a mere 1.5*10^13 watts.
In other words, no existing institution would accept the good doctor, so he made his own, and issued a press release written in false third person.
On the other hand even the current institutions started as someone creating them at some point.
And quite a lot of scientists were ridiculed by the establishment at a time they made a revolutionary discovery.
What worries me more is his unsubstantiated "if we just scale it up" argument. That doesn't stand basic math/logic/physics.
MIT also has a website for a materials science group promoting the idea of ridiculous superhero underwear (ridiculous because being able to spread the energy of impacts is how bullet proof stuff is made so nanometre thick stuff is not going to solve the problem on it's own) that none of their students would believe past first year. Loud Lysenkoism is how things are done these days even if the people actually doing the stuff are legit. We really need work on the K-12 education system because that is all our decision makers are really going to get, and currently snakeoil scams are attracting a lot of serious attention from poeple that we would hope would know better.
Because as we all know, it's just that easy! Nothing that worked at one scale ever proved impractical or impossible to do at another!
It's official. Most of you are morons.
I'd say that was funny, except I swear that's how some people actually think.
If Mr. Edison had thought smarter he wouldn't sweat as much. --Nikola Tesla
> Republicans, you mean.
Anybody who's read my posting history knows I'm a dyed-in-the-wool liberal, but I don't think we can singularly blame the GOP for this one. There's resistance to nuclear power coming from both extreme ends of the spectrum. Environmental activists who don't understand the science on the left, and oil industry lobbyists on the right.
I'm constantly frustrated with people who I know are well-intentioned and genuinely concerned, who are so afraid of nuclear power. I mean I agree, solar and wind power are great ideas, but right now we're generating power using f'ing COAL.
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Isn't "photonic laser" redundant?
Am I the only one getting Buckaroo Banzai vibes from this?
Dr. Bae of the Bae Institute? Seriously?
I went to the Bae Institute's site and found that it is "an independent space and medical research center."
Physics and space science: check.
Institute named after its physicist founder: check.
Medical stuff: check. Dr. Banzai, of course, in addition to being a great physicist, is also a top neurosurgeon. At the Bae Institute site, it says the Institute's medical technologies can be used, among other things, for treating "brain and spinal cord surgeries."
If Dr. Bae is also the leader of a rock band and says things like "wherever you go, there you are," I'll be surprised if we don't see a wave of stories submitted very soon, all by people named named John, saying that Dr. Bae's research cannot be trusted. I expect these submissions to cite the work of another physicist, Dr. Emilio Lizardo.
Laffa while you can, Monkey Boy!
I just showed my age in a way a low Slashdot UID never could.
"It is nice to know that the computer understands the problem. But I would like to understand it too." --Eugene Wigner