Laser Powered Paper Plane Takes Flight

RobertTaylor writes: "Ananova is reporting that Japanese scientists have developed a laser powered paper plane. A blast of light from a commercial laser heats up a droplet of acrylic polymer or water on its surface which acts as fuel. Full story here" Nature also has a story on this advance.

Comments

I think I've heard this one before.

[Saoshyant]

I'm pretty sure I've heard about using lasers to power spacecraft. The idea is that, rather than having spacecraft lug around a S%$tload of expensive fuel, keep the fuel back here on earth, and beam a laser at the craft. The craft harvests the energy in the laser, probably using photovoltaic cell technology. The beatiful part is that the craft will never outrun the power source.

Re:I think I've heard this one before.

[steveha]

rather than having spacecraft lug around a S%$tload of expensive fuel, keep the fuel back here on earth, and beam a laser at the craft.

Well... almost.

You can make an airplane that works this way: it sucks in cool air, a laser provides power to heat the air, the hot air jets out the back of the airplane engine and makes the plane go. The plane pushes itself along using air. We can call the air "reaction mass".

If you want to power a spacecraft with lasers, you need to do pretty much the same thing. However, in space you cannot suck in cool air, so you need to carry some other sort of reaction mass to jet out the back of the rocket. The laser provides energy to accelerate the reaction mass.

But the best, most practical application of lasers to transportation would be to make a vehicle that goes to space, using the airplane trick to get the vehicle started and then switching over at some point to more conventional rockets. As long as the laser is working and you can suck in cool air, you can jet out hot air and get some lift. This would mean your vehicle can carry less fuel and still reach orbit.

None of these will happen this year or next year.

steveha

Same idea, but without the laser...

[fingal]

Many, many, moons ago I got a job working here while I was doing my A levels and one of the things that they where working on was propulsion systems for extremely high speed planes. If my memory serves me (which is not guaranteed cos I was only humble code monkey and not privee to the finer arts of engineering theory and it was a long time ago), then they where planning to use conventional propulsion methods up to their maximum effective threshold and then start spraying fuel onto the trailing edge of the wings directly, which due to the intense heat and pressure due to the (already quite unfeasibly high) speed would spontaneously ignite thereby generating more thrust without all the hassles of trying to force an extremely unpredictable fluid down a tube at high speed. Absolutely no idea of whether or not they made any progress on this or whether or not I would be prepared to fly in one if they did...

Re:Something else like this.

[2ri]

And in space you can use photons instead of reaction mass. Yes, photons _do_ have an impulse. This would work like sailing on top of the laser beam. Got to get rid of the heat though, preferably as radiation directed towards the beam.