Japanese researchers develop 'microwave rocket'

Daily Yomiuri ^

[Trailer Trash]

 

Researchers develop 'microwave rocket'   Yomiuri Shimbun A group of Tokyo University researchers has successfully applied electromagnetic waves--normally used to heat food in microwave ovens--as the propulsion force for a "microwave rocket," the first time such an experiment has succeeded. According to the group led by Kimiya Komurasaki, an associate professor at the department of advanced energy, the development could enable cost and size reductions in rockets as they could use air in the atmosphere as a means of propulsion, rather than having to carry fuel. The group fired the microwaves at the rocket's base, rapidly heating the air and creating a burst of energy that propelled the rocket upward. The group used a powerful gyrotron developed by the Japan Atomic Energy Research Institute to heat an international thermonuclear experimental reactor to fire the beam at a dish-shaped metallic object shaped like a round-bottomed pan. The waves reflected off the object and converged, causing the air to reach ultrahigh temperatures and generating an explosive expansion that created the propulsive power. When the beam was applied for just one-thousandth of a second to a model rocket weighing 9.5 grams, it flew two meters into the air, the group said. According to the group, the beam could be continually fired from the ground at the rocket powering it to an altitude higher than 100 kilometers where there is no air. Once this altitude was reached, the rocket could switch over to a conventional rocket engine.

Copyright 2003 The Yomiuri Shimbun
 

[Trailer Trash]

Less fuel = more cool stuff in the sky.

I want my videophone.....

Only I want mine flavored with broadband, and delivered through a LEO pipe.

Happy Easter.

[alnitak]

Interesting, sounds like a microwave version of Leik Myrabo's "lightship" work.

I remember hearing a few years ago about how a microwave version would be better than laser because microwave generators could be scaled up more easily.

[anobjectivist]

I dunno about microwaves, but this has already been done here in the US with lasers instead of microwaves. Same principle, energy fired at a light and mirror-reflective dish, except ours went somewhere around 100 feet up. It had to be stabilized by rotation (they would get it spinning with compressed air right before take off).

I believe the discovery channel had a program on them.

[anobjectivist]

Well, you beat me to it.

[error99]

"...the development could enable cost and size reductions in rockets as they could use air in the atmosphere as a means of propulsion, rather than having to carry fuel..."
--
Yeah, now that heavy fuel can be replaced by heavy storage batteries.
And, there isn't any 'air' in space to heat up in order to get the propulsive effect.
Just a few of the bugs that need to be worked out, thats all.

[alnitak]

Early bird catches the worm :-) I saw this on TV too ("Tomorrow's World" here in the UK"), the thing I remember was them having trouble with the wind, and having to be careful to time their "flights" so as not to fry any satellites passing overhead!

Scientific American article here on new methods of spaceflight. (click the "box" link on page 6 of the article for some more details specific to Myrabo's scheme)

[alnitak]

The atmosphere is used as the reactant-mass while you're in it. The microwave energy is beamed up from the ground - this is the key point, existing craft have to carry all their fuel, which is heavy, hence step-rockets. Beamed energy solutions let you leave the fuel on the ground - not to mention the power plant. As for when you get out of the atmosphere, well you can carry anything to act as reactant mass, say liquid air or water, though I imagine liquid hydrogen would be best because of its low mass.

[error99]

You should test your links in 'preview'.

[alnitak]

Hmm, sorry about that, must be because I found the article via their search engine. Here's a direct link to the Myrabo article, and a link to the entire issue, which has many space related stories.

[robertpaulsen]

Moties?

[Sam Cree]

Seems like a microwave powerful enough to send up a serious, payload, say one measured in tons rather than grams, might be a serious weapon in its own right.

Kind of along the lines of the laser powered vehicles in "Footfall."

Wonder if microwaves can be used as guidance systems as lasers can. Perhaps they would not be deflected by smoke.

[Eala]

Kind of along the lines of the laser powered vehicles in "Footfall."

Heh. Was thinking the same thing. And another variation are the laser-powered sails in "The Mote in God's Eye."

[Libertarianize the GOP]

http://www.freerepublic.com/perl/bump-list

[chilepepper]

Way cool! ...and you can make popcorn with it to boot!

[Trailer Trash]

"Yeah, now that heavy fuel can be replaced by heavy storage batteries."

The microwave generator never leaves the ground. The beam is focused upon the aircraft, and the resulting reaction creates the thrust.

[Sam Cree]

I'd forgotten about those "sail" ships.

Your essay on the war against the Left on your home page is right on the money, IMO.

I agree that people always seem to be concentrating on the battles instead of the war. Why do you suppose that is? Heads in the sand, fear of sounding crazy? Having the same agenda, but not admitting it (acquisition of power)?

[Lawgvr1955]

I want my air car. I want to fold my car into a briefcase like George Jetson. I want to take a Pan Am rocket to the Moon like 2001. Where is all the cool stuff we were promised in the movies and television. Ya, this internet thing is nice, if unpredicted. Of course, future predictions aren't all that great. For instance, in Star Trek-The Next Generation, they cure all disease (including cancer) with a five minute stay in sick bay. Yet the Captain is still bald like a cue ball. Sotty to hear in the year 2300 they stil haven't found a cure for it.

[LenS]

But wouldn't the microwaves be a hazard to anything between the rising rocket and the microwave generator? Cooked birds, for example?

And if yes, wouldn't this make an excellent missile and air defense system?

If I were America's enemies, I would counter our air dominance by developing new air defense systems -- energy beams of all types or rail guns or whatever. Instead of trying to put together a complex system that took us a half century to achieve in the air, try to leap ahead and make it so that anything that flies, dies. Thus negating our edge and returning it to a ground battle where our edge isn't as huge.