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
 

[alnitak]

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

Yes, and anything above it too, due to leakage around the sides (satellites for example).

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

I doubt it. The generators are likely to be huge, static things (think airport sized), the beams would be steerable through only a narrow angle, and you would probably situate them away from major population centres.

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.

I am sure plenty of regimes would like to leap ahead of American military technology, especially air defense, but it's easier said than done :-)

[ASOC]

You might want to read the "StarFIST" series. Portable rail guns that strike at spacecraft, etc.

Fun read with a USMC "worms eye" view, The authors are ex-grunts.

[Mr170IQ]

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

Yes, high flux microwaves are hazardous to living things and electronics. However, missiles and military aircraft can be shielded against microwaves.

I've been doing some research into this field. I believe that microwave beamriders hold the key to low-cost SSTO. Here is a summary of my conclusions.

The transmitter antennas should not sit on the ground. They should be composed of several linked hexagonal airships, totalling about a kilometer in diameter, operating at about 10km of altitude, tethered by a long power line supported by intermediate balloons.

The effective range of the antenna would be less than 500km, therefore a full orbital launcher would probably have three transmitter antennas spaced about 600km apart. This would allow the spacecraft to accellerate to orbital speed over a 1800km trajectory

Although using liquid hydrogen as propellant would give the maximum ISP (about 1200), liquid ammonia is a much better choice, with its high density, low cost, and easier handling. Ammonia's ISP of about 800 would also be close to the ideal for minimum energy required for GTO.

Links for related information can be found here.

[Eala]

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

Thanks! (Would that it were otherwise, or that I was mistaken...)

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)?

That is a good question. I think maybe there is a general perception that there is a general war, but that it gets forgotten for the local battles, or ignored for fear of fighting on too many fronts. And there is really no organization, no coordination, and worst of all, no support for each other.

All too often, for example, we adopt the, er, linguistic practices the Left forces on us. Why? Because to refuse gets one singled out for attack (even if only verbal) from the Left. And the rest of the Right doesn't often rally to the poor soul's defence.

And the attack may be worse than merely verbal. The Left has so greatly infiltrated the judiciary that all sorts of bizarre takes on laws (not to mention the laws themselves) abound these days -- singling out and punishing the poor soul who broke their code, or law. And remember, to the Left the law (a straight code) is not a necessary component of civil life, it's just another tool to be twisted into a weapon against those who stand in the way of their all-out war for power.

[Semper911]

dunno about microwaves, but this has already been done here in the US with lasers instead of microwaves.

Before there were lasers (Light Amplification by Stimulated Emission of Radiation), there were masers (Microwave Amplification by Stimulated Emission of Radiation).

I don't know, but I suspect this is technically a maser beam, and is absent a light component.

[JerseyHighlander]

So every time a rocket is launched, there's a chance the ascent to orbit will turn into a multi-multi million dollar skeet shooting misadventure?

Is there a known substance that can withstand the huge forces of concentrated microwaves on the reflector dish of a satellite launch?

[anymouse]

Dr. Myrabo also did research on microwave versions of his lightcraft. I'm sure this is follow on research based on his work

[SunkenCiv]

Blast from the Past!