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Company Aims To Launch Spacecraft On Beams of Microwaves
MarkWhittington writes: The quest for cheap access to space, to make space travel as inexpensive as air travel, has eluded engineers, government policy makers, and business entrepreneurs from before the beginning of the space age. It has become axiomatic, almost to the point of being a cliché, that the true space age will not begin until launch costs come down significantly. Forbes reported about a company called Escape Dynamics that has a unique approach to the problem. The company proposes to launch payloads into low Earth orbit on beams of microwaves.
I hope this is built well away from tall buildings, airplane flight paths and other things that's don't mix well with high power microwaves.
...and underwear!
I don't think the article described the technology very well. Anybody find a better description elsewhere?
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NASA never went to the moon, the Van Allen belts weren't known then and would have killed the astronauts.
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Space is mostly an empty, radiation-blasted hell. Look, not even a hundred years ago we thought the *entire universe* was THIS galaxy!
When are people going to grasp the sheer scale of the emptiness of space? And that there is NOTHING for people to do there?
At best, you have some sort of expensive joyride. You go up, take in the view of the Earth, and come back down.
You can look at the night sky for free, getting 100 kilometers "closer" to the rest of the universe achieves nothing.
Why can't you nerds get over this obsession with space? You got over the obsession to colonize the bottom of the ocean, we never hear about that anymore.
I have been reading about beamed propulsion for a while, this is an interesting concept. It is very nice to see progress is being made here. The advantage of beamed propulsion is that we can leave the power components on the ground (instead of needing to carry the energy as chemical propellant), which makes it far more efficient and can make spaceflight much more accessible (see rocket equation, most of the energy for a normal rocket is spend moving propellant and other things like propellant tanks up; we usually need to do things like multiple stages, etc. which add complexity and make resuability much harder). I think beamed propulsion is on the right track.
From the article, it seems that the hydrogen propellant (which is heated and blasted out) is used at all altitudes. This ship is then still described by the rocket equation, since it is effectively firing out hydrogen propellant at a given speed (the energy for the firing is external, but still, the propellant must be all on board at the beginning). Is it possible to instead use an air intake as long as feasible, switching to the hydrogen only at very high altitudes? This will greatly reduce the amount of hydrogen propellant needed, which will help a lot (again, refer to the rocket equation). I know this has been considered with usual spacecraft, there the situation is very different as chemical rocket spacecraft have to be using propellant always (even if not oxidizer in the air-breathing phase), here we can have a ship that can initially ascend as slowly as it wants while using air intake (since it is externally powered and isn't using hydrogen propellant yet), can accelerate fastest when air density is optimal (there is air for the intake, but not too much drag), and then switch to hydrogen at the end. Has this been considered?
Good luck Escape Dynamics, you have a very good project.
this has been demonstrated (on bang goes the theory, for eg, i don't have the link) to work using scale models, where a strobed laser pulse is used to turn air to plasma inside a simple parabolic reflector, to direct the explosion downward.
perhaps a combination of the two, begining with laser/air, and phasing toward h2/uwave?
The airframe is a lifting body with a large flat undercarriage. This is the side that absorbs microwave energy, which is somehow transferred to the hydrogen fuel to provides thrust. After achieving orbit and delivering it's payload, the spacecraft deorbits and then the same lifting body surface that absorbed microwave radiation becomes the heat shield for reentry.
So how do you combine the ability to receive a large amount of microwave energy and then turn around and protect the airframe from reentry heat in the same structure? And in addition has the structural integrity to withstand launch and reentry stresses.
Microwaves are not invisible magic. They interact with the matter they encounter. Whatever heat shield material they use, it is going to absorb some of the microwaves that hit the vehicle. Can they keep this amount low enough and also fulfill the other requirements?
At this point there is so little technical detail, and so much marketing hype, that this has to go under the heading of geek fantasy daydreaming. I'm going to ignore this one until they show some real results or publish specific enough information that someone not on their payroll can say that it's feasible.
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everybody believes the TI is crazy. But for gov/mil use? everything is fine and dandy.
I can't wait to see the first test flight when a flock of sea gulls intercepts the beam, explode into flames, and their burnt carcasses rain down on the beach. The subsequent loss of thrust and fiery crash or range safety termination should also make for interesting viewing on YouTube.
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The company proposes to launch payloads into low Earth orbit on beams of microwaves.
And fresh popcorn will be served when you get to obit.
i've heard about these ground based power systems before with microwaves and lasers but what about the inverse square law?
how massive of a signal would you have to generate in order to have enough power when the thing is at height?
i assume that people have worked the numbers and it works out but i just have no idea how it possibly could. anyone care to field this?
what if the vehicle's roof is a giant magnifying glass focusing the rays of the sun into a heat exchanger? i know i know... that sounds stupid but still, i'm curious as to why something like that wouldn't work given how much power the sun is putting out. is it just a matter of large the magnifying glass would have to be?
or if that's the case, how about a huge, ground based parabolic mirror that aims at the craft as it ascends... i assume then, there will be problems with atmosphere getting in the way... but is that insurmountable?
Free and unlimited popcorn for all!
I realize that moving the power source off of the craft is going to help some but isn't THE major problem in the rocket equation reaction mass? Rockets have to carry it with them and this craft seems no different. Unless this propulsion system produces much higher exhaust velocities I don't see how its going to help much.
I recall a prof from RPI with a plan for something called "lightcraft" fairly similar to this. He was using microwaves and also lasers, as I recall; I think he might have built a small scale prototype.
https://en.wikipedia.org/wiki/Leik_Myrabo
Good luck to Escape Dynamics, this could reduce the cost of orbit access if it works. Myrabo's lightcraft always had the problem of small payloads (1-2 tons I think), I wonder if ED has gotten around that or just plans to launch cubesats and ISS supply loads so it doesn't matter? You need a lot of power and beamed delivery isn't exactly 100% efficient either, something I suspect puts a ceiling on payload given realistic limits on power supply (you're not going to build a 10GW power plant for this, though in theory you could).
Another website with pretty pictures and empty promises by people who don't know what they're talking about.
As of sometime around last year there are now MASERs which could be used instead of throwing most of the microwave energy in directions other than the one desired. Their snakeoil is out of date.
The second snakeoil clue is we are getting this from Forbes and not Scientific American or New Scientist.
Some haven't noticed it's got more than four words, but you people are brighter than that and will see the part which could be used on the end. Earlier MASERs had some shortcomings compared with the recent solid state room temperature devices so now they can be used for applications like this despite them being impractical before.
If you are just heating a gas to large pressures and then letting it expel out the back, you get the same thrust from any mass at the same velocity.
So why use hydrogen? which is somewhat uncommon down here on earth (at least as a pure gas), and erm wouldn't it burst into flame as it encountered O2 while it was still extremely hot? on a geologic scale, earth is already losing hydrogen to the solar window blowing it away from the upper atmosphere -- unless there's some huge advantage of using hydrogen, seems kinda strange to select it. ?
I guess it seems like H20, which seems to be extremely easy to heat with microwaves, would be a better reaction mass? easy to carry as a liquid, just boil it and get lots of steam pressure ?
Does the article say why? Is there some known property of hydrogen that reacts well with microwaves ?
Actually at very high temperatures water disassociates into 2xH & O.
Not sure that the fact that it holds more heat has as much to do with ISP as the molecular weights.