Company Aims To Launch Spacecraft On Beams of Microwaves 120
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.
What could possible go wrong? (Score:3)
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.
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Well, if the whole rocket launching thing doesn't work out, you can open up a bird restaurant. "Flash cooked in flight" and all.
There's no risk! [dilbert.com]
Re:What could possible go wrong? (Score:5, Informative)
I'd like you to point out any launch site for orbital rockets that is anywhere even remotely close to tall buildings or even aircraft flights? The FAA routinely makes a pretty large exclusion zone around any launch activity. With the recent launch disasters from SpaceX and Orbital-ATK, I think such warnings should be well heeded even for ordinary Kerosene fueled rockets, much less something with an exotic propulsion system like this. It sure isn't going to be launched out of Central Park or any other urban center.
Besides, the CEO addressed this specific issue [escapedynamics.com] in an interview recorded a few months ago. Not only is the launch going to be far from cities, it will also need to happen in an arid region in part due to the microwave power being absorbed by water in the atmosphere. In other words, it is likely that this won't be launched from KSC in Florida either.
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Equatorial. Dry.
Got it! A use for the Sahara.
Bring On the Tin Foil Hats! (Score:1)
"Tin Foil Hats" is not PC (Score:4, Funny)
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Nonono. Not a hipster. The term that a hipster would have used would be "Tin Foil Fedora".
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Cain y'all jus' slow it dayown a piece? Sounz lahk y'all one o' them Hindoos, words comin' out ya pie-hole sa fas'.
Ah 'members when NASCAR was runnin' them Chevy Luminums.
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Poorly described (Score:2)
Re:Poorly described (Score:5, Informative)
There is a whitepaper linked from the company website:
http://escapedynamics.com/wp-c... [escapedynamics.com]
The short story
Microwave provides source of energy by targeting heat-absorbing material
Heat exchanger is used to heat and compress Hydrogen to 150 atmospheres
Hydrogen is fed to aerospike nozzle, which provide impulse thrust gt 750 seconds
Claims launcher will be able to provide 8% to 12% of total weight as cargo
Right now most of the website is pretty pictures and videos, time will tell
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http://www.foxnews.com/scitech... [foxnews.com]
http://thesis.library.caltech.... [caltech.edu]
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Is this thesis written with Word or something?
I thought scientists used LaTeX.
Re:Poorly described (Score:4, Interesting)
So, you don't need to carry an oxidizer. If you wanted to run a turbopump to do the same in order to generate thrust, you'd need to react it with something. Neat idea, nice Isp, no idea if it's actually practical.
IANARS (I Am Not A Rocket Scientist).
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IAARS (I am a rocket scientist) (see my wikibook if interested: https://en.wikibooks.org/wiki/... [wikibooks.org] )
Beamed power for space launch has been discussed for decades - I have several ring binders of data on the subject. Practical depends a lot on your power storage. Space launch of anything larger than a teacup takes a lot of power. For example, the three liquid engines on the Space Shuttle put out a combined 21 GigaWatts of power, of which 156 MegaWatts was just to run the turbopumps to shove the propellants
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It's not a new idea. It's been kicking around for at least 3 decades. Is it a good idea? Maybe. I've no idea how practical it is. Is it brilliant? No. The design, the implementation, may be brilliant, but the idea is a bit long in the tooth.
Like many ideas, the trick is getting a good working implementation, not the idea.
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Note that the sending array is huge. 1 sq km in the linked article. That means that the energy density of the beam is low, so you don't cook passing birds, but more importantly, don't waste energy heating up the water vapour in the air either. The receiving antenna also needs to be big. The bigger the better, so you can keep the efficient coupling over a long distance. In this case, long enough to get it to orbit.
The interesting thing about this idea is getting the high
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In this case the 'receiving antenna' is the belly of the spacecraft, which is covered in ceramic tiles designed to covert the energy into heat and act as a heat exchanger. This introduces interesting problems with targeting since the large ground array all needs to hit the same few hundred square feet of target
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A similar technique was tested successfully by japanese researchers in 2010 [technologyreview.com], except their rocket model used ambient air directly, instead of H2 in a tank.
I wonder what kind of performance it would get from using maser-powered water vaporization for propulsion ? Water vapor holds twice as much heat as air [engineeringtoolbox.com], translating into twice the ISP. It would be very steampunk, too... I now envision aerospike-like rocket engine gloriously steaming into the stratosphere on top of a microwaved plume of vapor.
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In a normal flight, the LOX is more than 50% of the weight, which is no longer needed.
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The important thing is not the cost of propellant, nor the absolute mass of the launcher, but rather how reusable we can make the launcher parts [blogspot.fr]. Reentering the atmosphere at orbital velocities means that a very lightweight, fragile launch stage will NOT survive to be reused. But if we can afford making that stage bulkier and sturdier, by sarificing part of a much higher fraction payload, it may.
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I think it is quite nicely described on escape dynamics homepage
http://escapedynamics.com/edispacelaunch/
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https://en.wikipedia.org/wiki/... [wikipedia.org]
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It is listed in my space transportation wikibook: https://en.wikibooks.org/wiki/... [wikibooks.org]
All rockets heat a propellant, then expand it from a chamber and nozzle to maximize thrust. Conventional rocket heat the propellant by combustion of the propellant itself. But if you have an external energy source, you can heat it that way instead. In this case, the energy source is a microwave beam, and the propellant is Hydrogen gas. Engines like the SpaceX Merlin have exhaust products of CO2 and water, since their prop
Good Idea, and a Possible Modification (Score:5, Interesting)
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.
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Re:Good Idea, and a Possible Modification (Score:5, Informative)
Picking a launch vehicle more ar less at random, an Atlas V grosses 334,500 kg (737,400 lb). Now, at 80,000 ft (24,400 m) the lift of helium is 0.0375 kg/m^3. Even if the balloon and suspension massed nothing whatsoever, it would have to have a volume of 8.92 million cubic meters - 44.6 Hindenburgs in size. Counter-intuitively but still most impressively, a sphere 257 m (840 ft) in diameter would do it. But then again, such a balloon and suspension sufficient to lift 334,500 kg would be anything but zero mass. Most high altitude balloons lift only a few hundred kg of payload at most, which is why they do not suffer from scale problems like this.
Hydrogen has a tad more lift, but only a few percent, so the ludicrousness of the scale would not be appreciably affected, plus you'd have to be damn sure you wouldn't have to worry about static buildup in the extremely thin plastic film of the balloon.
Using either helium or hydrogen, you'd have to figure out how to inflate such a colossal structure in the open without it being wrecked by the tiniest zephyr.
Now, since the whole idea is to reduce that 334,500 kg gross weight by saving on fuel mass, it wouldn't be quite that bad, but clearly bad enough to be a spectacular non-starter.
I am thinking an air-breathing ramjet winged first stage would have more potential. It strikes me as spectacularly stupid to use rockets, with a gigantic oxidizer flow rate when the atmosphere is full of oxygen, all the way from zero meters; especially during the first few seconds when the fuel and oxidizer is getting sucked out faster than a cheap hooker could dream of, while the vehicle is barely moving at a snail's pace.
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Then launch it underwater where the balloon has more lift.
-A Space Nutter who is a programmer and has absolutely no clue about the physical world but will defend any outlandish idea to the death
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I. also, was thinking of an airbreathing lower stage, but what I was thinking of was using this same design, only having compressed air as the takeoff engine. You don't get quite as much lift as you do with Hydrogen, but you also don't need to carry it with you, if you can design the engine so that the microwaves can also pump the air into the aerospike chamber. Save the Hydrogen for when the air gets thinner. Not sure if this would work, though. Or maybe it's just too complex for a first model.
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Not sure if this would work, though.
It won't.
Rocket scientists have been working on rocket science for over a century, they have a pretty good idea how to build rockets.
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You are much too certain. They know the characteristics of designs that have been tried with the techniques and approaches previously tried. To go from this claim to the blanket claim that you are making is far overstepping both the evidence and what any reasonable expert would say. (Not to claim that there aren't unreasonable experts. Some will claim that things will work, but more will claim that they won't. Often they will turn out to be right, but not always. And very few of even the unreasonable
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I. also, was thinking of an airbreathing lower stage, but what I was thinking of was using this same design, only having compressed air as the takeoff engine. You don't get quite as much lift as you do with Hydrogen, but you also don't need to carry it with you, if you can design the engine so that the microwaves can also pump the air into the aerospike chamber. Save the Hydrogen for when the air gets thinner. Not sure if this would work, though. Or maybe it's just too complex for a first model.
Like a ground powered beam heated pulse jet.
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"no real attempt to move the launch platform up to 80,000 feet or so using gas balloon technology. I would have thought this would be feasible, and could result in a substantial fuel saving."
The fuel cost of a launch to low orbits is not for the altitude, but for gaining enough speed to stay in orbit, i.e. about 8 km/s. The gravitational energy becomes significant if you need altitudes comparable to the earth radius (6400 km).
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laser driven models (Score:1)
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?
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None of it is going to be cheap. Garriott told me that the R&D phases up to suborbital flight are expected to cost about $200 million, and the total cost to scale up to full orbital flights will be around a billion dollars. Which means the capital for the next phases of their development will need to be raised as the company moves along its development path.
I dont think elon has anything to worry about yet in terms of competition yet though the design seems to not really be that much cheaper than conventional ones. Cheaper yes but not an order of magnitude cheaper. At the very least you would have an impressive weapon for defense with minor alterations.
It's a nice PR touch
Re:Good Idea, and a Possible Modification (Score:4, Interesting)
I'm sure they've thought of that. This isn't really a new idea, and the use of beamed power engines that switch from using atmosphere to carried fuel isn't new either (you can even use it in Kerbal Space Program with the right mods). The problem is that the molecular mass of air is quite high, and that reduces your specific impulse and thrust for a given power input. So to get the same thrust with air you'd need a bigger transmitter (probably much bigger). With rockets you usually need your highest thrust early on, because you're lifting more fuel, gravity is stronger, and you need to go more or less straight up. Later on you can get by with less thrust. Unfortunately, that's the opposite of what an air/fuel switching beamed power engine provides. You can get around that using a spaceplane design, but you still need to get up to speed and altitude while in range of your ground station... or build more ground stations.
They're probably looking at getting something working first, then building out the infrastructure to do more. That fits in with their plan to make a suborbital ship first: if you go basically straight up you're always in range of a single ground station, but you can't get into orbit.
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I recall this piece of animation: Odin: Photon Space Sailor Starlight They were using lasers in that piece of anime. Still this was 1985, so the idea is certainly not new, and I doubt that is the first instance of it either.
The popular reference in science fiction is The Mote in God's Eye [wikipedia.org], first published in 1974.
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That sure as hell remains to be seen. Some of us would see it as clinical insanity.
Made of Unabtanium (Score:3)
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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Frankly, that is a pretty stupid question.
If you have a "heat shield" absorbing microwaves to heat the rocket fuel, you have a "heat shield" for reentrance.
What would be the difference? It is just "heat"!
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In an HX thruster, liquid propellant is pressure- or pump-fed to a lightweight planar heat exchanger. For orbital launch, the propellant of choice is liquid hydrogen. H2 provides a vacuum Isp of 600 seconds, sufficient for a robust single-stage-to-orbit capability, at a heat exchanger temperature of only 1000 C (less than 2000 F). The heat exchanger can therefore be made of ordinary materials, rather than exotic high-temperature alloys, which allows building cheap expendable vehicles.
Kare, Jordin T. "Modular Laser Launch Architecture: Analysis and Beam Module Design." Final Report USRA (2004). [usra.edu]
This report is about laser heat exchanger launch system but should be valid. Dr. Kare has studied both laser and microwave launch systems [caltech.edu]. A single-stage-to-orbit vehicle does not shed tanks or stages. When it reenters the atmosphere is it a big empty tub with a very low cross-sectional mass density. The temperatures it encounters are dramatically lower than a capsule or the shuttle.
In other words
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Melting the Sea Gulls (Score:2)
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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.
Around 1993 there was a proposal to turn an old coal fired power station owned by the org I was working for into a gas fired power station using the existing stack. The exhaust temperature would have been hot enough to incinerate any overflying bats from the adjacent colony of a few hundred thousand large bats (flying foxes). Having that happen at sunset in view of a very heavily populated area would not look good. That was only one of a very long list of problems that made it impractical (really neede
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Popcorn (Score:4, Funny)
And fresh popcorn will be served when you get to obit.
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i've heard about these ground based power systems before with microwaves and lasers but what about the inverse square law?
Focus, coward, focus. Instead of following every direct tangent.
Reaction mass? (Score:2)
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.
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The MASER exists now so I don't know why they are not using that to put their microwaves in the right place instead of throwing most of them away - which once again makes it look like yet another For
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Because all MASERs are inefficient, and little progress has been made on that front. Conversely you can stack microwave antennas across huge areas cheaply and easily and as a bonus don't create a giant invisible air hazard.
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Their snakeoil is out of date (Score:2)
The second snakeoil clue is we are getting this from Forbes and not Scientific American or New Scientist.
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Because we finished doing that, we just didn't invite you. For obvious reasons.
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We haven't finished colonizing the ocean bottoms. We've barely started, and I'm not sure it's such a good idea. (It needs a lot more study than it's had so far before I'll say that. It could be an ecological nightmare. Space, OTOH, is only dangerous to the explorers....well, colonization of space is only dangerous to the explorers.)
So I consider the colonization of space to be a lot better. It's also true, however, that human occupancy of space is going to require a lot of technical development that ha
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See HBO's From the Earth to the Moon, episode 12, discussing how the TV camera on the rover was remotely-controlled from earth (operators trying to manually account for command delay, resulting in some missed liftoff footage on some missions.)
The rover had its own high-gain antenna for direct communication with Earth, including transmitting TV footage while the rover was stopped (audio only while moving, using low-gain antenna.)