NASA boffins are looking into making a science-fiction staple - the idea of transmitting power to spacecraft using lasers or microwaves - into reality. Sending enough energy to replace commonly-used present day space propulsion via laser beam would be quite a feat. One of the most powerful lasers in the world that's capable of …
Not quite correct
The piece talks about "it takes about 190 gigawatts to power the first stage of a Saturn V rocket"
This includes lifting the weight of the liquid hydrogen/oxygen fuel which makes up most of the launch mass. Since a laser launch system will leave the power supply on the ground the mass of the spacecraft will be MUCH less. It might be a good idea to have two or more seperate lasers, a power failure on take off could be nasty!
How come this increases satillite's "endurance" ?????
"This combination of technologies could be applied to space propulsion, performance and endurance of un-piloted aerial vehicles"
i really vomit when i read US military products come out... We have developed this weapon as lowcost, hight performance, swiftly deployable, quick reaction, all weather, adaptable, cuzstomizable and sustainable design. Like just this was the missing wand to conquer Iraq/Afghanistan and its news will make insurgents so heartbroken that they will start smoking all the heroine themselves.
Just where the F*** will lazer transmission increase a satillite's "endurance" ???? orbit endurance require thrusters which require gas not electricity to push path/direction. plasma engines can barely move half-kg right now .. res aside tons of satelliete insisting to remain in its velocity direction cuz of several kms per sec.
"Sending enough energy to replace commonly-used present day space propulsion via laser beam would be quite a feat. One of the most powerful lasers in the world that's capable of keeping a beam going for any length of time - Boeing's Airborne Laser Test Bed - can put out only a few megawatts of juice, but (according to El Reg's back-of-a-pint-coaster calculations) it takes about 190 gigawatts to power the first stage of a Saturn V rocket and 4.1GW to make a single Delta IV core rocket go."
That assumes you're also carrying fuel, which for most rockets is about 90% of the mass of the vehicle.
And think what great..
.. orbital death-rays a laser that big would make! And you can blame any small.. incidents on hackers too!
It's a win-win I tell you. Pork ahoy!
190 gigawatts is surely unbelievable
Any fool knows that you only need 1.21 gigawatts to travel through time, 190 gigawatts would surely mean the entire planet would travel back to the late 50s.
going back in time
Consider the american manned space programme.
Nothing now, the scuttle in the 80s, the moon landings in the 60's
They ARE travelling backwards in time.
You mean "jigga"-watts, surely
Lightning (or arcing in general) is a form of power transmission through the air, and it sort of makes a lot of noise. If this is to be used to beam power to/from earth, wouldn't that massive amounts of energy required mean lots of thunder-like noise? Of course, it makes much more sense if the energy transfer is limited to use only in space.
Because light is the same thing as electricity.
Actually you might have a point, I honestly have no idea if a laser that powerful is noisy or not, but you're still comparing apples and oranges. Worst case, you're only get a thunder like boom when you first power it on, there's no way a sustained beam is going to be nearly as load.
The thunder, of course, is the result of the static electric arc that is the actual lightning bolt (think of lightning as a close encounter with a doorknob on a dry day--magnified millions-fold) rapidly superheating the surrounding air, resulting in a pressure wave that reaches us as high-amplitude, low-frequency sound much like a big drum hit really hard.
The firing of a high-energy laser beam in atmosphere has the potential to produce a similar effect: depending on the circumstances of the beam and atmosphere.
The Light beam is likely to be juiced up while the launch vehicle is relatively close to the source, (on the ground) and extend relatively slowly as the vehicle moves upwards through to the upper atmosphere...
... so the superheating effect will occur over both a longer time period and a longer distance than that of the average lighting bolt. We may experience that effect as a vortex effect causing quite high winds as the heated air funnels up the length of the beam sucking in cooler air below it...
...home made tornadoes anyone? How's that for man made climate change :-)
A multi-gigawatt energy beam should also be handy for blowing up stuff, I reckon.
It may take 190GW to power the 1st stage of a Saturn V rocket, but surely most of that energy is expended in lifting all the fuel the rocket needs off the ground.
With laser transmission about 90% of the weight of the rocket is gone, as there is no fuel required.
How many others read GigaWatts and immediately thought of Back to the Future?!
The Doc would've sorted it by now!
Using light beamed from earth to power spaceships .... OK, but isn't there already quite a large source of light available for free.
However, if you wanted to develop a realllllllly power laser for other purposes, such as burning holes in other countries, this would be a great cover story.
Once you have the technology
there's nothing stopping you putting the power station in orbit (theoretically).
Plus 'Solar Wind' charged particles, electrons and plasma
Lots of light already in space, plus a stream of charged particles, electrons, cosmic rays and plasma eminating from the sun and other stars 'nearby'. Would have thought it would take LOADSA power from a laser on the earth or even in orbit to overcome those other sources. Like blowing through a straw towards a gale force wind?
Errm... Not that this make it *easy* as such, but most of the power of a standard rocket stack is lifting the rest of the fuel out of Earth's gravity well, right? It's got to be orders of magnitude easier to lift just the payload, and even easier to just accelerate it across interplanetary space, etc when it's already reached escape velocity (although still not easy, I'm sure).
I remember seeing the LightCraft research on TV a few years ago. It's a cute demo.
Blast from the past.
I did a presentation on that guy's work as part of my Physics degree 1997. I honestly don't think I've thought about it since. The lightcraft wasn't even being tested at that stage (as far as I remember). It followed on from his work on an ionizing antenna fitted to the front of aircraft to create a shockwave that would ultimately reduce drag on supersonic aircraft.
What goes up, can come down
I'd imagine that the general "beamed power" function is the main focus of this project, regardless of the actual direction the beam is pointed.
Solar panels in space is one of the directions we need to go in to wean off fossil fuels, and a big fat extension cable draped through the atmosphere isn't going to work unfortunately, so beaming down is the only option.
Wouldn't like to be anywhere near the focal point if the aiming system went down, mind.
I expect I'm the fourteenth person to say this...
...but all a laser would need to push to the moon is three astronauts, the command module and the lunar module. Not the squillion tonnes of rocket underneath.
Bundling a few thousand of those laser pointers should do the trick - there must be a mountain of them somewhere as they're now banned IIRC.
190 gigawatts to power the first stage of a Saturn V rocket
But isn't most of that used to lift the as-yet-unburned fuel, which won't be required if the laser is ground-based?
I assume that ..
this would still need a mechanism to harness the energy to produce the considerable thrust to get the payload off the ground.
The current electricity consumption of the whole of the UK is about 42GW
I think your coaster must have been rather soggy.
I thought the power transfer was supposed to go the other way (and include a "Microwave Oops" disaster).
Nuke explosion icon if they still let us do that :-(
No mention of sharks?
Anyway, this sounds like the perfect use case for nuclear energy. Assuming they get the basic tech figured out, a nuclear plant sounds like the ideal way of generating the required energy. If the Greens bitch about the nuclear plant, it can just be pointed out how much damage a conventional rocket launch does to the environment.
considering how frequently NASA, et al, screw up their calculations and are just a teeny-tiny bit off, who would want to be strapped to a spaceship that has such a powerful laser focused at them? Sounds like a recipe for disaster...
Unlike, for example, being strapped to several tons of continuously exploding rocket fuel? If you don't want to risk life and limb, perhaps being an astronaut is not for you.
DOC!!! That's one hell of a flux capacitor!!!
Anyone else notice...
Did anyone else notice how everyone always wants to be beamed up Scotty? Personally I think that's rather gross, I'll pass.
Not for lift-off
The difference between current laser power output and the "190 gigawatts to power the first stage of a Saturn V rocket" isn't as big a deal as is being made out, since they don't seem to be talking about using it for lift-off. The term they used is "space propulsion", which to me means shifting objects that are already up there. Not such an unlikely scenario, then.
There's several ways to do this, but the most feastible would be a multi-stage setup.
One lower-powered one on an equatorial country (I'm claiming Baja California as a good one.)
Another on the moon, this time far more powerful thanks to far easier power collection in the form of solar arrays in stragetic places.
Schedule the launches appropriately, and you can chuck stuff up to the lunar facility. From there, you can hold it til launch windows open and el blammo! You have an accelerating mass towards Elipson Erdani. Or whereever.
The tricky part is the deacceleration at the end...
> The tricky part is the deacceleration at the end...
Not necessarily: nearing the destination, launch forward, along the flight path, a second transmitter with smarts enough to settle down on a large mass (moon, or planet, for example, in the vicinity of where you're heading). The propulsion for that transmitter is built-in, of course; it beams the oomphs back at your vessel from mid-trip launch, partially decelerating your vessel even as the transmitter-cum-brake accelerates toward its target. Once settled, the transmitter pushes back from a much larger mass, and your vessel comes in at a useful, manageable speed...
Have I got the fissics broadly right? I think I should, since I'm cribbing from Clarke, or maybe Asimov (kinda).
If I'm way off MoonBase Alpha, then mine's the one with the Space Pockets.
The plan is to use the atmosphere as propellant and beamed power to heat it. This is much a much more effective way to get from the Earth's surface to low Earth orbit than building a huge propellant tank and using enormous amounts of propellant to lift the propellant.
1MW of beamed power puts 1kg of spacecraft into low Earth orbit. Here are some spaceship masses:
4547kg: Apollo Lunar ascent stage. (Takes you from the surface to the moon to lunar orbit).
14696kg: Apollo Lunar descent + ascent stages. (Take you from lunar orbit to the lunar surface and back again).
5560kg: Apollo command module. Holds three astronauts during their trip to lunar orbit and back. Has a heat shield and parachutes for re-entry into Earth atmosphere and a splash landing (Do not try this at home unless you have a large navy to rescue you afterwards).
44776kg: Apollo service module + command module + descent stage + ascent stage. Takes you from Earth orbit to the moon and back to the Earth (well, the sea anyway).
10809kg: Altair ascent module.
45864kg: Altair descent + ascent modules.
8500kg: Orion crew module (Holds 7 astronauts).
66864kg: Orion service module + crew module + Altair
Going to Earth orbit and back would require a 5 to 10 GW laser depending on whether you choose Apollo or Orion kit (Dragon is about 10000kg, Soyuz is about 7250kg). Going to the Moon in a single launch would require a 50 to 70 GW laser. If you can bolt the modules together in orbit, you could cut that back to 10 to 20 GW depending on how good you are at construction in orbit.
A Falcon 9 lifts 10450 to 26610 kg into low Earth orbit, so a 10 to 25 GW laser could do the same sort of things ie resupply the ISS or launch a commercial satelite with a rocket big enough to put it in geostationary orbit.
If you combine beamed power with VASIMR, you can substantially reduce the mass of the service module (20000 to 25000 kg) or low earth orbit to geostationary orbit transfer rocket.
I would seriously like to read the source material that this article is based on as I doubt anyone outside of DARPA believes using a ground based launch system is in any way feasible at the moment. Perhaps transmitting power to a craft already in space as a way of supplementing solar power collectors?
"I would seriously like to read the source material that this article is based on as I doubt anyone outside of DARPA believes using a ground based launch system is in any way feasible at the moment. "
You've never met Leik Marybo.
Where are Chris Knight and Mitch Taylor...?
They'll get it sorted out...!
Actually they want Jordin Kare on this one. He has the advantage of actually existing, and building real laser applications including working beamed power.
"Continuously shooting a gun at the ground and riding the recoil to orbit"
Much more sensible to ride the bullet.
Sorry Jules Verne, but No.
Good luck with ending up as anything other than a fleshy pancake if you're sat in something that is given enough oomph in one hit to get it into orbit. Even sat on top of a stack of exploding propellant over several minutes provides anough G-force to be severely unpleasant for the astronauts in question, one of the reasons they are expected to be in peak physical fitness.
put a massive dynamo inside the rocket and strap massive xenon thrusters on.. a stupid little dynamo with 25mph wind will give you 250kw
upscale it 190000000 x and your off
What you're saying is, it will still be far cheaper to use a Falcon 9. Since our current airborne laser project has eaten some 5 billion and managed to develop a 1 Megawatt(?) laser that can barely burn holes/ignite liquid rockets. So we only need 10,000 more of them?
Then there is the whole problem of how to catch a 10 GW laserbeam w/o exploding.
you need a laser shot into a octahedron polarizing prism with each new beam reflected off a few trillion mirrors and finally reaching a central point... or something
So DARPA want to fire a MW laser at things and make them blow up...
And NASA want to fire a GW laser at things and make them *not* blow up...
One of them is going to be awfully disappointed.
Rather confusing title...
While the project is called 'Ride the Light', it doesn't sound like NASA are proposing photonic propulsion at all; they want to transfer electricity to satellites and UAVs.
When they talk of 'space propulsion', they are most likely referring to station keeping for satellites and the like. Conventional thrusters require a fair bit of fuel for reaction mass which increases the size and weight of satellites; ionic thrusters require relatively little reaction mass – thus lighter, cheaper, longer lived satellites – but they do need a lot of electricity to function, which means either really, really big solar panels or nuclear reactors. Solar panels drastically increase drag – which is a problem, particularly for low orbit satellites – and while there have been a few nuclear reactors in orbit (and I'd bet there still are at least a couple of secret military ones) they seem to generate a fair bit of bad PR along with their megawatts. Both solutions are also very heavy.
If you could fire lots of power from a big power station on Earth at the satellite, it could have ionic propulsion without the difficulties of having to be attached to a massive power plant. If you had a good battery which could stand the cold of space, you could do away with any kind of solar, nuclear or radioactive-decay based power; if the satellite went out of view of the big ground laser, the battery would keep it going until it came back in range.
From what I can gather, then, the project is not about photonic propulsion, nor are NASA intending to use lasers to replace rockets. The only thing 'riding the light' would be power.
It's basically a project for a massive extension cable.
Sattelites generally only need to make course corrections periodically, so I doubt you'd even need the big battery. You'd be able to adjust orbits without risking them decaying quite happily on a daily (or longer) basis I would have thought.
Do not look directly at the operational end of the device.
They tried this in the movies once,....
and it killed everyone on earth except 3 people
Sounds an awful like the set up described in 'Future Histories' / 'High Justice' (can't remeber which) by Niven and Pournelle. Personally if we are borrowing ideas from science fiction I think we should go with the atlas drive option of detonating nukes under an upturned bowl...
...which is the one I always think of first when someone mentions 'NASA' and 'Orion' together.
Icon - Orion flavour (thermo?)nuclear pringles.
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