Plasma-spaffing boffins plan spaceships driven by FRIKKIN' LASERS Russian boffins reckon with the right configuration, lasers can help make rockets more efficient, and could even herald an era of Mach 10 aircraft. Laser-driven propulsion isn't just the domain of the sci-fi fan. The aim of any rocket propulsion system is to take some kind of mass, and heat it up to generate thrust. The amount …
With today's tracking capability it is no problem to track the rocket engine.
http://www.youtube.com/watch?v=5_9ac-w4DW8#t=40
The tests I saw used hot air blasted by the laser to power the jet. No fuel was needed except the electricity to power the laser. The laser can be based on the ground by a fixed point, and track the engine for thrust. Science like this may save huge amounts of fuel for the regular aircraft industry, as it could aid in liftoff, which is where most of the fuel is burned in the first place.
So... big tank full of fuel & oxidant and someone's going to point a big laser at it...? Well, the video will be fun, at least. I like explosions. (/humour-off)
Seriously though, high-powered lasers are still off in the distance, the power requirements are huge and there's a lot of work to do before you can effectively shoot a laser up a rocket's bum while it's moving without going off-target and causing an oopsie.
My opinion, for what it's worth, is that by the time they get all the bits together to make this work, we'll have low-cost rockets and spaceplanes plus enough orbital infrastructure to make this method unneeded.
Now lasers and solar sails in deep space ala Robert Forward's Flight of the Dragonfly, now that's something I'd like to see...
?? I don't remember that, but must be 25 years since I read it. I do remember (who could forget!) that Footfall used Project Orion style Nuclear bombs as a propulsion.
"The Mote in God's Eye" (Larry Niven and Jerry Pournelle, 1974) has an awesome ground based laser speed a Light sail propelled craft. The 1990 approx sequel is good too.
In the novel, the humans manage to take out a laser not long after a Fifthp ship launches, causing it to lose thrust & so crash.
While hostile military action isn't likely, the chance of a power-outage or BSOD shutting the laser down and so causing a loss-of-vehicle is something to worry about...
What source of energy would those lasers use? Anything below a thorium reactor would seem inadequate. I mean, the experimental airborne lasers and their 'batteries' fill most of the innards of a 747, and they only carry enough energy for a few shots. The source of energy for this should be able to work for several minutes (in the case of rockets) or for several hours for jets.
Yeah this article doesn't really make clear whether the laser is onboard the rocket, or ground based and pointed at the back of the rocket?
I think this is an interesting hybrid between a normal chemical rocket, and proposals to just use a ground based laser to heat a fairly inert mass such as helium or nitrogen.
An onboard laser would probably require an incredibly dense power source such as a molten salt thorium fission reactor or fusion reactor...
I think fission reactor powered rockets would have the same controversy of what happens if they crash as did the proposed nuclear powered drone aircraft a few years back.
"The abstract and the other link talk about the laser being ground based"
Yes, but how would you set up a ground based laser to work in this fashion with a jet plane? Even with rockets working in the atmosphere, their trajectories aren't usually vertical, so you would be pointing at the rocket's nozzle with a significant angle, which would cause an asymmetry in the impulse, which is probably a bad thing for this scheme.
Other options include intense arc lamps, but all systems will need substantial power systems.
There is a reason why people use rockets and drive them with combustion driven turbo pumps.
They generate huge power levels in compact systems.
It is pretty clear that a ground-based laser would never work adequately to consistently power a jet. You would need a wide spread network of laser bases - (planetary defense bases when not employed propelling aircraft). The obvious alternative would be an onboard system with a highly efficient power supply. Such a system would have several major advantages. For one thing, the inverse square law says that the nearer the beam source is to the target, the less energy at the source is required to deliver a given amount to a target, so distances of fractions of a meter would be less costly in energy than distances of kilometers. Clearly, small, powerful laser sources would be a better solution than even multitasking planetary defense bases.
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