Solar-pumped laser power transmission, a way to dramatically decrease launch costs?
in [Physics]
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From: Scott M. Kozel on 19 Feb 2010 23:37 William Mook <mokmedi...(a)gmail.com> wrote: > > INTERPLANETARY LASER LIGHT SAIL > > The 63 GW beam bouncing off a laser light sail that's 99.9% reflective > at the operating wavelength (1 micron in this case) beaming energy at > a 20,000 sq m disc (500 ft diam) that masses 1 metric ton and operates > at 420 Kelvin. This boosts a 103 ton payload at nearly 1 gee without > consuming ANY propellant!! > > So, the more compact vehicle lands and takes off using laser propelled > rockets. The vehicle then deploys a laser light sail to boost at 1 > gee through interplanetary space! > > So our 103 ton payload module equipped with a laser light sail, > operating in conjunction with our advanced solar power satellite > network, is capable of sending payloads efficiently across the solar > system. > > At 1 gee the moon is only 3 and a half hours away. The planets are > nearly all less than 2 weeks away using this fleet; > > Mercury 2 days 5 hours > Venus 1 days 15 hours > Mars 2 days > Ceres 3 days 20 hours > Jupiter 5 days 20 hours > Saturn 8 days 8 hours > Uranus 12 days 8 hours > Neptune 15 days 10 hours > > Though efficiencies (and thrust) fall off far from the Sun - without > some sort of lens system in place to recollimate the beams. > > Alternatively, larger diameter emitters may be built - and higher > energy levels - which mean larger thrusts. How much faster would those be if they used a superlaser?
From: Pat Flannery on 20 Feb 2010 02:31 Scott M. Kozel wrote:. > How much faster would those be if they used a superlaser? You also may want to slow down so you can land on them rather than hitting them while going full tilt under your 1g acceleration. So you had better double your transit times, as during the last half of the trip you will be slowing down: http://www.transhuman.talktalk.net/iw/TravTime.htm Pat
From: William Mook on 20 Feb 2010 13:16 On Feb 19, 5:40 pm, David Spain <nos...(a)127.0.0.1> wrote: > William Mook <mokmedi...(a)gmail.com> writes: > > So, the program here would be to; > > > (1) Acquire United Space Alliance and other Space Shuttle related > > Assets from NASA > > (2) Operate them to deploy advanced solar power satellites described > > here > > (3) Use the revenue stream to develop a propulsive laser satellite > > and spacecraft fleet > > (4) Deploy the satellite and fleet and retire the shuttle > > (5) Build a lunar village with the new fleet of spacecraft. > > Somewhere in there: > > (6) Profit!!! :-) > > Well, I admire your optimism, even if we don't agree. > > I have serious doubts concerning the practicality of the material engineering > in your plan, esp. the active cooling so close to the sun. (What is your heat > sink? You do have a place to transfer the heat to? Why do you *have* to be > so close to the sun? How do you keep electronics working at those temperatures? > etc. etc.). > > I would also prefer to see the shuttle still in operation until > something better comes along. I don't think this plan is it, but who's to > stop you? It's only money... > > I don't believe in it (SPS), I don't believe your numbers and I believe there > are cheaper energy options out there than SPS but that doesn't prevent me > from wishing you luck. > > Good luck, > Dave What is the heat sink? In vacuum its all done by radiant heating. That's why Stephan Boltzman is so important. Radiant heaters operating above 1600K would dump heat into the vacuum faster than the sun is dumping it into the system. That's the whole point. Diamond and graphite semiconductors would operate at these temperatures. You are correct that the materials are key.
From: William Mook on 20 Feb 2010 13:17 On Feb 19, 11:37 pm, "Scott M. Kozel" <koze...(a)comcast.net> wrote: > William Mook <mokmedi...(a)gmail.com> wrote: > > > INTERPLANETARY LASER LIGHT SAIL > > > The 63 GW beam bouncing off a laser light sail that's 99.9% reflective > > at the operating wavelength (1 micron in this case) beaming energy at > > a 20,000 sq m disc (500 ft diam) that masses 1 metric ton and operates > > at 420 Kelvin. This boosts a 103 ton payload at nearly 1 gee without > > consuming ANY propellant!! > > > So, the more compact vehicle lands and takes off using laser propelled > > rockets. The vehicle then deploys a laser light sail to boost at 1 > > gee through interplanetary space! > > > So our 103 ton payload module equipped with a laser light sail, > > operating in conjunction with our advanced solar power satellite > > network, is capable of sending payloads efficiently across the solar > > system. > > > At 1 gee the moon is only 3 and a half hours away. The planets are > > nearly all less than 2 weeks away using this fleet; > > > Mercury 2 days 5 hours > > Venus 1 days 15 hours > > Mars 2 days > > Ceres 3 days 20 hours > > Jupiter 5 days 20 hours > > Saturn 8 days 8 hours > > Uranus 12 days 8 hours > > Neptune 15 days 10 hours > > > Though efficiencies (and thrust) fall off far from the Sun - without > > some sort of lens system in place to recollimate the beams. > > > Alternatively, larger diameter emitters may be built - and higher > > energy levels - which mean larger thrusts. > > How much faster would those be if they used a superlaser? What is a superlaser? I'm using a free electron laser with a helical accelerator - in 2 dimensions - radiating into the third. PV cells on the sun side - laser window on the sky side.
From: William Mook on 20 Feb 2010 13:21
On Feb 20, 2:31 am, Pat Flannery <flan...(a)daktel.com> wrote: > Scott M. Kozel wrote:. > > How much faster would those be if they used a superlaser? > > You also may want to slow down so you can land on them rather than > hitting them while going full tilt under your 1g acceleration. > So you had better double your transit times, as during the last half of > the trip you will be slowing down:http://www.transhuman.talktalk.net/iw/TravTime.htm > > Pat 1 gee aceleration to the halfway point, then flip over - while under thrust - and 1 gee slowing for the other half so you arrive at zero altitude zero speed at either end. The transit times are based on that figure. Distance = 1/2 acceleration x time ^2 so time = sqrt(2*distance/acceleration) To the halfway point this would be time = sqrt(distance/acceleration) then double this because you're at the halfway point - but outside the sqrt function time = 2*sqrt(distance/acceleration) time = seconds distance = meters acceleration = 9.802 m/s/s This is how I calculated it. Bouncing the beam around, or placement of the satellites to get it to where its needed is an infrastructure detail that I didn't treat - but there' s no reason to limit performance with this tech. |