Reply #31: Interesting Solaren patent from 2005

[bananas]

Solaren patent from 2005: http://www.google.com/patents?id=YEcVAAAAEBAJ&dq=Solaren
Free-floating reflectors instead of a massive rigid structure.
No assembly required.

One of the news articles said it will only take 4 or 5 launches to send the whole thing up. They didn't specify which rocket. According to wikipedia http://en.wikipedia.org/wiki/Comparison_of_heavy_lift_launch_systems
the Falcon 9 Heavy costs around $100M per launch carrying 30,000kg to LEO or 15,000kg to GEO.
4 launches would be $400M, total weight 120,000kg to LEO or 60,000kg to GEO.
For a 200MW system, the launch cost is $2/W, averaging 3.3W/g or 1.25W/g.

Getting from LEO to GEO, I only took a quick look at the Solaren patent, maybe they can act as solar sails.
Or maybe they'll use something based on this:

http://en.wikipedia.org/wiki/Variable_specific_impulse_magnetoplasma_rocket

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Based on data released from previous VX-100 testing<7>, we can expect that the VF-200 engine (to be installed on ISS) will have a system efficiency of 60-65% and thrust level of 5N. Optimal specific impulse appears to be around 5000s using low cost argon propellant.

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On December 10th, 2008 Ad Astra Company signed an agreement with NASA to arrange the placement and testing of a flight version of the VASIMR, the VF-200, on the International Space Station (ISS). Its launch is expected to be in 2011-2012.<8><2><9>

The ISS VASIMR engine will operate in burst mode. Since ISS's power generation is not great enough, the system will include a trickle-charged battery system allowing for 10 min pulses of thrust. This however, is expected to be sufficient to maintain ISS altitude, eliminating the need for costly, periodic chemical rocket reboosting operations.

Space tug : Orbital Transfer Vehicle

The most important near-future application of VASIMR-powered spacecraft is transportation of cargo. Numerous studies have shown that, despite longer transit times, VASIMR-powered spacecraft will be much more efficient than traditional integrated chemical rockets at moving goods through space. An OTV (space tug) powered by a single VF-200 engine would be capable of transporting about 7 metric tons of cargo from Low Earth Orbit (LEO) to Low Lunar Orbit (LLO) with about a six month long transit time. NASA envisages delivering about 34 metric tons of useful cargo to LLO in a single flight with a chemically propelled vehicle. To make that trip, about 60 tonnes of LOX-LH2 propellant would be burned. A comparable OTV would need to employ 5 VF-200 engines powered by a 1 MW solar array. To do the same job, such OTV would need to expend only about 8 metric tonnes of argon propellant. The OTV transit times can be reduced by flighting with lighter loads and/or expanding more argon propellant with VASIMR throttled down to lower Isp. For instance, an empty OTV on the return trip to Earth covers the distance in about 23 days at optimal specific impulse of 5000s or in about 14 days at Isp of 3000s.

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