Obama Transition Team Examining Space Solar Power

DynaSoar writes "President-elect Obama's transition team has published for public comment a white paper entitled Space Solar Power (SSP) — A Solution for Energy Independence & Climate Change. The paper was prepared and submitted by the Space Frontier Foundation and other citizen space advocates, and calls for the new Administration to make development of Space Solar Power a national priority. The SSP white paper was among the first ten released by the Obama transition team. It is the first and only space-related white paper released by the team to date. With 145 comments thus far, it is already among the top five most-discussed of the 20-some white papers on Change.gov."

Comments

From The Economist

[airfabio]

Recent space solar power article from The Economist

http://www.economist.com/science/tq/displaystory.cfm?story_id=12673299

Re:Numbers?

[rbrander]

I read the Economist article and noted the name of the scientist ("Mankins") who researched it.

I typed "mankins microwave transmission efficiency loss" into Google and the second link was an IEEE article with the abstract appended below.

Your number is 45% for DC-to-
DC.

So not assuming that solar-cell efficiency can make it to 50%, but cheerfully assuming that the kind of cells that will do well in an industrial setting space for long periods can reach today's in-the-lab max of 40%, your area comes to:

560 km^2 / 40% / 45% = 3111 km^2.

And so what? There's a lot more space than that out there. (See opening paras of Hitchhiker's Guide for how much.) The question is the available money, not the available space. Those 556GW of nuclear had a total capital cost of well over a trillion. (And a land area sucked up of well over 3111 km^2 by the way, add up all the mines and waste dumps and reprocessing facilities, not just the plants. And that's area we can use for other things, down here; not a lot of other things to do with 3111 km^2 of orbit.)

The Economist article is unequivocal: SSP would cost FIFTY CENTS per kWh. That's just awful, way worse than earth-based solar or wind, even backed up with 85 watts per 100W so that they are base-load capable.

But one lives, and allocates research dollars, in hope. I'd bump the fusion budget from $300M to $500M, and match that with SSP research funds...about $400M of which would go to "cheaper lift costs", the truly key barrier.

Space solar power programs and microwave wireless power transmission technology
McSpadden, J.O.; Mankins, J.C.
Microwave Magazine, IEEE
Volume 3, Issue 4, Dec 2002 Page(s): 46 - 57
Digital Object Identifier 10.1109/MMW.2002.1145675
Summary: Future large-scale space solar power (SSP) will form a very complex integrated system of systems requiring numerous significant advances in current technology and capabilities. Ongoing technology developments have narrowed many of the gaps, but major technical, regulatory, and conceptual hurdles remain. Continuing systems concept studies and analyses will be critical to success, as will following a clear strategic R&T road map. This road map must assure both an incremental and evolutionary approach to developing needed technologies and systems is followed, with significant and broadly applicable advances with each increment. In particular, the technologies and systems needed for SPS must support highly leveraged applicability to needs in space science, robotic and human exploration, and the development of space. Considerable progress has been made in the critical area of microwave power transmission. At 5.8 GHz, DC-RF converters with efficiencies over 80% are achievable today. Rectennas developed at 5.8 GHz have also been measured with efficiencies greater than 80%. With optimized components in both the transmitter and rectenna, an SPS system has the potential of a DC-to-DC efficiency of 45%.