NASA’s new overarching goal should be to lead the joint public-private development and deployment of space-based solar power as a baseload power source. It’s a goal that would encompass many other technologies (non-rocket launch methods, AI-based robotic assembly in space, mining of lunar and NEO resources, lunar base operations, energy conversion and transmission methods, etc.) and inspire young people get advanced educations and be a part of making the planet a better place for everyone, much like the Apollo program did.
The unique aspect of NASA adopting space-based solar power as an overarching goal is that the long-term result would be a revenue positive system owned and operated by the United States of America. We would become a net exporter of clean, virtually unlimited energy.
Prohibitive launch costs are cited as the primary roadblock to space-based solar power today. Let’s come up with an elegant solution, such as a mass driver launch system initially powered by terrestrial solar power and eventually powered by the first space-based solar power satellite. It’s a positive upward spiral. The more power available, the more payload put in orbit and assembled into additional satellites resulting in more power available … and repeat. Once such a self-proliferating system harvests more energy than it uses, the excess energy can be directed into existing or new distribution grids.
Citizens for Space Based Solar Power 
Demanding decisive action from politicians at this stage seems neither realistic nor fair. There is no organization capable of taking on a project of this magnitude, or of executing it. And it’s real hard to put one together, too. The enthusiasts of both SBSP and non-rocket launch technologies (which are hardly viable without each other) are independent thinkers with natural aversion to management, bureaucracy, and the kind of massive organization one needs to pull this off. I’d love to see at least some attention paid to the practical management aspects of the SBSP approach, for without a path forward, it will always remain no more than an elegant mental exercise. Who are the politicians supposed to fund to develop SBSP? Is it going to be public or private? Who is going to own what? Who is going to manage what?
Good points and appropriate questions, Alex.
Expecting decisive action from politicians on anything of importance these days seems a bit too much to wish for. My opinion is that the U.S. Government should use taxpayer dollars to do at least some of the preliminary research to prove that space-based solar power is a viable endeavor. The U.S. Government should also spend some of our hard-earned money creating an environment to encourage private-sector development and deployment of space-based solar power. The precedents for such public-private efforts I see cited most often are the Pacific Railroad Act of 1862 and the Communications Satellite Act of 1962. Let’s hope we don’t have to wait until 2062 to see a SunSat Act (as outlined by the Space Solar Power Workshop at Georgia Tech) passed.
As for ideas on a path or paths forward, if you haven’t read it already, you might find the recent IAA report, The First International Assessment of Space Solar Power:Opportunities, Issues and Potential Pathways Forward, of interest.
Thanks for taking time to enter the discussion about space-based solar power here.
The launch cost problem is solvable given that the goal is accepted and the project is done at the proper scale. The scale to consider is supplying a significant, say 10% of baseload power by 2035. Doing this with nuclear or other options can be calculated. We would be talking at least a couple trillion dollars of investment. Achieving say $150 / kg launch costs could then be achieved on a defined timeframe. There were fully reusable launch options cosidered when the shuttle was being designed that per a recent article would have provided launch costs at that level. Low launch costs require frequent launches – a requirement for large-scale assembly in space.
I believe that the launch cost issue is solvable, too. Frequent launches with chemical rockets may not be the solution, though. While this is rocket science and I’m not a rocket scientist, a mass ratio (wet mass:dry mass) of even 10:1 means that we’d have to burn at least ten times more fuel than the huge amount of material that would be required to build even one space-based solar power collector. For reference, I believe the mass ratio of the Space Shuttle was about 16:1. The cost and environmental impacts of burning this much fuel may be difficult to surmount.
My thoughts include a mostly electric-powered launch system with vehicles approaching a mass ratio of 1:1. These nearly ballistic vehicles would carry the bulk of construction materials into space, perhaps 100 to 1000 kilograms at a time and launching on an hourly schedule. More conventional launch systems would supplement the program for sensitive components and humans, when necessary.
While I have a mechanical engineering degree, I’m much closer to a science fiction writer than I am to a rocket scientist so not knowing all the reasons this “can’t be done” doesn’t limit my imagination.
There are several ways to solve the launch problem, but they all depend on higher exhaust velocity than you can get from chemical fuels. Still, even with these, a mass ratio of 1 is really hard to do.
Incidentally, 1000 kg/hr isn’t even close to what is needed. At 5 kg/kW, a GW takes 5000 tons of parts. It takes over 60 tons per hour to get to the 100 GW per year production rate.
Skylon will put 30 tons in a suborbital trajectory where is can be picked up and put into geosynchronous transfer with 500 MW of lasers run full time. I went into considerable detail here: http://www.theoildrum.com/node/7898
There might be other even less expensive ways to do it with microwaves powering the first step and lasers the second. It is tricky with microwaves because you have only a limited time when the vehicle is in view and in range.
If you can make the engines light enough, it really pays to use air part of the way up. That’s the reason Skylon gets any payload to LEO at all.
Thanks for the basic figures that lead to the required launch mass rate … it helps me to understand the magnitude of the launch problem much more accurately. Also, thanks for the link to your excellent article on TOD. It’s the best reference I have read since the 2007 NSSO study. I read down through the extensive comments, both supporting and opposing, and I’m still on the “supporting” team!
Installed power plants in the US are around a TW, worldwide maybe 5 TW. 10% would be 500 GW. Considering that the smallest practical power sat production rate would be around 100 GW/year, that only 5 years of production.
Done at the most economical rate (which is fast) the transport system could be in place 5-7 years after starting. Power sat production would be up to the 100 GW/year by 8 years in. But the amount of power needed to replace oil with synthetic fuels is in the 10 TW range, so there is plenty of reason to grow the production rate by to at least a TW of new power sats per year.
I am all for it, but thing would have to change at the policy level.
DoE doesn’t do space projects and NASA doesn’t do energy.
See Peter Sage’s TED talk about this.
Keith Henson
Keith, I agree that the “energy not space / space not energy” policy conflict exists between DoE and NASA. (I posted Peter Sage’s talk on this blog last year.) Of all the challenges facing space-based solar power, a policy change by Congress seems like it would be one of the least expensive to address. The biggest challenge seems to be instilling the will for Congress to act on this potentially game-changing technology. We just have to keep after them.
If you really want to “instill the will” in Congress, I think you are going to have to start with the organizations and people who “instill the will.” Exxon and BP at present don’t seem likely. Chevron and Shell might be more likely to consider this as a long range approach to a supply of synthetic oil. Shell in particular makes a lot of synthetic fuel out of natural gas. The plants would work just as well on electrolytic hydrogen and CO2 out of the air. For a capital cost of $10 per bbl (scaled off the Sasol plant in Qatar) and penny a kWh power, they could make synthetic oil for $30/bbl. Two cent power would make $50/bbl oil. The key to power this inexpensive is $100/kg to GEO. I make a case that physics permits this.
Do you know about NASA’s entry into beamed energy? There has been no PR about it.
The key to the whole space-based solar power question seems to be cracking the launch cost puzzle … at least until we have the good sense to set up a lunar base from which to mine raw materials, process them and launch them to GEO from a much shallower gravity well. Thanks for the note about NASA’s power beaming entry … the competition I found online seemed to be about beaming power into space for several applications instead of the other way around!