The Return of Space-Based Solar Power to the Conversation?

Back in the 1970s a great deal was said of the prospect of space-based solar power--of massive arrays of photovoltaic solar panels placed in orbit which would transmit the electricity they generated back down to Earth, with Gerard K. O'Neill famously offering a particularly detailed proposal of the type in that '70s-era space development classic The High Frontier. (The tired sneer of the renewables-bashers is that the sun does not shine all the time. But the sun really does shine all the time in space, permitting a much more consistent and greater output from solar panels situated in orbit than on Earth.)

Of course, no such project ever materialized. There were many reasons for that, among them the unswerving commitment of business to fossil fuels, and government commitment to business' reading of its interests (which, to the lament of those concerned for climate change, endures almost unaltered). But there was also the reality that a crucial part of such plans--given the sheer amount of infrastructure that had to be constructed in space--was bringing down the very high cost of space launch. Key to this vision generally, and O'Neill's vision in particular, was the expectation that the space shuttle--which was, as the name indicates, expected to indeed be a shuttle, with a rapid turnaround time providing very regular Earth-to-orbit transit --would produce a drastic fall in space launch costs, with three to four flights a month thought plausible.

Alas, rather than three or four flights a month the shuttles we got in practice could at best manage three or four flights a year--while as the fate of the Challenger and Columbia tragically showed, the risk of their failing to return safe and sound from a mission was well over one percent. As might be expected, the space shuttle was anything but a "shuttle," and while the cost estimates vary greatly, absolutely no one regards it as having cut the price of space launch the way its proponents had hoped. The result was that any attempt to utilize space-based solar power on any significant scale was prohibitively expensive in the circumstances.

Still, the idea never altogether went away, and has received renewed attention in the wake of a British government proposal to pursue such a project. Plausibly also contributing to this attention are the claims by sympathetic analysts that SpaceX has succeeded in achieving lower space launch costs (not nearly so low as O'Neill had banked on--five times O'Neill's figures, in fact, $2500 a pound or so to low Earth orbit as against the $500 or so O'Neill had in mind--but still a considerable improvement); while photovoltaic solar panels have become an ever cheaper way of generating electricity (indeed, the cheapest ever), as well as thinner and lighter, with all that implies for the possibility of designing lighter, more compact and therefore more cost-effective space-based arrays to cut down on cargo size and launch cost.1

I am generally sympathetic to both space development, and to renewable energy, but I also have to admit my doubts in regard to this particular combination of them--in part because every gain in the efficiency of solar panels that makes electricity production from space-based solar cheaper and more efficient also makes terrestrially-based solar cheaper and more efficient, minus the immense launch costs, and the difficulties posed by the continued lack of convenient, regular physical access. (Earth orbit is a crowded, dangerous place--and a massive investment in such a project if we do not have the capacity to effect repair in the case of accident or a collision with a meteorite or piece of space debris seems problematic at best.) Especially barring a much more drastic fall in launch costs than have been claimed by even the most sympathetic for SpaceX; or the advent of the kind of robotics capability that would make humans completely unnecessary to the construction, maintenance, repair of such an infrastructure; or preferably both; it seems to me impractical. Indeed, for the time being it seems to me the safer course to develop solar power on Earth, with RethinkX's "Clean Energy Super Power" concept seeming to me a more compelling approach to the problems posed by the intermittency of solar-generated electricity--and deserving of far more attention than it has received to date.

1. O'Neill's 1976 book estimated that the cargo variant of the space shuttle on which he was counting would get cargo up to low Earth orbit at the price of $110 a pound. Adjusted for inflation using the Consumer Price Index $110 in 1976 would be the equivalent of about $520 in 2021.