Fun Facts: The International Space Station's New Solar Panels

Reading through the many stories on NASA’s delivery of a new solar array to the International Space Station (ISS), I found myself curious: Who makes these cells? How effective are they?  What were the costs? Oddly, none of the coverage mentioned their origin, and it took quite a bit of searching to track it down in a week-old press release: Boeing subsidiary Spectrolab.

No big surprise there. Spectrolab specializes in high-efficiency solar cells, and only has one real competitor, Emcore, which is a significantly smaller company. And Emcore is not exactly bursting with energy. its stock is currently down to $0.77 from a high of $15.10 in Feb. 2008; if it slips much lower the company could lose its Nasdaq listing.

But, interestingly enough, the expensive array — pegged at $300 million by Reuters — is not exactly an active budget item for Spectrolab. The release mentions that the 45-foot truss segment has been sitting around at the Kennedy Space Center in Florida since late 2002. The space station itself launched in 1998.

Although the panels may sound expensive, compared to the overall cost of over $150 billion for the ISS, they’re just another line in a very large budget. In fact, the cost of simply getting them into space easily exceeded their purchase price. According to a Futron white paper, in 2000 the Discovery cost $300 million just to launch, and its price per pound of payload was $4,729, meaning the 16 ton panel and truss array would about another $150 million. Inflation adjusted, the total is about $550 million today.

Even with price as no object, NASA still managed to hurt itself by buying the panels, if only due to their timing. In mid-2000, around when Spectrolab would have been getting the contract to make the array, its cell efficiency record was at 29 percent. Today it’s at 41 percent. That’s a 70 percent increase, so it’s easy to imagine the array being significantly smaller (and thus easier to launch and install) if it used modern technology.

No need to cry, though. The ISS was launched in 1998, so its oldest panels are about a decade old now. On the ground, that would mean they were less than halfway through their period of optimum efficiency. In space, though, panels degrade much more quickly, because they’re constantly exposed to sunlight and can be damaged by debris and solar flares. That means the older panels are about 2/3 cooked.

So Spectrolab will likely get the chance to offer replacements soon enough. Unfortunately for it, by the time it does, there will be plenty of viable alternatives. Startups like Wakonda Technologies promise cheaper high-efficiency cells, while others, like Cyrium Technologies, say they can reach new efficiency records.

Of course, there’s always the off-chance that all of the above will be looking at a significantly-expanded market if we one day master space-based solar power. But don’t hold your breath; that would require per-pound launch costs to drop under $1,000, according to the Economist.