When the Russians sent up Sputnik, it had a battery that lasted for two weeks. When the Americans sent up Vanguard, it had a solar cell from Bell labs on it, and it lasted for six years. Solar works in outer space. It's extremely reliable.
I was at a conference recently talking to an expert scientist from the NREL. I was saying that I wanted a really good date, and I asked how long these things really last. If they're built properly, he said that they don't know, but it's probably at least 40 or 50 years. In fact, to use an example, and I'll touch a bit on innovation shortly—