Could you leave everyone you love for the chance to settle on Mars? Sonia Van Meter describes herself as an "aspiring Martian" - she hopes to be one of the first humans on the planet in 10 years' time. But it would mean never seeing her husband again.
"I don't think you can apply for something like this and not be the tiniest bit insane," says Sonia Van Meter. "But this is the next great adventure, and I'm going to do absolutely anything I can to be a part of this."