"We hope to try our first sodium detection experiments this fall, " Baumgardner said.

BBC: Close up on Mercury

Until then, Mr Baumgardner and his colleagues will just have to hang on.

ECONOMIST: Genetically modified crops

As the twin towers were coming down, he got a call from Susan Baumgardner, a fan, a woman he had briefly encountered 10 years before.

NPR: Conductor James DePreist