Exploring the Inferno

Despite their hostility, Mercury and Venus are targets for future exploration. NASA's MESSENGER mission orbited Mercury from 2011 to 2015, mapping its entire surface and confirming water ice in permanently shadowed polar craters — deposits first detected by Earth-based radar in 1991. The BepiColombo mission, a joint European-Japanese effort, is currently en route to Mercury for an even more detailed study.

Venus exploration is experiencing a renaissance. NASA selected VERITAS and DAVINCI missions to study Venus in the coming decade. DAVINCI will drop a probe through the atmosphere, sampling gases on the way down. Private companies have even proposed balloon missions to explore the cloud layer.