The Earth has almost half a million different species of beetles. Mars, seemingly, has none. But it has had, and still has, robotic landers, rovers, beetling across its surface, making videos to radio back home to Earth, sampling the dust and the scanty gases that float above it, listening for vibrations that travel through the innards of the planet. And these rovers make Mars the most studied planet, after our own. Plans, though not yet finalized, are in place to send humans. There is a lot of planning still to do. The very fastest, but probably most expensive, round trip would take at least 8 months, with just a short length of time for exploration once there. And the journey requires lots of life-support systems, starting with air itself, maintained at the right mix for human breathing. On arrival, there is no opportunity to step out from the confines of the spacecraft to stretch the legs or to pop behind a boulder for a little bladder comfort—not without a lot of protection. Mars has an atmosphere, but it’s weak and thin compared with the Earth’s, and it has no oxygen. It also provides little protection from the Sun’s UV or the solar wind of energetic particles – a wind that can penetrate a human body, leading to radiation sickness. The challenges are considerable, but the venture is possible. It’s just that the planning will have to be the best.