Craft That Will Probe Beyond the Surface of Mars.

NASA Mars Insight

The train to Mars pulls out only once every two years. That’s how often Earth and its neighbor move into alignment for the quickest possible journey from one planet to the other. NASA plans to make good use of the 2018 window, with the planned launch in May of the Mars InSight lander, which, as its name suggests, will give scientists their best look ever at the interior of the Red Planet. (The InSight was initially slated to launch in ’16, but glitches in its seismograph system led to delays.) Unlike Curiosity and other Mars rovers, this craft will stay in one place. But with good reason: it will hammer a probe more than 16 ft. into the Martian surface to study the planet’s thermal history—in effect, taking its geological temperature. Meanwhile, the seismometers will study Mars’ composition, an X-ray radio link will analyze wobble (the way Mars spins on its axis and is gravitationally tugged by other bodies in the solar system), and cameras will return panoramic and 3-D pictures. The space- craft should operate for 728 Earth days (708 Martian sols)—or until just about the time the 2020 flight is ready to go. —Jeffrey Kluger