InSight Lander

InSight was a mission unlike any other sent to Mars: instead of roving the surface or studying the sky, it was built to listen to the planet's interior. Its name stands for Interior Exploration using Seismic Investigations, Geodesy and Heat Transport. Launched by NASA in May 2018 and landing that November, InSight was a stationary lander designed to study the deep structure of Mars — its crust, mantle, and core.

Its centerpiece was an extraordinarily sensitive seismometer, placed directly on the surface to detect marsquakes. Over its mission, InSight recorded hundreds of these seismic events. By measuring how the vibrations traveled through the planet, scientists were able to map the interior of Mars for the first time, determining the thickness of the crust, the structure of the mantle, and the surprising size of the planet's liquid core. It was, in effect, the first time humanity had taken the internal pulse of another rocky planet.

Not everything went as planned. A heat-flow probe designed to burrow beneath the surface struggled with the unexpected properties of the Martian soil and never reached its target depth. But the seismic science was a triumph. Like all solar-powered surface missions, InSight's life was ultimately limited by dust; as its panels grew coated and power dwindled, the lander gradually went quiet, having rewritten the textbooks on what lies beneath the Martian surface.