NASA has narrowed down the potential landing sites for the agency’s upcoming InSight mission from twenty-two to just four. The four sites are close together in an area called Elysium Panitia near the martian equator.

InSight (Interior Exploration Using Seismic Investigations, Geodesy and Heat Transport) is a stationary lander that will study the interior of Mars. The lander will deploy a seismometer on the surface and will use a heat probe to penetrate into the martian ground. The mission will help astrobiologists understand how Mars was formed, and will provide valuable data about the evolution of rocky planets. InSight is currently scheduled to launch in March of 2016.

In the coming months, NASA’s Mars Reconnaissance Orbiter will gather additional information about the four candidate sites in order to help mission planners select the most suitable location for InSight.