NASA Down to Four Possible Landing Sites for Next Mission to Mars

NASA has narrowed the potential landing sites for its next mission the Martian surface down to four locations, the agency announced Wednesday. The semi-finalists were selected from a total of 22 candidates and all lie near each other on an equatorial plain in Mars's Elysium Planitia.

Set for a 2016 launch, the Interior Exploration Using Seismic Investigations, Geodesy and Heat Transport (InSight) lander will investigate the processes that formed and shaped Mars, offering insight into the evolution of the solar system's rocky planets.

For this reason, the lander's touch-down point is determined less by what is located on the area's surface, leaving the researchers free to focus instead on safety considerations.

"This mission's science goals are not related to any specific location on Mars because we're studying the planet as a whole, down to its core," Bruce Banerdt, InSight principal investigator at the Jet Propulsion Laboratory (JPL), said in a statement. "Mission safety and survival are what drive our criteria for a landing site."

For this reason, according to JPL geologist Matt Golombek, the leader in the site-selection process, the final four all boast "mostly smooth terrain, few rocks and very little slope."

Elysium represents one of three regions on the Red Planet that fulfills two basic engineering criteria for InSight, one being that it is close enough to the equator so as to provide adequate power to the lander's solar array. The other includes an elevation low enough to provide enough atmosphere to act as a cushion during the lander's descent.

According to NASA officials, the two other areas that meet these requirements are too rocky and windy to allow for a safe landing.

A second consideration in the case of InSight is what lies beneath th surface. The lander will require a penetrable ground in order to engage its heat-flow probe designed to hammer itself between 3 and 5 yards into the ground where it will measure the heat emanating from the planet's interior. For this reason, researchers have used images obtained by the Mars Reconnaissance Orbiter to determine whether the subsurface contains any rocks that could thwart the probe's digging efforts.

"For this mission, we needed to look below the surface to evaluate candidate landing sites," Golombek said.