The exploration of Mars is going strong with the Curiosity Rover in Gale Crater and the Opportunity Rover on Meridiani Planum making great discoveries along with three active orbiters, Odyssey, Mars Express, and the Mars Reconnaissance Orbiter, plus MAVEN and India's Mars Orbiter Mission arriving in orbit this month. Europe has its plans for a mixed armada of orbiters, landers, and a rover in cooperation with Russia and even NASA is planning another Curiosity-class rover to launch in 2020. To add to this impressive invasion of Mars is another modest, but highly important lander, InSight, that has an assignment unlike any other spacecraft sent to Mars so far.

InSight is a stationary lander that will not be capable of roving, and will use sophisticated geophysical instruments to probe deep beneath the surface of Mars to measure seismic activity, heat flow, and Mars' wobble on its axis. This will give a clue on how Mars and the terrestrial planets formed and evolved. Mars is smaller than Earth, has less geological activity and no plate tectonics, so it retains a more complete record of its history in its core, mantle, and crust. InSight will seek to understand the formation of the terrestrial planets. No other mission to Mars has looked beneath the surface for seismic activity, which is especially necessary if there are to be manned missions and permanent colonies.

InSight is a NASA Discovery-class mission capped at $425 million, not including the launch vehicle, and uses the tried-and-true hardware and design of the highly successful Phoenix lander that discovered ground ice near the north pole of Mars in 2008. It will have two solar panels similar to Phoenix that will provide power and will have cameras to image the seismic probe and to take panoramic images of the landing site. Two instruments will perform the critical tasks: the Seismic Experiment for Interior Structure and the Heat Flow, and the Physical Properties Package. InSight's communication system will be used to provide precise measurements of the rotation and wobble of Mars. InSight will launch on March 8, 2016, or shortly after, and will land on Mars on September 20, 2016 with a planned operational lifetime of 720 days (one Martian year). An extended mission may be possible, especially if the spacecraft remains healthy and seismic activity is detected.

Landing will occur in a volcanic lowland called Elysium Planitia where the exact location will be flexible since the spacecraft will use rocket power to slow it down to a soft landing instead of using air bags or a sky crane. Landing on Mars is never easy even with the recent string of successes, so there will once again be several minutes of terror until a safe landing is confirmed. InSight may not be fondly remembered among planetary scientists as it beat out a highly favored mission to explore a sea on Titan during fierce competition in August 2012 in a tight budget environment. Diversity in exploring the planets is important when trying to determine the origin, evolution, and eventual fate of Earth. However, the internal workings of Mars are poorly understood and InSight is designed to unlock the mysteries and provide insight as to how Mars works, inside and out.