Mars is set to play host to another robot. The InSight (Interior Exploration using Seismic Investigations, Geodesy and Heat Transport) mission, announced yesterday in a NASA press conference, will launch in March 2016 and land on the red planet on September 20 of the same year. Unlike Curiosity, InSight is a stationary scientific platform, based largely on the highly successful Phoenix probe, but with a much broader mission.
The Mars rovers (Sojourner, Spirit, Opportunity, and Curiosity) were designed for surface chemistry and geology work, but there are many unknowns when it comes to the Martian interior. Mars occupies a special niche in the Solar System: it is relatively Earth-like in terms of composition and probable internal structure, but smaller and far less tectonically active. (A recent paper has claimed the discovery of Martian tectonic plates, but that assertion is controversial.) In fact, because Mars is less active than Earth, its interior may preserve its history far better than our home world, revealing new insights into the formation and evolution of terrestrial planets.
InSight will contain seismic instruments, heat-flow probes, and gravitational detectors, built by American (JPL), French (CNES), Swiss (ETH), British (Imperial), and German (DLR) laboratories. Together with a powerful drill, these instruments will provide data about Mars' shape, rotational wobble, internal temperature, and density. Particularly, InSight should be able to determine the properties of the planet's core and mantle, through the reflection and refraction of seismic waves through Mars' interior. Coupled with data about the history of water on Mars, this mission should help us gain a more complete picture of the history and structure of terrestrial worlds.
InSight is a Discovery-class mission, a highly successful NASA program initiated in 1992 to send relatively inexpensive robotic craft into space. Other Discovery missions include Dawn (visiting the asteroids Vesta and Ceres), MESSENGER (in Mercury orbit), and Kepler (the exoplanet-hunter).
Unfortunately, budget constraints at NASA limited the number of possible missions to support in this cycle, so in choosing InSight, other equally worthy programs were not funded. With the huge successes of other Discovery probes and the enormous public response to Curiosity's landing, there seems to be a need for more rather than fewer missions. Perhaps InSight will help inspire such an investment, as it probes into the history of our Solar System.