InSight/HP3

INterior exploration using Seismic Investigations, Geodesy and Heat transporT

Just six months after its launch in May 2018, the InSight lander touched down on the surface of Mars. The mission is part of NASA’s successful Discovery Program, and is, for the first time, intensively examining the interior of Earth’s planetary neighbour – its crust, mantle and core. While Earth has experienced many changes as a result of plate tectonics, Mars has undergone less radical change since its formation four-and-a-half billion years ago. Scientists are hoping that InSight will provide answers to questions regarding the earliest evolution of Mars and enable them to draw conclusions about the evolutionary history of both the Red Planet and Earth. The landing site in Elysium Planum is located in the northern lowlands, approximately 1500 kilometres south of the Elysium Mons volcano.

After the landing, the Seismic Experiment for Interior Structure (SEIS) started to record the seismic waves from ‘Marsquakes’ and to provide data to understand the planet’s history. The Rotation and Interior Structure Experiment (RISE) is registering very small changes in the alignment of the planet’s axis and allowing conclusions to be drawn about its interior structure. DLR has sent a heat flow probe to the Red Planet, namely the Heat Flow and Physical Properties Package (HP³). The probe is nicknamed ‘the Mole’ and has begun using an internal hammering mechanism to drive itself into the subsurface, with the goal of reaching a depth of five metres and carrying temperature sensors into the ground.

These sensors will supply temperature readings fully automatically and from various depths during an entire Martian year – the equivalent of two Earth years. An infrared radiometer will measure the diurnal temperature changes on the surface, and sensors inside the mole will measure the soil’s thermal conductivity. The combination of these data sets makes it possible to determine the heat flow from the planet’s interior. The instrument was primarily developed at the DLR Institute of Planetary Research and tested at the DLR Institute of Space Systems. Once InSight landed, DLR’s Microgravity User Support Center in Cologne took over HP³ operations.

German Aerospace Center (DLR)
Ulrich Köhler · E-Mail ulrich.koehler@dlr.de · dlr.de/en