Rotation and Interior Structure Experiment

[3][4] The radio science equipment is largely the same as used for the Mars Exploration Rover mission,[5] and it includes two medium-gain horn antennas (MGAs) on the lander deck, and an X band radio transponder (8 GHz) and transmitter inside the lander, where electronics can be shielded from the harsh conditions of space.

[5] In principle, after InSight lands on Mars, the lander reflects a signal sent from Earth, revealing its exact location and velocity in space.

[3][5] The goals of the RISE experiment are to deduce the size and density of the Martian core through estimation of the precession and nutation of the spin axis.

The precession and nutation estimates will be based on measurements of the relative velocity of the InSight lander and tracking stations on Earth known as the Deep Space Network.

The longer wobble, called precession, takes about 165,000 years and it is directly related to the mass and diameter of the iron-rich core.