First Results from the Rotation and Interior Structure Experiment on the InSight Mission to Mars

The Rotation and Interior Structure Experiment (RISE) on the InSight mission uses the lander's X-band (8 GHz) radio system in combination with tracking stations of the NASA Deep Space Network (DSN) to determine the rotation of Mars. We will cover the results from the first Earth year after landing. The first day of DSN data was sufficient to provide an accurate position for use in scheduling images of the lander from orbit. The difference between the position derived from DSN tracking from the position determined from orbiter images may, in part, be related to the evolving definition of longitude on Mars. The first year of data provides an improved estimate of the Mars precession rate. This gives an improved estimate of the total polar moment of inertia that constrains interior structure models. The second Earth year of data is expected to allow observations of the effect of the interior structure on the Mars nutation, providing significant additional constraints on interior structure.