The HP3 Radiometer on InSight

Abstract

Introduction: The Heat Flow and Physical Properties Package (HP³) includes an infrared Radiometer attached to the deck of the InSight lander. The main objective of this part of the instrument is to con-strain the surface thermal boundary condition for the heat flow derivation by the instrumented tether de-ployed into the subsurface. The heat flow in the subsurface can be affected by seasonal and diurnal temperature variations, by radiation from the lander, its shadow, and the change in surface albedo caused by dust removal during landing and later deposition. The radiometer will observe the seasonal variation over the course of the mission. Fitting of diurnal temperature curves provides an estimate of albedo and other thermophysical properties of the near surface.