HP3 – Heat Flow and Physical Properties Package

HP³ – Heat Flow and Physical Properties Package

The core component of HP³ is an instrumented, electromechanical 'mole', equipped with an active, and a passive Thermal Measurement Suite (TEM-A and TEM-P), as well as a combined accelerometer and tiltmeter (ACTIL), which uses an internal hammering mechanism to penetrate through the ground. The thermal probes are located on a five-metre long flat ribbon cable known as a ‘Science Tether’, which measures its temperature and gradient through to its maximum length. The Department of Landing and Exploratory Technology and the Department of Mechanics and Thermal Systems based in Bremen were both involved.

The instrument can carry out measurements that will provide answers to a whole range of fundamental questions in the field of planetary science, such as the development of former – and possibly even current – habitats, or how geological processes work. Prior to redefining the ExoMars mission at the start of 2009, which resulted in the cancellation of all geophysical experiments, HP³ was part of the Humboldt payload. During the Discovery Program led by NASA in 2012, the mole was selected as a payload for the InSight mission. Furthermore, other uses for the instrument have been identified, such as its use on the Moon (International Lunar Networks, etc.). InSight was launched en route to Mars on May 5, 2018, landing is scheduled for November 26, 2018.

The mole is based on the PLUTO mole (PLanetary Underground Tool), which was developed by DLR for the Beagle-2 mission. An internal hammering mechanism allows for the forward motion of the whole system (mole and Science Tether) into the ground. The mole contains the active thermal probe TEM-A and ACTIL, as well as the necessary electronics that are isolated by a damping mechanism from the high shock levels experienced when in use. The Science Tether enables energy and data to be transferred between the supporting frame and the mole, which stays on the support system. An Engineering Tether connects the support system with the lander. During the descent, the thermal and mechanical properties below the surface are measured at various depths. Once the mole has reached its final depth of three to five metres, the temperature gradient can be monitored along the drill depth over the course of several months. This, together with the measurements of the physical soil properties, will enable researchers to determine the heat flow from the inside of the planet.

External links:

http://solarsystem.nasa.gov/insight/home.cfm

http://solarsystem.nasa.gov/insight/videos.cfm?VideoID=4

https://de.wikipedia.org/wiki/InSight