Development of the mobile penetrometer (Mole) as sampling tool for the Beagle2 Lander on Mars Express 2003

The Mole, an hammer based penetrometer to be used as a sampling tool on the Beagle2 Lander (ESA Mars Express 2003 mission) was the object of several investigations, to identify the main parameters ruling its intrusion process and subsequently optimize and improve it. The working environment of the Mole (Martian sand-like soil) was simulated and fully characterized to allow repeatable test conditions. For this characterization a Piezocone able to detect the frontal force and the lateral friction during the penetration was also used. A Mole simulator was used for fast testing of the frontal resistance. Once a good and “repeatable” Mars simulant was obtained the Mole performed several intrusions and extractions. An accelerometer mounted behind the tip was used to investigate the dynamical behaviour of the Mole. From the data acquired it was possible to implement a mathematical model of the Mole, used to study the intrusion dynamics vs. the change of the internal and external variables. For sake of brevity, in the following paper just the most important results are presented.