171 A Multi -Sectioning, Reconfigurable Electromagnetic Hammering Propulsion   for Mole Penetrators  

Jerzy Grygorczuk*, B artosz  Kędziora *, Łukasz  Wiśniewski* , Marta Tokarz*, J. Krasowski*, Krzysztof  Bieńkowski1**, M. Drogosz **, R. Graczyk * and Marcin Dobrowolski*  

Abstract    This paper presents a new generation  electromagnetic direct drive for low-speed penetrator s, which  makes them  capable of underground mobility within regolith while carrying scientific instruments (such as  sampling tools or thermal  sensors) in planetary missions, where Mars and the Moon are the mostly  foreseen destinations. The propulsion combines new ideas and earlier achievements, both of which had  influence on the concept and would demonstrate the technology. A laboratory model d evice was  successively developed  and tested . Its principle of operation is based on electromagnets arranged in  stock and supplied with high impulse power by rechargeable and dischargeable capacitor . 

Introduction    Principle of  operation of penetrators  is based on interaction of three masses of the device (hammer,  casing and counter -mass),  between which the energy exchange is performed and as a result hammering  action is achieved.  Examples of mole- type penetrators include: mole penetrator for the Beagle II mission,  HP3 mole penetrator for the Exo- Mars mission (under development) , and prototypes of KRET -1 and  KRET -2 [1] mole penetrators developed by CBK PAN within ESA PECS projects. All of them have stroke  mechanical energy accumulated in their driving springs.  EMOLE is the first mole- type penetrator in which  the electromagnetic linear drive system has been  implemented. Since the mole penetrator  has been  foreseen as a carrier of a sample return system, electronics and sensors, its power settings  regulation  has allowed accommodating the power to the concrete soil mechanical properties and in many cases  saving sensitive components from higher, more destructive overloads. This was  possible through major  modification of the previous electromagnetic drive technology introduced in the MUPUS penetrator  [2]  (40-cm rod) onboard PHILAE for the Rosetta mission, CHOMIK sampling device for Russian Phobos - Grunt and the prototype High En ergy and Efficiency Penetrator . Thanks to the EMOLE project, new and  more accurat e simulations are being performed confirming that the novel concept of splitting a large  MUPUS- like coil into stack of  small coils is feasible without losing (or possibly even gaining) the energy  performance in comparison  to mechanical moles.  

Principle of  Operation    Like in the previously presented solutions, the propulsion principle of operation is based on the interaction  of three masses of the device  but unlike in all the previously developed mole penetrators, the force is  generated by a set of reluctant electromagnets arranged in stock and supplied with high impulse power in  sequence rechargeable and dischargeable capacitor .   The major novelty of propulsion concept is twofold – the penetrator has much higher  reliability of the  drive,  and its new drive system is able to have power settings. The first advantage is a consequence of a  mechanical simplicity of the drive. Foreseen is only one linear motion of the hammer instead of a number  of motions, which  are typical for the spring dri ven systems consisting of an electrical motor, reduction  gear box, rollers and screw -shaped surface (based on Gromov idea) or  helical screw, nut, special latch                                                    * Centrum Badań Kosmicznych PAN, Warsaw, Poland  ** Warsaw University of Technology, Warsaw, Poland  

Proceedings of the 43rd Aerospace Mechanisms Symposium, NASA Ames Research Center, May 4-6, 2016