15 Injection of a B ody into a G eodesic: Lessons Learnt from the   LISA Pathfinder C ase 

Daniele Bortoluzzid, M Armanoa, H Audleyb, G Augerc, J Bairdn, P Binetruyc, M Bornb, D Bortoluzzid, N Brandte,   A Bursit, M Calenof , A Cavallerig, A Cesarinig, J Conklinu, M Cruiseh, K Danzmannb, I Diepholzb, R Dolesig,   N Dunbari, L Ferraiolij, V Ferronig, E Fitzsimonse, M Freschia, J Gallegosa, L Gambinid, C Garci a Marirrodrigaf ,   R Gerndte, LI Gesak, F Gibertk, D Giardinij, R Giusterig, C Grimanil, I Harrisonm, G Heinzelb, M Hewitsonb,   D Hollingtonn, M Huellerg, J Hueslerf, H Inchauspec, O Jennrichf, P Jetzero, B Johlanderf, N Karnesisk, B Kauneb,   I Koekere, N Korsakovab, C Killowp, I Llorok, R Maarschalkerweerdm, S Maddenf, D Mancej, V Marti nk,   F Martin -Porquerasa, I Mateosk, P McNamaraf, J Mendesm, L Mendesa, A Moronit, P Nellenv, M Nofrariask,   S Paczkowskib, M Perreur-Lloydp, A Petiteauc, P Pivatog, E Plagnolc, P Pratc, U Ragnitf, J Ramos -Castroqr, J Reicheb,  J A Romera Perezf, D Robertsonp, H Rozemeijerf, G Russanog, P Sarrat, A Schleichere, J Slutskys, C F Sopuertak,   T Sumnern, D Texiera, J Thorpes, C Trenkeli, H B Tug, D Vetrugnog, S Vitaleg, G Wannerb, H Wardp, S Waschken,   P Wassn, D Wealthyi, S Weng, W Weberg, A Wittchenb, A Zambottid, C Zanonid, T Zieglere, P Zweifelj 

Abstract  

Launch lock and release mechanisms constitute a common space business, however , some science  missions  due to very challenging function al and performance requirements  need the development and  testing of dedicated systems. In the LISA Pathfinder mission,  a gold- coated 2 -kg test mass must be  injected into a nearly pure geodesic trajectory with a minimal residual velocity with respect to the  spacecraft. This t ask is performed by the Grabbing Positioning and Release Mechanism, which has been  tested on- ground to provide the required qualification. In this paper , we describe the test method that  analyzes the main contributions to the mechanism performance and focuses on the critical parameters affecting the residual test mass velocity at the injection into the geodesic trajectory. The test results are also presented and discussed.  

                                                     d University of Trento, Trento, Italy   a European Space Astronomy Centre,  European Space Agency, Madrid, Spain   b Albert -Einstein -Institut, Hannover, Germany   c Universite Paris Diderot, Paris, France   e Airbus Defence and Space, Immenstaad, Germany   f European Space Technology Centre, European Space Agency, Noordwijk, The Netherlands   g Dipartimento di Fisica, Universita di Trento, Trento, Italy   h Department of Physics and Astronomy, University of Birmingham, Birmingham, UK   i Airbus Defence and Space, Stevenage, UK   j Institut fur Geophysik, Zurich, Switzerland  k Institut de Ciencies de l'Espai, Bellaterra, Spain   l Istituto di Fisica, Universit_a degli Studi di Urbino, Urbino, Italy   m European Space Operations Centre, Darmstadt, Germany   n The Blackett Laboratory, Imperial College London, UK   o Physik Institut, Universitat Zuric h, Zurich, Switzerland   p SUPA, Institute for Gravitational Research, University of Glasgow, Glasgow, UK   q Department d'Enginyeria Electronica, Universitat Politecnica de Catalunya, Barcelona, Spain   r Institut d'Estudis Espacials de Catalunya, Barcelona, Spain s NASA Goddard Space Flight Center, Greenbelt, MD   t CGS S.p.A, Compagnia Generale per lo Spazio, Milano, Italy   u Department of Mechanical and Aerospace Engineering, University of Florida, Gainesville, FL v RUAG Space, Zurich, Switzerland  

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