On the possibility of measuring relativistic gravitational effects with   a LAGEOS-LAGEOS II-OPTIS-mission
  In this paper we wish to preliminary investigate if it would be possible to use the orbital data from the proposed OPTIS mission together with those from the existing geodetic passive SLR LAGEOS and LAGEOS II satellites in order to perform precise measurements of some general relativistic gravitoelectromagnetic effects, with particular emphasis on the Lense-Thirring effect. 
Lorenzo Iorio, Ignazio Ciufolini, Erricos Pavlis, Stephan Schiller,   Hansjoerg Dittus, Claus Laemmerzahl