Analysis of surface composition of a Martian moon with the instrument LIMA-D onboard the Mars mission PHOBOS

First results obtained with the MPI supported laboratory setup of a long distance time-of-flight mass-spectrometer confirm the applicability of the method to use laser-ionisation for remote analysis of small celestial bodies. After ratification of the treaty on Soviet-German cooperation in science, a grant by the BMFT enables us to participate in the LIMA-D flight instrument. We have now improved the operating system for the instrument and the data collection algorithm. In the laboratory we set up a unit to check the response of a multiplier system to complex input currents as they occur e.g. in the case of a mass spectrum. As laser-ionisation is a highly non-linear process, where ion yields depend on a lot of parameters, an extensive laboratory study, in which we cooperate with colleagues from IKI in Moscow, FMI in Helsinki, and the University of Kaiserslautern, shall give actual ion yields and ion energies for the range of laser and focus conditions used in the PHOBOS flyby configuration. These data shall be available when the flyby takes place in December 1989. (orig.)