MORO - A EUROPEAN MOON ORBITING OBSERVATORY

Provisional results are presented from the current ESA-funded Phase A Study of a Moon O Rbiting Observatory (MORO) which is one of five cand idates for selection as the third medium-class mission (M3) in ESA's H orizon 2000 Science Programme. If selected for development, MORO space craft will be launched in 2003 and targeted towards the Moon, where it will enter a nominal circular polar operating orbit at 100 km altitud e. During a mission life of at least 1 year in this orbit, global char acterisation of the Moon's topography, geochemistry and gravity will b e achieved. In the baseline mission concept (Option 1) a payload mass of about 80 kg will be carried on a spacecraft weighing about 1300 kg in total. A reduced ''smallsat'' version (Option 2) is also being inve stigated in which the payload and spacecraft masses would be reduced s ignificantly. In both options the scientific payload includes a high-r esolution stereo camera, a mapping spectrometer, a microwave instrumen t, and a geodesy subsatellite equipped with the means for accurate ran ge-rate determination with respect to MORO main spacecraft. The select ion of nadir-pointing 3-axis stabilisation as the preferred mode of sp acecraft control is just one of many important trade-off studies which has been carried out. Summary descriptions of Options 1 and 2 will be given with due emphasis on approaches that are being proposed to mini mise the total programme cost. Copyright (C) 1996 Elsevier Science Ltd