Development of the BepiColombo Laser Altimeter BELA

Abstract

The BepiColombo Laser Altimeter (BELA) is the first European Laser Altimeter for planetary exploration which has been selected by ESA for flight aboard of ESA's BepiColombo mission to planet Mercury. A consortium led by the Physikalisches Institut Bern and Institute for Planetary Research at the German Aerospace Center (DLR) will develop a laser altimeter based on the classical principle of laser pulse time of flight measurement. The instrument is based on a longitudinally pumped Nd:YAG laser with 50mJ pulse energy and pulses of about 3 ns pulse duration, operating nominally at 10 Hz repetition rate. BELA performs global topographic mapping with high accuracy of 1m and a surface shot to shot spacing in the range of 300m. Laser Ranging will be done at a distance up to 1000 km with a detection probability >70%. The ground footprint of the laser beam amounts to about 100m.