The BELA laser altimeter on ESA’s BepiColombo mission

The BELA laser altimeter
The BELA laser altimeter on ESA’s BepiColombo mission
BELA is the first European-made laser altimeter for a planetary mission. It provides information about the global shape, rotation and topography of Mercury. In Mercury orbit, a neodymium-doped yttrium-aluminium-garnet laser will transmit 10 laser pulses per second towards Mercury via the transmitter (left in the picture) at a height of less than 1000 kilometres and, after a few milliseconds, will receive the signal reflected from the surface in the focal point of the BELA telescope (right in the picture). The telescope has a diameter of 20 centimetres and the entire system including electronics has a mass of 15 kilograms. The higher a landscape point is located, the shorter the time required for the laser pulse to travel to the surface and from there to BELA’s sensor. From the duration of millions of laser pulses, a 3D model of the entire surface of Mercury will emerge in the course of the mission. In addition, researchers can use the shape of the reflected pulses to determine the surface roughness to better understand the physical and geological processes shaping the planet. By determining the rotation and tides, conclusions can also be drawn about the internal structure and development of Mercury.

University of Bern.