Abstract:
This contribution reassesses progress in the development of satellite laser ranging (SLR) technology and its
scientific and societal applications in South Africa. We first highlight the current global SLR tracking stations
within the framework of the International Laser Ranging Service (ILRS) and the artificial satellites currently
being tracked by these stations. In particular, the present work focuses on analysing SLR measurements
at Hartebeesthoek Radio Astronomy Observatory (HartRAO), South Africa, based on the MOBLAS-6 SLR
configuration. Generally, there is a weak geometry of ILRS stations in the southern hemisphere and the
SLR tracking station at HartRAO is the only active ILRS station operating on the African continent. The
SLR-derived products – such as station positions and velocities, satellite orbits, components of earth’s
gravity field and their temporal variations, earth orientation parameters – are collected, merged, achieved
and distributed by the ILRS under the Crustal Dynamic Data Information System. These products are used in
various research fields such as detection and monitoring of tectonic plate motion, crustal deformation, earth
rotation, polar motion, and the establishment and monitoring of International Terrestrial Reference Frames,
as well as modelling of the spatio-temporal variations of the earth’s gravity field. The MOBLAS-6 tracking
station is collocated with other geodetic techniques such as very long baseline interferometry and Global
Navigation Satellite Systems, thus making this observatory a fiducial geodetic location. Some applications of
the SLR data products are described within the context of earth system science.
