The primary task of the ILRS is the timely collection, merging, archiving, and distribution of laser ranging data to various approved spacecraft properly equipped with retroreflectors. Geodetic satellites are dedicated passive satellites used in defining the Terrestrial Reference Frame and gravity field and in scientific studies of tectonic plate motion, regional crustal deformation, Earth rotation and polar motion, postglacial uplift, etc.
Altimetric satellites are usually limited life missions lasting approximately three to ten years.
Typical scientific goals include dynamic sea surface topography, mean sea level and wave height determination, global ocean circulation, ice sheet thickness and topography, and, with future laser altimeters, land surface topography including biomass estimation. The Point of Contact for every organization requesting tracking support of new satellites or modification of the adopted tracking priorities is the ILRS Central Bureau. It is the responsibility of the Spacecraft or Mission sponsor requesting laser tracking support to file a Laser Tracking Support Plan with the ILRS Central Bureau. In the past, NASA has generated the Laser Tracking Support Plans for most new missions, including many non-NASA experiments. These plans are required to obtain tracking approval at NASA and many non-NASA sites.