Subnanoradian, Groundbased Tracking of Spaceborne Lasers

Over the next few decades groundbased tracking of lasers on planetary spacecraft will supplement or replace tracking of radio transponders. This paper describes research on two candidate technologies for groundbased, angular, laser tracking: the infrared interferometer and the optical filled-aperture telescope. The motivation for infrared and optical tracking will be followed by a description of the current (10-50 nanoradian) and future (subnanororadian) stellar tracking demonstrations with the University of California-Berkeley Infrared Spatial Interferometer (ISI) and the University of California-San Diego Optical Ronchi Telescope.