Work on pulsed ranging lasers for satellite tracking started at Goddard about 1961/2. Its main purpose was to develop a high precision tracking system for 'future' needs. As it turned out it was in retrospect, a very fortunate step. As early as 1964, the first laser corner cube equipped spacecraft, Beacon Explorer-B, was launched into orbit and tracked with our laser ranging system. Tracking errors of several metres were obtained at this time. Over the last decade, considerable progress was made in reducing these errors. Today ten laser corner-cube equipped spacecraft are in orbit and routinely tracked by ultra-precision laser ranging systems whose ranging noise and accuracy are in the deci- and subdecimetre range. Laser ranging errors (bias and noise) were about 50-70 cm in 1971, 10-30 cm in 1973 and are now about 5-8 cm. Advanced studies of the Earth's gravity field, polar motion, and Earth rotation variations are now being pursued using these laser systems. This paper describes the latest Goddard systems, their uses for our Earth dynamics program, and further discusses the accuracies obtained using actual field data.