About MGO

The McDonald Geodetic Observatory (MGO) is located within the University of Texas McDonald Observatory. Founded in 1939, McDonald Observatory is located near Ft. Davis, Texas, and is a part of the University of Texas at Austin (UT Austin) Department of Astronomy. MGO presently consists of a geodetic VLBI (operational, designated as VGOS 9), six geodetic GNSS stations (operational), and the SGSLR (under construction) Рall provided by NASA as part of its Space Geodesy Project. The UT Austin experiments within the MGO core site include a superconducting gravimeter, occasional absolute gravity and deflection-of-vertical measurements, laser metrology for system ties, and other site characterization research. UT Austin provided construction funding of the infrastructure necessary for the MGO.

The McDonald Observatory has been a pioneering site for lunar and satellite laser ranging development since the 1960s. Lunar laser ranging became a reality in the summer of 1969 when reflector arrays were deployed on the Moon as part of the NASA Apollo manned lunar program. The University of Texas at Austin developed and tested the first Transportable Laser Ranging System (TLRS-1) at the site during the late 1970s and early 1980s. About the same time, the Mobile Laser Ranging System (MLRS) was being developed. The first acquisition of LAGEOS satellite laser ranging by the MLRS occurred in August, 1981, and the first lunar acquisition occurred in August, 1983. In 1988, MLRS was relocated from its original location between Mt. Locke and Mt. Fowlkes to its site on Mt. Fowlkes. The MLRS stopped collecting data regularly in 2015, and was decommissioned in 2019, ending 35-year legacy of providing fiducial positions representing the motion of the North American Plate in the official Terrestrial Reference Frame. A Very Long Baseline Array (VLBA) site of the National Radio Astronomy Observatory (NRAO), located approximately 8 km from the MGO, had been used previously for geodetic VLBI data collection.

The MGO continues the legacy of geodesy at McDonald Observatory, collecting high accuracy metrology data necessary to realize the next generation Terrestrial Reference Frame in continuity with the 30-plus year record of geodetic positioning data collected at that precise location.

Last Updated: April 18, 2021