The McDonald Laser Ranging Station (MLRS) is a dedicated laser ranging
station capable of measuring round trip light travel times to a
constellation of artificial earth satellites and lunar retro-reflectors
to a precision of about 1 centimeter and time of laser firing to about
35 picoseconds. Data from this station as well as 30-40 similar
satellite-capable systems and one other regularly contributing lunar-capable
system around the world are used for a variety of scientific pursuits
including study of the earth's gravitational field, plate tectonics, earth's
orientation in space, high precision time transfer, relativity, lunar
and solar system dynamics, and providing high precision orbits for
GPS and ocean top mapping missions.