NASA and several other federal agencies, including the U.S. Space Force, U.S. Space Command, the U.S. Naval Research Laboratory, and the National Geospatial-Intelligence Agency are improving the location accuracy of these measurements down to the millimetre with a new set of laser retroreflector arrays, or LRAs.

"The primary benefit of laser ranging and LRAs is to improve the geolocation of all of our Earth observations," said Stephen Merkowitz, project manager for NASA's Space Geodesy Project at NASA's Goddard Space Flight Center in Greenbelt, Maryland.

A team of scientists and engineers with the project tested these arrays earlier this year to ensure they were up to their task and they could withstand the harsh environment of space. Recently the first set of these new laser retroreflector arrays was shipped to the U.S. Space Force and Lockheed Martin in Littleton, Colorado, to be added to the next generation of GPS satellites.

Laser retroreflector arrays make it possible to do laser ranging - using small bursts of laser light to detect distances between objects. Pulses of laser light from a ground station are directed toward an orbiting satellite, which then reflect off the array and return to the station. The time it takes for the light to travel from the ground to the satellite and back again can be used to calculate the distance between the satellite and the ground.

Read more in Space Daily article.