NASA’s laser retroreflector array arriving for inspection and approval. Credit: Surrey Satellite Technology Ltd.

NASA delivered the first flight hardware for the Lunar Pathfinder mission to ESA (European Space Agency), which formally accepted the instrument on Nov. 4. NASA's Goddard Space Flight Center in Greenbelt, Maryland, developed the instrument, a laser retroreflector array, which will test new navigation techniques for lunar missions.

NASA and ESA plan to launch Lunar Pathfinder via a future Commercial Lunar Payload Services delivery. In addition to testing navigation capabilities, Lunar Pathfinder will operate as a commercial communications relay and provide communications services for exploration missions on the .

The Lunar Pathfinder mission is led by Surrey Satellite Technology Ltd (SSTL), and ESA arranged for the mission to provide to NASA. Teams from NASA, ESA, and SSTL completed inspections when the retroreflector array arrived at SSTL's facility in Guildford, U.K., where it will be installed in the satellite.

Laser retroflectors are mirrored devices that reflect light back at its source; engineers can bounce laser signals off the arrays to precisely measure the position of the spacecraft and check the performance of Global Navigation Satellite Systems (GNSS) capabilities around the moon. Validating and developing these capabilities will help NASA navigate as it travels to and explores the moon with the Artemis missions.

In addition, the retroreflectors will allow NASA to learn more about lunar science and space geodesy, which uses satellite measurements of celestial bodies to understand their structure.

The Artemis missions are bringing humans back to the moon and will test the technologies needed to one day journey to Mars. NASA is doing this through collaborative agreements with international partners and commercial companies. Delivery of the laser retroreflector array is the first milestone completed in a memorandum of understanding between NASA and ESA that the agencies signed in June.