NASA and JAXA Achieve Laser Communication Between Moon's Surface and Lunar Orbit

NASA's Lunar Reconnaissance Orbiter (LRO) successfully transmitted a laser pulse to a small retroreflector aboard JAXA’s (Japan Aerospace Exploration Agency) SLIM lander on two occasions, pinging the lander 44 miles overhead. Remarkably, during these two special orbits on May 24, 2024, the laser pulse reflected back, marking a significant achievement despite the non-ideal positioning of the reflector.

Retroreflectors—usually mounted atop landers—offer a 120-degree angle window for laser aiming. However, the SLIM's sideways orientation on the Moon’s surface restricted LRO’s target range. To increase success, the LRO team, in collaboration with JAXA, calculated the exact location and orientation of SLIM and strategically planned LRO's orbit to align with its retroreflector's limited range.

Xiaoli Sun, heading the team responsible for SLIM’s retroreflector, highlighted that the LRO’s laser altimeter was originally intended for mapping lunar topography, not for targeting such small devices. The accomplishment showcases the resilience of these tiny devices. SLIM, which landed on January 20, carried a Laser Retroreflector Array, one of six such NASA instruments delivered to the Moon.

The inaugural successful laser communiqué between LRO and a NASA retroreflector occurred with ISRO's Vikram lander on December 12, 2023. Since then, LRO has achieved three additional reflections with Vikram’s retroreflector.

Each NASA retroreflector is a durable device composed of eight quartz corner-cube prisms set within a two-inch, dome-shaped aluminum frame, requiring no power or maintenance. These reflectors can function for decades, guiding future missions and marking locations for astronauts and spacecraft. LRO's laser altimeter, although crafted for mapping, continues to perform beyond its intended capability by engaging such pinpoint reflections, aiding the comprehensive mission goals.

Launched on June 18, 2009, LRO has amassed invaluable lunar data, contributing significantly to expanding human knowledge and preparing for future lunar missions, with both commercial and international partnerships on board. The project is managed by NASA’s Goddard Space Flight Center, supporting broader space exploration ambitions.

Earlier, SSP wrote about a nanoscale device that leads the way to future wireless communication channels.