For the first time at the Moon, a laser beam was transmitted and reflected between an orbiting NASA spacecraft and an Oreo-sized device on ISRO’s (Indian Space Research Organisation) Vikram lander on the lunar surface. The successful experiment opens the door to a new style of precisely locating targets on the Moon’s surface.

At 3 p.m. EST on Dec. 12, 2023, NASA’s LRO (Lunar Reconnaissance Orbiter) pointed its laser altimeter instrument toward Vikram. The lander was 62 miles, or 100 kilometers, away from LRO, near Manzinus crater in the Moon’s South Pole region, when LRO transmitted laser pulses toward it. After the orbiter registered light that had bounced back from a tiny NASA retroreflector aboard Vikram, NASA scientists knew their technique had finally worked.
ISRO’s (Indian Space Research Organization) Vikram lander, with a NASA retroreflector on it, touched down on the Moon on Aug. 23, 2023. The camera aboard NASA’s LRO (Lunar Reconnaissance Orbiter) took this picture four days later. The lander is in the center of the image, its dark shadow visible against the bright halo around it. The halo formed after rocket plume interacted with the fine-grained regolith (similar to soil) on the Moon’s surface. The image shows an area that’s 1 mile, or 1.7 kilometers, wide.
Only 2 inches, or 5 centimeters, wide, NASA’s tiny but mighty retroreflector, called a Laser Retroreflector Array, has eight quartz-corner-cube prisms set into a dome-shaped aluminum frame. The device is simple and durable, scientists say, requiring neither power nor maintenance, and can last for decades. Its configuration allows the retroreflector to reflect light coming in from any direction back to its source.