NASA Beams Laser Between Orbiter and India's Vikram Lunar Lander, Enabling Precision Targeting on the Moon

In August 2023, India became the fourth nation to land on the moon with Chandrayaan-3. The Vikram lander, carrying the Pragyan rover, collected Moon data, including moonquakes. Despite a shutdown in September, NASA finds the defunct lander intriguing. Before the mission, NASA attached a small mirror, a retroreflector, to the lander.

This 2-inch-wide device, made of quartz-corner-cube prisms, reflects lasers to orbiting spacecraft. Recently, NASA achieved a groundbreaking laser bounce off the "Oreo-sized" mirror on India's lunar lander. This maneuver, a first, has potential applications for future high-precision moon landings.

LRO Laser 'Pings' Indian Moon Lander

Repeatedly attempting to bounce lasers off the Vikram lander's retroreflector, NASA's Lunar Reconnaissance Orbiter (LRO) faced challenges after the lander went offline. Despite eight unsuccessful tries, the breakthrough occurred on December 12, 2023, when LRO, the only laser-armed spacecraft orbiting the Moon, successfully pinged the array from a distance of 62 miles.

This achievement serves as a crucial proof-of-concept for NASA, particularly as the agency plans to incorporate more retroreflectors in future lunar missions, including the upcoming Artemis missions.

Xiaoli Sun, a research scientist at NASA's Goddard Space Flight Center leading the mission, emphasized the demonstrated capability to locate the retroreflector on the Moon's surface from lunar orbit. The next step involves refining the technique for routine use in missions utilizing retroreflectors.

This is not the first instance of bouncing lasers off the Moon, previous successes involved Earth-fired lasers reflecting off panels from the Apollo missions. These reflections have contributed to ongoing lunar research, revealing the Moon's gradual movement away from Earth at a rate of about 1.5 inches (3.8 centimeters) per year.

LRO encountered difficulties in achieving laser reflections off the Vikram lander due to its original design for surface mapping, not precise maneuvers. Operating 13 years beyond its initial mission parameters, the spacecraft was designed to map the lunar surface by firing spaced bursts of thin laser lines toward the moon. The wide spacing of these lines presented challenges in accurately targeting the small retroreflector on the Vikram lander.

NASA's Retroreflectors: Revolutionizing Lunar Navigation and Exploration

NASA's innovative retroreflectors are designed for practical applications, aiding unmanned spacecraft in precise moon landings. These devices enable measurements of the spacecraft's distance from the lunar surface by calculating the time taken for lasers to bounce back.

This technology is crucial for future lunar bases, facilitating landings near existing objects and enabling astronaut missions in complete darkness on the moon's far side. Similar to precision markers aiding spacecraft docking at the International Space Station, these retroreflectors enhance navigation and positioning.

Future spacecraft targeting these retroreflectors will employ more precise lasers, increasing accuracy, and firing them from closer distances. NASA aims to expand retroreflector deployment on the moon for further experiments, though recent setbacks, including the Peregrine lunar lander's burn-up and SLIM lander issues, have posed challenges.

Despite these setbacks, NASA anticipates additional opportunities for experimentation, especially with the delayed Artemis missions scheduled for 2026. More so, the space agency is committed to deploying more retroreflectors on the moon for further experimentation.