NASA Deploys 10-Centimeter Lunar Reflectors to Sharpen Gravity Tests as Moon Recedes 3.8 Centimeters a Year
Updated
Updated · spacedaily.com · May 23
NASA Deploys 10-Centimeter Lunar Reflectors to Sharpen Gravity Tests as Moon Recedes 3.8 Centimeters a Year
2 articles · Updated · spacedaily.com · May 23
NGLR-1—a next-generation lunar retroreflector about 10 centimeters across—reached Mare Crisium in March 2025, and U.S. and European stations ranged to it within days.
The new devices expand the Moon’s fixed laser targets beyond the five Apollo and Lunokhod reflectors, improving the geometric baseline for distance measurements and gravity experiments.
NASA plans another reflector for the lunar south pole later this year on Astrobotic’s Griffin-1 mission with Astrolab’s FLIP rover, with other CLPS landers also adding packages.
The upgraded network could enable Differential Lunar Laser Ranging, which simulation studies suggest may improve estimates of lunar orientation and core properties by a factor of 100 within five years.
That work builds on a 57-year experiment that measures the Moon to millimeter precision, tracks its 3.8-centimeter annual drift from Earth, and has repeatedly tightened tests of general relativity.
What secrets will next-generation lunar reflectors unlock about the Moon's core and the future of Earth's tides?
Why does new data from lunar reflectors now challenge Einstein's theory of gravity after decades of apparent confirmation?
How does a simple, unpowered mirror from the 1960s continue to be one of our most vital tools for cosmic discovery?
Precision Across Decades: How Next-Gen Lunar Laser Ranging Reflectors Are Transforming Earth-Moon and Planetary Science
Overview
The original five lunar laser reflectors, placed on the Moon by Apollo and Lunokhod missions, now return much weaker signals—often just a tenth of what was expected. This decline is mainly due to lunar dust, likely stirred up by micrometeorite impacts, settling on the mirrors. The dust blocks light and may cause the mirrors to overheat, making them less efficient and harder to use for precise measurements. To address this, the Lunar Reconnaissance Orbiter carries a new, clean reflector, helping scientists compare performance and better understand the causes of signal loss.