Leonard David's INSIDE OUTER SPACE

An LRA consists of eight tiny retroreflectors mounted on a small, high hemispherical platform.
Image credit: NASA TV/Space.com screengrab

Reflect on this!

For the first time at the Moon, a laser beam from NASA’s Lunar Reconnaissance Orbiter (LRO) was transmitted and reflected between LRO and the Indian Space Research Organization’s (ISRO) Vikram lander on the lunar surface.

ISRO’s successful Moon lander touched down near the lunar south pole on August 23, 2023. It carried the tiny NASA Laser Retroreflector Array, or LRA for short.

LRA (Laser Retroreflector Array) is a collection of eight retroreflectors that enable precise measurements of the distance between the orbiting or landing spacecraft and the lander.
Image credit: NASA/GSFC

Bounce back

That ISRO Vikram lunar lander was some 62 miles (100 kilometers) from the LRO, silently sitting near Manzinus crater in the Moon’s South Pole region. The laser light show between LRO and Vikram took place on December 12, 2023 with LRO transmitting laser pulses toward the lunar lander, with LRO then registering the light that had bounced back.

NASA LRA mounted on Chandrayaan-3 lunar lander.
Image credit: ISRO/NASA

 “We’ve showed that we can locate our retroreflector on the surface from the Moon’s orbit,” said Xiaoli Sun, who led the team at NASA’s Goddard Space Flight Center in Greenbelt, Maryland, that developed the retroreflector placed on Vikram as part of a partnership between NASA and ISRO.

“The next step is to improve the technique so that it can become routine for missions that want to use these retroreflectors in the future,” Sun said in a NASA/Goddard statement.

India’s 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.
Image credit: NASA’s Goddard Space Flight Center/Arizona State University

More to come

Several NASA retroreflectors are slated to fly aboard public and private Moon landers, including one device carried by the Astrobotic Moon lander that’s now set to reenter the Earth’s atmosphere on January 18 due to a spacecraft propulsion mishap.

Another Laser Retroreflector Array is onboard the Japan Aerospace Exploration Agency’s SLIM lander, due to land on the Moon in a few days time, on January 19.

Also, an LRA is onboard an upcoming Intuitive Machines lunar lander set to launch in mid-February. Intuitive Machines will carry six NASA payloads, including the retroreflector, under NASA’s Commercial Lunar Payload Services (CLPS) initiative.

For more information on the LRA program, go to my Space.com story – “NASA’s Lunar Retroreflector Network could make landing on the moon much easier” at: 

https://www.space.com/the-universe/moon/nasas-lunar-retroreflector-network-could-make-landing-on-the-moon-much-easier