NASA Realizes Another Breakthrough in High-precision Lunar Landing

In a recent experiment, NASA's Lunar Reconnaissance Orbiter successfully reflected a laser beam off an "Oreo" cookie-sized mirror on India's Vikram lunar lander and returned it to the orbiting spacecraft that launched it.
The successful demonstration opens the door to a new method of accurately locating targets on the lunar surface, which will hopefully help achieve high-precision landings on future lunar missions.
In August 2023, India's Moon Ship III mission deployed the Vikram Lunar Lander near the Manzinus crater in the Moon's south polar region, making it the fourth country to land a spacecraft on Earth's largest satellite. The lander also carried the Pragyan rover, which spent weeks collecting data on the moon - including valuable evidence of moonquakes - but in September it went on schedule and failed to "wake up" after a power outage. but failed to "wake up" after a planned power outage in September. But the derelict lander still piqued NASA's interest.
Before the mission began, the agency arranged for the lander to be fitted with a small, multi-faceted mirror called a laser reflector array (LRA) or retroreflector. The 2-inch-wide (5-centimeter) device, made of eight quartz-corner cubic prisms set in a dome-shaped aluminum frame, was designed to enable the reflection of laser light from virtually any angle to the orbiting spacecraft.
A Successful Progression
Since the lander went offline, NASA's Lunar Reconnaissance Orbiter (LRO) has made several unsuccessful attempts to reflect lasers from the retro-reflector. But on December 12, 2023, after eight failed attempts, LRO finally hit the array from 62 miles (100 kilometers) away and received a laser ping signal.
The Lunar Reconnaissance Orbiter (LRO) is the only spacecraft currently orbiting the moon that is equipped with a laser weapon. This success is an important proof of concept for NASA, which plans to use more reflectors on future lunar missions, including the upcoming Artemis mission.
Xiaoli Sun, a research scientist at NASA's Goddard Space Flight Center and the mission's leader, said in a statement: "We have demonstrated that we can locate backward reflectors on the lunar surface from lunar orbit. The next step is to improve this technique so that it becomes a routine mission for future missions that want to use these reflectors."
This isn't the first time scientists have fired lasers on the moon. In the past, NASA has successfully reflected lasers fired from Earth onto reflectors left on the lunar surface during the Apollo missions. That experiment showed that the moon was slowly moving away from Earth at a rate of about 1.5 inches (3.8 centimeters) per year.
However, the new retro-reflector was designed with a more practical use in mind: the National Aeronautics and Space Administration plans to use the device to help unmanned spacecraft land next to existing objects on the Moon, by being able to accurately measure how far they are from the lunar surface (based on the amount of time it takes for the lasers to reflect back to the spacecraft).
This could be important for building future moon bases, and could even allow astronauts to land on the backside of the moon in complete darkness. Similar "precision marking" could help the upcoming docking of the astronaut capsule and cargo module to the airlock of the ISS.
What improvements have been made?
It took several attempts for LRO to successfully reflect the laser from the Vikram lander, as the orbiter was not designed for such precise maneuvers. The spacecraft has now been operating for 13 years, exceeding the parameters of its original mission, which was designed to map the lunar surface.
To do this, it fires fine laser lines at the moon and measures the time it takes for them to bounce back to the spacecraft. But because the lines are so far apart, it's difficult to accurately hit such a small target.
In the future, spacecraft that target backward-facing reflectors will have more precise lasers and may fire them from much closer distances. So, according to NASA, they should theoretically be able to hit their tiny targets every time.
NASA plans to place more reflectors on the moon for similar experiments in the future. However, their last few attempts did not go well.
One of their proposed retro-reflectors was mounted on the privately owned Peregrine lunar lander, which suffered a catastrophic propellant leak shortly after its Jan. 8 launch and recently burned up in Earth's atmosphere. The other was attached to Japan's SLIM (Smart Lander for Investigating the Moon) lander, which successfully landed on the moon on Jan. 19, but may have "died" due to power problems.
These problems may have hindered NASA's research on the reflector. But with the first manned Artemis mission delayed until 2026, they may have a few more chances before those missions arrive.