Astronomers close in on long-lost Soviet lunar lander
For almost 60 years, the first man-made object to successfully land on the Moon has been missing. However, researchers may be closer than ever to finding the Soviet Union’s Luna 9 spacecraft. Using an advanced machine learning program, an international team of scientists believes they have finally narrowed down the list of finalists for Luna 9’s location. Their evidence is presented in a study recently published in the journal npj Space exploration.
The case of the missing lunar lander
While the United States beat the USSR by successfully landing a human on the Moon on July 20, 1969, that outcome was anything but certain three years earlier. For a while, the Soviets even seemed on the path to victory after engineers successfully made a soft landing on the Moon with their Luna 9 spacecraft on February 3, 1966. Luna 9 was also the first to send back photographs of another celestial object.
However, unlike the footprints of Neil Armstrong or Buzz Aldrin, no one has had a clear idea of ​​the location of the Soviet Moon probe for decades. This is due in part to outdated calculations, as well as Luna 9’s unique landing method. Before the spacecraft landed, it deployed a spherical landing capsule built with inflatable shock absorbers. These allowed it to bounce safely several times before stopping.
After the conclusion of the mission, the Soviets published their estimated landing coordinates in the newspaper, Pravda. Since then, the exact location remains a matter of debate. In 2009, images from NASA’s Lunar Reconnaissance Orbiter Camera (LROC) confirmed the big problem: Luna 9 was not where it was supposed to be. Plus, it’s possible that it’s miles away from what the experts thought.
YOLO!
To continue his research, Lewis Pinault, a data scientist at University College London, recently began designing a machine learning algorithm by training it on LROC images of several Apollo landing sites. Dubbed YOLO-ETA (You-Only-Look-Once-Once-Extraterrestrial Artifact), the program ultimately proved good enough to identify hard-to-discern surface features created by the landers. The team tested YOLO-ETA on unknown images, including some from the Soviet Luna 16 that landed in 1970. Overall, the program displayed a high level of accuracy and confidence in its estimates.
Finally, it was time to give YOLO-ETA its biggest mission yet. Researchers asked him to scan the approximately 3.1 mile by 3.1 mile Luna 9 landing zone listed in Pravda article. YOLO-ETA came back with several possible locations worth a closer look, each displaying potential signs of disturbing an artificial lander on the lunar soil.
Fortunately, it won’t be another six decades before the team knows if any of these contenders are right. India’s Chandrayaan-2 orbiter is expected to fly over the area in March 2026 as part of its ongoing surface mapping project. From there, researchers will be able to compare their landing sites with the high-definition data, possibly ending a long-standing space mystery.
The best new PopSci 2025 releases
