Fifteen years later, scientists locate a lunar impact site

In 2009, NASA intentionally crashed a spacecraft on the moon and used a small trailing spacecraft to observe the results: the Lunar Crater Observation and Detection Satellite (LCROSS) was designed to search for water lunar jelly and other volatile substances into the lunar regolith by striking them. outside the moon.

Volatile materials are materials that easily vaporize or change from liquid to gas. The LCROSS impact raised a regolith cloud containing a lot of water (5.6% by mass), as well as small amounts of carbon dioxide, sulfur dioxide, methane, and ammonia. But it did so in a constantly shadowed area of ​​the moon, leaving scientists unable to directly observe the crater after it formed.

Now, new research has located the crater left by the LCROSS mission, allowing scientists to better contextualize the mission’s results and inform future efforts to locate and use resources on the Moon. The study is published in the journal Geophysical research letters.

To do this, Fassett and his team used two data sources. The Lunar Reconnaissance Orbiter’s (LRO) miniature radio frequency instrument observes the moon at radar wavelengths to search for groundwater ice. The ShadowCam of the Korea Pathfinder Lunar Orbiter is a hypersensitive camera launched in 2022, specially designed to see inside the eternally dark areas of the moon. Its capabilities allowed researchers to directly view the LCROSS crater and confirm that changes in radar reflectivity observed by LRO after the impact corresponded to a new crater.

The LCROSS impact crater is about 22 meters in diameter, the researchers report, slightly smaller than the LCROSS team had initially estimated. To determine the age of the volatiles ejected by LCROSS, the research team incorporated knowledge of the moon’s tilt throughout history and information about how impacts disrupt the lunar crust into a model.

They found that regolith ejected from the crater had likely been disrupted between 100 and 500 million years ago and that the LCROSS impact site had entered permanent shadow only about 900 million years ago, which made him relatively young. This result supports previous evidence suggesting that the volatiles themselves are young and originate from outside the Moon – perhaps from comets, asteroids or the solar wind – rather than from volcanic eruptions early in the Moon. history of the Moon.

These results gave researchers deeper context on the origins and distribution of water on the Moon. This data could be supplemented by future missions, such as the Volatiles Investigating Polar Exploration Rover (VIPER).

This story is republished courtesy of Eos, hosted by the American Geophysical Union. Read the original story here.