Apollo 17 mission commander Eugene Cernan drives the lunar roving vehicle with the Lunar Module in the background.
Sensors placed on the surface of the Moon during the Apollo 17 mission picked up a mysterious tremor, one that regularly occurred as the Sun rose to its peak position over the lunar surface. Unlike regular moonquakes that are triggered by the varying temperatures of the lunar environment, however, this one had a rather peculiar, human-made source.
During the Apollo 17 mission in 1972, astronauts placed seismometers on the lunar surface to measure moonquakes. More than 50 years later, a group of scientists reanalyzed the data collected by the last crewed mission to the Moon using new techniques such as machine learning. The reanalysis revealed a new kind of seismic activity that took place at the same time during the lunar mornings, which turned out to be coming from the Apollo 17 lunar lander.
The newly detected tremors on the Moon, while not originating from the Moon itself, could provide valuable insights into the thermal expansion and contraction of the Apollo 17 lander, potentially guiding the design of future lunar landers.
Studying moonquakes also helps scientists better understand what goes on beneath the lunar surface since seismic waves travel at different speeds through different material. Husker hopes to be able to place seismometers on the Moon’s permanently shadowed regions where there may be reservoirs of water ice beneath the surface, measuring seismic waves as they travel slower through water.
“It’s important to know as much as we can from the existing data so we can design experiments and missions to answer the right questions,” Husker said.
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