Leonard David's INSIDE OUTER SPACE

Apollo 17 Moon lander: Ascent and Descent segments.
Image credit: NASA

Snap, crackle and pop! That’s the prognosis from the Apollo 17 landing site according to new research.

Back in the heady days of the Apollo lunar landing program, the moonwalkers deployed Apollo Lunar Surface Experiments (ALSEP) packages. Each was a little different for individual Apollo missions.

In 1972, the Apollo 17 ALSEP included a Lunar Seismic Profiling Experiment (geophones).

Deployed seismometers

According to work led by NASA’s Francesco Civilini, thousands of signals were recorded during an 8-month span from 1976 to 1977 on four seismometers deployed during the Apollo 17 activities on the Moon.

Left on the Moon – Challenger lunar lander descent stage.
Image credit: NASA/GSFC/ASU

Lunar Seismic Profiling Experiment (LSPE) Antenna, pre-flight photo.
Image credit: NASA/The Apollo Lunar Surface Journal

 “We developed algorithms to accurately determine the arrival timing of the waves, measure the strength of the seismic signal, and find the direction of the moonquake source, Civilini and colleagues explain.

“We found that impulsive moonquakes are not due to natural processes, but are vibrations generated from the lunar module descent vehicle left by the astronauts in 1972.”

The research team found two classes of seismic signals: impulsive and emergent events produced by the lunar module and regolith processes respectively.

Apollo 17 landing site: Image credit: From Coordinates and Maps of the Apollo 17 Landing Site from Isabel Haase, et al.

Civilini and fellow researchers note that the duration of the non-impulsive events is correlated with temperature.

“The hotter the temperature, the longer the seismogram. We think that this behavior might be due to changes in regolith properties or stronger events during the day.”

Active seismic research hardware deployed during Apollo 17 mission in 1972.
Image credit: NASA/The Apollo Lunar Surface Journal

For an informative look at the new research, go to – “Mysterious moonquake traced to Apollo 17 lunar lander base” by Stefanie Waldek at Space.com.

Go to:

https://www.space.com/new-moonquakes-traced-to-apollo-17-lander

To access the research paper – “Thermal Moonquake Characterization and Cataloging Using Frequency-Based Algorithms and Stochastic Gradient Descent” – go to:

https://agupubs.onlinelibrary.wiley.com/doi/abs/10.1029/2022JE007704