NASA Studies Moonquakes to Prepare for Artemis Lunar Missions

As NASA prepares for a new era of lunar exploration under the Artemis program, scientists are delving into the fascinating phenomena of moonquakes, using samples collected during the Apollo 17 mission along with observations from the Lunar Reconnaissance Orbiter (LRO). The insights gained from these sources not only deepen our understanding of the lunar surface but also pose significant implications for future human expeditions to the Moon.

Moonquakes, akin to earthquakes, occur on the Moon due to the movement along active fault lines within its crust. These fault lines manifest as cracks resulting from the Moon’s gradual cooling and contraction over billions of years. While moonquakes are significantly less intense than their terrestrial counterparts, with the strongest reaching magnitudes of around 5.0, they can pose risks to future missions, especially those involving long-term human presence on the lunar surface.

“The hazard probability goes way up depending on how close your infrastructure is to an active fault,” stated Thomas Watters, senior scientist emeritus at the Smithsonian National Air and Space Museum and a co-investigator on the LRO mission. This concern highlights the importance of understanding the Moon’s geology and seismic activity as we plan for sustained lunar habitation.

During the Apollo missions, a network of seismometers was deployed, capturing thousands of vibrations between 1969 and 1977. By analyzing this historical data alongside new LRO observations, researchers like Watters and Nicholas Schmerr, a planetary seismologist at the University of Maryland, have developed innovative methods to investigate moonquakes. Their approach involves studying surface changes in regions where moonquakes are likely occurring, particularly focusing on areas like the Lee-Lincoln fault in the Taurus-Littrow valley.

Data from the LRO, which has been orbiting the Moon since 2009, has been crucial in identifying thousands of potential active faults. The scientists specifically chose the Lee-Lincoln fault because of the extensive geological data gathered during the Apollo 17 mission, which landed a mere four miles from the fault in December 1972. Astronauts Gene Cernan and Harrison Schmitt collected crucial rock samples, providing a wealth of information for ongoing analysis.

Watters and Schmerr’s research revolves around examining dislodged boulders and landslides in the vicinity of the fault. They have concluded that a magnitude 3.0 moonquake likely occurs near this region every 5.6 million years, providing a glimpse into the Moon’s seismic past and future potential for activity. “One of the things we’re learning from the Lee-Lincoln fault is that many similar faults have likely had multiple quakes spread out over millions of years,” Schmerr noted, emphasizing the ongoing nature of the Moon’s geological activity.

During the Apollo 17 mission, the samples collected included boulders that displayed tracks indicating they had rolled downhill, likely dislodged by a moonquake. By analyzing the internal chemistry of these rocks, scientists can infer how long they had remained in one position and, crucially, when they were moved. This data is pivotal for understanding the frequency of seismic activity in this region.

The Apollo 17 crew’s geological explorations revealed a boulder field that showcased evidence of past moonquakes, and by measuring the size of these boulders and their movements, scientists can not only determine the intensity of the seismic events but also gain insights into the lunar geological processes.

Watters and Schmerr’s findings suggest that the likelihood of experiencing a moonquake during Apollo 17’s short window of exploration was extremely low, estimated at one in 20 million. However, as NASA eyes further explorations, particularly towards the Moon’s south pole, where active faults may be more prevalent, these insights will be invaluable.

In upcoming missions, NASA plans to deploy more seismometers on the Moon. The Farside Seismic Suite, featuring two seismometers, is set to land in the Schrödinger basin on the Moon’s far side, while the Lunar Environment Monitoring Station is slated for deployment during the Artemis III mission. These advancements will enhance our understanding of moonquakes and refine strategies for ensuring astronaut safety during extended lunar missions.

The ongoing investigation into moonquakes using Apollo samples and modern observational technology illustrates how past explorations continue to inform future endeavors. As we look forward to the next chapter of lunar exploration, the findings from Watters and Schmerr provide an important foundation for understanding and mitigating the risks associated with seismic activity on the Moon.