In November 2018, NASA completed its internal reconnaissance with seismic surveys, geodesy, and heat transport (InSight) on Mars. Shortly thereafter, he began to prepare for his scientific operations, which consisted of studying the seismology of Mars and its heat flow, to learn how this planet – and all other terrestrial planets in the solar system (like the Earth) – has formed and developed over time.
With well-performing scientific operations, InSight "listened" to Mars to learn what it can learn about its internal structure and composition. A few weeks ago, mission controllers discovered that the lander's Seismic Experiment for Interior Structure (SEIS) instrument had detected its most powerful seismic signal (also known as "Marsquake") to date. This weak earthquake could tell a lot about the Red Planet and its genesis.
The weak seismic signal detected by the lander's SEIS instrument (SEIS) was recorded on April 6 or the 128th Mars Day (Sol 128) since the lander landed. This is the first recorded seismic signal that appears to come from inside the planet and is not caused by wind.
NASA scientists are now investigating the SEIS data to determine the exact cause of the signal that may have originated from within Mars or was caused by a meteorite falling on the surface of the planet and waves crashing through the mantle sent. On Earth, seismic activity (aka "earthquakes") is the result of actions between tectonic plates, especially along the fault lines.
Although Mars and Moon do not have tectonic plates, they still experience tremors, mostly due to the constant warming and cooling of their surfaces. This results in expansion and contraction, ultimately resulting in a stress that is strong enough to break the crust. While the new seismic event was too small to provide solid data on the Martian interior, it gives the mission team an idea of how the seismic activity on Mars works.
For example, this event is similar to those measured by the Apollo astronauts in the late 1960s and early 1970s. Starting with Apollo 11 NASA astronauts installed a total of five seismometers on the lunar surface, which measured thousands of lunar earthquakes between 1969 and 1977. With the help of this data, the scientists were able to learn a lot about the interior of the moon structure and composition.
InSight continues this in a tradition that began with the Apollo missions. Renee Weber, a planetary scientist at NASA's Marshall Space Flight Center, recently said in a NASA press release:
"We thought Mars would probably be somewhere between Earth and the Moon [in terms of seismic activity]. It's very early in the mission, but it looks a bit more moon-like than Earth.
Unlike the earth's surface, which is constantly trembling with seismic noise generated by the planet's oceans and weather, the surface of Mars is extremely calm. This allows SEIS, which was provided by the French National Center for Space Research (CNES) and built by the French National Aerospace Center (ISAE) in Toulouse, to absorb weak rumble movements that would go unnoticed on Earth.
As Lori Glaze, director of the Planetary Science Division at NASA Headquarters, said:
"The Martian Sol 128 event is exciting because its size and longer duration correspond to the profile of the moonquakes that occurred during the Apollo missions were discovered on the lunar surface. "
InSights SEIS, brought to the surface in December 2018, allows scientists to collect similar data about Mars. Just as the compositional data on the Moon gave scientists the hypothesis that the Earth-Moon system has a common origin (the Giant Impact Theory), we hope that this data will shed light on how the rocky planets of our solar system have formed.
This is the fourth seismic signal detected by the InSight Lander. The previous three took place on March 14 (Sol 105), April 10 (Sol 132) and April 11 (Sol 133). However, these signals were even weaker than those discovered on April 6, which makes them even less clear about their origins. Again, the team will continue to study and try to learn more.
Regardless of the cause of the April 6 signal, detection is an exciting milestone for the team. As Philippe Lognonné, chairman of the SEIS team at the French Institute of Physics of Paris (IPGP), said:
"We have been waiting for months for such a signal. It's so exciting to finally have proof that Mars is still seismically active. We look forward to sharing detailed results as we have had the opportunity to analyze them. "
The SEIS team has indicated from the four events recorded since December that the instrument has exceeded its expectations sensitivity. "We are very excited about this first achievement and are eager to make many similar measurements with SEIS in the years to come," said Charles Yana, SEIS mission manager at CNES.
The Lander continues to investigate the interior of the planet from his point of view in Elysium Planitia, a plain near the equator of Mars. At present, the mission controllers are still trying to figure out how to remove the Heat and Physical Properties Package (HP3) heat sensor, which was jammed in the buried rock in February while trying to hit the ground to measure temperatures ,
View this photograph of the seismic event courtesy of NASA JPL and the SEIS team:
Further reading: NASA, Nature