Chapter 1: Introduction to the InSight Mission

NASA's Mars InSight lander has returned its first set of results, offering a comprehensive understanding of conditions on the Red Planet.

On November 26, 2018, NASA's InSight lander, known as the Interior Exploration using Seismic Investigations, Geodesy, and Heat Transport, successfully landed in the Elysium Planitia region, close to Mars' equator. Equipped with advanced measurement tools, InSight's mission aims to monitor the 'vital signs' of Mars to uncover details about its interior structure, formation, and evolutionary processes in relation to Earth. Nearly ten months of data collection have culminated in significant findings published in various Nature journals.

"This mission is the first of its kind dedicated to examining the deep interior of Mars," states W. Bruce Banerdt, Principal Investigator for InSight and author of a summarizing paper on these groundbreaking results. "By employing geophysical methods, we seek to enrich our understanding of Earth's formation and the habitability of rocky planets."

Among the critical discoveries outlined in the papers are the identification of 20 'marsquakes' with magnitudes between 3 and 4, as well as 174 additional seismic events indicating volcanic and tectonic activity. These findings suggest that Mars experiences moderate seismic activity, falling between that of Earth and the Moon. An unexpected discovery was the local magnetic field at the landing site, which is ten times stronger than anticipated. Additional results include insights into Martian atmospheric phenomena, such as gravitational waves and infrasound.

InSight's mission to Mars sends back first results - YouTube

Chapter 2: Analyzing Mars' Interior

The primary instruments aboard InSight include the Seismic Experiment for Interior Structure (SEIS), the Heat Flow and Physical Properties Package (HP³), and the Rotation and Interior Structure Experiment (RISE). Together, these devices allow researchers to form a nearly complete image of Mars' inner structure.

While HP³ and RISE require more time to yield substantial results, SEIS has already provided critical data by delivering the first direct seismic measurements of Mars' upper crust and subsurface. Deployed by a robotic arm and shielded by a dome, SEIS has been pivotal in gathering valuable insights.

"This mission is the first focused on obtaining direct geophysical data from any planet aside from Earth, offering us a fresh perspective on Mars' internal structure and geological dynamics," remarks Nicholas Schmerr, an assistant professor of geology at the University of Maryland and co-author of a related study. "These findings aid our comprehension of the planet's seismicity and activity levels."

Over a span of 235 Martian days—each slightly longer than a day on Earth—SEIS detected 174 seismic events, with 150 of them classified as high-frequency, akin to measurements recorded on the Moon. More notably, 24 low-frequency events were identified, displaying wave patterns similar to Earthquakes resulting from tectonic shifts. The research team successfully pinpointed the source and magnitude of three of these low-frequency marsquakes, with plans to analyze ten additional significant quakes.

"We were thrilled to record these low-frequency events, as they allow us to analyze subsurface structures," explains Vedran Lekic, an associate professor at UMD and co-author of the study. "By examining how seismic waves travel through the crust, we can identify geological layers and trace the quakes' origins."

The sensitivity of SEIS is remarkable, detecting ground vibrations on Mars that are 500 times quieter than the faintest vibrations on Earth. Previous missions, such as the Viking 1 & 2, also carried seismometers, but their mounted design hindered effective data collection. The Viking 2 was further hampered by noise from Martian winds, underscoring the importance of SEIS being placed directly on the Martian surface.

Journey to the Center of Mars - Scientific Results of the InSight Mission - YouTube

Chapter 3: Unveiling Mars' Atmospheric Conditions

In addition to assessing Mars' internal structure, SEIS has also gathered significant data regarding the planet's weather and atmospheric patterns. SEIS is capable of detecting the impact of low-pressure systems and wind columns on the Martian surface. When dust devils disturb the ground, SEIS can identify the tilt of the substrate, while strong winds create distinct seismic signatures. By integrating this data with information from meteorological instruments such as the Temperature and Wind for InSight (TWINS), the team has begun to outline the daily atmospheric cycles around the lander.

The researchers found that Martian winds exhibit a periodic pattern, peaking in the late afternoon when warmer air rises and atmospheric pressure drops. This leads to increased dust devil activity. By night, the conditions become remarkably quiet, allowing SEIS to detect deeper rumblings from the planet's interior.

"The data we've gathered paints a beautifully intricate picture of what a day on another planet looks like," Lekic adds.

While SEIS captures present-day atmospheric conditions, other aspects of InSight's research are shedding light on the historical atmosphere of Mars and its potential for supporting life.

Chapter 4: Magnetic Insights into Mars

The stark contrast between Earth's and Mars' capacity to harbor life is largely attributed to Earth's protective magnetosphere. This magnetic field shields our atmosphere from solar winds that could otherwise erode it, leaving Mars barren.

Catherine Johnson and her team discovered that the magnetic field at InSight's location is unexpectedly ten times stronger than previous satellite data suggested. This finding has significant implications for understanding Mars' geological history.

"The magnetometer on InSight is the first to be placed on Mars' surface," Johnson explains. "Measuring for the first time often reveals surprises! The unexpectedly strong magnetic field at our landing site was indeed a revelation."

The team's magnetic field measurements provide insights into Mars' structure and evolution, including electric fields and atmospheric currents. While satellite missions have detected ancient magnetic fields, smaller-scale magnetic fields remain undetectable from orbit.

"Mars currently lacks a global magnetic field, so the signals we measure originate from rocks buried deep beneath the surface, which were magnetized in a much older field," Johnson elaborates. "We know that very ancient rocks, likely around 4 billion years old, lie beneath the InSight landing site."

Johnson believes that variations in magnetic fields can help probe Mars' interior, particularly its electrical conductivity.

"As we refine our measurements and learn to interpret the magnetic data, we will gain insights into the early magnetic field of Mars, which is crucial for understanding how the planet lost its thicker atmosphere and its implications for early habitability," Banerdt concludes.

InSight's investigations on Mars are set to continue until at least November, with some instruments still gathering data. Banerdt expresses hope for a mission extension: "We are currently working on a proposal for NASA to extend InSight operations for another two years, as we aim to deepen our understanding of the early formation and evolution of Earth's crust and interior."

Special thanks to Catherine Johnson, Domenico Giardini, and W. Bruce Banerdt.