The Mars InSight lander died after more than four years of listening to vibrations and quakes below the Martian surface.
InSight last checked in with Earth on Dec. 15, 2022, after months of dwindling power. The lander’s solar panels had also become covered in dust. InSight did not respond to the last two communication attempts from Earth.
“We’ve thought of InSight as our friend and colleague on Mars for the past four years, so it’s hard to say goodbye. But it has earned its richly deserved retirement,” said the mission’s principal investigator Bruce Banerdt, who works at the Jet Propulsion Laboratory (JLP) at the California Institute of Technology.
NASA will continue listening for a signal from the lander, although the agency knows they will likely never hear from InSight again.
The InSight mission was declared a success. Scientists used the seismometer and monitoring equipment to detect 1,319 marsquakes. Data collected from the seismometer will be studied for decades.
The most powerful quake registered 4.7 on the Richter magnitude scale, which on Earth is powerful enough to rattle shelves and knock down small objects but cause minimal damage. The lander also detected quakes caused by meteoroid impacts. One impact in 2021 hit Mars with enough force to kick up boulder-sized chunks of ice.
The shockwaves from the quakes and impacts allowed InSight to be used like a sonar and learn about the crust, mantle and core of Mars. These seismic waves confirmed the Martian crust is thinner than expected, ranging from 20 to 37 kilometres deep. Beneath the crust is the mantle, which reaches 1,560 kilometres below the surface. The Martian core has a radius of 1,830 kilometres.
“It took scientists hundreds of years to measure Earth’s core; after the Apollo missions, it took them 40 years to measure the Moon’s core. InSight took just two years to measure Mars’ core,” said Simon Stähler of the Swiss research university ETH Zurich and lead author of the core paper in a July 2021 announcement from NASA.
InSight still had its challenges. It failed to fully deploy its heat flow probe, which was supposed to burrow three to five metres underground. The probe could not gain traction in soil that was too clumpy.
The last time NASA tried sending probes below the Martian surface was in late 1999, when the Mars Polar Lander brought two probes to the edge of Mars’ southern polar ice cap.
The probes were meant to slam into the planet and burrow into the Martian soil on impact. NASA was never able to establish contact between the lander or probes, and the mission was declared a failure. But InSight was still able to use its probe to learn about Mars. The lander’s robotic arm buried the probe just below the surface to collect measurements on soil heat transfer. The data will be useful for future human or robotic missions attempting to dig underground.
“With InSight, seismology was the focus of a mission beyond Earth for the first time since the Apollo missions, when astronauts brought seismometers to the Moon,” said Philippe Lognonné of the Institut de Physique du Globe de Paris —the principal investigator of InSight’s seismometer. “We broke new ground, and our science team can be proud of all that we’ve learned along the way.”
