- Mars and Earth both had conditions suitable for life for some periods of time 3 to 4 billion years ago, until Mars lost its atmosphere and became a cold, dry desert.
- NASA's InSight spacecraft has been studying Mars' interior since 2018 to learn how other worlds, including Earth-like exoplanets around other stars, evolve.
- InSight is now in an extended mission listening for Marsquakes that will help us learn more about what lies beneath the surface.
Why we need InSight
Space exploration missions to Mars have taught us that for at least some periods of time 3 to 4 billion years ago, Mars had conditions that could have supported life as we know it. Then, Mars lost its magnetic field and the Sun stripped away its atmosphere.
Why did this happen on Mars but not Earth? To learn why our planet took such a different evolutionary path and what the possibilities are for other worlds including Earth-like exoplanets, we need to learn about Mars' interior.
NASA's InSight spacecraft, an acronym for Interior Exploration using Seismic
Investigations, Geodesy and Heat Transport, launched to Mars in May 2018 and landed later that year in November. Its mission is to learn more about how Mars' interior is layered so scientists can compare Mars with what we know about other planets and Earth.
One of InSight's primary science instruments, a heat-flow probe known as the mole, failed to work because the soil at the landing site was different than predicted. InSight is now operating in an extended mission, listening for Marsquakes that will help us learn more about what lies beneath the Martian surface.
NASA will spend $814 million on InSight over the project's lifetime. The Planetary Society has additional context to help you understand this number.
How does InSight work?
InSight's design is based on NASA's Phoenix lander, with a robotic arm and dual solar arrays that power the spacecraft's instruments. The spacecraft measures about 6 meters (20 feet) wide including its solar panels and sits about a meter (3 feet) above the surface.
InSight has two main science experiments: a seismometer called SEIS to measure Marsquakes and a heat-flow probe called HP3 designed to burrow up to 5 meters beneath the surface to collect temperature readings. InSight used its robotic arm to place both on the surface shortly after arrival.
As of December 2020 SEIS has only recorded gentle Marsquakes, with none larger than magnitude 3.7. The waves from the quakes are different than those seen on Earth and the Moon, indicating Mars' uppermost layers may be heavily fractured or that the quakes come from deep within the planet. The quakes have not yet provided scientists with a hoped-for understanding of Mars'mantle, which lies about 400 kilometers (250 miles) beneath the surface. But the longer InSight operates, the more scientists will be able to understand what's happening.
The soil at InSight's landing site is different than any seen before on Mars, and did not provide enough friction for the HP3 temperature probe known as the mole to burrow beneath the surface. After nearly two years of efforts with InSight's robotic arm to help the mole dig, NASA formally called off the effort in January 2020.
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