NASA InSight lander set to measure Marsquakes
Artist’s rendering of the inner structure of Mars. The topmost layer is known as the crust, underneath it is the mantle, which rests on an inner core. Image Credit: NASA/JPL-Caltech
NASA’s next robotic mission to Mars should provide researchers their first look into the Red Planet’s interior. InSight, which stands for Interior Exploration using Seismic Investigations, is set to measure Marsquakes to learn about the Martian crust, mantle and core.
The first robotic lander dedicated to exploring the subsurface of Mars could help answer the fundamental question of how planets form. Scientists have found some of the answers here on Earth through seismology, the study of quakes. But while the Earth has been churning its geological record for billions of years, Mars churns far less, preserving the planet’s early history.
“During formation, this ball of featureless rock metamorphosed into a diverse and fascinating planet, almost like caterpillar to a butterfly,” Banerdt said. “We want to use seismology to learn why Mars formed the way it did, and how planets take shape in general,” said Bruce Banerdt, Insight’s principal investigator NASA’s Jet Propulsion Laboratory in Pasadena, California via an agency-issued release.
Quakes are the seismic waves given off when rocks crack or shift. These waves travel at different speeds depending on the geological materials they pass through. Seismometers, like InSight’s SEIS instrument, measure the size, frequency and speed of quakes, giving researchers a “snapshot” of the material they travel through.
“A seismometer is like a camera that takes an image of a planet’s interior,” Banerdt said. “It’s a bit like taking a CT scan of a planet.”
The geological record of Mars includes lighter rocks and minerals which rose from the planet’s interior to form its crust, with heavier rocks and other materials sinking to form the mantle and core. By learning how these materials form layers, scientists should be able to explain the different ways that planets can evolve, an essential factor in understanding where life can appear in the universe.
Whenever a quake occurs on Mars, it should give InSight a snapshot of the Martian interior. The mission team estimates the lander should observe between a couple dozen to several hundred quakes during the mission. Small meteorite impacts will also provide seismic snapshots.
“It will be a fuzzy picture at first, but the more quakes we see, the sharper it will get,” Banerdt said.
InSight isn’t the first mission to do seismology on another world. The Apollo missions put four seismometers on the Moon. Astronauts exploded mortar rounds to create vibrations, offering a glimpse about 328 feet (100 meters) beneath the lunar surface. They also crashed the upper stages of rockets into the Moon, generating waves that enabled them to probe its crust. Scientists detected thousands of moonquakes and meteorite impacts.
Seismology on Mars was first attempted using the Viking landers in the late 1970’s. Unfortunately, the seismometers were located on top of the landers, which swayed in the wind on shock absorber-equipped legs.
“It was a handicapped experiment,” Banerdt said. “I joke that we didn’t do seismology on Mars — we did it three feet above Mars.”
InSight will avoid these problems by using its robotic arm to place a seismometer directly on the surface and cover it with a wind and thermal shield. InSight should also use the arm to place a self-burrowing probe designed to measure heat from the planet’s interior.
Video courtesy of NASA/JPL-Caltech
Jim Sharkey
Jim Sharkey is a lab assistant, writer and general science enthusiast who grew up in Enid, Oklahoma, the hometown of Skylab and Shuttle astronaut Owen K. Garriott. As a young Star Trek fan he participated in the letter-writing campaign which resulted in the space shuttle prototype being named Enterprise. While his academic studies have ranged from psychology and archaeology to biology, he has never lost his passion for space exploration. Jim began blogging about science, science fiction and futurism in 2004. Jim resides in the San Francisco Bay area and has attended NASA Socials for the Mars Science Laboratory Curiosity rover landing and the NASA LADEE lunar orbiter launch.
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