InSight and the 'Vital Signs' of Mars

Artist's Concept of InSight on Mars

Artist's Concept of InSight on Mars


    InSight studied the deep interior of Mars and was designed to take the planet's vital signs: its pulse, temperature, and reflexes. InSight was the first mission to give Mars a thorough checkup since the planet formed 4.5 billion years ago.

    Previous missions to the Red Planet investigated its surface by studying its canyons, volcanoes, rocks, and soil. But the signatures of the planet's formation can only be found by sensing and studying its vital signs far below the surface.

    Taking the Planet’s Pulse

    Mars Interior Annotated
    Mars' Interior: Artist's rendition showing the inner structure of Mars. The topmost layer is known as the crust, underneath it is the mantle, which rests on a solid inner core.

    The InSight lander carried a seismometer, SEIS, that listened to the pulse of Mars. A seismometer records the waves traveling through the interior structure of a planet. Studying seismic waves tells us about the regions they pass through. They also give us clues about what might be creating the waves. On Mars, scientists suspected that the culprits might be marsquakes, or meteorites striking the surface, and they were able to study those that were detected.

    Checking the Planet's Reflexes

    Like Earth, Mars wobbles a little as it rotates around its axis. To study this, the RISE experiment used InSight’s radio link with Earth to track the location of the lander very precisely. This helped scientists test the planet's reflexes and gave them information about how the deep interior structure affects the planet's motion around the Sun.

    Taking the Planet's Temperature

    The goal of InSight's Heat Flow and Physical Properties Package, HP3, was to burrow deeper into the Martian regolith (broken rocks, sand, and dust) than any of the other scoops, drills, or probes used on other Mars missions. The probe, called the “mole,” attempted to hammer below the Martian surface to measure the planet’s internal temperature. The unexpected crusty layer in the top few inches of the soil meant the self-hammering mole lacked the friction needed to drive itself to a sufficient depth to make the measurements as designed.

    Layers of a Planet
    A Rocky Planet Forms: As a rocky planet forms, the planet-forming material gathers in a process known as "accretion". This material then separates into layers as it cools, which is known as "differentiation". A fully formed planet slowly emerges, with an upper layer known as the crust, the mantle in the middle, and a solid iron core.

    InSight Science Goals

    InSight sought to uncover how a rocky body forms and evolves to become a planet by investigating the interior structure and composition of Mars. The mission worked to determine the rate of Martian tectonic activity and meteorite impacts.

    InSight's Three Science Instruments

    • Seismometer
      SEIS sensed seismic waves to study the crust, mantle, and core of Mars. Meteorites impacting the surface, magma moving at great depths, or movement along a fault can all cause seismic waves on Mars. Studying the depths of Mars with the seismometer tells scientists about the temperature, pressure, and composition of the material that first formed the rocky planets.

    • A Heat Flow Probe
      HP3 was designed to burrow below the Martian surface and investigate how much heat is still flowing out of Mars. Due to the unexpected soil properties it encountered, the mole was unable to take the measurements as designed.

    • RISE
      RISE measured the slightest changes in the location of the lander to reveal how Mars wobbles on its axis. These measurements provide information on the nature of Mars' molten metallic core.

    All of InSight's science tools helped the lander look back in time, to when the rocky planets of the solar system first formed. Their interrelated measurements help inform each other.