We’ve photographed Mars from orbit, drilled into its surface and sniffed its atmosphere looking for clues on how a warmer, wetter world went cold and dry. Now it’s time to go deep.
In March 2016, NASA plans to launch the InSight Mission that will place a single lander on Mars to study its deep interior. Named InSight (Interior Exploration using Seismic Investigations, Geodesy and Heat Transport), it will land in September and spend the next two years investigating the planet’s interior to determine the makeup of the Martian core, the thickness of the the crust and the composition of the mantle, the broad zone of rock between crust and core.
Using the SEIS seismometer, we’ll learn about the number and distribution of marsquakes caused by both internal stresses and meteorite impacts. The information will also help us unravel the structure of Mars’ hidden interior just as the study of earthquakes here on Earth has taught us much about the internal structure of the ball beneath our feet. We know that Earth’s center is avocado-like with a solid inner core of iron-nickel surrounded by a softer, liquid outer core.
The lander packs a unique “mole” or heat probe that can hammer over 16 feet (5-meters) into the Martian crust, deeper than all previous drills, scoops, arms and probes, to learn how much heat flows from the planet’s interior. As the mole burrows down in the crust it will pull a tether of heat sensors along to measure the increase in temperature with depth. Heat flow sounds obscure but it’s critical in understanding where and how mountain ranges and volcanoes form.
Another experiment, the Rotation and Interior Structure Experiment or RISE, will use variations in the receive time of the lander’s radio signals to measure minute wobbles in Mars’ rotation axis that will tell us more about the size of the core and whether it’s solid or not.
Because Mars has been less geologically active than the Earth – it lacks plate tectonics that recycles and renews its crust – it actually retains a more complete record of its history in its own basic planetary building blocks of core, mantle and crust. Scientists hope that insights from InSight will help us understand the forces that shaped not only Mars but all the rocky planets across the solar system.
Don’t forget the cameras! InSight will carry a navigation camera similar to those on the the Mars rovers mounted on the lander’s arm. In addition to black and white panoramas, it will shoot photos of the instruments on the lander’s deck and a 3-D view of the ground where the seismometer and heat flow probe will be placed. Mission controllers will also use it to guide them in the placing of the instruments to the ground. A second wider angle camera like the hazcams on the rovers will provide a second perspective on the scene.
I don’t know about you, but I can never get enough Mars. I’m eager to see the mission underway.