NASA launched its Mars InSight lander from California on May 5 – the first interplanetary launch from the Vandenberg Air Force Base – and it is expected to reach its destination in late November. Sending a lander to Mars will allow researchers to peer inside the planet and learn about what’s below the surface, as well as the planet’s history. UBC planetary scientist Catherine Johnson is the only researcher from Canada involved in the mission.
What makes this mission unique?
The mission is the first time we will deploy a seismometer on the surface of another planet. Astronauts installed seismometers on the Moon as part of the Apollo missions, but InSight is the first mission to put a seismometer on another planet’s surface. The seismometer will tell us where and when “marsquakes” (earthquakes, but on Mars) occur and provide a look at Mars’ interior.
What is your role in this experiment?
I’ll be involved in studying marsquakes. We want to know where marsquakes occur geographically and at what depth, to try and understand where there are active faults.
A big part of what we’ll be doing is working with data returned from the magnetometer. This is the first time an instrument that measures the magnetic field will be deployed on the surface of Mars. We’ll hope to get some information about the magnetization of rocks near the surface and perhaps more importantly, to be able to measure the magnetic field and how it varies over time, for example, between day and night. Those variations might be able to tell us how electrically conductive the rocks in the interior of the planet are and, in turn, help us understand the composition and water content of those rocks.
This will be an important experiment to try and understand the history of water on the surface of Mars. We’d like to know how much is tied up in the interior of Mars to understand the water inventory of the planet.
How will we use this information to understand the planet’s history?
We know from surface measurements from Mars Rovers and from images and satellites we’ve had in orbit for the last couple of decades that the planet’s early history was a very different place than it is today. Surface water and ice were much more abundant and the atmosphere was much thicker.
The big question is where did the water come from and where did it go? We know the history of water on the planet’s surface and in its atmosphere, but we don’t know about the interior and how much water is tied up in rocks inside Mars. Understanding the water content in the interior of the planet is a key part of being able to understand the history of water.
It’s also important for comparative studies to better understand how much a planet changes during its history. Very early in its history, Mars went through the same general processes as Earth-heavy materials (metals) sank to the center to form the iron core, and rocks, which are lighter “floated” on top forming the crust and the mantle.
Mars, like Earth and Venus, is a rocky planet but it isn’t as large, so it has undergone less reworking from its interior to its exterior over time. It has had tectonics and volcanism like Earth and Venus but the record of early processes should still be seen in its interior structure. By looking inside Mars, we hope to get a window into the early processes that all these rocky planets have experienced.