UBC professor hopes to glean new insights about Martian interior as part of NASA mission

At 4:05 a.m. on May 5, an Atlas-V rocket climbed into the dark, foggy skies above the Vandenberg Air Force Base in California, carrying a landing craft destined for Mars as part of NASA’s InSight mission, which aims to provide important new insights about the Martian interior.

The successful launch marked a major milestone for Dr. Catherine Johnson, a professor in the UBC department of earth science who has been involved with the mission for nearly a decade.

There are three main kinds of data that the InSight lander will collect: seismic data, temperature data and data about how Mars moves through space.

To collect the seismic data, the lander will employ a seismometer, an instrument that can precisely measure planetary tremors.

The lander will collect temperature data using a sensor that will be bored into the planet’s surface, where readings will not be skewed by variables like the presence or absence of the sun. This sensor will track how temperature changes at different depths, which will allow scientists to build a picture of how heat is lost as you move progressively farther from the planet’s core.

In order to determine how Mars moves through space, the lander itself will function as a measurement instrument. It is equipped with radio antennas that will allow scientists to fix its position on the planet and see how that fixed point moves as Mars proceeds on its continual journey around the sun.

With the combination of seismic data and data about the planet’s movement, scientists hope to be able to determine information about the size and composition of its core and mantle.

The lander also has a host of environmental sensors that will primarily serve to allow scientists to control for seismometer readings triggered by factors other than seismic events, but will also enable them to study the local weather patterns in the area around the lander.

Johnson originally became involved with the mission as a member of the InSight seismology team, and once the lander touches down and begins transmitting data, she will assist in analyzing the information collected by the seismometer and parsing out its geophysical implications.

Specifically, Johnson will be looking for what the size and location of tremors picked up by the seismometer can reveal about the composition of the planet’s interior.

She will also be involved in analyzing data from the lander’s magnetometer, one of the environmental instruments that will measure the local magnetic field around the landing site. Data from this instrument is influenced by the electric current flowing through the rocks that make up the planet and can be used to glean information about the water content of these rocks.

The InSight mission ultimately aims to determine the size and composition of the Martian core, as well as the thickness of its crust.

From this information, scientists can build models of how the planet has cooled over time, which could shed light on questions about significant planetary processes like the disappearance of Mars’ global magnetic field and whether that event is linked to the disappearance of its atmosphere.

According to Johnson, the discoveries scientists hope to make about Mars using the mission data could prove invaluable for better understanding some of earth’s early history.

“One of the nice things about studying Mars is it’s big enough to have undergone processes early in its history that are similar among the different planets,” she said.

With new information about Mars, scientists could take what they know about the interiors of earth and planets like Venus and make comparisons that could yield a more complete picture of our planet’s relation to its cosmic neighbours.

“Those kinds of comparisons really give us a good idea about how representative the Earth is,” Johnson said. “Your tendency is to think it’s representative, but it may not be.”

The InSight lander is not scheduled to reach the Martian surface until November 26, but in the meantime, the science team will be busy preparing through exercises like simulated mission days that will allow them to stress test their decision-making frameworks.

When discussing how it felt to be present for the May 5 launch, a major landmark in a project that has spanned almost 10 years, Johnson described a combination of excitement, joy and relief, as well as a sense of fulfillment that those years of work had suddenly become so relevant in the public eye.

“It’s funny,” she said, “because that’s when everybody else is excited about it, and you realize that you have just been living this for a long time.”