Secrets Of Mars

How a new fleet of missions will help us to solve the red planet’s mysteries

- Nicholas Booth and Elizabeth Howell

The Red Planet keeps a tight rein on its secrets. Many enduring mysteries about Mars have taken years of research to resolve, only to be replaced by newer, ever more puzzling ones. If exploring Mars directly over the last five decades has taught us one thing, it is sure that even today – after intense scrutiny from above, on the surface and now probing directly below – the Red Planet can still spring surprises.

Mars is a freezing, desiccated desert on which a constant swirl of dust plays havoc with delicate instruments. Worse, mechanical failures and anomalies cause headaches for those who have sent robots in their stead. Even so, most researchers wouldn’t have missed any of it for the world.

“It’s been an amazing journey,” says Dr. Anna Horleston, a seismologist based at Bristol University. “My study faces south, and as it gets dark I have been able to see Mars rise through the window in the early evening. And then I can look down at my screen at wiggly lines, and know they have come from there.”

Those lines represent one of the holy grails of Mars research, the telltale signs of seismic activity. NASA’s InSight (Interior Exploration using Seismic Investigations, Geodesy, and Heat Transport) has been making detailed maps of the Martian interior for the first time. It had long been suspected that the Red Planet had a small core and was more Moon-like in terms of its activity, certainly not as seismically active as Earth. Since the InSight landing in November 2018, more than 450 marsquakes have been identified. Residual heat deep within the interior is still causing small-scale seismic waves.