The latest Mars lander is six metres long

THE MARS INSIGHT lander should have arrived on the surface of the red planet at the end of November, after a seven-month journey. Though landers (and their moving cousins, rovers) are not new to Mars’ surface, Insight will be the first to collect data about the planet’s geophysical make-up. To do that, it will utilise its surprisingly unique feature: a robotic arm that lifts instruments off the lander and places them on to the ground. While previous landers included instruments attached to arms, Insight will have to drop its two main instruments: a seismometer, which will measure ‘Marsquakes’ and seismic waves to learn more about Mars’ internal layers, and a heat-flow probe, which will dig itself five metres below the surface of Mars like a self-hammering nail and get a geothermal measurement (underground temperature). That sounds simple, but it’s not: The seismometer is extremely sensitive, and because the lander was calibrated for Martian gravity, which is weaker than Earth’s, Insight couldn’t actually lift the seismometer in tests here at home. Engineers had to build a replica of the same shape but altered to match its Martian weight.

So what’s the point of digging around in the crust of our planetary neighbour? First, says Troy Hudson, a member of Insight’s engineering team, it will help us figure out why Earth and Mars, which started out relatively similar billions of years ago, are so different. Earth has tectonic plates, for example, while Mars does not. Earth also has a magnetic field – Mars used to, but now it does not. But beyond that, knowing more about the red planet will also help with searches well beyond our solar system. ‘These geological features are all helpful for life as we know it,’ Hudson says. ‘As we discover more planets around other stars, we want to understand the probability and the likelihood that these phenomena might occur in other places.’