NASA's InSight probe is set to start looking "at the interior of Mars".
The probe has successfully landed on the surface of the planet, and will begin collecting data on the planet as a whole, including what's happening deep beneath the surface.
Tanya Harrison, Director of Research for the NewSpace Initiative, Arizona State University, told Gizmodo: "InSight is the first mission sent to look at the interior of Mars. We have so many unanswered questions about its interior because we haven't had a good look at it before."
InSight has delivered three new instruments to the planet's surface: One to measure how heat flows out of the planet, another which will use the planet's poles to study its core, and the final one for hunting "Marsquakes".
Scientists will spend two to three months analysing its landing area to determine where to place two of these three instruments, SEIS or the Seismic Experiment for Interior Structure and HP3 or the Heat Flow and Physical Properties Probe.
A third experiment, the Rotation and Interior Structure Experiment or RISE, sits on the lander itself and will monitor the position of Mars' North Pole to determine how much the planet is wobbling.
The information will be used to study how rocky planets form and evolve, as well as seeking to understand how much tectonic activity Mars has, and how actively things are moving on and below it surface.
Kirsten Siebach, assistant professor in Rice University's Department of Earth, Environmental, and Planetary Sciences, said: "This is a whole new way to compare what's happening on another planet to what we see on Earth. This will help us understand the formation and evolution of planets as a whole."