After 3 years on Mars, InSight has revealed the heart of the planet!

On November 26th, 2018, NASA’s InSight mission landed on Mars, and a few weeks later, the SEIS seismometer was deposited on the surface of the red planet. Since February 2019, SEIS’s Very Wide Band sensors, designed by IPGP, have been continuously measuring vibrations in the Martian soil. In the latest episode of the Université de Paris web series “SEIS, the seismometer on Mars”, scientists from the InSight team at IPGP and Université de Paris explain how the ten or so earthquakes detected on Mars by these ultra-sensitive sensors are, for the first time, revealing the internal structure of Mars right down to its core.

After a few months of operation in which the sensor (and the researchers) learned to live in the harsh Martian environment, SEIS recorded its first “Mars quake” on April 7, 2019. More than two and a half years later, from a dozen low-frequency earthquakes detected on Mars by the very wide-band seismometer, and despite the difficulties associated with ambient noise and the planet’s low seismicity, the international InSight mission team has been able to unveil the internal structure of Mars. In three studies published on July 23 in the journal Science, it reveals, for the first time and thanks to the analysis of seismic waves, reflected and modified by the planet’s internal interfaces, an estimate of the size of the core, the thickness of the crust and the structure of the mantle.

• The InSight team takes a look back at this discovery on video: See the video “SEIS, the heart of Mars”.

After more than two years of Martian seismic monitoring, the first model of Mars’ internal structure has been obtained. And, as is often the case in planetary exploration, new questions are being raised about crustal alteration and the implications of this model for the formation and evolution of Mars. With the two-year extension of the InSight mission and the additional electrical power obtained following the cleaning of its panels carried out by JPL, new data will consolidate and further improve these models.

And for the seismometer, another adventure is about to begin, as the SEIS twin is set to equip a forthcoming NASA mission to study the seismicity of the far side of the Moon!