Based on the analysis of marsquakes recorded by NASA's InSight mission, the structure of Mars's crust has now been determined in absolute numbers for the first time. Beneath the InSight landing site, the crust is either approximately 20 or 39 kilometers thick. That is the result of an international research team led by geophysicist Dr. Brigitte Knapmeyer-Endrun at the University of Cologne's Institute of Geology and Mineralogy and Dr. Mark Panning at Jet Propulsion Laboratory, California Institute of Technology (Caltech). InSight stands for "Interior Exploration using Seismic Investigations, Geodesy and Heat Transport." NASA's lander, which landed on Mars on 26 November 2018, explores the crust, mantle and core of the red planet. The paper "Thickness and structure of the Martian crust from InSight seismic data' will appear in Science on July 23.