NASA Insight lander reveals Mars' deep interiors for 1st time Before NASA's InSight spacecraft touched down on Mars in 2018, the rovers and orbiters studying the Red Planet concentrated on its surface Sunday July 25, 2021 12:47 PM, IANS Washington: NASA's Insight lander has revealed deep interiors of the Red Planet for the first time, confirming that the planet's centre is molten (Earth's outer core is molten while its inner core is solid). Three papers based on the seismometer's data on stationary lander were published in the journal Science, providing details on the depth and composition of Mars' crust, mantle and core. The scientists found the crust was thinner than expected and may have two or even three sub-layers. It goes as deep as 20 kms if there are two sub-layers, or 37 kms if there are three.