NASA has postponed its next Mars mission for at least two years.

NASA has examined the surface of Mars with rovers and satellites, but gaining a fuller understanding of the planet requires looking beneath the surface. That’s the goal of the InSight mission, which was supposed to launch next year. However, a problem with the main instrument has resulted in a delay that could end up with the entire mission being scrubbed. This is a setback for Mars research to be sure.

InSight (Interior Exploration using Seismic Investigations, Geodesy and Heat Transport) is a stationary lander with the goal of analyzing the interior of Mars, which would be only the second planet examined in such a way after Earth. By learning more about the internal structure of mars, scientists can draw conclusions about the evolution of not only that planet, but perhaps all rocky planets.

To accomplish this, NASA equipped the lander with three main instrument packages. There’s the Seismic Experiment for Interior Structure (SEIS), Heat Flow and Physical Properties Package (HP3), and Rotation and Interior Structure Experiment (RISE). The SEIS instrument (seen below as a prototype) is the most important part of the mission, and sadly, that the cause of the delay as well. This sensor will be placed on the surface to monitor any seismic activity within Mars, everything from shifts in the crust to responses to meteorite impacts. For this incredibly sensitive seismometer to work, it needs to be vacuum sealed. Engineers have detected a broken seal on the SEIS package that will probably take a few months to fix.