Pile it on
March was a busy month for InSight and SEIS. Not only did the seismometer detect two large quakes, but the spacecraft also began working toward one of its next mission goals: scooping up dirt to cover the cable linking SEIS to the lander. This will insulate the cable against temperature swings, reducing noise in its data.
“The seismometer is on the surface and, although protected by a shield, it does pick up wind and is exposed to big daily thermal cycles,” Suzanne Smrekar, InSight’s deputy principal investigator, told Astronomy last year. “Thus, we need to do careful work to remove non-seismic sources using our wind, temperature, and pressure sensors. This slows down publication of results — we don’t want to interpret a glitch as a quake!”
Over the course of a single sol, which lasts about 24 hours and 40 minutes, surface temperatures at InSight’s location can swing between about 32 degrees Fahrenheit (0 degrees Celsius) during the day to –148 F (–100 C) at night. So, covering the cable with dirt will help keep it insulated, allowing SEIS to better hear what it came for: real marsquakes.
The lander began its task March 14, using its steam shovel-like arm to pick up and drizzle a scoop of martian soil over SEIS’ dome. That allowed the dirt to slide down the curved surface of the dome before falling on top of the cable, all without risking the robotic arm interfering with the dome’s seal against the ground. The lander will now continue to drop scoop after scoop of dirt along the cable’s length.
With less interference from wind and weather, researchers hope the seismometer will be even more sensitive to marsquakes in the future, allowing them to more quickly identify real events as well as delve even deeper beneath the Red Planet’s surface to discover what lies within.