Amid reports of declining power levels, NASA's InSight lander looks set to keep its science instruments running for most of summer.
InSight has been on Mars since 2018 and far surpassed its original mission duration. However, despite the probe's longevity, its lifespan is dictated by the twin masters of funding and power. The former is set to run until the end of 2022 as part of a two-year mission extension. The latter, however, is proving a challenge as dust accumulates on the lander's solar panels.
Because of the hard work of my team, solar power has improved. At the start of the year we thought we’d stop collecting science for six months; now I’ll be operating for most of the summer. This is all “bonus” science since I’ve completed my main mission goals. pic.twitter.com/ovC52IjIVo— NASA InSight (@NASAInSight) June 25, 2021
Although the decline in power was expected, the team had hoped for some of the "cleaning events" experienced by the Spirit and Opportunity rovers. However, while InSight's weather sensors detected passing whirlwinds, none managed to lift any dust from the panels. Attempts to use the solar panel deployment motors to shake off some of the dust also failed.
Reports last week painted a somewhat gloomy picture for the lander, with instruments looking likely to be turned off in order to eke out the available power ahead of Mars being at its furthest point from the Sun.
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Earlier this month, engineers turned to a somewhat counterintuitive method of cleaning the panels where sand was trickled from the scoop of the lander's robot arm near the panels in the hope that the larger grains might carry off some of the smaller dust particles. The procedure appears to have worked to the extent that power margins exist to keep InSight's instruments running. For now, at least.
A NASA spokesperson told The Register: "We've been expecting this for almost a year now... The falling power was a natural consequence of Mars getting farther from the Sun, regardless of how much dust was on our panels."
It has not been a completely smooth mission for the lander. Most notably, a key part of the payload, the "mole" of Heat Flow and Physical Properties Package (HP3), was effectively written off earlier this year after failing to burrow anywhere near the hoped-for depth of five metres due to a surprising soil type. However, the seismometer (SEIS), radio experiment (RISE), and the weather instruments remain operable.
The mission has been extended until December 2022, although without some "cleaning events" the team has a challenging time ahead. While the latest update proudly proclaimed that things should keep ticking over during most of the summer, the Mars Solar Conjunction, due in October, will cut communications while the Earth and Mars are on opposite sides of the Sun. Power levels will also drop once more in 2022.
Why not a brush or blower to clear the dust? "Equipping the spacecraft with brushes or fans to clear off dust would add weight and failure points," explained NASA.
"Some members of the public have suggested using the Ingenuity Mars Helicopter's whirring blades to clear off InSight's panels," added the agency, "but that's not an option, either: The operation would be too risky, and the helicopter is roughly 2,145 miles, or 3,452 kilometers, away."
So there. ®