NASA scientists are working hard to keep the barren, unpredictable landscape of Mars from claiming another of its robots. While the world was focused on the Perseverance rover and the Ingenuity helicopter, a different Mars robot is in peril.
The InSight Mars lander has lived on the red planet for nearly three years, recording earthquakes, weather patterns, and attempting to probe Mars’ core. It relied on solar panels for power during its 3-year stay on the red planet, but an unexpected amount of dust recently dropped the panels’ efficiency down to 27% of their total capacity.
Usually, this isn’t a problem, since one of the 10,000 dust devils the InSight has tracked over the years blows the debris away in what NASA calls a “cleaning event.” But Mars’ windy season is over, according to NASA, and no storm came close enough to clear the panels. The planet is also heading towards the farthest point from the Sun in its orbit, meaning even less energy for InSight.
To save the lander from going completely dead, the InSight team is deciding over the coming weeks which equipment needs to be shut down to conserve energy, according to NASA and Business Insider. The lander is already in “hibernation mode” and might need to be turned off entirely at Mars’ farthest point from the sun.
Insight lander and the dangers of outer space
This situation shows why designing machines to operate on Mars — and anywhere else off our planet — is so treacherous. The red planet is in a constant state of flux, and temperatures can range from 70 to -200 degrees Fahrenheit, depending on the season and location. Storms with heavy winds batter the surface. Even well-established facts about Mars, like its unpredictable winds and storms, can’t be relied upon 100% of the time. And it’s stating the obvious, but there are no repairs on Mars. When the Spirit rover’s front wheel broke, NASA just drove it backward for years, dragging the broken part behind it.
Dust accumulation and storms have proven to be the most dangerous situations for robots on Mars. The Soviet Union landed the first rover on Mars in 1971, called the PrOP-M, but lost communication 20 seconds after initial transmission. The prevailing theory is the robot was damaged by a powerful dust storm taking place at the time of landing. The American rover Spirit got lodged in sand in 2010, and without the use of all of its wheels, it was irreparably stuck. The Spirit’s twin, Opportunity, was lost in a massive dust storm in 2018.
A notable exception to the curse of Martian Dust Death is the American rover Sojourner, which went dark after its lander and communications relay, called Pathfinder, suffered a battery failure and died.
Why there’s still hope for the Insight lander
NASA has an incredible track record of underpromising and overdelivering with its Mars robots. The Opportunity rover lasted more than 50 times its original 90-day lifespan and puttered around Mars for 15 years. Its twin, the Spirit rover, lasted six years. InSight’s original mission ran from November 2018 to November 2020, and the team now expects to collect data until 2022.
This longevity is due in part to the rigorous testing process that NASA puts the rovers through on Earth. NASA scientists blasted the most recent rover, Perseverance, with more than 140 decibels of sound to simulate the noise of a rocket launch, heated it in a vacuum chamber with powerful lamps to imitate the sun, and then chilled it down to minus 200 degrees Fahrenheit to test protection against cold Mars nights.
Newer rovers also have a more independent power source. Instead of using solar panels, the Curiosity and Perseverance rovers are powered by plutonium, which decays and releases heat. That heat is converted into electricity by a thermoelectric generator and has the added bonus of warming the rover from sub-zero Martian temperatures.
Plutonium has been a staple of space exploration, dating back to the Apollo lunar missions. On Mars, the stationary Viking 1 and Viking 2 landers recorded images and data for NASA in the 1970s, powered by a similar plutonium and thermoelectric generator system. Plutonium also provided power for the Cassini, Galileo, New Horizons, Pioneer, Ulysses, and Voyager space probes.
But unlike sunlight, nuclear energy isn’t a renewable energy source. The plutonium outfitted on Perseverance is set to last at least 14 years, according to NASA. When the heat from the radioactive material is no longer strong enough to support the robot, there’s no other way to power it.
This ticking clock isn’t necessarily a bad thing, though. The rover’s official mission is only about two Earth years, and if there’s more to do, the nuclear-powered Pioneer probe set the precedent for a 30-year lifespan on a plutonium battery.
If InSight makes it through the harsh Martian winter, though, there’s no real end in sight for how long the lander could last.
“We’ve got a great vehicle and a top-notch team; I’m looking forward to many more new discoveries from InSight in the future,” Bruce Banerdt, Insight’s principal investigator, said in a press release.