Robots

We can save the Mars robots from dust death as despite all odds they refuse to die.

Last week, NASA Mars InSight lander died slowly from dust. The robot, built to study the tectonic activity on Mars, has been running on less and less power for months as its 25-square-foot (4.2-square-meter) solar power array gradually vanished beneath a thick blanket of dust.

NASA declared the mission dead on Wednesday (Dec. 21), saying it hadn't heard from the lander in days. InSight, which landed in the flat, seemingly uninteresting Elysium Planitia basin south of Mars' equator in November 2018, lasted two years longer than expected. Many people wondered if anything could have been done to save the otherwise perfectly healthy robot, which had been delivering groundbreaking science about Mars' internal life.

Cost vs. benefit

NASA explained the trade-offs engineers faced when designing a mission for the notoriously dusty Mars in a Twitter thread (opens in new tab) posted about six weeks before InSight's demise. "People frequently ask if I have a way to dust myself off (wiper, blower, etc.). It's a reasonable question, and the short answer is, "NASA tweeted from the lander's account. "Such a system would have added cost, mass, and complexity. The simplest and most cost-effective way to achieve my objectives was to bring solar panels large enough to power my entire mission, which they did (and then some!)."

Season of dust storms

Space agencies typically try to avoid Mars' dust storm season, which occurs during the planet's northern autumn and winter seasons. Because a year on Mars lasts about two Earth years, most recent landers and rovers, including InSight, have survived multiple dust storm seasons. The Curiosity rover, now in its 11th year on Mars and still going strong, has witnessed several dust storm seasons. The rover even measured the amount of dust that accumulated on its sensors and deck (opens in new tab), revealing how seasonal winds and dust devils help rovers last longer. InSight was unlucky when it came to Mars' natural cleaning aid. There will be no dust devil car wash.

Dust devils have been spotted cleaning NASA's older Mars rovers, Spirit (opens in new tab), and Opportunity. Opportunity, in particular, was able to continue its mission for more than 14 years, outlasting its three-month lifespan dozens of times. Regular dust devil sweeps and wind-driven cleaning events were critical to that record-breaking mission. Finally, in 2019, a massive dust storm overwhelmed the little rover, bringing an end to its record-breaking journey of discovery.

InSight appeared to be in a "particularly unfavorable position for dust removal," according to Mike Williams, Chief Engineer at Airbus Defence and Space, which is currently rethinking the dust defense approach for the European ExoMars Rosalind Franklin rover.

Solar panels that tilt

When it comes to dust-proofing Mars-exploring spacecraft, Williams agrees that NASA's approach of oversized solar panels is the best, safest, and cheapest. However, Airbus is currently considering the addition of a dedicated dust defense capability, and they have plenty of time to do so. The mission, which was built in collaboration with Russia, was put on hold following Russia's invasion of Ukraine. The planned launch in September has been canceled, and Airbus is now storing the ExoMars rover in a clean room while some critical components, originally built by Russia, are replaced.

When the ExoMars mission was first conceived, engineers considered a variety of dust-cleaning technologies, including brushes, wipers, gas blowers, and electrostatic wipers, according to Williams. They decided at the time that the rover, whose nominal mission in Oxia Planum was only 180 Martian days, or sols, didn't need to self-clean. With a new launch date of no earlier than 2028, they are reconsidering their strategy. To get rid of dust, engineers considered a variety of dust-cleaning technologies, including brushes, wipers, gas blowers, and electrostatic wipers, according to Williams. They decided at the time that the rover, whose nominal mission in Oxia Planum was designed to last only 180 Martian days, or sols, didn't need to self-clean. With the new launch date set for no earlier than 2028, they are reconsidering their strategy.