by NASA’s Mars InSight lander slowly died of dust last week. For months and months, the robot, built to study tectonic activity on the Red Planet, has been running on less and less energy as its 25-square-foot (4.2 square meter) solar array has gradually disappeared under a thick blanket of dust. . On Wednesday (Dec. 21), NASA announced that it had not heard from the lander for days, officially declaring the mission dead.
Insightwhich landed in the flat, seemingly uninteresting basin of Elysium Planitiasouth of it Marsequator in November 2018, exceeded the expected duration of its mission by two years. However, many questioned whether anything could have been done to save the otherwise perfectly healthy robot, which was delivering cutting-edge science on inner life of Mars.
Related: NASA’s Mars InSight lander ends mission after running out of power
Cost versus benefit
In a thread on Twitter (opens in new tab)published about six weeks before InSight’s eventual collapse, NASA explained the trade-offs engineers faced when planning a mission to notoriously dusty Mars.
“People often ask: don’t I have a way to dust myself off (wiper, fan, etc.)? It’s a fair question and the short answer is this,” NASA wrote on the lander’s Twitter account. “A system like this would have added cost, mass and complexity. The simplest, most cost-effective way to achieve my goals was to bring solar panels large enough to power my entire mission – which they did (and then some!) .”
Dust storm season
When sending landers to Mars, space agencies usually try to avoid those on the planet dust storm season, which occurs during the northern seasons of Martian autumn and winter. Since a year on Mars lasts about two Earth years, most of the recent landers and rovers, including InSight, have made it through several seasons of dust storms. The Rover curiosity, now in its 11th year on Mars and still going strong, has seen several seasons of dust storms. The rover even took measurements (opens in new tab) of the changing amount of dust that accumulates on its sensors and deck, revealing how seasonal winds and dust devils help the rovers keep moving for longer. As it turns out, InSight has been rather unlucky when it comes to Mars’ natural cleaning aid.
Dust free devil car wash
Dust devils have famously been seen cleaning up NASA’s older generation of Mars rovers, Spirit (opens in new tab) and Opportunity. Opportunity, in particular, was able to continue its mission for more than 14 years, exceeding its planned three-month lifespan by dozens of times. Regular dust devil sweeps and wind-driven scouring events played a major role in this record-breaking mission. In the end, a huge dust storm in 2019 finally engulfed the little roverending the record-breaking voyage of discovery.
According to Mike Williams, Chief Engineer at Airbus Defense and Space, which is currently reviewing the dust protection approach for the European ExoMars Rosalind Franklin roverInSight appeared to be in a “particularly unfavorable position for dust removal.”
Tilting solar panels
Williams agrees that NASA’s approach to oversized solar panels is the best, safest and cheapest when it comes to dust-proofing Mars-exploring spacecraft. However, Airbus is currently looking at adding a special dust protection capability and has plenty of time to do so. The mission, built in cooperation with Russia, was suspended after Russia invaded Ukraine. The planned September launch was canceled and Airbus is now storing the ExoMars rover in a clean room as some critical components, originally made in Russia, need to be replaced.
“Sizing the arrays to be able to handle the least amount of sunlight reaching them because of the dust is the best and simplest solution,” Williams told Space.com. “It’s the lowest level of complexity. It requires the least number of subsystems and functions and therefore has the least risk. From a mission design perspective, that’s definitely the most preferable way to go about it.”
Williams said that when the ExoMars mission was first designed, engineers looked at a variety of dust-cleaning technologies, including brushes, wipers, gas blowers and electrostatic wipers to get rid of the dust. At the time, they decided that the rover, whose nominal mission to Oxia Planum was designed to last only 180 Martian days, or sol, didn’t need to clean itself. With the new release date now expected no earlier than 2028, they are rethinking their approach again.
“With ExoMars now being reborn, we’re looking at potentially restoring some of that capability,” Williams said. “We could use something like tilting the solar panel to potentially remove some of that dust. It would also help point the panels more efficiently at the sun, which might also have some benefits.”
Williams added that Airbus engineers, like those at NASA, must come to terms with the fact that ExoMars, like other Mars rovers, may eventually succumb to dust, and she won’t be disappointed if the rover is limited to its lifetime. his planned mission. Although they hope to get some help from the Martians like Spirit and Opportunity.
“It’s just, it’s just the way with space missions, unfortunately,” Williams said.
InSight’s self-cleaning effort
Although InSight wasn’t built to mop up dust on its own, NASA made some last-ditch efforts to help the lander clear some of the dust in the final months of its life, as the amount of electricity generated by its panels decreased.
In May, ground controllers instructed InSight’s robotic arm to sprinkle some sand on one of the lander’s dust-covered panels. As the wind blew the grains of sand onto the panel, they actually picked up some of the dust along the way, reducing the thickness of the dust blanket that blocks the sun.
The operation allowed the lander to acquire about 30 watt-hours of power per sol at that time, according to a NASA statement (opens in new tab).
In the end nature won. As always happens. And InSight certainly didn’t go down without a fight.
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