The Martian climate has given a lander more time to capture earthquakes.
NASA Lander InSight landed Mars in November 2018 with tools intended to help scientists see deep into the Red Planet. InSight works in sunlight and dust has coated its solar panels, leaving the lander capable of generating only a tenth of the power it could muster as a newcomer to Mars. Scientists expected it would running out of energy by the end of the summer, but InSight is still collecting scientific data and may continue to do so for several months to come, potentially even as late as January.
“However, if we get a dust storm or something, then it may be sooner,” Chuck Scott, InSight project manager at NASA’s Jet Propulsion Laboratory in California, which runs the mission, told Space.com. “We have gone so low now that if we have any kind of weather on Mars, that could mean the end of the mission.”
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How much energy InSight can produce each Martian day, or sol, depends on two factors: the dust accumulated on its solar panels and the dust in the Martian atmosphere. During a dust storm, both factors can cause problems.
Many Martian explorers have faced the same problem: although the perseverance And Curiosity the thieves use nuclear energy, their predecessors the twin Spirit And Chance the thieves both fought the accumulation of dust ea sandstorm ended the Opportunity mission.
But Spirit and Opportunity found unexpected help from “cleansing events,” probable gusts of wind – from, ironically, dust storms – that cleared the dust and increased their energy production. InSight didn’t have that kind of luck and tries to shake off the dust and mimic a cleaning event by spraying dust near the panels hasn’t done much.
So already in June 2021, the staff of InSight valued that the lander would be forced to close this spring. By May, they thought the spacecraft could continue until late summer and implemented a mode intended to prioritize power to the seismometer. The team also reverted InSight’s rules to avoid the protective “safe mode” spacecraft usually enter when something is wrong – it will work until it does.
But the lander still works. “Since then, we’ve changed our operations a bit and we’ve also had some time on Mars which is lucky for us, because we haven’t had any major sandstorms or anything,” Scott said.
Now, InSight is entering a season during which scientists usually see some regional sandstorms, which they thought would hasten the lander’s demise. But the season is starting softer than ever before, giving InSight a respite.
“We expected there would be some regional sandstorms and that this would cause a problem for us,” said Scott. “But looking at the weather this year, people predicting the weather on Mars believe we won’t see regional storms for another couple of weeks.”
When InSight landed, it could generate 5,000 watt-hours per sol (which is about 40 minutes more than a Land day). Since then, the potency has decreased. “Whenever there is a storm or something on Mars, it will come down,” Scott said. Some storms have reduced production by 100 watt-hours, others as low as 1,000, he added. “It will vary depending on how big the storm is.”
The spacecraft is currently producing around 400 watt-hours per sol, which is less than a tenth of the capacity it had on landing. The lander must produce about 300 watt-hours per sol to keep the seismometer, communications and basic functions running, Scott said.
One day, when the lander hasn’t hit it, it will put itself in what mission personnel call a “dead bus,” when the spacecraft silently runs out of its last battery. “It will come to a point where the battery will fail and there will be no way to restart,” said Scott.
Mission personnel aren’t sure how long the final battery drain will last, but it could take a couple of years. And there’s a small chance that a friendly gust of wind during that time will remove enough dust for the solar panels to get back to work.
“Based on what we have seen, we believe the likelihood of this happening during the period of time before the battery actually fails is perhaps 10%,” said Scott. “So once we get into a dead bus, that’s pretty much the end of the mission.”
But even with a “dead bus” looming, the team is working to get all the data possible from InSight. The mission scientists have determined that the lander can go down to eight-hour observation sessions and still provide useful data. For now, the lander is using about half the day to recharge and half the day to run its seismometer. As energy supplies dwindle, that balance will shift until the lander watches for eight hours at a time, so it takes a couple of sols to recharge between sessions.
“We’re still getting earthquakes; we can still see things happening in the seismometer,” Scott said, noting that the lander captured an earthquake in late August.
“We expect it to continue until the end of the mission,” he said. “We’re just really trying to get as much science out of the vehicle as possible, all the way to his death.”