Martian weather gave a lander more time to catch the marsquakes.
from NASA InSight Lander landed on March in November 2018 with tools to help scientists see deep inside the Red Planet. InSight runs on sunlight, and dust has coated its solar panels, leaving the lander capable of generating only a tenth of the power it could harvest as a Martian newcomer. Scientists expected the lander run out of power by the end of the summer, but InSight is still collecting scientific data and could continue to do so for several months, even until January.
“However, if we have a dust storm or something, it may be sooner,” Chuck Scott, project manager for InSight at NASA’s Jet Propulsion Laboratory in California, which manages the project, told Space.com. assignment. “We’ve sunk so low now that if we get any kind of weather on Mars, it could mean the end of the mission.”
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The amount of energy InSight can produce each Martian day, or soil, depends on two factors: the dust accumulated on its solar panels and the dust in Martian atmosphere. During a dust storm, both of these factors can cause problems.
Many Martian explorers have faced the same problem: although the Perseverance and Curiosity rovers use nuclear energy, their predecessors the twin Spirit and Opportunity rovers both struggled with the buildup of dust, and a dust storm ended the Opportunity mission.
But Spirit and Opportunity found unexpected help in “cleansing events”, likely gusts of wind – ironically, dust storms – which lifted dust and increased their energy output. InSight hasn’t had that kind of luck and tries to shake off the dust and mimic a cleaning event by pouring dust near the panels didn’t do much.
Thus, as of June 2021, InSight staff valued that the lander would be forced to stop this spring. In May, they thought the spacecraft could go on until the end of the summer and implemented a mode intended to prioritize power to the seismometer. The team also reset InSight’s rules to avoid the protective “safe mode” that spacecraft typically enter when something goes wrong – it will work until it doesn’t.
But the lander still works. “Since then we’ve changed our operations a bit and we’ve had some time on Mars as well, which is lucky for us because we haven’t had any big dust storms or anything,” said Scott.
Now InSight is entering a season in which scientists typically see regional dust storms, which they believe will hasten the lander’s demise. But the season is off to a slower start than in the past, giving InSight a reprieve.
“We were kind of expecting there to be regional dust storms and that would be a problem for us,” Scott said. “But looking at the weather this year, the people who forecast this weather on Mars, they believe we’re not going to see any regional storms for a few more weeks yet.”
When InSight landed, it could generate 5,000 watt hours per ground (about 40 minutes longer than a Earth daytime). Since then, the potency has declined. “Whenever there’s a storm or something on Mars, it drops,” Scott said. Some storms reduced output by 100 watt hours, others by more than 1,000, he added. “It will vary depending on the size of the storm.”
The spacecraft currently produces around 400 watt hours per ground, which puts it at less than a tenth of the capacity it had on landing. The lander needs to produce about 300 watt-hours per ground for the seismometer, communications and basic functions to work, Scott said.
One day, when the lander hasn’t touched this, it will go into what mission personnel call “dead bus”, when the spacecraft silently drains the last of its battery. “It will get to a point where the battery will fail and there will be no way for it to restart,” Scott said.
Mission personnel don’t know exactly how long the final battery discharge will last, but it could take a few years. And there’s a small chance that a friendly gust of wind during this time could blow off enough dust to get the solar panels back to work.
“Based on what we’ve seen, we think the chance of this happening in the run-up to battery failure is maybe 10 percent,” Scott said. “So once we enter a dead bus, that will be pretty much the end of the mission.”
But even with the “dead bus” looming, the team is working to get all the data from InSight possible. Mission scientists have determined that the lander can go down to eight-hour observing sessions and still provide useful data. For now, the lander uses about half a day to recharge and half a day to operate its seismometer. As power supplies dwindle, this balance will change until the lander observes for eight hours at a time, and then needs a few 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 caught an earthquake in late August.
“We expect this to continue until the end of the mission,” he said. “We’re really trying to get as much science as possible on the vehicle, all the way to the end until it actually dies.”