NASA’s InSight Mars lander is trading less life for more science after the space agency decided to let the spacecraft’s remaining science instrument run until the lander’s solar power system fails completely sometime in August or September.
The InSight lander has been on Mars since November 2018 and has been supplied with power by two circular solar arrays with a diameter of 7 ft (2.2 m) each. When first deployed, these generated 5,000 Wh of power each Martian day, but over the last three and a half years dust has accumulated on the panels. As a result, the spacecraft is now subsisting on less than 500 Wh per day as the output falls on a daily basis.
When it became evident that InSight would run out of power by the end of 2022, NASA engineers originally planned to shut down all of the lander’s science instruments so the craft could continue to function as long as possible, sending back telemetry and the occasional image.
According to NASA, the original plan was to shut down the last instrument still online, the seismometer, by the end of June. Now, the engineers will allow the instrument to continue functioning for as long as there is power, which will be until sometime in August or early September. This will give the seismometer the chance to detect additional marsquakes, having detected a series of the longest and strongest on record in recent months.
However, the decision involves more than just leaving the “on” switch engaged. InSight’s design includes a fault protection system that sends it into a safe mode under certain conditions, such as severe power loss. To keep the seismometer running, NASA has had to order InSight to disable its fault protection. This will prevent the lander from going into safe mode, which would require mission control to address the fault to get the systems running again, but it also means that a sudden power loss or low temperatures could cause the lander to fail completely.
“The goal is to get scientific data all the way to the point where InSight can’t operate at all, rather than conserve energy and operate the lander with no science benefit,” said Chuck Scott, InSight’s project manager at NASA’s Jet Propulsion Laboratory in Southern California.