This may be the last ever image sent from NASA’s Mars InSight spacecraft.
After a four-year mission on the red planet, the robotic lander – which famously snapped the first “selfie” ever taken on Mars – is powering down.
Thick windblown dust has covered InSight’s solar panels, with NASA expecting to lose contact with the probe soon.
The American space agency posted the news on the craft’s Twitter page, saying: “My power’s really low, so this may be the last image I can send.
“Don’t worry about me though: my time here has been both productive and serene.
“If I can keep talking to my mission team, I will – but I’ll be signing off here soon. Thanks for staying with me.”
NASA announced the £630m InSight project 10 years ago as a follow-up to its successful Curiosity rover.
The InSight lander’s goal was to discover how Mars was formed, with the aim of giving scientists a better understanding of how rocky bodies like the Earth were created.
Before that, the spacecraft had to successfully make the 300 million-mile journey to Mars before enduring “seven minutes of terror” to descend to the surface.
Just 40% of missions to the red planet have safely made it through the thin atmosphere.
Pic: NASA/JPL-Caltech.
A combination of a heatshield, parachute and retrorockets helped slow InSight from 13,000mph to 5mph in just six minutes to allow it to land on the Elysium Planitia, a featureless plain just north of the location of the Curiosity rover.
Once it unfurled, the craft rammed a temperature probe five metres into the surface to measure the heat flowing from the planet’s core.
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Five months after landing, InSight’s quake monitor recorded a faint rumbling. NASA’s scientists concluded that it came from within the planet, dubbing it a “Marsquake”.
One of InSight’s chief accomplishments was establishing that the red planet is, indeed, seismically active, recording more than 1,300 marsquakes.
NASA’s robotic lander, InSight. Pic: NASA/JPL-Caltech.
The recording kicked off a new research field of “Martian seismology”, NASA said, which could help find out more about how rocky planets were formed.
It also measured seismic waves generated by meteorite impacts, revealed the thickness of the planet’s outer crust, the size and density of its inner core and the structure of the mantle that lies in between.
But there was also time for some fun. The craft famously snapped the first ever “selfie” taken on Mars, using a camera attached to its robotic arm to beam a photo all the way back to Earth.
InSight takes a ‘selfie’ on the surface of Mars using a camera on its robotic arm.
NASA’s Jet Propulsion Laboratory (JPL) near Los Angeles will continue to listen for a signal from the lander, just in case.
But hearing from InSight again is unlikely, experts say.
The three-legged stationary probe last communicated with Earth on 15 December.
InSight has changed our understanding of the solar system
Where flashy wheeled Mars rovers boldly go, InSight boldly sat. The robot geologist never trundled over the Martial surface looking for exciting discoveries. Its job – as the first mission ever designed to study the interior of another planet – was to sit and listen for action. And it happened.
Over its 4-year life on Mars, InSight recorded more than 1300 “marsquakes”. Each tremor, serving like an ultrasound scan of the planet’s hidden interior. Using InSight, scientists discovered Mars has a liquid metal core proportionally much larger than Earth’s. It had key differences in its molten rocky mantle too. These discoveries help explain why Mars isn’t volcanic, though once was early in its 4.5 billion-year history. Also, why it lost its magnetic field.
But the biggest breakthrough for the lonely and patient listening post came On Christmas Eve last year. InSight’s seismometer recorded what scientists at the time thought was a major marsquake.
It was only the following year, scientists with another robotic mission: Mars Reconnaissance Orbiter spotted a new impact crater on the red planet’s surface. What InSight had “heard” was a huge meteorite crashing into the surface of Mars. After the discovery “everything clicked,” says Prof Tom Pike at Imperial College London, one of the InSight science team.
Knowing exactly what caused the tremor and where and when, they were able to fine-tune their previous measurements in a way they hadn’t been able to by just listening to mysterious rumbles from inside Mars. This impact, one of several, massively improved the quality of the science InSight has delivered. And it nearly didn’t happen. The probe’s mission was originally just two years.
“We were very lucky,” says Prof Pike. “It was beyond the expected lifetime of the mission. Each of these events have been valuable in adding another dimension to the information that we have. It is actually only in the last few months that we’ve got enough information to really build up quite a complex view of what is happening inside of Mars – and we’re going to keep on working on this data.”
There’s a chance – albeit a slim one – a storm could blow the dust off InSight’s solar panels and give it a new lease of battery life. If not, the dead probe will gradually be buried by the planet it came to study. But the data it collected in its short scientific life will be studied for years to come and has already changed our understanding of the solar system.