During a recent daring Martian flight by the Ingenuity helicopter July 5, the chopper acted like an aerial scout for the Perseverance rover as it sailed over rough but intriguing terrain.
Now, photos taken during the 2,051-foot-long flight are helping the Perseverance science team develop the rover’s exploration plan.
This Martian helicopter did things it had never done before.
This ninth flight by Ingenuity broke the helicopter’s records for flight duration, distance and cruising speed. Unlike any of the previous flights, Ingenuity dipped down into a crater, descended over undulating terrain and ascended before landing on a flat plain.
This aerial excursion, lasting two minutes and 26 seconds, provided the best look yet at challenging terrain that would be difficult for Perseverance to travel, as well as science targets that the rover won’t reach for a while.
Surprisingly, this terrain was tough for Ingenuity to negotiate as well, even from the air. That’s because Ingenuity’s navigation system was designed to fly over flat surfaces. But the little chopper that could conquered its initial five test flights over flat terrain months ago. Now, Ingenuity has the chance to prove itself as a scout for Perseverance.
Ingenuity’s team on Earth sent some instructional help to the copter’s navigation system so it could fly over the Séítah dune field, and it worked. While the two-ton, six-wheeled rover detours around these risky dunes, Ingenuity flew overhead and snapped photos showcasing different rocky layers.
These layers preserve the geologic and ancient climate record of Mars, revealing how and when it changed. The images also show areas Perseverance may want to avoid as it ventures across Jezero Crater.
This capability is unprecedented. Previously, rover teams have had to rely on images taken by the rover’s cameras or photos from orbiters that are miles above the planet. Ingenuity is much closer, flying about 33 feet above the ground, and its cameras can capture much more detailed images.
“Once a rover gets close enough to a location, we get ground-scale images that we can compare to orbital images,” said Ken Williford, Perseverance deputy project scientist at NASA’s Jet Propulsion Laboratory in Pasadena, California, in a statement. “With Ingenuity, we now have this intermediate-scale imagery that nicely fills the gap in resolution.”
Billions of years ago, the crater was home to an ancient lake. Perseverance’s main science mission, which began about a month ago, is to observe different areas of the crater and use its instruments to study and collect samples. These samples, which will be returned to Earth by a future mission, could reveal whether microbial life existed on Mars billions of years ago when the red planet was much warmer and wetter.
As Ingenuity flew over the dune field, it took images of rock features that the scientists have nicknamed “Raised Ridges.” These ridges are part of a fracture system where water may have once flowed underground. If it did, that water could have helped dissolve minerals to help feed ancient microbes beneath the Martian surface. These ridges may be the perfect place to search for signs of ancient life and collect samples to return to Earth.
“Our current plan is to visit Raised Ridges and investigate it close up,” Williford said. “The helicopter’s images are by far better in resolution than the orbital ones we were using. Studying these will allow us to ensure that visiting these ridges is important to the team.”
While ridges sound like a threat to the rover, the real terror is sand dunes. The dunes are deceptive. They appear innocent, but in reality, they could reach knee or waist height on a human – and act as a sand trap for heavy robotic rovers.
“Sand is a big concern,” Olivier Toupet, a rover driver at JPL who leads the team of mobility experts that plans Perseverance’s drives, said in a statement. “If we drive downhill into a dune, we could embed ourselves into it and not be able to get back out.”
When asked if Perseverance can zip over these dunes and use them as a shortcut to reach other features, Toupet said no. While the rover has an AutoNav feature, which allows for autonomous driving based on artificial intelligence algorithms, human drivers on Earth can still identify hazards and help Perseverance avoid them to prevent an early end to the mission.
Sand traps have ended other Martian missions, like NASA’s Spirit rover in 2011.
Ingenuity’s images have shown the Perseverance team that the Séítah dune field is indeed too sandy for the rover to explore. But the helicopter’s aerial images offer enough detail that scientists can study the photos to learn more about the rocks there.
While Perseverance circumnavigates the field, it may be able to make a “toe dip” – something the rover team uses to refer to as temporary short paths when they spy something worth investigating.
“The helicopter is an extremely valuable asset for rover planning because it provides high-resolution imagery of the terrain we want to drive through,” Toupet said. “We can better assess the size of the dunes and where bedrock is poking out. That’s great information for us; it helps identify which areas may be traversable by the rover and whether certain high-value science targets are reachable.”
Perseverance is on a schedule; it will be exploring as much of the crater and the ancient river delta that fed into Jezero for the next two years. Meanwhile, Ingenuity will continue to act as a scout on future flights, imaging features and areas of interest the rover may never have time to reach.
The rover is preparing for the next big milestone in its journey since landing on Mars in February. On Wednesday, the rover team will share the first science results gathered by Perseverance – and prepare to collect its first Martian sample.