NASA’s Perseverance rover is currently collecting rock and soil samples at Martian crater Jezero that will one day be returned to Earth. Under the current plan, in 2030 the rover itself will deliver sample tubes to a Mars lander for transport home. But if something goes wrong, a pair of small helicopters will be ready to swoop in, as NASA’s Mars Sample Return team announced at the end of July.
If that happens, the Exemplary Recovery Helicopters will be the second and third aircraft ever to fly to another planet. And their inclusion in the Mars Sample Return mission, a joint effort of NASA and the European Space Agency, could signal the beginning of a new chapter in Mars exploration—a chapter in which small helicopters and easily orbit the Red Planet regularly.
News of the addition of helicopters to the Mars Sample Return mission comes just over a year after the first aircraft in history took powered flight to another planet, when NASA’s Ingenuity helicopter took to the skies of Mars in April 2021. Since then, the experimental wheel has taken 28 more flights, far exceeding expectations.
“The whole point of Ingenuity was to be that Wright Brothers moment that leads to a future down the road of additional aerial exploration of Mars,” says Teddy Tzanetos, Ingenuity Mars Helicopter Team Leader at NASA’s Jet Propulsion Laboratory. s. “The purpose of ingenuity was to make flying boring… Now we can just keep making boring flights and doing exciting things with boring flights.”
Originally, the Mars Sample Return mission concept included a so-called fetch rover: A robot capable of collecting samples already stored in tubes from the Perseverance rover. The towed rover would have transported them several hundred meters across the Martian surface to a lander near Jezero Crater, where the sample tubes would be transferred to the Mars Lander. The rocket-propelled vehicle would then launch the container with the sample tubes into orbit where it would await a spacecraft with its sights set on returning to Earth.
But, says Ann Devereaux, who is Deputy Manager of the Mars Sample Return Program, “getting a rover big enough and capable enough to go and do a reasonable job of collecting samples was problematic.” It would be expensive to design and transport such a rover along with the lander to Mars.
The team was exploring other concepts just as Ingenuity made its first test flights. After the rotorcraft proved successful, engineers began studying whether helicopters might be the best option for retrieving samples stored by Perseverance.
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Helicopters are smaller, lighter and more maneuverable than rovers in many situations, Devereaux says. Although planes need a safe place to land, they don’t have to worry about crossing dunes with heavy tires.
The design for the return helicopter samples will not differ much from the Ingenuity. “When you’re talking about robots in space, legacy is extremely important,” says Tzanetos. “We want to stick with the Ingenuity design as much as possible because we know it’s reliable, we know it’s strong.”
Because the Martian air is so thin — about 1 percent of Earth’s density — any plane on Mars would have to be extremely light and have large, fast-spinning rotor blades to provide enough lift, explains he. Ingenuity’s repeated flights confirmed that NASA’s aerodynamic simulations were accurate — so much so that the models will guide how engineers build the new pair of flying robots.
However, the sample recovery helicopters will not be an exact replica of the Ingenuity. The team will have to make some changes, Tzanetos says, because these two wheels will have to do more than just fly. They would have to travel about 2,300 feet from the ground to the depot site, pick up a tube, fly back to the lander and drop it at a designated launch site — and then repeat that cycle 15 times, he says. .
And that means the helicopters will have to carry more weight than the 4-pound Ingenuity. The current concept for sampling helicopters requires additional tools, such as arms to take the samples and wheels to maneuver to storage and disposal sites, which can add another kilogram to the robots, according to Tzaneto.
“We’ve done the math, we’ve realized there are some changes we can make to the rotor system to make it lift more mass,” he says. Now that the leaders of the Mars Sample Return mission have decided to continue with the concept of the retrieved helicopter, Tzanetos and his team are focusing on making those changes.
One of their first steps is to determine how much further they can push Ingenuity’s original rotor system. Just in case the Martian environment was more challenging than the team’s models predicted, engineers designed the test helicopter to have more lift than thought necessary.
“We’re starting to work on figuring out what the optimal point is where you can market all these different mass applications,” he says. “We can spin the blades a little faster, we can ask more of the rotor system, for example, and we can carry a heavier aircraft that allows us to accomplish the mission.”
However, helicopters may not be necessary at all. They will fly to Mars only in the event that the Perseverance rover cannot deliver samples or the robot meets its demise before the retrieval is completed.
But the future of helicopters on Mars can already be predicted by Ingenuity’s success.
“This helicopter has been phenomenal,” says Devereaux, describing how Ingenuity proved it could fly ahead of the Persistence rover and look ahead for the rover’s ground sleuthing. She adds that helicopters offer us an additional perspective of our neighboring planet. Perhaps one day a drone-like rover could zip through canyons like those that make up the Valles Marineris, revealing the Red Planet’s geological layers up close where rovers can’t go.
“Rovers are now commonplace” for Mars exploration, Tzanetos says. “We understand how to build rovers, we understand how to operate rovers. I hope we’ll be saying the same thing about helicopters in the decades to come.” Perhaps fleets of aircraft, he says, with wings like airplanes or blades like helicopters, will one day fill the skies of Mars.