On Tuesday, the Jet Propulsion Laboratory (JPL) held a press conference where it detailed plans for the Ingenuity drone to take a ride to Mars, mounted on the bottom of the Perseverance rover. The scientists and engineers behind the drone have announced that they have now selected a location for what is expected to be the first powered flight on another planet. With the location settled, they are now targeting the April 8 flight, which will be the first in a series of month-long test flights to validate the technology.
Ingenuity, pictured above, is familiar to anyone who has seen the plethora of small consumer drones that have developed over the past decade. But, as Ingenuity’s chief engineer Bob Balaram put it, “It’s the first aircraft designed for powered flight on another planet,” and that makes some substantial differences from terrestrial drones. For starters, the hardware is much larger than it appears in the photos, as each of the two counter-rotating blades is 4 feet (1.2 meters) long. Ingenuity also weighs 1.8 kilograms (four pounds) on Earth, although it is less than half that weight on the red planet.
Balaram also said that “this is basically an aircraft that is also a spacecraft,” noting that it had to survive the stresses of launch and landing, as well as the extreme temperatures of its flight to Mars and time on the surface. That necessitated a heating element in Ingenuity’s hull, which keeps things like the batteries and electronics operational overnight. Once released onto the Earth’s surface by Perseverance, Ingenuity will be responsible for supplying its own power, which it obtains through a solar panel placed above the blades.
The fuselage contains some ready-to-use components in the form of commercial lithium-ion batteries and a chip that may have powered a smartphone that was current a few years ago. Normally, NASA would use radiation-sensitive hardware for critical components of a science mission, but this is intended as a technology demonstration and it will not conduct mission-critical science. Instead, the drone will test whether the technology is ready for use in future missions. Lori Glaze, director of NASA’s Planetary Science Division, suggested that future rovers could rely on drones to explore routes for them or obtain samples from areas otherwise inaccessible to a wheeled vehicle.
While the weight of the components is undoubtedly highly optimized, Ingenuity contains a small piece of strange mass. After their first powered flight on Earth, the Wright brothers sold small squares of fabric from their craft to get the money they needed to build improved versions. One of those squares will be carried aloft on Ingenuity when it flies on Mars.
Ingenuity chief pilot Håvard Grip said the test flights required two different areas, both of which had to be flat. The inner part, which he called the airfield, had to contain very little material to hinder the landings. That had to be surrounded by a larger area called the flight zone, which had to contain enough material for the drone’s onboard image processing system to track individual features to aid in navigation.
Grip said the search for a suitable area began within hours of Perseverance’s landing. That’s because Grip and his colleagues know where Perseverance has been helped by seeking satellite images of the area. Once operational, the rover provided higher resolution images of potential locations.
In the end, it couldn’t be much more convenient, as the rover landed on what will be the edge of the flight zone, which extends north from the landing site.
But that doesn’t mean the procedure is easy from now on. It will take the rover a few days to drive to the airport in that area, and deploying Ingenuity itself will take a few more days. At this point, the drone is tucked against the underside of the rover and images have confirmed that the debris shield that protected it during the landing has fallen off. Once on site, Ingenuity will need to be turned 90 degrees and its legs deployed before it can be deposited on the surface of Mars; each step in that process will be checked for success before moving on to the next. Farah Alibay, who is coordinating the rover team’s support for the test, called the latest fall the “most stressful” part of the process.
Assuming the drone lands upright on the surface, the next important step is to get the rover out of there quickly, as Ingenuity only has enough battery capacity to power a heating element overnight. Charging from the solar panel is essential. The perseverance will retreat to a location some distance from (and several meters above) the airfield to follow the test flights.
While Perseverance cleans up, the drone embarks on a week-long commissioning project, checking out the onboard hardware and sensors. Assuming that’s all correct, there’s good reason to believe we’ll manage to get the craft into Mars’ thin atmosphere. After all, a mock-up flew in a room capable of matching Martian conditions here on Earth (although Balaram showed a video of some early test versions failing due to some dramatic crashes).
Grip said the first flight will include a take-off, a ten-foot climb, a short glide, and then a landing. Balaram said each subsequent flight will be “progressively more aggressive”, but there is a limit to how far aggression can go when the onboard batteries limit the flight time to about 90 seconds. In all, five flights are planned, with a maximum height close to five meters.
While Mars’ thin air makes getting enough lift a challenge, it actually reduces the risk of losing the rover during the test period. If Ingenuity were to fall over in the wind (while flying or parked), there is no obvious way to recover it. But Balaram said it’s unlikely that Mars’ thin air will generate enough power to cause this sort of problem.
The drone has a relatively low bandwidth connection to the rover, so we probably shouldn’t expect video from every single flight. But an important aspect of the flight will be to find out how well the system can navigate using optical data and whether it would be able to explore routes for the rover. So we can certainly expect a fair number of photos from these efforts.
Not too long. If all goes well with depositing Ingenuity and checking out its systems, the earliest flight we could see in two weeks is on April 8. A month has been set aside for five flights, with extensive system checkouts between each. During this time, however, Perseverance cannot proceed to its main scientific mission.
It is not clear what will happen if the hardware passes all the technical tests and is still in good working order. Obviously, delaying the rover’s science mission to test it further isn’t going to go particularly well, and no one at JPL was interested in speculating what they’d do with a fully functional Mars helicopter that would otherwise be abandoned — and that’s not because reporters asked them not to speculate.
But for the next month and a half, the focus will be on getting everything ready for the tests and getting them done.