JPL Prepares to Fly First Helicopter on Another Planet

When the NASA/JPL Perseverance rover landed on Mars back in February, I didn't emphasize it, but the rover is carrying a bold experiment in the form of an autonomous drone helicopter that will be the first flying vessel that humans have ever flown on another planet; a remarkable little drone helicopter called Ingenuity.  Tuesday, they had an open conference to discuss the plans for the coming missions.

They've now picked a site for what's expected to be the first powered flight on another planet. With the site settled, they're now targeting April 8 for the flight, which will be the first in a month long series of test flights to validate the technology.

Ingenuity, pictured above, looks familiar to anyone who's seen any of the profusion of small consumer drones that have developed over the last decade or so. 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 for some substantial differences with Earth-bound drones. For starters, the hardware is much bigger than it might seem from the photos, as each of its two counter-rotating blades is 1.2 meters (four feet) long. Ingenuity also weighs in at 1.8 kilograms (four pounds) on Earth, although it's less than half of that weight on the red planet.

During the landing coverage from JPL in February, they did a fairly extensive story on Ingenuity including how it was tested in a large vacuum chamber at JPL that allowed them to fly in the simulated thin Martian atmosphere.  I thought I saw some thin wires that partially supported the drone's weight to get the thrust/weight balance that the system needs.   What they didn't mention that's an interesting touch is that while the craft was very carefully optimized to fly on Mars, it does carry some additional weight.  Following their first powered flight on Earth, the Wright brothers sold small squares of fabric from the Wright Flyer to get the funds they needed to build improved versions. One of those squares will be carried aloft on Ingenuity when it takes flight on Mars.

Håvard Grip, Ingenuity's chief pilot, said that the test flights required two distinct areas, both of which needed to be flat. The inner part, which he called the airfield, had to have very little material that could interfere with landings. That needed to be surrounded by a larger area, called the flight zone, that had to have enough material in it that the drone's onboard image-processing system could track individual features in order to assist with navigation.
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In the end, things 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.

The drone is tucked away on the underside of Perseverance, folded up, and was initially protected by a cover.  That cover was dropped on the surface a couple of days ago.  Once on site, Ingenuity will have to be rotated 90 degrees and have its legs deploy before it can be deposited on the Martian surface; each step in that process will be monitored for success before moving on to the next. Farah Alibay, who is coordinating the rover team's support of the test, called the final drop the "most stressful" part of the process.

Assuming the drone ends up standing up properly on the surface, the next step is to get the rover out of the way because the drone is going to need to sit in the sun to charge up its battery.  Here's where the thin atmosphere actually helps it survive; the air is so thin the winds shouldn't be able to knock the drone over. 

The first flight is listed as No Earlier Than August 8th, two weeks from Thursday (tomorrow as I write).  The first flight will involve a takeoff, a climb to three meters, a brief hover, and then a landing. Chief Engineer Balaram said that each ensuing flight will be "progressively more aggressive," but there's a limit to how far aggression can go when the onboard batteries limit flight time to about 90 seconds. All told, five flights are planned, with a maximum altitude in the area of five meters.  A month has been set aside for the flights, with extensive checkouts of the system between each.

The drone will have a relatively low-bandwidth connection back to the rover, so we probably shouldn't expect video from every single flight. But a key aspect of the flight will be figuring out how well the system can navigate using optical data and whether it would be capable of scouting routes for the rover. So we can definitely expect a fair number of pictures from these efforts.

It's a technology pathfinder and not a science mission.  If the probe flies successfully, they move on to how far the drone can fly, how easily it can navigate, and other important capabilities like that. 

The ironic aspect is that the main science mission of Perseverance will be on hold until its test flights are over.  If Ingenuity is spectacularly successful and the five test flights are brimming with exciting data, the program then has to turn it off, turn the rover's back on it, and get on with the rest of the science objectives.