In the process of setting up the Ingenuity helicopter for its next flight on Mars, NASA engineers found a problem: One of the helicopter’s navigation sensors is not working.
The sensor is called the inclinometer, which is actually two accelerometers that are supposed to measure gravity before the helicopter begins its takeoff procedures. That information is fed into the algorithms of Ingenuity’s navigation computer. In other words, with a conked-out inclinometer, the helicopter doesn’t have the ability to orient itself relative to the ground — an important skill for a helicopter.
Impressively, this is the first major technological hitch Ingenuity has dealt with since it landed on Mars (tucked away below the Perseverance rover) in February 2021. Before this, a solar conjunction in October briefly put the rotorcraft out of commission (along with all other Martian spacecraft), and more recently the shifting Martian climate forced the little machine into a safe mode. The former event was foreseen, and the latter is now being attended to, with the helicopter effectively shutting down during the Martian nights to conserve energy.
These are just some of the steps NASA has had to take to keep the rotorcraft functional. Ingenuity has amazed scientists and the public alike with its longevity. It was supposed to merely demonstrate that flight was possible on Mars, with the understanding that it would probably crash and be destroyed in the process.
Instead, Ingenuity was upgraded from a technological demonstration to a scout for the Perseverance rover. It’s so far flown 28 times in the year-and-change it’s been operational, and it has only gotten more ambitious in its flight time, ground speed, and distance flown.
As we’ve previously said, it’s not wrong to want Ingenuity to crash — if it did, it would indicate that NASA figured out a technical limitation to correct for in the future. But the helicopter just keeps on buzzing, though now the team needs to find a new way to initialize the helicopter’s navigation algorithms.
To that end, and thankfully, the spunky rotorcraft is well-endowed with sensors. In a recent blog post, Håvard Grip, Ingenuity’s chief pilot, detailed a workaround: Ingenuity’s inertial measurement unit — another component of its navigation system — has its own accelerometers, though those devices aren’t built to make measurements when rotorcraft is static.
Grip wrote that the inertial measurement unit’s accelerometer could be an “acceptable fallback that will allow Ingenuity to resume flying.” For it to work, the team is applying a software patch to Ingenuity’s computer, allowing the helicopter to replace the inclinometer’s data with new data. Because the NASA team is almost obsessively well-prepared, the patch was pre-written, in case this exact event happened.
Should everything go according to plan, Ingenuity will take its 29th flight soon — southwest of its current location, to stay within range of Perseverance, which continues to roll along on its rock-sampling endeavours.