Havard Grip is among many engineers and scientists working with NASA JPL on the ambitious Mars 2020 mission, but he has the high-profile job of pilot for the Ingenuity helicopter.
Ingenuity has gone well beyond its original technology demonstration of five flights, reaching 13 flights recently. Some of its later flights have included scouting for locations where the Perseverance rover will dig and retrieve dust and rock samples.
Grip described in a recent blog how the latest flights are getting harder because the density of the Martian atmosphere is getting even thinner due to seasonal variations on Mars. Engineers on Earth had tested Ingenuity to handle Martian density of 1.2% of Earth’s, but densities are projected to go as low as 1% of Earth’s in coming months.
“The difference may seem small but it has a significant impact on Ingenuity’s ability to fly,” he wrote. At the lower atmospheric density, the helicopter could be operating close to an aerodynamic stall. To compensate, it means spinning up the helicopter’s two rotors faster than before, and even faster than during any tests on Earth.
“This is not something we take lightly,” he added, noting that tests will reach a peak rotor speed of 2,800 rpm—10% faster than before. NASA tweeted on Sept. 17 that the 2,800 rpm test had been completed with a short flight expected at 2,700 rpm.
Already, Perseverance has dug up two rock samples revealing a “potentially habitable sustained environment,” according to Ken Farley of Caltech, project scientist for the mission. “It’s a big deal that water was there a long time.”
Grip spoke in a video interview (above) how Ingenuity flies and is piloted in the thin Martian atmosphere and how it navigates without GPS, using an inertial measurement unit and commercial off-the-shelf sensors.
Editor's Note: Grip’s insights were streamed over the internet as part of Sensors Converge in San Jose, California, on Tuesday. Other sessions continue through Thursday and can be retrieved on-demand by registering for free for the event.