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IT’S A HOARY old joke of fixed-wing aviators that helicopters don’t really fly; it’s just that the Earth repels them. With this in mind, it’s time to celebrate another rotary-wing achievement: Planet Mars seems to repel them as well!
Here are tidbits on the NASA Mars helicopter Ingenuity, which has now executed three perfect flights into Mars’ sparse atmosphere. As Kenneth Chang reports in The New York Times, April 25, 2021, ” ‘Nothing Short of Amazing’: NASA Mars Helicopter Makes Longest Flight Yet.”
The Challenge of Martian Flight. The Martian atmosphere is only one percent as dense as Earth’s, making it much more difficult to generate lift, even though Martian gravity is only one-third of Earth’s. Thus, the Ingenuity helicopter had to be extremely light with fast-spinning rotor blades.
Depending on Earth’s and Mars’ orbits, communication delays amount to around 20 minutes. Therefore, Ingenuity’s operation has to be autonomous, triggered but not controlled by NASA scientists.
Martian Copter Features. Ingenuity is about 19 in. high and weighs about 4 lbs. Its two rotors have a four-foot span and counter-rotate at 2400 rpm; the counter-rotation, to balance torque on Ingenuity’s chassis.
Ingenuity is solar-powered via its topmost panel and automatically maintains its own charge. It has wireless communication and is equipped with computers, navigation sensors, and two cameras (one color, the other black-and-white).
To put its 2400-rpm rotor speed in perspective, NASA notes that Ingenuity’s rotors “are much larger and spin much faster than what would be required for a helicopter of Ingenuity’s mass on Earth.”
Ingenuity’s Wright Brothers Day. On April 19, 2021, Ingenuity lifted off the Martian surface for the first time, making it “the first powered flight by an aircraft on another planet.”
“The triumph,” The Texarkana Gazette reported, “was hailed as a Wright brothers moment. The mini 4-pound copter even carried a bit of wing fabric from the Wright Flyer that made a similar history at Kitty Hawk, North Carolina, in 1903. It was a brief hop—just 39 seconds and 10 feet—but accomplished all the major milestones.”
Ingenuity’s Second Flight. On April 22, 2021, Ingenuity’s second flight lasted 51.9 seconds and reached an altitude of 16 feet. It hovered briefly, then autonomously performed a five-degree tilt which moved the craft sideways by some seven feet.
Håvard Grip, Ingenuity’s chief pilot at NASA’s Jet Propulsion Lab, said, “The helicopter came to a stop, hovered in place, and made turns to point its camera in different directions. Then it headed back to the center of the airfield to land. It sounds simple, but there are many unknowns regarding how to fly a helicopter on Mars. That’s why we’re here – to make these unknowns known.”
Ingenuity’s Third Flight. Ingenuity’s greatest achievement—so far—came on its third flight, April 25, 2021. As Kenneth Chang describes in The New York Times, April 25, 2021, “NASA’s Mars helicopter went up again, going faster and traveling a total distance that was about the length of an American football field on its third trip through the wispy air of Mars.”
“Like the first two flights,” Chang writes, “the small experimental flying robot, named Ingenuity, perfectly executed its instructions from Earth. At 1:31 a.m. Eastern time — 12:33 p.m. local Mars time — it lifted 16 feet off the ground, then flew a round-trip distance of 328 feet before landing back where it started.”
Chang Gives Details: “That was about 25 times as far as the second flight flew three days ago. The helicopter reached a top speed of 4.5 miles per hour, and the flight lasted about one minute and 20 seconds.”
“The flight,” Chang continues, “was a test of the helicopter’s navigation system, which visually keeps track of its location by comparing ground features recorded by its onboard camera. The farther it traveled, the more images its camera had to take to remember the landscape below. If it flew too fast, the helicopter could lose track of where it was.”
Hurrah for Ingenuity! The brothers had no cameras aboard during their epic flights of the Wright Flyer. ds
© Dennis Simanaitis, SimanaitisSays.com, 2021
It’s an amazing flying machine. It has a mass of 4 pounds, which is about 1.5 lbs on Mars. They estimate the copter will fly up to 24.5 MPH. If 4.5 MPH sounds slow, the new rover travels 3X faster than previous and moves about .01 MPH. Unfortunately, Ingenuity is tethered to its landing area and the solar panels are becoming covered in dust. We look forward to future flying machines which will be useful, perhaps scouting for the rover and going places a rover can’t reach, once the copter can pick safe landing areas. Even with Ingenuity’s limitations, it could scout days’ of terrain for the rover.