Mars is a lousy place to try to fly a helicopter. There’s the temperature, for one thing—a paralyzing -90º C (-130º F), frigid enough to cause nearly any machinery to freeze up and lock. There’s the remoteness too; Mars is currently 287 million km (178 million mi.) from Earth, meaning that radio signals, even moving at light speed, take nearly 16 minutes to travel just one way between the two worlds. And then there’s the tenuous Martian atmosphere—just 1% the density of Earth’s, making it awfully hard for rotating blades to get any bite at all.
But flying a helicopter on Mars is precisely what NASA did today, when the little Ingenuity drone lifted off from the floor of Jezero Crater at 3:34 AM EDT (just after noon, Mars time), hovered at an altitude of 3 m (10 ft) for 40 seconds, and touched gently back down, kicking up a plume of rusty red dust. It was the first flight of a powered aircraft on another planet, coming 118 years after the Wright Brothers achieved the same feat on Earth. For the record, Ingenuity’s total time aloft was more than three times the duration of the Wrights’ 12 seconds.
“We do kind of compare it to the Wright Brothers,” says NASA Acting Administrator Steve Jurczyk. “The first powered flight on Earth used twin-blade, counter rotating propellers in two gas powered motors in an aircraft configuration. We’re using two four-foot long counter rotating propellers on the helicopter, driven by electric motors.”
The modest flight on Mars was made by an equally modest machine. Ingenuity stands just .49 m (19 in.) tall and weighs 1.8 kg (4 lbs), small enough and light enough to have spent the entire cruise between Earth and Mars tucked inside the belly of the car-sized Perseverance rover. But Ingenuity’s humble dimensions belie its complex engineering—and its $80 million price tag. The helicopter has its own on-board computer, heater, guidance system, cameras and laser altimeter. Its 1.2 m blades spin at a dizzying 2,537 revolutions per minute—or five times the speed of terrestrial helicopter blades—which is necessary to gain lift in the whisper of Martian air.
Still images and stop-action video of the flight were captured by two cameras aboard Ingenuity—one black and white and one color—and another aboard Perseverance, which before the flight had backed a safe 65 m away from Ingenuity’s 10 m by 10 m flight zone. A microphone aboard Perseverance also attempted to capture audio of the helicopter motor, though as of this writing that data had not yet been processed.
Today’s flight might not have happened at all had the controllers not resolved a problem when Ingenuity first tried to test its blades at high speed on April 9. As the system was transitioning from its pre-flight to flight mode, a so-called “watchdog switch” shut it down after it detected an anomaly in the system. Ultimately NASA determined that the solution was to upload patches to the helicopter’s software to eliminate bugs.
That degree of caution was in keeping with the entire go-slow way Ingenuity has been handled from the start. Merely unstowing the helicopter from the rover and lowering it to the surface was a six-day, multi-step job that involved activating a bolt-breaking device, firing a cable-cutting pyrotechnic, rotating Ingenuity to its upright position, extending its four legs, and finally dropping it the final 13 cm (5 in.) to the ground. The machine’s light weight combined with Mars’s relatively lower gravity—just 38% that of Earth—made the fall an easily survivable one.
This first brief flight will by no means be Ingenuity’s only one. It is scheduled to make four more flights over the course of the next month—all from a site NASA has now given the playful airport designation JZRO, for Jezero. The altitude and distance of each flight will grow steadily greater and the airborne maneuvers more complex. “We’ll work up to 300 meters downrange and to 90-second flights,” Jurczyk says. None of that will be easy since the radio signal lag makes it impossible to fly the helicopter in real time; rather, as with the rover’s travels, all of the commands must be radioed up and preloaded in advance.
Unlike Perseverance, which was sent to Mars to conduct research, Ingenuity is able to conduct no science beyond merely scanning its surroundings with its cameras. Like the Wright Brothers’ first flight, it is merely a demonstration mission—testing whether Martian aircraft can someday be used both as advance scouts for rovers and humans and as a means of conducting research on hillsides and high outcroppings that would be otherwise out of reach. In a nod to its engineering lineage, Ingenuity does carry one bit of non-essential cargo: a tiny swatch of fabric from the Wrights’ original plane taped to its underside—a swatch that long ago flew on the beaches of North Carolina and today flew again, in a crater on distant Mars.