After overcoming an earlier software glitch, NASA’s $80 million Ingenuity helicopter spun up its carbon-composite rotors and lifted off the dusty surface of Mars early Monday to become the first aircraft to fly on another planet, a “Wright brothers moment” that could pave the way to future interplanetary aircraft.
Tipping the scales at just 4 pounds — 1.5 pounds in the lower gravity of Mars — Ingenuity’s counter-rotating 4-foot-long rotors, spinning at more than 2,500 rpm, were commanded to change their pitch, “biting” deeper into the thin atmosphere for a liftoff from the floor of Jezero Crater around 3:30 a.m. EDT.
With the Perseverance rover looking on from a safe distance, Ingenuity climbed 10 feet straight up, hovered, turned in place and then landed to complete a test flight spanning just 40 seconds or so.
That was more than enough to make space history.
“We can now say human beings have flown a rotorcraft on another planet!” an elated MiMi Aung, the Ingenuity project manager at NASA’s Jet Propulsion Laboratory, told her socially distanced team. “We’ve been talking so long about our Wright brothers moment on Mars, and here it is.
“We don’t know from history what Orville and Wilbur did after their first successful flight. I imagine the two brothers hugged each other. Well, I’m hugging you virtually right now. … We together flew at Mars, and we together have our Wright brothers moment.”
Data confirming the historic flight reached Earth three hours after the flight, relayed through NASA’s Mars Reconnaissance Orbiter. Once on its way, the data took nearly 16 minutes to cross the 178-million-mile gulf between Mars and Earth.
The telemetry began showing up on computer screens at JPL just after 6:30 a.m. EDT. First, the team confirmed the data had made it back successfully. Then, peering intently at his display, JPL’s “pilot,” Håvard Grip, announced the results, confirming Ingenuity “performed spin up, take off, climb, hover, descent, landing, touchdown and spin down.”
“Altimeter data confirms that Ingenuity has performed the first flight of a powered aircraft on another planet!” he said as engineers burst into cheers and applause.
Moments later, initial images were displayed, including a short video shot by Perseverance showing the small helicopter lifting off, hovering and setting down. A sharp black-and-white still image, taken by a camera aboard Ingenuity, showed the helicopter’s shadow on the surface of Mars, its rotors sharply defined.
As each image appeared on a screen at the front of the control room, the engineering team cheered and applauded with evident relief.
Ingenuity’s short up-and-down maiden flight might sound trivial given the performance of inexpensive drones on Earth. But flying in a mostly carbon dioxide atmosphere just 1 percent as thick as Earth’s on a planet so far away direct human control isn’t possible and where the temperature drops to more than 100 degrees below zero every night poses a major technological challenge.
Based on the results of Ingenuity’s mission, more sophisticated drones may eventually be sent to Mars and elsewhere in the solar system to carry cameras and science instruments to locales that are not accessible to rovers or, eventually, astronauts.
Ingenuity was carried to Mars bolted to the belly of the Perseverance rover, which landed in Jezero Crater on Feb. 18. The rover later dropped the helicopter to the surface and backed away to observe the first of up to five short test flights.
Equipped with two cameras, the helicopter does not carry any science instruments. It was added to Perseverance’s mission solely to determine the feasibility of powered flight in the red planet’s thin atmosphere.
Rooting out Ingenuity’s flight issue
The initial test flight originally was planned for April 11. But two days earlier, a rotor spin-up test was aborted by the helicopter’s flight software when it failed to transition to flight mode as planned.
Engineers at JPL reviewed telemetry and came up with two solutions. One required uplinking a few additional commands to the control software, an approach expected to work about 85 percent of the time.
The other option was to replace the flight software with a modified version that’s been uplinked and stored aboard Perseverance. That would completely eliminate the problem, but it would require several more days to implement and introduce at least a slight element of additional risk.
After a detailed analysis, the helicopter team went with the first option.
“This solution is the least disruptive to a helicopter that, up until we identified the (command sequence timing) issue, has been behaving just as we expected,” Aung said earlier in a blog post. “It is the most straightforward, since we do not have to change its configuration.”
Up to four more test flights are planned over the next several days, pushing the helicopter to slightly higher altitudes and more far-ranging traverses to put its compact systems through their paces.
After that, Perseverance will move on to its primary science mission, leaving the helicopter behind as the rover begins searching for signs of past microbial life in ancient lakebed deposits on the floor of Jezero Crater.