A small robotic helicopter named Ingenuity made space exploration history on Monday when it lifted off the surface of Mars and hovered in the wispy air of the red planet. It was the first machine from Earth ever to fly like an airplane or a helicopter on another world.
In NASA’s Jet Propulsion Laboratory in California, engineers cheered just before 7 a.m. Eastern time as an image was transmitted back to Earth by the helicopter showing its shadow looming over the Martian surface during its flight, which occurred around 3:30 a.m. on Mars.
The achievement extends NASA’s long, exceptional record of firsts on Mars. But it was also something different for NASA — a high-risk, high-reward project with a modest price tag where failure was an acceptable outcome.
That approach is more similar to that of nimble space companies like SpaceX than large traditional development programs that work through every possible contingency to build a full-scale machine that has to work the first time.
What happened during the test flight?
The first flight was a modest up-and-down trip, rising up to an altitude of just 10 feet. There, it hovered for up to 30 seconds and then descended to a landing. Its onboard camera recorded images, helping the navigation system keep the helicopter steady. On the ground more than 200 feet away, the Perseverance’s cameras also recorded the flight.
With the successful test flight, up to four more flights could be attempted. The first three are designed to test basic abilities of the helicopter. The third flight could fly a distance 160 feet and then return.
The final two flights could travel farther, but NASA officials did not want to speculate how much.
NASA wants to wrap up the tests within 30 Martian days of when Ingenuity was dropped off, so that Perseverance can commence the main portion of its $2.7 billion mission. It will leave the helicopter behind and head toward a river delta along the rim of Jezero crater where sediments, and perhaps chemical hints of ancient life, are preserved.
Ingenuity was an $85 million nice-to-have, add-on project but not a core requirement for the success of Perseverance.
Why is flying a helicopter on Mars so difficult?
There is not much air to push against to generate lift.
At the surface of Mars, the atmosphere is just 1/100th as dense as Earth’s. The lesser gravity — one-third of what you feel here — helps with getting airborne. But taking off from the surface of Mars is comparable to flying at an altitude of 100,000 feet on Earth. No helicopter on our planet has flown that high, and it’s more than two times the typical flying altitude of jetliners.
Why is NASA flying a helicopter on Mars?
Until 1997, all of the spacecraft sent to the surface of Mars had been stationary landers. But that year, the Pathfinder mission included something revolutionary for NASA: a wheeled robot. That rover, Sojourner, was roughly the size of a short filing cabinet, and planetary scientists quickly realized the benefits of being able to move around the Martian landscape. Four more NASA rovers, including Perseverance, have since followed to the red planet.
Ingenuity is in essence the aerial counterpart of Sojourner, a demonstration of a novel technology that may be used more extensively on later missions. And demonstrating that the helicopter can fly on Mars may help inform flight attempts on other worlds in our solar system, such as Titan, the moon of Saturn where NASA plans to send a nuclear-powered quadcopter.
Why was the earlier flight postponed?
NASA planned the first flight of Ingenuity on April 11. But on April 9, there was a problem during a test in which the rotors had spun up to flight speeds without the helicopter taking off. Telemetry indicated that some of the steps during the test took longer than expected, and a timer that keeps watch to make sure nothing goes wrong expired. Ingenuity’s computer then stopped the test before it entered what NASA calls “flight mode.”
The helicopter was safe and undamaged, NASA said, but the engineers needed to understand what happened and devise a solution to the problem.
Initially, NASA said that it would need to upgrade Ingenuity’s flight software and that it would not even announce a new date until this week. Although the changes were simple, engineers worried that a coding error could accidentally “brick” the computer, leaving it unresponsive and impossible to fix. Installing and testing the upgraded software also would have taken several days.
In a blog post on Saturday, MiMi Aung, Ingenuity’s project manager, said that the upgrade now appeared not to be necessary. The engineers came up with a simpler, quicker fix — adjusting the commands from Earth to tweak the timing of the transition to flight mode while leaving the helicopter’s software untouched.
This was not a perfect fix — in tests on Earth, it failed about 15 percent of the time — but this solution worked on Friday when Ingenuity was able to complete the full-speed spin test that had been cut short a week earlier.
That paved the way for attempting the first flight sooner, on Monday.
“We also know that if the first attempt does not work on Monday, we can try these commands again,” Ms. Aung wrote, “with good probability that subsequent tries in the days following would work even if the first doesn’t.”
If the current approach did not succeed, the engineers have sent the modified Ingenuity flight software to Perseverance. If needed, the rover could install those changes to the helicopter’s computer.
What else can we expect from Mars in the next months?
NASA wasn’t the only visitor to the red planet from Earth this year.
China’s Tianwen-1 probe also arrived in February, and it entered a steady orbit of the planet weeks later. As early as late May, it will release a lander and rover that will try to reach the surface of the red planet. If it succeeds, it will be China’s first successful touchdown on another planet — it has landed on the moon three times already.
The United Arab Emirates’ Hope probe also arrived at Mars two months ago. After a firing of its thrusters on March 29, it has entered into an orbit where it can begin a close study of the planet’s atmosphere and weather. That phase of scientific research was scheduled to begin last Wednesday.