WASHINGTON (AFP) - Nasa successfully flew the Ingenuity helicopter on Mars on Monday (April 19), data downloaded from the aircraft confirmed.
"Altimeter data confirms that Ingenuity has performed the first flight of a powered aircraft on another planet," announced an engineer in the Jet Propulsion Laboratory as the control room cheered.
The space agency had originally planned the flight for April 11, but postponed it over a software issue that was identified during a planned high-speed test of the aircraft's rotors.
The issue has since been resolved, and the four-pound (1.8 kilograms) drone was expected to achieve its feat by around 3.30am Eastern Time (0730 GMT). The data, however, didn't arrive until several hours later.
"That's because Mars is over 178 million miles (286 million kilometers) away, so there's a little bit of a delay," said Jet Propulsion Laboratory engineer Taryn Bailey during a webcast ahead of the flight.
"The data is expected to hit the Deep Space Network at about 3.34am Pacific Time (1034 GMT), and we'll start processing the data shortly after that to see how we did," she added.
The Deep Space Network (DSN) is Nasa's international array of giant radio antennas that supports its interplanetary spacecraft mission.
"Our team has been working on the Mars helicopter for over six years, and unfortunately even longer towards this ultimate dream," added lead engineer MiMi Aung.
The first powered flight on Earth was achieved by the Wright brothers in 1903 in Kitty Hawk, North Carolina.
A piece of fabric from that plane was tucked inside Ingenuity in honour of that feat.
The helicopter travelled to Mars attached to the underside of the rover Perseverance, which touched down on the planet on Feb 18 on a mission to search for signs of extraterrestrial life.
Ingenuity's goal, by contrast, was to demonstrate its technology works, and it won't contribute to Perseverance's science goals.
But it is hoped that Ingenuity can pave the way for future flyers that revolutionise our exploration of celestial bodies because they can reach areas that rovers can't go, and travel much faster.
The timing of the helicopter flight is chosen with the weather on Mars in mind.
Wind was the big unknown and could have jeopardised the mission.
The flight was challenging because the air on Mars is so thin - less than one per cent of the pressure of Earth's atmosphere.
That made it much harder to achieve lift, even though it was partly aided by a gravitational pull that is a third of Earth's.
The helicopter was supposed to rise for about six seconds, hover and rotate for about 30 seconds, then go back down.
The flight was autonomous, pre-programmed into the aircraft because of the 15 minutes it takes for signals to travel from Earth to Mars.
Ingenuity itself was to analyse its position with respect to the Martian surface.
After the flight, Ingenuity sent Perseverance technical data on what it had done, and that information was transmitted back to Earth.
This included a black and white photo of the Martian surface that Ingenuity was programmed to snap while flying.
Later, once its batteries have charged up again, Ingenuity is to transmit another photo - in colour, of the Martian horizon, taken with a different camera.
But the most spectacular images are supposed to come from the rover Perseverance, which will film the flight from a few metres away.
Shortly after this filming, six videos of 2.5 seconds each were to be sent to Earth.
Nasa hopes at least one of them will show the helicopter in flight.
The entire video will be sent over the following few days.
Nasa plans another flight no more than four days later. It plans as many as five altogether, each successively more difficult, over the course of a month.
Nasa hopes to make the helicopter rise five meters and then move laterally.
Ingenuity's "lifetime will be determined by how well it lands" each time, said Ms Aung - meaning whether it crashes.
"Once we get to the fourth and fifth flight, we'll have fun," she said. "We are going to take very bold flights and take high risk."