Ingenuity Helicopter (2021): First Powered Flight on Mars

The Ingenuity helicopter made the first powered, controlled flight on another planet on 19 April 2021, hovering briefly above the floor of Jezero Crater on Mars. The small NASA aircraft had travelled to Mars attached to the underside of the Perseverance rover. Planned as a short technology test, Ingenuity went on to make 72 flights and showed that aerial vehicles can explore other worlds.

Background: flying in thin air

Mars has an atmosphere, but it is extremely thin, only about 1 percent as dense as Earth’s at sea level. A helicopter there gets far less lift from its rotor blades, roughly what it would get at more than 30 km above Earth, far higher than any terrestrial helicopter can fly. Gravity on Mars, about 38 percent of Earth’s, helps a little.

Engineers at NASA’s Jet Propulsion Laboratory (JPL) in California began serious work on a Mars helicopter in the mid-2010s, led by chief engineer Bob Balaram, with MiMi Aung as project manager. They tested prototypes in a large vacuum chamber filled with thin carbon dioxide to mimic Martian air. In 2018 NASA approved sending the helicopter as a technology demonstration with the Perseverance mission.

Design

Ingenuity weighed about 1.8 kg on Earth and stood about half a metre tall. Two stacked rotors, each 1.2 metres across, spun in opposite directions at around 2,400 revolutions per minute. A solar panel on top charged lithium-ion batteries, and heaters kept the electronics alive through nights that fall to around minus 90 °C.

Because radio signals between Earth and Mars take many minutes, the helicopter could not be flown by remote control. It flew autonomously, following instructions uploaded in advance and using a downward-facing camera and sensors to track its own motion. Its processor was a commercial smartphone-class chip, an unusual choice for a space mission.

A postage-stamp-sized piece of fabric from the wing of the Wright brothers’ 1903 Flyer was fixed beneath the solar panel, a tribute to the first powered aeroplane flight.

From Earth to Jezero Crater

Perseverance and Ingenuity were launched on 30 July 2020 from Cape Canaveral, Florida. On 18 February 2021 the rover landed in Jezero Crater, an ancient lake bed, using the same sky-crane technique pioneered by the Curiosity rover.

On 3 April 2021 Perseverance gently dropped Ingenuity onto the ground and drove away so the helicopter’s solar panel could see the Sun. The helicopter survived its first freezing night alone, an important milestone. The flight was planned for 11 April, but a rotor spin test on 9 April ended early because of a timing issue in the flight software. Engineers adjusted the commands, and the attempt was rescheduled.

The first flight

On 19 April 2021, at about 07:34 UTC and around midday local time on Mars, Ingenuity spun up its rotors, lifted off, climbed to about 3 metres, hovered, turned and landed. The whole flight lasted 39.1 seconds. Perseverance watched from about 65 metres away and recorded video.

Because of the signal delay and relay through orbiting spacecraft, the team at JPL received the data about three hours later. The airfield was named Wright Brothers Field, and the International Civil Aviation Organization gave it the ceremonial code JZRO, with Ingenuity designated IGY.

From experiment to scout

The original plan allowed up to five test flights within about 30 Martian days. After the fourth flight, NASA extended the mission and used Ingenuity as an aerial scout, photographing terrain ahead of Perseverance to help plan routes and identify scientific targets.

Ingenuity reached altitudes of up to 24 metres and speeds of up to about 10 metres per second. It survived dust storms, the Martian winter and software problems that engineers fixed from Earth. In total it made 72 flights, covering about 17 km and spending more than two hours in the air.

On 18 January 2024, during its 72nd flight, the helicopter landed hard in featureless sandy terrain where its navigation camera struggled. Images showed damage to at least one rotor blade. NASA announced the end of the flight mission on 25 January 2024. The helicopter remained on the surface, still able to send data to Perseverance for a time.

Timeline

• 2018, May: NASA approves the Mars Helicopter as part of the Perseverance mission.
• 2020, 30 July: Perseverance and Ingenuity launch from Cape Canaveral.
• 2021, 18 February: Perseverance lands in Jezero Crater.
• 2021, 3 April: Ingenuity is placed on the Martian surface.
• 2021, 19 April: Ingenuity makes the first powered, controlled flight on another planet.
• 2021, 30 April: After the fourth flight, NASA announces an extended operations demonstration.
• 2021, 7 May: The fifth flight, the first to a new landing site, completes the planned test series.
• 2024, 18 January: Ingenuity’s 72nd and final flight ends with rotor damage.
• 2024, 25 January: NASA announces the end of Ingenuity’s mission.

Why it matters

Ingenuity proved that controlled flight is possible in the thin atmosphere of Mars, a feat many engineers once doubted. Its success as a scout showed how aircraft could extend the reach of future rovers and landers, and it directly inspired later designs. Like earlier pioneers such as the Mars Pathfinder mission, it opened a new way of exploring the planet.