Why the flight of the helicopter of ingenuity to Mars is so great

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Yesterday at 21:00, the standard time of Eastern Australia, the Ingenuity helicopter – which landed on Mars with the Perseverance rover in February – took off from the Martian surface. More importantly, he hovered for about 30 seconds, three meters above the surface, and descended again.

It may not sound like a huge feat, but it is. The flight of ingenuity is the first motorized flight of an aircraft to another planet. It marks an important stage in the story of exploring human space.

While the Apollo 11 spacecraft reached the famous Moon, on relaunch it simply had to leave the gravity of the Moon and return to Earth. However, sustaining the flight in the environment of a world without atmosphere is a different story.

The now historic Ingenuity helicopter lasted six years. We can understand why, once we understand the complexity of what was needed.

Why local flight to Mars is a big issue

There are several technological challenges to making a helicopter flight to another world. First and foremost, helicopters need an atmosphere to fly.

The blades or “rotors” of a helicopter must rotate fast enough to generate a force called “lift”. But uplift can only be generated in the presence of some kind of atmosphere. While Mars has an atmosphere, it is much, much thinner than that of Earth – in fact, about 100 times thinner.

The flight of ingenuity in the atmosphere of Mars is, therefore, the equivalent of flying with a helicopter on Earth at an altitude of 100,000 feet. For reference, commercial aircraft fly 30,000-40,000 feet above the Earth’s surface, and the highest I’ve ever been in a helicopter on Earth is 42,000 feet.

Testing the craft on Earth required a pressure chamber, from which much air would have been extracted to emulate the atmosphere of Mars.

Then, Martian gravity must be considered, which is about a third of the force of gravity on Earth. In fact, this gives us a slight advantage. If Mars had the same atmosphere as Earth, less gravity would mean that we could lift our ingenuity with less power than would be necessary here.

But while the gravity of Mars works to our advantage, this is offset by the lack of atmosphere.

The success of ingenuity marks the first time such a flight has even been attempted outside of Earth. And the reason for this may simply be that, as we have shown above, this task is very, very difficult.

Read more: “7 minutes of terror”: a look at technology Perseverance will be needed to survive by landing on Mars

Advanced manufacturing

There are two main ways in which ingenuity has managed to overcome the obstacles presented in the atmosphere of Mars. First, to generate lift, the two rotors (made of carbon fiber) had to rotate much faster than any helicopter on Earth.

On Earth, most helicopters and drones have rotators that rotate at about 400-500 rotations per minute. The ingenuity rotor rotated at about 2,400 revolutions per minute.

It also has a distinct relationship between aircraft and span. While the body of ingenuity is about the size of a tissue box, its blades are 1.2 m from tip to tip.

Even the transmission of the signal to start the flight required a number of advanced technologies. Although it only takes minutes for the radio signals to travel between Earth and Mars, there was still a delay of hours for these signals to reach the helicopter.

This makes sense when you consider the journey these signals must take – from a computer on Earth, to a satellite dish, to the Mars Reconnaissance Orbiter, to the Perseverance rover, and then finally to the helicopter. .

This image shows the Perseverance Mars rover with the Ingenuity helicopter about 4m behind it.
Credit: NASA / JPL-Caltech / MSSS