VOICE OVER: This is the moment that the Ingenuity helicopter made history,
making the first ever powered flight on another planet.
ANUBHAV DATTA: It will tell us whether our understanding of how we fly is correct.
So that's the first thing we want to discover: can we fly on Mars?
So we think the math says we can, our understanding of basic principles say we can,
with difficulty, but yes we can.
Now this will be the proof.
VOICE OVER: 290 million kilometers away, NASA's Ingenuity helicopter
has taken the first step towards a new type of space exploration.
ANUBHAV: We have been walking on Mars and there's nothing wrong with that, you need to walk to discover,
but now we can run.
VOICE OVER: Before the historic flight Nature spoke with Dr Anubhav Datta,
who was part of the team that helped test the craft.
ANUBHAV: In terms of range, reach and resolution it's hard to
beat an aircraft that can fly and can fly at low speed in controlled hover mode.
Particularly on Mars, the places that we're interested in are up the slope,
down the crater, into the caves, on the cliffs,
and so those are very inaccessible terrain.
Especially with no roads and rocky terrain on Mars.
VOICE OVER: But flying on Mars is far from straight forward.
ANUBHAV: Just to be able to carry a flying vehicle 292 million miles and deploy it, unfold it,
all in one piece, still alive and beaming - that is an incredible achievement just by itself.
We learned how to fly on Earth after eighty years of experimentation, trial, error, flight tests,
wind tunnel tests, building special wind tunnels, so the first challenge is obvious;
that we don't have that chance, for trial and error, and design, build, fly on another planet,
so we have to rely on simulation
and our very carefully scaled testing that we can do on Earth and extrapolate our knowledge.
VOICE OVER: But getting to Mars safely is not the only problem,
Mars has a much thinner atmosphere than Earth and that means that the parameters
flight relies on, like the viscosity and density of air, are all different.
ANUBHAV: The fundamental ingredient of lift, lift is what keeps aeroplanes afloat in air,
is viscosity, and there is viscosity on Mars, so you can fly on Mars.
How much lift you generate depends on density.
VOICE OVER: The Martian atmosphere means that scientists like
Datta need to think about design completely differently.
ANUBHAV: When you try to design something on the basis of viscosity with very low density
it's, it's a new kind of design that relies on what is, what is called Reynolds number.
VOICE OVER: Reynolds number is related to airflow,
but it's not especially relevant to the design of large craft on Earth.
ANUBHAV: Some people interested in insect flight zoom into that number but in big aircraft we ignore
that number, but that number becomes the the driving factor for Martian design.
VOICE OVER: Ingenuity's design had to contend with a unique set of challenges different from those faced by
craft on Earth, but to an aerospace engineer these challenges also offered opportunities.
ANUBHAV: If you think in a different way there are many advantages of flying on Mars.
There's low density means low drag, which means you don't have
to shape the fuselage or the airframe you know in a particular, particularly aerodynamic manner.
So you can have science instruments sticking all around the aircraft, all you have to do is
to let the rotor carry you to where you want to go. That's an enormous benefit.
VOICE OVER: Ingenuity's first flight; three meters up into the Martian air,
followed by a 90 degree turn and a safe descent may not sound like much,
but its significance for the future of planetary exploration will be felt for years to come.
ANUBHAV: You know sometimes people think 'oh it'll just pop into the air and maybe not go anywhere'. Well,
remember for vertical lift and for helicopters that's the most difficult mode of flight,
the rock-solid hover, and so that's what it's going to try and attempt, so yes it's a short
flight but it's by no means a simple flight, in fact it is the most difficult flight.
Oh, the implication is huge, so if we can fly and give a platform to our planetary scientists,
an unparalleled platform to have access to all the remote corners and interesting features of Mars,
that they don't have now, so as i said it's like we were walking,
the last 25 years we have had rovers we have covered a total of 44 miles, in total,
of flat simple terrain. Now all of a sudden we are opening up this new space.
For a long time, you know conventionally aeronautics is the tax you pay for space research,
because you can't get to space or come back from space without aeronautics,
but now it can provide a, you know, launching pad for new exploration in space.