How the Mars Helicopter will soar in an air-less atmosphere?
On February 18th, 2021 NASA’s next rover, Perseverance, will land in the Martian crater, Jezero.
Unlike previous rovers sent to the red planet, Percy (that is his nickname) will not be alone.
Currently nestled inside the safety of Percy’s belly is Ingenuity, the first-ever of its kind.
Ingenuity is a robotic helicopter that is set to test whether an aerial flight is possible on the alien planet, opening the possibility for future missions to involve flight elements.
If successful, Ingenuity will be the first-ever powered flight on another planet.
Several key challenges had to be overcome to get this mission off the ground (pun intended), let us start with the biggest and most obvious one.
How will it fly in that atmosphere?
We are all familiar with the concept of Helicopters here on earth and so the obvious question is “how can a helicopter fly in an environment without oxygen?”
Technically Mars does have oxygen, it just makes up 0.17 of its chemical makeup!
However, Mars is not a vacuum, it has an atmosphere but it is very thin, comprised of 95% carbon dioxide and an atmospheric pressure less than 1% of ours.
Which is enough of an environment, just, for a vehicle that expels downward force to lift off.
While Mars’s reduced gravity, 62% less than ours, will give the robotic helicopter a bit of a boost, the thin atmosphere will make its job exceedingly difficult.
To achieve flight in such conditions Ingenuity had to be as light as possible while exerting an incredible amount of downward thrust.
Ingenuity weighs only 1.8kg and is made up of a small avionics’ computer, solar panels, batteries, heating, a camera, sensors, and its legs and rotor blades.
Those blades in question will spin at a whopping 2400 rpm! For comparison Helicopters here on earth spin between 300–600rpm.
The incredible speed at which the blades will spin combined with such a small body will be what allows Ingenuity to fly in this alien and airless environment.
How will it deploy?
As Ingenuity is hiding inside the belly of Percy, once the rover has successfully touched down and confirmed all systems are go it will be time to deploy. Ingenuity will be the first scientific Percy supervises.
However, some hatch on the top of Percy isn’t going to open up allowing Ingenuity to fly off as you would presumably expect.
Because Ingenuity is hitching a ride on the rover, not a core part of its design, it hanging off Percy’s belly protected by an outer shell.
Once it’s go time, Percy will drop the shield to the ground, drive a bit, and begin unfolding the helicopter from its resting position. Once in the right configuration, Percy will release Ingenuity to the ground where it will rest on its four legs.
You can watch a video here.
Percy will then drive forward again to give Ingenuity some breathing room and the next test will begin.
Which will not be take-off but survival.
How will it survive the conditions?
Ingenuity’s first test is to survive a Martian night.
It can get as cold as minus 130 degrees Fahrenheit (-90c) overnight and so Ingenuity, now out from under the protection of Percy will need to keep itself warm. Its internal heating system will draw from its battery supply to keep it at a safe operating temperature.
The next step is to start recharging its batteries using the attached solar panels. Mars is a lot further away than Earth, that combined with factors such as Martian dust and seasonal weather means that solar panels are not as reliable as they would be here or in space. The Martian Rovers run on nuclear generators because of this.
Once those major milestones are passed the helicopter confirms that it can talk to its base station located on Percy, as well as ensuring that Percy can relay that information back to earth. It will then test its motors and blades by performing some spin tests on the ground.
Where will it fly and how will it navigate?
Several more problems stand in the way of Ingenuity flying on the red planet.
For one the unstable magnetic field around the planet prevents the use of a compass and so Ingenuity will track the Sun’s location instead of that.
The communication lag between Earth and Mars means that Ingenuity will need to fly by itself. Using a myriad of sensors Ingenuity will also use a visual navigation algorithm to help it land safely once airborne. Making the necessary adjustments by itself should it find itself in a landing scenario that could cause it to fall over.
Ingenuity will attempt up to five flights within its 30-day window. After which time the Ingenuity mission will be over and Percy will move on to his next mission leaving his little pal where he lands.
Each test will be informed by how successful the previous test flight was, if the data suggests that Ingenuity did not meet mission parameters, they may opt to make it repeat the previous test.
Ingenuity will have its own airfield where it will start and end every test. The flight paths will only last 90 seconds and will run a maximum of 50 meters in length and only ever go as high as 3–5 meters.
The thing to stress here is that this is a test mission, spanning 30 days only. After that Percy needs to carry on the rest of its mission and will leave the Mars Helicopter behind. Ingenuity while an amazing piece of technology is simply just a tech demo that will have a very short lived life on the red planet.
