The first helicopter on Mars

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Sequence of the first launch of the first Martian helicopter Ingenuity (scheduled for April):

  1. The helicopter will undock from the rover. The rover drives off.
  2. The helicopter takes off 13 cm, but with a cable connection to the rover.
  3. The wire is fired off with a pyro-charge.
  4. The helicopter takes off up to 3 meters (climb speed – 1 m per second).
  5. 30 seconds hovering (helicopter power reserve 90 seconds).
  6. Landing.

The Ingenuity helicopter will carry a piece of fabric from the Wright Brothers Flyer 1. Ingenuity is not the first NASA spacecraft to carry a piece of Flyer 1 off Earth. Another piece flew to the moon and back aboard Apollo 11.

Under the cut – synopsis 2019 video report on Ingenuity and a conversation with the developers.

First powered flight over another planet

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In 1985, the USSR used flying helium balloons to explore Venus. As part of the Vega mission, two probes transmitted data from an altitude of 54 km for more than 46 hours.

Flight conditions on Mars

Flying a helicopter in the Martian atmosphere is like flying 30 kilometers above the Earth. Not a single helicopter has taken off more than 12 km, and the record for aircraft is 26 km.

The density of the atmosphere on Mars is 1% of the density of air at the Earth’s surface. On Earth, a cubic meter of air weighs 1.205 kg, the same volume on Mars will weigh somewhere around 15-18 grams.
You need a powerful stream to fly. The simplest solution is to rotate the blades faster.

The density of the atmosphere on Mars is 1% of the earth’s.
The gravity on Mars is 38% of that on Earth.

The speed of sound on Earth is 340 m / s
Sound speed on Mars – about 240 m / s

The rotation speed of Ingenuity blades will be 2300-2900 rpm (40-50 rps).
The rotation speed of the blades of the earth’s helicopter is 500 revolutions per minute (9.5 revolutions per second.

There is a limitation: it is impossible for the tips of the helicopter blades to exceed the speed of sound, because of the shock waves, non-standard aerodynamics and transonic flows occur. In the calculations, the blade speed is 70% of the speed of sound.

The weight of the helicopter is 1.7 kg.

Propellers and blades

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The Ingenuity helicopter has two blades made of foam board covered with a layer of carbon fiber. Each blade weighs 35 g. The blades rotate 40 revolutions per second during flight. The helicopter is designed for 90 seconds of flight.

We did not take a quadrocopter as a basis, because the blades of the quadcopter must be so long that the aircraft would not fit on the Rover.

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The helicopter is made in a coaxial scheme with two propellers 1.2 meters in diameter, which will allow it to float in the air. Two coaxial propellers are the simplest solution because they are more effective at generating lift when they are on top of each other.

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Coaxial scheme – a scheme for constructing a helicopter (or aircraft propellers), in which a pair of parallel propellers rotates in opposite directions around a common geometric axis.

On Mars, grains of sand are carried by the wind, and they can accumulate a triboelectric charge. The discharge can ionize gases near the surface, which could affect the chemistry of the Martian atmosphere. If discharges occur at night, sparks can be seen.

Triboelectric effect – the appearance of electric charges in a material due to friction. It is a type of contact electrification in which some materials become electrically charged after they come into frictional contact with another material.

The Copp-Etchells effect is one of the special cases of triboluminescence (see also Triboluminescence). The term comes from the Greek τρίβειν – “friction” and the Latin lumen – “light”. Light is generated due to the breaking of chemical bonds in a material during its separation, rupture, crushing, rubbing, or other similar mechanical action.

One American journalist noticed an unusual glow that occurs when a helicopter lands or takes off in the desert due to the friction of the helicopter blades against particles of sand and dust in the air. The phenomenon was named after two American soldiers – Kopp and Etchels – who died in July 2009 in Afghanistan.

Simulator of the rarefied atmosphere and gravity of Mars on Earth

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Building 150 – Twenty-Five-Foot Space Simulator

there is Twenty-Five-Foot Space Simulator, there you can recreate any pressure and check the aerodynamic component, but you cannot simulate reduced gravity.

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Twenty-Five-Foot Space Simulator

To test the helicopter, they used gravity unloading. Those. pulled the helicopter up so that it only lifted 30% of its mass, as it would be on Mars.

They used a high-tech reel, a brushed DC motor, a torque transducer and a block mounted high above the ceiling that pulled the fishing line with just the right amount of force.

We pumped out the air, turned on the gravitational unloading system, in fact, the helicopter ended up “on Mars” under the same conditions.

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Early prototype with joystick control

They tried to control the prototype with a joystick, but it would be super difficult to do even if the pilot was on the surface of Mars (not to mention the delay of the signal from the Earth). Due to aerodynamics, there is a delay between the command and the reaction of the aircraft, so it is difficult for a person to pilot it. And it is impossible to control from the Earth – there will be a delay of 20 minutes. The helicopter needs automatic control.

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The helicopter can fly autonomously thanks to the gyroscope, accelerometers, camera, altimeter and tilt sensor.

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All devices will work in real time. Take off the surface, measure the speed, position of the aircraft. The assessment of the state during the flight occurs continuously, it is hundreds of times per second. The data is constantly fed into the feedback system to correct the blade tilt according to the incoming data.

Wind

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Dust storm on Mars 2018.

Wind speed on Mars: 2-7 m / s (summer), 5-10 m / s (autumn), 17-30 m / s (dust storm)

Engineers assembled an impromptu open transverse wind tunnel from 960 (computer) fans, it became clear that the helicopter can withstand flight in 11 m / s wind.

Battery

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The helicopter charges in 1 full Martian day (sol). Battery capacity from 35 to 40 Watt-hours. It’s like 3 smartphone batteries. But most of the energy is not spent on flight.

The helicopter must withstand low night temperatures from -80 to -100 degrees Celsius. The battery is constantly heated. He was covered with electronics so that it would also be heated. Approximately 2/3 of the energy will be spent on heating and maintaining the temperature regime of the elements and warming up parts for work. Only a third of the energy is spent on flight.

Thermal insulation

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A solar battery with an antenna is installed on top, a rotary-wing system is located below, and a cube, also known as a fuselage, is below.

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This cube is closed.

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In the center of the cube there is a ring of batteries. There is free space between batteries and boards. We’ll close the fuselage and put on a special skin. It will hold carbon dioxide inside. Thus, we use carbon dioxide as an insulating material.

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Initially, airgel was considered as an insulating material, but it turned out that carbon dioxide fully meets the requirements of our thermal model. Plus it’s extra weight.

Way to Mars

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You must first fly to Mars. The helicopter must withstand the starting overload. Vibration loads over 80 g. Then 7 months of cosmic background radiation.

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After 9 g in the Martian atmosphere, the device still needs to be unpacked.

The helicopter will fly to Mars under the bottom of the Perseverance rover, covered by a shield to protect it during descent and landing. At a suitable location on Mars, the shield will drop. The team will then unpack the helicopter in several stages to safely bring it to the surface.

The helicopter will detach from the rover with a burst bolt.

When the helicopter is on the surface, the Rover will retract 100 m. Then a two-hour countdown begins. The helicopter is waiting for a radio signal from the rover.

The base station on the Rover will send a signal to fly. The goal of the first flight is to take a joint selfie.

The best time before flight is 11 a.m. Martian time. During the night, most of the battery charge will go to heating, by 11 the battery will be restored. Plus the Slant will get up, you can save on warming up. Afternoon is not good because of the heat. After 12, the density of the atmosphere burns down, the wind rises. After the first flights, there will be more data, for the experiment we will try to take off in the second half of the day. But the safe time is from 9 am to 12 noon.

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The development team is monitoring the tests.

What for

What is the purpose of this mission? Marscopter demonstrates technology, it is intended to show that flight to another planet is possible. He will shoot color photos and videos, but his goal is not scientific discoveries. He will help to obtain technical data in order to understand how best to build aircraft for future missions.


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Vacancies

NPP ITELMA is always glad to young specialists, graduates of automotive, technical universities, as well as physics and mathematics faculties of any other higher educational institutions.

You will have the opportunity to develop software of different levels, test, launch into production and see in action the finished automotive products that you had a hand in creating.

The company has organized a special testing center, which makes it possible to conduct research in the field of ICE control, including in a car. The testing laboratory includes motor boxes, drum stands, temperature and climate control units, a vibration stand, a salt fog chamber, an X-ray unit and other specialized equipment.

If you are interested in trying your hand at solving the problems that we have, write in a personal.

About ITELMA

We are a large development company automotive components. The company employs about 2,500 employees, including 650 engineers.

We are perhaps the strongest center of competence in the development of automotive electronics in Russia. Now we are actively growing and have opened many vacancies (about 30, including in the regions), such as software engineer, design engineer, leading development engineer (DSP programmer), etc.

We have a lot of interesting tasks from car manufacturers and concerns that are driving the industry. If you want to grow as a specialist and learn from the best, we will be glad to see you in our team. We are also ready to share our expertise, the most important thing that happens in automotive. Ask us any questions, we will answer, we will discuss.

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