June 30, 2022
Physics in aircraft |  Why don't planes go into space?

Physics in aircraft | Why don’t planes go into space?

Watching the astonishing and complex launch of a rocket carrying astronauts, you may be asking yourself: “If an airplane can ‘defy gravity’ and fly, why can’t it go into space?”. It’s a good question: what prevents you from “climbing a little higher” and reaching the International Space Station, which is only 400 km away?

Commercial aircraft, which carry millions of passengers annually, fly at altitudes of up to 12 kilometers, as do the airline’s passenger jets. Boeing and Airbus. On the other hand, turboprop and twin-engine aircraft do not exceed 6 km. On the other hand, there are planes capable of reaching dizzying heights – Concorde was a supersonic passenger plane Able to reach nearly 18 km of altitude!

The Kerman Line is the fictional “limit” that marks the beginning of space at an altitude of 100 km (Image: Reproduction/NASA Marshall Space Flight Center)

Although this altitude is high compared to commercial aircraft, it is still far from the “beginning” of space. In general, scientists consider that space begins from what is called Kerman line, an imaginary limit at an altitude of 100 km. Not even ordinary commercial aircraft can approach it for two main reasons: the fuel and its design.

Why don’t planes go into space?

Before we discuss why Airplanes don’t go into space, It is important to first understand how they fly and stay in the air. And it’s all about physics.

With the help of its engines, aircraft can accelerate. When air meets the surface of the moving wing, it splits into two layers. The layer that passes through the top of the wing, which is round, moves faster than the layer that passes through the bottom, which is “straight”.

This difference in air travel speed generates a pressure difference that is greater at the bottom of the wing than at the top. This creates a thrust that pushes the plane up and lifts the wing and the plane along with it.

The wings help keep the plane in the r because of its shape (Photo: Reproduction/Unsplash/Johny Goerend)

Now, keep in mind that air at high altitudes is thin, that is, the higher you are, the fewer molecules of gases it consists of, including oxygen, in a given space. This creates two problems: With less oxygen, it’s harder to burn engine fuel, which is necessary to keep the plane moving.

Also, there are fewer particles to “stabilize” the plane at the top. One way to compensate for this is to increase the speed, but this requires better fuel combustion, which requires more oxygen … Do you understand the problem? If a commercial airliner climbs above the “ceiling” height, its engine will be turned off. His speed will decrease and there will not be enough thrust to keep him in the air and he will fall.

We also have to take into account Earth’s gravity, with an acceleration of about 9.8 m/s². This means that the velocity of a falling body increases by 9.8 m/s every second. To escape from it and get into orbit, Commercial aircraft have to travel at a speed of about 40,000 km/h.

But commercial aircraft reach much lower speeds: during take-off, for example, a commercial airliner travels at a speed of up to 280 km / h. In the so-called cruise phase, when the plane flies Between 9100 and 12400 metersThe speed can reach 850 km / h.

On the other hand, there are planes that can exceed this speed – one of them is Lockheed SR-71 Blackbirda military aircraft capable of easily passing 3500 km / h, and therefore one of the fastest aircraft in the world.

In case you are wondering how Missiles move through spaceKnow that their motion is closely related to Newton’s third law, which describes that every action generates a reaction with the same intensity, but in the opposite direction. This principle is applied to rockets from the launch stage, in which thrusters are activated and gases are pushed out; These, in turn, push the missile back and move it up.

Some of the “planes” that went into space

There are some air vehicles that, although based on aircraft design, can reach space. Among them is the X-15, an aircraft developed in the United States during the 1950s to serve the US National Advisory Committee for Aeronautics (NACA), an organization that preceded current NASA.

The first flight of the X-15 took place in 1959, and in 1963 one of these aircraft reached an altitude of 100 km, that is, it officially reached space.

The X-15 was part of a series of experimental aircraft (Image: Public Domain)

The X-15 helped shorten the distance between manned flights in the atmosphere and provided important lessons for the US space program. Some of them have been put into practice in Space Shuttle Program, systems consist of three main parts. One was the orbiter, an airplane-like component that houses the astronauts; The others were the orange outer tank and the solid thrusters resembling two thin missiles.

you Space ship Launched vertically like rockets, the thrusters and thrusters of the orbital vehicle helped the system leave Earth; Two minutes after launch, the orbiter was released from the thrusters which returned and landed in the ocean for further use. The tank was released only after all the fuel had been consumed, since it was burned in the atmosphere. After the missions ended, the orbital vehicles returned to Earth flying like airplanes, landing on traditional airstrips.

Space Shuttle Atlantis landing, last program (Image: Reproduction/NASA/Bill Ingalls)

Recently, Virgin Galactic, a company founded by Richard Branson, awarded The launch in space tourism last year, with the launch of the VSS Unity space plane. During the first voyage, Branson and other crew traveled on board the aircraft, which was carried by the “mother ship” VMS Eve to an altitude of approximately 13 km; Subsequently, the VSS Unity was launched and launched its rocket engines, reaching a speed of three times the speed of sound and about 85 km in height.

Source: via: Focus on scienceAnd NASAAnd long live science