Why is it a rocket🚀 is used to go straight up into outer space and not just use an airplane ✈️ ? I’m sure there is a good reason but it seems that the gradual assent would be preferred over the straight up approach.
In: Engineering
Planes don’t carry their own supply of an oxidizer to burn fuel against, since the atmosphere provides oxygen for the engines. They are also designed to propel themselves laterally with engines, using lift generated from the wings to lift the aircraft.
Airplane engines need oxygen to burn their fuel, so they cant go into space. And the straight-up approach makes it easier to reach the speed needed to escape the earth’s atmosphere. (Feel free to fact-check these statements)
Airplanes require airflow to generate lift under the wings. After the air thins to a certain point, the plane can’t go any higher
Planes are held aloft by the lift generated from air flowing over the wings. If you go high enough there isn’t enough air to create the necessary lift, and so you come down.
Engines require oxygen and the wings require air passing over them to provide lift, in addition height isn’t the problem for orbit it is velocity, rockets don’t go straight up, they just take off vertically shortly after lift off they then lean over and have a lot of horizontal movement https://youtu.be/Zu-Sp3I0c1Q
Long story short: airplanes use air as fuel. Rockets have all their fuel built into them. If you fly an airplane high enough it eventually runs out of air and thus fuel and stops working. This is known as the airplane’s ceiling.
If you replaced all the jet fuel with rocket and fuel and oxidizer… it still wouldn’t work. To get into space, you have to be going *really* fast, sideways, about 7.5 km/s fast. To get that fast you need a ton of fuel, rockets carry roughly 10kg worth of fuel just to get 1kg worth of payload into space. In order to make getting into space more efficient, rockets drop their expended fuel tanks and engines. Planes can’t really do this and the extra weight of all the control flaps and whatnot means you’d need large wings to be able to lift this weight. Bigger wings means greater drag which also means you’ll need more fuel, but wait! That’s more weight which means bigger wings, more fuel…. you get the picture. Spaceplanes are really, really hard, even harder than rockets.
Rockets don’t go straight up, they go slightly diagonal at first and then when the air thins out they start going perpendicular to try and fall past the Earth aka get into orbit. The ISS and satellites are really just falling, but they are going so far sideways they keep missing the ground/Earth.
The air is what keeps airplanes aloft and air is needed for engines to work. At a certain point there becomes too little air for lift and to burn fuel.
Ignore where this image came from (a flat earth site), but this is the [flight path a rocket takes to get into space](http://fenewsnet.com/wp-content/uploads/2018/07/Flat-Earth-Rocket-Curve-Not_Hit_Dome.jpg)
They normally fly East because it is easier to follow Earth’s rotation and it gives them a speed boost to get to orbital speed.
Airplanes, by definition, require air to work. They generate lift from the motion of air passing over their wings. Propellers and jet engines also need air to generate forward thrust, for more or less the same reason.
There is no air in space. An airplane could get you quite high, but it cannot take you into space any more than a submarine can travel above the surface of the ocean.
It’s not actually that hard to get to the edge of space. The space program uses rockets not so much for the going-up part, but because to get into orbit (or to leave the Earth entirely) you need to go sideways really really fast.
TLDR: There’s no air in space
Jet engines and gas engines need air to burn/explode fuel so they can’t work in space. While Rocket engines carry a supply of their own oxidizer so they don’t need air.
Airplanes also need air flowing over the wings to generate lift. However this can be overcome by having a powerful enough engine to provide rocket like thrust and to maneuver once the wings stop working. It just isn’t currently practical to design an aircraft that way.
Airplanes also don’t have enough thrust to achieve escape velocity to attain orbit. However again this is more a case of practicality than a physical limitation on the airplanes themselves.
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