In light of the recent launches I was wondering why rockets launch straight up instead of taking of like a plane.
It seems to take so much fuel to go straight up, and in my mind I can’t see to get my head around why they don’t take off like a plane and go up gradually like that.
Edit – Spelling and grammar
Edit 2 – Thank you to everyone who responded. You have answered a life long question.
In: Physics
Planes go up mostly because of their wings. Wings work by turning forward speed into a push that pushes the plane up. So, if a plane wants to go up fast, it also really wants to go forward fast. For that reason, the best way for a plane to go up a lot quickly is to go diagonally. (The exact diagonal direction depends on each plane.)
Rockets don’t have wings. The only way for them to go up is to push upward really hard with their rocket engines. If they pointed diagonally like a plane, they wouldn’t get as much upward push as if they just point directly up, and go.
But there’s more! That’s just for rockets that want to go up as high as possible. Rockets that want to go into orbit have to go up high, but they also have to be going sideways fast. It takes both things to make it into orbit. So rockets actually kind of want to go diagonally too, but for different reasons than planes. For rockets, when you’re close to the Earth you really want to concentrate on just pushing up with your engines. The further you get from the Earth, though, the less you have to concentrate on just going up, so the more you start to push sideways.
That’s why you will see rockets launch directly up, but gradually start to tilt diagonally. Eventually, the rocket engines are pushing pretty much all sideways, and not up at all! Watch a rocket launch and see if you can spot the slow change in which way the rocket is pointed.
If you want to know how they figure out how fast to change direction, you will need to learn something called “calculus,” but you can wait another 10 years or so and post your questions to “ELI15”.
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