Why did the rocket launch vertically upwards?

The rockets we often see are launched vertically, which can greatly shorten the time to break through the atmosphere and enter space, but why do rockets have to be launched vertically? Let's start with the shape of the rocket. Generally, launch vehicles are huge, with a length of ten to tens of meters and a diameter of several to ten meters. If it is launched obliquely, it will have a longer sliding trajectory than a rocket arrow. This sliding track is not only heavy, unstable and difficult to move, but also the vibration generated during launch will inevitably affect the accuracy of rocket entry. In addition, there must be a very open and flat launch site to place the taxiing track.

When the rocket is ignited, the tail will emit flames. Imagine that if the rocket is tilted, it needs to have a fairly long safety zone. Using vertical launch can solve these problems, simplify the launch equipment, and easily make the rocket stand on the launch platform 360? Within the rotation range, the rocket can take off as long as the thrust slightly exceeds the take-off weight when launching. In addition, vertical launch is also beneficial for the rocket to pass through the atmosphere quickly, reducing the loss of flight speed caused by air resistance and helping to accurately determine the initial position of the rocket.

The vertical launch rocket flies out of the dense atmosphere in the shortest distance, and then turns to accelerate its flight around the earth. If you launch directly horizontally, even if the technology is perfect, you won't bump into strange things on it. Instead, you will fly longer in the dense atmosphere. The faster the speed, the greater the resistance and the more fuel you consume! The carrying space of the rocket has been refueled, which is not worth the loss! !

Finally, the propellant used in large launch vehicles is generally liquid, and vertical launch is convenient for propellant filling or discharging, but the vertical flight time of rockets should not be too long. Because when flying vertically, the rocket will lose a lot of speed due to gravity. Therefore, at present, the vertical flight segment of launch vehicle is generally 4 ~ 10 second. ?