According to fuel dynamics,to burn the substances at least 16% of oxygen is needed to ignited. At the sea level the quantity of oxygen is 21% in atmosphere & when we goes rise to the altitude the ratio of oxygen is air goes decreased from 21%.As we have told that at-least 16% of oxygen is needed & for your information at the height of 4500 meter the ratio of oxygen goes down to the 16% so up to 4500 meter we can’t burn the fuel or fire.
As all of we know mount everest in the highest mountain or peek of the world, this mountain is from Nepal. The height of highest peek mount everest is 8,848 meter (approximately 9 kilometer), at the altitude of 8,848 meter the ratio of oxygen goes down to 6.6% & at this quantity of oxygen we can’t burn up the fuel or fire. Usually rocket fly up to 500 km & at this altitude the ratio of oxygen is zero, & at this condition we can’t burn up anything in normal condition. That’s why Limitedscience.com is here to solve out this question.
Since there is no air and space, rockets need to take oxygen with them into space. Inside the rocket’s engine, fuel and oxidizers are ignited in the combustion chamber, creating hot, expanding gases. That gas has pressure, and it pushes harder against the top of the rocket than the bottom, making it go up or forward. Since the fuel is burning, exhaust is released out the bottom.