Anonymous asked in Science & MathematicsAstronomy & Space · 2 months ago

why rockets are not powered with gasoline?

as you kwnow, rockets can be fueled by kerosen, liquid hydrogen, hydrazine, methane, ethanol... but any type of "rocket grade" gasoline is not used in the aerospace industry. why? it's only a curiosity, i don't need an detailed explanation only your opinion. thank you!


Thank you to you all for your great answers!

Attachment image

5 Answers

  • 2 months ago
    Favorite Answer

    The simple answer is that rockets depend on burning the other fuel. Oxygen is used along with the main fuel to get this to happen. Usually, the rocket has hydrogen and oxygen, in highly compressed form. The expanded gas then gets expelled, which provides the thrust -- Newton's third law, more or less. 

    Kerosen, hydrazine, methane, ethanol are heavy compared to hydrogen, and don't expand as much, so they are rather inefficient in the amounts required to get the desired thrust. They do tend to work well, when one has an external source of the oxygen required for maximum combustion, but not when you have to carry the oxygen internally.

    We could power rockets with salami, and get a decent thrust, but it's the weight that becomes the major limiting factor.

    But what we really need is a reactionless engine -- one that delivers thrust without needing to expel it to push the rocket. (there are current ones, but they only deliver about 1/100 of one G or less, which is not enough to give the lift needed to even get into orbit.)

  • ?
    Lv 7
    2 months ago

    Obviously because there are no gas stations in space. Duh!

  • 2 months ago

    Gasoline requires oxygen. Rocket fuel has to have oxygen as well. That's why liquid oxygen adds extra mass to rockets. There isn't enough oxygen at high altitudes for gasoline to combust. 

  • Bill-M
    Lv 7
    2 months ago

    Gasoline does not provide enough power.

  • How do you think about the answers? You can sign in to vote the answer.
  • 2 months ago

    In fact, a few were powered by gasoline, back in the early days... but, gasoline is a rather long molecule; it burns hot and fast, but the thrust it delivers is not as robust (or constant) as simpler forms of fuel - Liquid Hydrogen, RP-1 (close to kerosene derivative) and others... but for it's weight, other fuels work better than gasoline. 

Still have questions? Get your answers by asking now.