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Up, Up and Away

In our high-tech, wireless world, space flight is no longer as big a deal as it once was. Still, a rocket launch is a big deal. Even small-scale rockets are relatively large, complex machines requiring a huge amount of force to propel them beyond the earth's atmosphere and into space.

Rocket propulsion is based on Newton's Third Law of Motion, which says for every action there's an equal and opposite reaction. Rockets work by shooting out hot gas towards the earth and moving away in the opposite direction, towards the sky. Rocket fuel consists of two components, a propellant and an oxidizer, that is, some form of oxygen that allows the fuel to burn. It really has to burn to create enough propulsion to blast the rocket into space.

Different kinds of rockets use different types of propellants. The Space Shuttle, for example, uses a combination of liquid propellants and solid propellants. The huge solid rocket booster that blasts the shuttle into orbit use a hard, rubber-like solid fuel with the consistency of a pencil eraser. Once ignited the propellant burns without stopping until there's none left. Once in orbit, the shuttle uses liquid propellant. This propellant combines chemicals that ignite on contact and help the shuttle enter orbit, maneuver, and leave orbit to blast back down to earth.

Rocket launches may no longer make the front page, but the fuel used to make them happen is still pretty impressive, and worth knowing about.

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