SpaceX successfully test fired the first stage of F9R—an advanced prototype for the world’s first reusable rocket—in preparation for its first test flight in the coming weeks. Unlike airplanes, a rocket’s thrust increases with altitude; F9R generates just over a million pounds of thrust at sea level but gets up to 1.5 million pounds of thrust in the vacuum of space.
The F9R testing program is the next step towards reusability following completion of the Grasshopper program last year. Future
