Static fire

Static fire

A static fire test includes a wet dress rehearsal and adds the step of firing the engines at full thrust. The engine(s) are fired for a few seconds while the launch vehicle is held firmly attached to the launch mount. This tests engine startup while measuring pressure, temperature and propellant-flow gradients, and can be performed with or without payload. The data gathered in such tests may be used to form a unique (rocket- and engine-specific) set of criteria as part of the go/no-godecision tree in the launch software that is used on launch day. Some static fire tests have fired the engines for twelve and even twenty seconds, although shorter firings are more typical.