What is the highest rate of acceleration of the space shuttle?

The shuttle carries passengers (pilots and other astronauts) and therefore its acceleration is kept around 3g so as not to cause undue stress to those on board.

The shuttle reaches a speed of approx 17,500 mphin order to attain low earth orbit, it uses its solid fuel rocket booster to achieve this. The shuttles theoretical top speed is higher at around 22,000 mph.

Acceleration is the rate of change of velocity with time, as it is a vector it needs to be expressed in terms of magnitude and direction. Acceleration occurs when speed increases, when speed decreases and/or when the direction of motion changes. g is commonly used to as a measure of acceleration. The SI unit for acceleration is metres per second squared.