ROCKET SCIENCE

Rockets of all kinds are still our only way of reaching space but just how do they work?

- Giles Sparrow

HOW A ROCKET’S MOTORS WORK

Rocket engines are complex machines that must endure ferocious heat and pressure 

Modern rocket motors have come a long way from fireworks. Relatively simple solid rockets, most often used as boosters to provide extra thrust at launch, still rely on the same basic principle of igniting a tube containing a combustible mix of fuel and oxidant. Once ignited, a solid rocket will burn until its fuel is exhausted, but the rate at which fuel is burnt – and thus the amount of thrust – can be controlled by changing the amount of surface exposed to ignition during different times in the rocket’s flight by packing the fuel-oxidant mix with a hollow gap down the centre, running along the length of the rocket. Depending on the profile of this gap, which may be circular or star-shaped, for instance, the amount of exposed surface will change during the flight.