How do rockets reach space?

Unlike jet engines, rockets carry their own oxygen supply, so they can keep working where there is no air. Most of a rocket’s launch mass, often around 85 to 90 percent, is propellant. To save weight, rockets are built in stages that drop away once their fuel is used up. Reaching space is the easy part: to stay in orbit, a spacecraft must travel sideways at about 7.8 kilometres per second, or 28,000 kilometres per hour. Rockets are often launched towards the east to borrow extra speed from Earth’s rotation.