Rocker power!
All space flight depends on the use of rockets that burn huge amounts of fuel. They burn high-energy fuel in a chamber which directs the burning gases through a nozzle. As the gases stream out through the nozzle they provide the thrust to push the rocket up into space.
Some rockets are powered by burning kerosene or liquid hydrogen with liquid oxygen, but this requires very careful handling. Other rockets burn solid fuel in a controlled explosion.
One giant leap!
The Apollo project was the United States’ plan to get humans on the Moon during the 1960s. It used the world’s most powerful rocket, Saturn V, to launch the three-man Apollo spacecraft. While orbiting the Moon, the Apollo craft would separate into two parts. The landing module carried two astronauts down onto the Moon’s surface, while the main part remained in orbit with the third astronaut.
How do satellites stay up?
The speed with which a satellite is launched helps to keep it in orbit. To stay up above the Earth, a satellite must be launched at a speed of about 8 km per second. If the orbit is less than 200 km above the Earth, faint traces of air will gradually slow the satellite so it loses height and eventually crashes to the ground. Satellites that are much higher can stay up indefinitely. Some satellites are placed in a geostationary orbit. This means that their speed exactly matches that of the Earth’s rotation, and they seem to stay above a fixed point on the ground.