Space Exploration
Astronauts are carried in spacecraft to orbit the Earth and travel in space. These spacecrafts are launched by rockets that like the ones used to launch probes and satellites, are called launch vehicles.
The most powerful launch vehicle the United States has ever built was called the Saturn 5 (depicted to the right) and carried astronauts to the moon. It weighed more than 6 million pounds. The 11 rocket engines it used to propel three stages gave it the ability to send spacecraft that weighed more than 100,000 pound to the moon. Space shuttles were reusable rocket-powered spacecraft that could to and from space repeatedly, but the United States closed this program in 2011. Engineers have worked towards developing space tugs, smaller rocket-powered vehicles that could tow satellites, boost space probes, and carry astronauts over shorter distances in orbit. |