DK Science: Space Travel
Less than four years after the launch of the first satellite into space, Sputnik 1 in October 1957, human space travel began. Since then, American astronauts have walked on the Moon, and Russian cosmonauts have remained in space for more than a year at a time in space stations. Today astronauts travel in both rockets and the SPACE SHUTTLE. In the decades to come, astronauts are likely to return to the Moon to set up bases, and even travel to Mars to explore the secrets of our neighbouring planet.
The link-up between a US Apollo and a Soviet Soyuz spacecraft in June 1975 was the first international manned mission. It was called the Apollo-Soyuz Test Project. The crews visited each other’s spacecraft and conducted joint experiments, remaining docked together for two days.
The last Apollo space mission, Apollo 17, took place in December 1972. Eugene Cernan and Harrison H. Schmitt landed on the Moon’s surface in a lunar module. In all, six Apollo spacecraft made successful landings on the Moon.
Yuri Gagarin was first man to travel in space, on 12 April, 1961, orbiting Earth once. The first American to orbit Earth, John Glenn, flew into space on 20 February, 1962.
On 20 July, 1969, Apollo 11 made the first Moon landing. Neil Armstrong and Buzz Aldrin walked on the Moon. Michael Collins manned the command module.
After launch, all American manned space missions are controlled from Mission Control at Houston, Texas. Controllers oversee all aspects of mission operations, such as checking spacecraft engineering data, following in-flight experiments, and communicating with the crew.
When it was first launched, on 12 April, 1981, the space shuttle began a new era in space flight. Until then, all launch vehicles had been expendable – they could be used only once. But the space shuttle is re-usable – most parts can be used again. The shuttle is made up of twin booster rockets, a winged orbiter which carries the crew, and an external fuel tank.
Space Shuttle Endeavour is the most recent orbiter. It has completed 17 flights since it was first launched in 1992. The winged orbiter houses the crew and carries the payload (cargo). The crew fly the shuttle from the upper flight deck and have their living quarters on the mid-deck. There are three orbiters in use – Discovery, Atlantis, and Endeavour.
The space shuttle is piloted from a two-man cockpit in the front of the orbiter’s upper deck. The crew are surrounded on all sides by instruments and controls, and are seen here wearing orange launch and entry suits (LES). The LES protects the astronaut in the event of a pressure leak in the flight cabin. It also provides an emergency oxygen supply, a parachute, life raft, emergency water supply, and full survival and rescue kit.
The shuttle operates from Complex 39 at the Kennedy Space Center in Florida, USA. The different parts are put together in the huge Vehicle Assembly Building, originally built to house the gigantic Saturn V Moon rockets. The shuttle stack sits vertically on the launch pad on top of a mobile launcher. It stands about 56 m (184 ft) high. During launch, the orbiter discards first the twin boosters, then the external tank, before climbing into orbit.
The orbiter’s main engines and the twin solid rocket boosters (SRBs) all fire together at lift-off.
About 2 minutes after lift-off, the SRBs separate and parachute back to Earth to be recovered from the sea.
About 6 minutes later, the external fuel tank is jettisoned. It is not recovered, but burns up in the atmosphere.
Orbiter enters orbit, circling Earth about every 90 minutes. It usually stays in orbit for about a week.
On its return, the orbiter re-enters the atmosphere. Its heat shield glows as it is heated by friction.
