At the beginning of the space mission era, there was only one form of space craft, single-use capsules. Former USSR cosmonaut Yuri Gagarin used one during the first space mission in 1961. Since then, scientists have developed a range of single-use and reusable craft to propel spacemen and women into the big beyond.
Single-use spacecraft depend on rockets to lift them off the Earth and one example of this type is China's Shenzhou series. Launched on the (long march) multistage rocket, the Shenzhou spacecraft consist of a booster module, an orbiting module, a re-entry capsule and two pairs of solar energy panels.
The craft's crews sit in the re-entry capsule that, as the name suggests, is the only part of the vehicle that returns to Earth. The orbiting module stays in outer space while the booster module is abandoned and burns up (in the atmosphere).
In contrast, the US-developed space shuttles are reusable space transport vehicles. The shuttles are launched vertically like a rocket，orbit like a satellite, and land just like an airplane.
Each shuttle consists of a reusable orbiter, a large expendable external fuel tank, and a pair of reusable solid-fuel booster rockets. Unlike the single-use spacecraft, the shuttle is assisted by its main engines and two reusable boosters.
Actually, no true reusable launch system exists but the space shuttles are the closest examples. The vehicle's orbiter and most of the solid rocket boosters are reusable, but the external tank is not. The orbiters and boosters require several months of work to refit them for each launch.
The shuttles are generally considered to provide the best prospect of lower-cost access to space. The reusable launch vehicle is capable of launching more than one payload into space and can transport more cargo than a single-use craft. Each shuttle's cargo bay is designed to have a lifetime of 100 space missions, carrying up to 20 tons at a time.
Shuttles also have the advantage of being able to carry satellites to space as well as send up crews to repair them in orbit or return them to the Earth for refurbishment and re-use.
Since the space shuttle Columbia lifted off in 1981, the shuttle project has transported more than 620 people into space.
Moreover, the regular spacecraft and the Space Shuttle have one function in common... building and serving space stations. There have been more than ten shuttle missions ferrying materials and equipment to the International Space Station. Spacecraft can also link up with other vehicles. The Apollo-Soyuz Test Project in 1975 was the first human space flight mission managed jointly by two nations, the United States and the former Soviet Union.
Human beings are now on the brink of the age of space tourism. US millionaire Dennis Tito was the first person in history to pay for his own space trip beyond the Earth's atmosphere. Tito's journey to the International Space Station in 2001 is being viewed as one small step towards a potential giant leap into space travel.
And now, China is following in the steps of Russia and the US by sending human beings into space, making a breakthrough in China's manned space travel technology.
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