A brief history of international space exploration

A file photo of Soviet astronaut Yuri Gagarin, who was the first human to orbit the earth. [Photo: Youth.cn]

The successful launch of the Tiangong-1 space cargo ship puts China one step closer to its eventual goal of establishing a space station by 2022. However, man's desire to explore outer space has long existed.

Following World War II, a "space race" between the Soviet Union and the United States intensified man's quest for space exploration.

On October 4, 1957, the Soviets launched the first unmanned satellite, Sputnik 1, which remained in outer space for three months. Sputnik 2 was launched less than a month later, carrying a dog in orbit for seven days.

The Americans closely followed suit, launching their first satellite, the Explorer 1, several months later in January 1958.

On April 12, 1961, Russian astronaut Yuri Gagarin became the first human to orbit the earth onboard Vostok 1, reaching 327 kilometers in altitude during his 108-minute flight. The Americans managed to fly a man into space that same year and completed a manned orbital flight a year later.

In 1961, US President John F. Kennedy raised a national goal of "landing a man on the moon and returning him safely to Earth within a decade." NASA's Apollo program achieved that feat, when American astronaut Neil Armstrong stepped onto the moon on July 20, 1969 during a flight of the Apollo 11.

Space exploration experienced a boom in the 60's and 70's. On April 19, 1971, the Soviet Union launched the first space station of any kind, the Salyut 1, with more stations following under the Salyut program. The US also launched its first space station, Skylab, which orbited the earth between 1973 to 1979.

In 1975, the Soviets and the Americans put their hands together and conducted the world's first international space flight, the Apollo Soyuz Test Project.

In 1981, the US launched space shuttle Columbia under the country's Space Shuttle program, which employed reusable shuttles. The program, which was eventually retired in 2011, saw 133 successful flights. However, two fatal accidents also overshadowed its achievements. 

On January 28, 1986, the Challenger exploded 73 seconds after its liftoff, killing all seven astronauts onboard. On February 1, 2003, the Columbia was lost shortly before its expected landing on Earth, resulting in another seven casualties.

Currently, the International Space Station (ISS) orbits Earth as the largest structure humans have ever put in outer space, serving as a lab and observatory for scientific research.

With its first component launched in 1998, the ISS is a collaborative project by many countries, but mainly the US, Russia, Canada, Japan and European countries. The 100-billion-dollar project was finished in 2011.

More than 100 crew members have been stationed onboard the ISS, while nearly 230 people have visited the station.