China on Tuesday launched an unmanned spacecraft to carry out a key docking mission, taking its next step towards the goal of building its first space station by 2020.

Below are the key dates of China's long march into space:

1956: China, still an overwhelmingly rural society mired in poverty, opens its first Missile and Rocket Research Institute.

1960: China develops its first rocket, aided by Russian scientists. It marks the start of an entire series of rockets, all named CZ (abbreviation for Changzheng, or "Long March").

1970: On April 24, China becomes the fifth country in the world to send a satellite into , as the DFH-1 is lifted into space on board a Long March rocket.

1992: As China makes manned space flight its mid- to long-term objective, the State Council, or cabinet, adopts "project 921," which is as secretive as past projects, and is later known by the name Shenzhou ("Divine Vessel").

1995: China's space programme suffers a setback when a CZ-2E rocket explodes during take-off from Xichang, in the southwestern province of Sichuan, killing six people.

1999: The first Shenzhou spacecraft is launched on November 20 on a CZ-2F rocket and returns to earth after 14 orbits. It carries several kilograms (pounds) of .

2002: Shenzhou III is launched on March 25 in the presence of president Jiang Zemin. On April 1, after orbiting the earth 108 times, the craft returns to earth.

On December 29, Shenzhou IV is sent into orbit, and returns to earth on January 4. The same month, China says it plans its inaugural manned space flight.

2003: On October 15, Shenzhou V blasts into orbit, carrying China's first man in space, Yang Liwei. He returns after 21 hours and 14 trips around the Earth.

2007: China launches the Chang'e-1, its first , which orbits the moon and takes high-resolution pictures of the lunar surface.

2008: Zhai Zhigang successfully completes China's first-ever .

2010: On October 1, China launches Chang'e-2, its second lunar probe.

2011: On September 29, China launches the Tiangong-1 or "Heavenly Palace" experimental module, its first step towards building a space station by 2020

2011: On November 1, China launches Shenzhou VIII in preparation for its first docking in