Back in 1970, the year China launched its first satellite into space, some Chinese scientists suggested that the government should open the country's lunar exploration program.

However, their suggestion was turned down by Premier Zhou Enlai out of consideration of the technological, technical and financial difficulties.

About 24 years later, Song Jian, a renowned space scientist and former head of China's top science planning body, proposed that the nation could take advantage of a new-generation carrier rocket, which was under research and development at that time for manned spaceflight, to send robotic probes to the moon for scientific survey.

Like what happened in 1970, the idea did not become reality because China didn't have the technology and facilities required for such sophisticated endeavors.

In 1997, several top Chinese scientists launched an initiative, calling for the central government's attention to lunar exploration. Since then, the country's science circle kept urging space authorities to start lunar programs.

In November 2000, the government announced in a space white paper that preparatory research about lunar exploration was included in its space planning agenda.

In February 2003, the government said it was ready to open a lunar program and appointed three scientists as heads of the project team.

In January 2004, the first phase of the Chang'e Program was officially approved, marking the formal opening of China's lunar exploration mission.

After nearly four years of preparation, the first spacecraft stemming from the program -- Chang'e 1 -- was launched on Oct 24, 2007 from the Xichang Satellite Launch Center in Southwest China's Sichuan province. It was tasked with verifying China's lunar probe technologies, obtaining lunar images and performing scientific surveys.

It obtained a lot of scientific data and generated the nation's first map of the entire lunar surface. In March 2009, the probe was taken out of orbit and then was controlled to impact onto the lunar surface.

Chang'e 2, a backup of Chang'e 1 with some technical improvements, was launched on Oct 1, 2010 from the Xichang center to carry out high-definition imaging of the moon and scout possible landing sites for the next mission, Chang'e 3. It has become an uncontrolled satellite in the solar system.

Chang'e 3, a milestone in China's space exploration history, lifted off from the launch pad on Dec 2, 2013, from Xichang. It was the first Chinese spacecraft to soft-land on the moon and also the first manmade craft to achieve this goal in nearly four decades since Luna 24, a probe from the former Soviet Union that landed on the moon in August 1976. Chang'e 3 released the first Chinese lunar rover, Yutu, on the moon. Yutu worked there for nearly 1,000 days, while the Chang'e 3 lander is still operational, sending back data to Earth.

On Dec 8, 2018, China launched its fourth lunar probe, Chang'e 4, toward the far side of the moon, which eternally faces away from the Earth.

After 26 days on its journey, the spacecraft made a soft-landing on the Von Karman crater in the South Pole–Aitken basin of the far side, inaugurating mankind's first close observation of the little known "dark side of the moon".

The ongoing Chang'e 4 mission enables scientists to discover what they haven't known about the moon and deepen their knowledge about the early histories of the extraterrestrial body and the solar system. The Yutu 2 rover, the second of its kind made by China and the world's first to reach the far side, has become the second longest operational rover on the moon.(Chinadaily)