China has launched a relay satellite to prepare for a lunar rover mission planned for later in the year.
The Queqiao spacecraft will establish a communications link between Earth and the landing mission, which looks set to launch in the next six months.
The satellite was launched at 22:28 BST on Sunday (05:28 local time) from Xichang launch centre in the country's south-west.
It will settle in an orbit about 455,000 km (282,555 miles) from Earth.
This orbit will also take it more than 60,000 km from the lunar farside, where China will aim to put down with a lander and rover - a mission called Chang'e 4.
Queqiao should be well-positioned to provide near-continuous contact between China's robotic assets on the lunar farside and a ground station on Earth.
"The launch is a key step for China to realise its goal of being the first country to send a probe to soft-land on and rove the far side of the moon," the state news service Xinhua quoted Zhang Lihua, the satellite project's manager, as saying.
In addition to its onboard communications equipment, Queqiao will also carry two scientific instruments and will deploy two microsatellites.
The forthcoming Chang'e 4 mission will explore the Moon's South Pole-Aitken Basin with a payload of scientific instruments. It is a key step in China's long-term plan to further its ambitions as a major space power.
China previously landed a robotic lander and rover, collectively known as Chang'e 3, on the Moon in December 2014. The rover continued to transmit data until March 2015.