China's Dark Matter Particle Explorer, nicknamed "Wukong" or "Monkey King," will extend its mission in space by another year, as it is still functioning well after five years of service.

The satellite was launched in December 2015 as China's first dark matter probe satellite and originally designed to serve in space for three years, but its operators decided at the end of 2018 to extend its service life by two years.

Chang Jin, an academician with the Chinese Academy of Sciences (CAS) and chief scientist of the Wukong project, said the satellite's latest mission extension was greenlighted by the National Space Science Center under the CAS after an evaluation of its current condition.

Its key performance indicators have barely changed compared to five years ago when it was launched, Chang said, adding that his team is quite confident about the satellite working another year in space.

As of Thursday, Wukong has orbited the earth 27,822 times in a sun-synchronous orbit at an altitude of 500 kilometers, detecting around 9.36 billion cosmic particles.

Wukong has been helping scientists search for the invisible dark matter by detecting the high-energy electrons and gamma rays in space, which might be generated in the process of annihilation or decay of dark matter. The satellite has also been used for astrophysical studies and researching the origin of cosmic rays.

The satellite has completed its original objectives and contributed to a number of influential academic results, according to the team.

Yuan Qiang, another scientist from the team, said they will focus on analyzing elements including boron, carbon, oxygen and iron in the cosmic rays detected by Wukong, which may shed light on how cosmic rays travel in the Milky Way galaxy.

Dark matter is a hypothetical form of matter that is thought to account for around 80 percent of the matter in the universe and about a quarter of its total energy density. It has not been observed directly. (Xinhua)