An "abnormal situation" occurred at Russia's Luna-25 spacecraft on August 20 as it was preparing to transfer to its pre-landing orbit, Russia's national space agency Roskosmos said.
The Russian spacecraft is scheduled to land on the south pole of the moon on August 22, part of a big power race to explore a part of the moon which scientists think may hold frozen water and precious elements.
"During the operation, an abnormal situation occurred on board the automatic station, which did not allow the manoeuvre to be performed with the specified parameters," Roskosmos said in a short statement.
