A Chinese space crew is stranded at the country’s Tiangong space station after tiny pieces of space debris were believed to have struck their return capsule, China’s spaceflight agency said Wednesday.

Axar.az informs, citing Fox news, the three-member Shenzhou-20 team had been scheduled to return to Earth on Wednesday, but their mission has been temporarily extended as engineers conduct impact analysis and risk assessments on the damaged spacecraft, the China Manned Space Agency (CMSA) said in a statement.

Their return date has been postponed indefinitely, according to state broadcaster CCTV, which offered no further details.

The crew's return capsule is believed to have been hit by tiny fragments of space junk – an increasing hazard in low Earth orbit. CMSA has not specified the extent of the damage or what repairs, if any, will be required. If the spacecraft cannot be repaired, protocol states the Shenzhou-20 crew will use the Shenzhou-21 team’s capsule to return to Earth.

The Shenzhou program regularly sends crews of three Chinese astronauts to and from the Tiangong space station for six-month missions, where they carry out tasks ranging from scientific experiments to repairing debris damage.

The Shenzhou-20 astronauts – mission commander Chen Dong, fighter pilot Chen Zhongrui and engineer Wang Jie – arrived at Tiangong in April for a six-month rotation. They were nearing the end of their mission when the issue occurred.