Three astronauts find themselves stranded in orbit after their return capsule was likely impacted by an unidentified object.

Having already spent six months in space, the crew was scheduled to land back on Earth on Wednesday, but their craft seems to have suffered damage from debris orbiting the planet.

Since April, Chen Dong, Chen Zhongrui, and Wang Jie have been aboard the Tiangong space station, where they have been conducting scientific experiments, executing spacewalks, and experiencing life in zero gravity as part of China’s Shenzhou 20 mission.

The incident occurred shortly before the team was set to officially hand over control of the station to the incoming crew.

This collision left a visible mark on the hull of their spacecraft, prompting concerns that internal damage could compromise the safety of their return journey.

Their replacements had already arrived at the space lab after taking off in their own rocket on October 31.

The two crews will now have to comb through the spacecraft to check for any critical problems before attempting to use the vessel again. The next return data has not yet been released.

It’s the second time this year that astronauts has been stranded in space due to a problem with their space capsule, taking place just seven months after NASA’s Suni Williams and Butch Wilmore were rescued from the International Space Station (ISS).

Astronauts Chen Dong, Chen Zhongrui, and Wang Jie (Pictured) have been stranded on the Chinese space station Tiangong until their return vehicle can be repaired

Shenzhou 20, seen launching in April, was scheduled to go back down to Earth on Wednesday, but it’s believed that space junk damaged the return craft

Chinese officials are unsure what struck the spacecraft, but the damage is believed to have been caused by space debris, which is basically junk floating around the Earth from older space missions and rocket launches.

This could include anything from bits from broken satellites and dropped tools from spacewalks to giant pieces of discarded rocket parts.

This floating garbage is moving around the planet at incredible speeds of up to 17,000mph, the average velocity for objects in low Earth orbit.

This can be a real hazard for manned spacecraft, similar to driving through a hailstorm of bullets.

Right now, there are about 19,000 pieces of space debris in Earth’s orbit that the US is tracking, not counting the satellites still working. 

However, experts at NASA think there could be over half a million smaller pieces too small to track easily.

‘The impact analysis and risk assessment are underway,’ officials at CMSA said, according to CNN.

However, the agency did not provide any details on how long it might take the crews of Shenzhou 20 and 21 to check the ship and repair whatever damage was done.

China’s Tiangong space station (Pictured) was launched in 2021 and orbits about 250 miles above Earth

This isn’t the first time debris has struck a manned spacecraft while astronauts orbited the Earth.

Russia’s Mir station was repeatedly hit by tiny pieces of space junk during its lifespan in the 1980s and 1990s.

The ISS has also been on the receiving end of several collisions with debris, including some incidents that caused significant damage to the US and Russian-led lab.

In 2021, a piece of space junk left a hole in one of the station’s robotic arms.

Just a year later, an unknown object hit a docked Russian Soyuz craft, putting a nearly inch-wide hole in its radiator and causing a coolant leak.

As for the crew of Shenzhou 20, it is not currently known what the backup plan will be if the damage to their craft cannot be repaired.

The Shenzhou 21 mission was also scheduled to last for six months on board the station, which is exclusive to Chinese astronauts.

Tiangong, which means Heavenly Palace, was launched in 2021 and orbits about 250 miles above Earth.