Russia launches spacecraft to rescue cosmonauts, astronaut stranded on ISS

Russia plans to send an uncrewed spacecraft to the International Space Station in order to bring two Russian cosmonauts and a US astronaut back to Earth after they were stranded there, NPR reported on Friday.

According to the report, Roscosmos cosmonauts Sergey Prokopyev and Dmitri Petelin and NASA astronaut Frank Rubio arrived at the ISS in September in the Soyuz MS-22.

However, on December 14, an external coolant leak was detected on the Russian spacecraft, rendering it inoperable for a standard return mission and effectively stranding Prokopyev, Petelin and Rubio.

Cause of the leak

The leak was likely caused by a small meteoroid colliding with the MS-22's radiator, Sergei Krikalev, director of crewed space flight programs at Roscosmos, said, according to The Guardian.

The Guardian noted that micrometeoroids - traveling at speeds of about 17,000 mph (27,400km/h) - along with space junk from anti-satellite missile tests, are a threat to human spaceflight. 

Russian and US officials planned to launch an uncrewed Soyuz MS-23 to the space station on Sunday. However, a coolant leak was discovered in a different vessel on the station, the Russian cargo ship Progress 82, the NPR report added.

Rescue craft expected to reach ISS on Sunday

Due to the leak on the Progress 82, the launch of the MS-23 was postponed until Friday. The spacecraft is expected to reach the ISS on Sunday, where it will deliver a payload consisting of 948 pounds of cargo.

Prokopyev, Petelin and Rubio will return to Earth on the MS-23 in September.

The damaged MS-22 will be returned to Earth so engineers can study it.