NASA astronauts complete installation of new solar arrays on ISS days after Soyuz leak

NASA astronauts Josh Cassada and Frank Rubio have successfully installed new solar arrays aboard the International Space Station (ISS) after a seven-hour spacewalk that started on December 22. According to NASA, the spacewalk ended at 1:57 am IST on December 23 after the installation of the Roll-Out Solar Array (iROSA) on the 4A power channel on the port truss. The agency says that iROSAs will increase the station's power generation capability by up to 30%, increasing the total available power from 160 kilowatts to up to 215 kilowatts. 

The spacewalk was first delayed by a few days due to a coolant leakage that was detected on Russia's Soyuz MS-22 spacecraft docked at the Rassvet module of the ISS. Suspected to have resulted from a micrometeoroid strike, the leakage lasted for over three hours and stopped only when the fluid completely vented out of the Soyuz. After waiting for the flight controllers to conclude their investigation of the leak, Cassada and Rubio stepped out for their third spacewalk whereas it was the 257th overall spacewalk for the assembly, upgrades, and maintenance of the station. 

Both astronauts are part of the Expedition 68 crew which includes three from the US, three from Russia and one from Japan. They are all part of a six-month-long mission to demonstrate new technologies for future human and robotic exploration missions, including lunar missions.

What's with the leak?

The leak was detected on December 15 and was found near the radiator of the cooling system of the MS-22 spacecraft. This coolant is used to maintain optimum temperature for the astronauts and the avionics inside the capsule as it throws the inside heat out into space. Many feared that the lack of coolant in MS-22 would cause its overheating due to its exposure to the sun, however, Roscosmos, Russia's space agency confirmed that the temperature is at acceptable levels. 

This is still a matter of concern, as Rubio along with cosmonauts Sergey Prokopyev and Dmitri Petelin was scheduled to board the same spacecraft for their return early next year. However, Roscosmos is now planning to send a replacement spacecraft MS-23 and the agency's Director-General Yuri Borisov said that he might send a new capsule by February 19 if the MS-22 is not up to the safety standards.