WASHINGTON, May 11 (Itar-Tass) - U.S. astronauts Chris Cassidy and Tom Marshburn have removed a 260-pound pump controller box that may be the source of an ammonia leak on the International Space Station (ISS) and replaced it with a spare during a spacewalk on Saturday, May 11.
Now the cooling system works normally and no new ammonia leaks have been detected after the pump controller replacement. “That’s good news,” the Mission Control Centre in Houston said during a communication session with the astronauts who have been working outside the ISS for more than four hours.
They inspected the outer surface of the station’s cooling system and took snapshots of equipment for more thorough examination by Mission Control specialists.
Cassidy said he had found nothing unusual. But the astronauts replaced a pump controller box suspected of leaking ammonia coolant. The device contains the mechanical systems that drive the cooling functions for the station's port truss.
Specialists believe that ammonia might have been leaking through a crack in the cooling system of one of the eight solar panels on the American segment of the ISS. A leak of ammonia coolant was detected on May 9, coming from a location on the station’s P6 truss. Additional checks showed that the coolant was leaking quite fast. This might have caused the cooling system to turn off automatically and the Mission Control made the decision to shut it down. The affected solar panel was deactivated as well, but the remaining seven continue to supply enough power to the station, and there is no threat to its operation or to the life of its crew.
The ISS six-member resident crew consists of Pavel Vinogradov, Alexander Misurkin and Roman Romanenko of Russia, U.S. astronauts Chris Cassidy and Tom Marshburn, and Chris Hadfield of Canada. Three of them - Romanenko, Marshburn and Hadfield - are to return to Earth on May 14 aboard the Russian spaceship Soyuz.