One of the two cooling system pumps at the International Space Station (ISS) in Cape Canaveral, Florida, shut down suddenly over the weekend, forcing astronauts to power down equipment and flight controllers. It started 8 p.m. Saturday, when one of the two ammonia-fed cooling loops shut down, signaling alarms and causing a circuit breaker to trip. To repair the system, U.S. astronauts Douglas Wheelock and Tracy Caldwell-Dyson will have to disconnect and reconnect electrical cables and ammonia cooling lines. The spacewalk repairs could start as early as Thursday, with NASA approving a preliminary plan for the repairs on Sunday.
Malfunctions are nothing new to the ISS, as they shouldn’t be for any station of this magnitude. The $100 billion station is an internationally developed research facility that is being assembled in low Earth orbit. The production of the station is expected to be completed in 2011. It’s history has been filled with technical repairs and mechanical upkeep. In August 2005, space walkers were successful in repairing a spacecraft’s heat shield for the first time. In late 2000, spacemen had set out to tighten a loose blanket on an ISS solar wing after NASA took steps to eliminate any shock hazard from two new outpost arrays. Repairs done in December 2001 had astronauts taking in a panoramic view of Earth as they soared around the planet at 25 times the speed of sound while fixing a motor drive in the station’s solar wings.
The need for repairs has been sporadic since the ISS’s inception back in 1998, repairs needing to be done at least a couple of times a year. Because it is such a mammoth project, malfunctions are likely. There are no other space stations of this size, no other space stations comprising completely of operations in orbit. In fact, there have been a multitude of repairs since its inception, several occurring in the past couple of years. And, as the ISS nears completion, only more can be expected, as NASA expects it to orbit the Earth until 2015.
Marcia Dunn, “Space station system suddenly cools down” the Associated Press
William Harwood, “Space Station Malfunction Prompts Shutdowns”, the New York Times
Tariq Malik, “Discovery’s Heat Shield Successfully Repaired in Third Spacewalk”, Space.com
Todd Halvorson, “Space Station Repair Efforts Begin Third Endeavor Spacewalk”, Space.com
Todd Halvorson, “Spacewalkers Set to Scale Station During Critical Repair Job”, Space.com