Astronauts on the International Space Station spotted small white flakes floating away from an area of the International Space Station’s P6 truss structure yesterday (Thursday, May 9) and determined an ammonia-based coolant was leaking from the solar array system. While the coolant is vital to the operation of the ISS, NASA says at this point, the crew is not in any danger.
“It is a serious situation,” ISS Commander Chris Hadfield tweeted today, “but between crew and experts on the ground, it appears to have been stabilized. Tomorrow we find out for certain.”
The ammonia is used to cool electronics associated with solar arrays which provide electricity to station systems. NASA said the crew used handheld cameras and Mission Control used external television cameras to gain additional imagery in an attempt to narrow down the leak’s location.
The crew reports, along with imagery and data received by flight controllers in Mission Control in Houston, confirmed that the rate of the ammonia leaking from this section of the cooling system has increased.
Each solar array has its own independent cooling loop. There was a minor leak in the same area that was first identified in 2007 – thought to have been caused perhaps by a micrometeorite impact — and in November 2012 two astronauts went on a spacewalk to fix the problem. They rewired some coolant lines and installed a spare radiator, and it appeared the problem had been fixed.
NASA does not yet know whether this increased ammonia flow is from the same leak, which at the time of the spacewalk, was not visible. The early analysis by thermal control systems specialists indicates that the leak rate could result in a shutdown of this one cooling loop in about 48 hours.
Plans are being developed to reroute other power channels to maintain full operation of those and other systems normally controlled by the solar array that is cooled by this loop.
Current ISS Capcom in Mission Control Doug Wheelock radioed to the crew that “Tomorrow we’ll plan to get the (robotic) arm in the game to see if we can better pinpoint the location of the leak.”
Three of the crewmembers, Chris Hadfield, NASA astronaut Tom Marshburn and cosmonaut Roman Romanenko are scheduled to depart the station on Monday, May 13. Hadfield asked Wheelock is this leak might impact their undocking, but Wheelock said that they are still “getting their arms fully around the issue,” and would have more information for the crew by tomorrow morning.
Source: Universe Today, story by Nancy Atkinson