WATCH: NASA says the alarm triggered on the ISS for a possible ammonia leak was probably due to a faulty sensor. Omar Villafranca reports.
TORONTO – Three astronauts aboard the International Space Station are back in their American module after a possible ammonia leak on the International Space Station forced a partial evacuation Wednesday morning.
Around 3 a.m. an alarm was sounded when an increase in pressure in one of the systems was detected. This can sometimes indicate an ammonia leak, though NASA stressed that they had no confirmation that this had actually occurred.
“There is no hard data to indicate a real ammonia leak,” NASA said in a station update early Wednesday morning.
After analyzing the data, it appeared that the alarm could have been triggered by a faulty sensor.
“It’s been a stronger case that this was a falsification,” NASA spacecraft communicator Jim Kelly said to Wilmore around 8:15 a.m. Wednesday.
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“Outstanding news,” Wilmore said.
The crew was allowed back into the American module shortly after 2 p.m. and reported no indications of any ammonia.
In an update late Wednesday morning, Mike Suffredini, Manager of the Space Station Program Office said that engineers and controllers were continuing to work on the issue.
“At this point the team does not believe we leaked ammonia,” Suffredini said. “We’re now in the position where we think everything looks good.”
The ammonia system lies outside the station and helps to regulate temperatures. However, there is a heat exchanger between internal water coolant and the external ammonia coolant. The alarm triggered Wednesday when it appeared that the accumulator was filling up, indicating a possible ammonia leak.
The astronauts were evacuated, but when it was unable to be confirmed were allowed back in the U.S. module.
However, when NASA ground engineers saw an increase in cabin pressure — another possible indicator of a leak — they once again evacuated the crew and powered down several systems.
This is not the first time the ammonia pumps have malfunctioned: In 2010 astronauts had to complete three spacewalks after a pump module failed in one of the ammonia pumps. In 2013, a valve in the pump failed causing one of the two cooling loops to automatically shut down. However, at no time were the crews evacuated.
Before allowing the crew back in, the NASA teams had to recover some data that may have been lost to determine that the system is not indeed leaking.
A few science experiments were to have been conducted, though they were not threatened.
After shutting down various systems in the American section when the alarm sounded, NASA began to power up the section slowly around 8 a.m.
When the alarm was sounded, NASA astronauts Barry “Butch” Wilmore and Terry Virts, as well as Italian astronaut Samantha Cristoforetti followed emergency procedures to power down the section, donned masks and closed the hatch of the American section as they took refuge in the Russian module of the station.
Three Russian cosmonauts are also on board the space station.
The first segment of the space station was launched into space in 1998.
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