NASA cancels ISS spacewalk due to spacesuit coolant leak (video)

NASA cancelled a spacewalk at the International Space Station today (June 24) following a spacesuit coolant leak in the hatch.

NASA astronauts Tracy Caldwell Dyson and Mike Barratt were told by Mission Control at 8:52 a.m. EDT (1252 GMT) to stop the planned 6.5-hour spacewalk outside the International Space Station (ISS). The pair had already switched over to the internal power in their suits at 8:46 a.m. (1246 GMT), meaning the spacewalk had technically started. Following the cancellation, astronauts opened the hatch into the ISS at 9:51 a.m. EDT (1351 GMT), officially ending the spacewalk. 

While being broadcast on a NASA Television livestream, they had reported "literally water everywhere" as they were moving their suits to internal power to prepare for the extravehicular activity. The leak appeared to be coming from a servicing and cooling umbilical (SCU) on Dyson's spacesuit, she reported. While the situation was serious, the astronauts were not in any danger due to the leak. 

NASA issued a brief official statement following the cancellation, adding that additional information will follow on the agency's ISS blog. They made the call to cancel as it was unclear how much water was left in Dyson's suit following the leak, as a precautionary measure, officials added on NASA Television.

Astronaut Mike Barratt is brought into the International Space Station following a cancelled spacewalk on June 24, 2024. (Image credit: NASA TV)

"I could see the ice crystals were flowing out there, and then, just like a snow machine, there was ice forming at that port on the SCU," Dyson told Mission Control. The SCU is designed to connect to the ISS airlock as astronauts are in the hatch preparing for the final stages of disconnecting for the EVA. They were still in the hatch when the leak happened, with the external door open, but closed it moments after the spacewalk was terminated. "It was a pretty impressive snowstorm," astronaut Butch Wilmore said during NASA's livestream.

This is the second time this particular spacewalk was postponed, after a June 13 attempt with a different astronaut group (Matt Dominick and Tracy Dyson) was postponed due to a "spacesuit discomfort" issue with Matt Dominick. A July 2 spacewalk is supposed to happen as well, but it is unclear if that will go ahead under these circumstances.

The total length of the spacewalk was 31 minutes, based on the time that elapsed between switching the suits to internal power and repressurizing the crew airlock. That brings Tracy Dyson's total EVA time to 23 hours and 20 minutes across four spacewalks, and Mike Barratt's total time to 5 hours and 37 minutes across three EVAs.

Related: NASA calls off spacewalk at International Space Station due to 'spacesuit discomfort'

NASA astronaut Tracy Caldwell Dyson (center) checks the spacesuits of NASA crewmates Michael Barratt (right) and Matthew Dominick during spacewalk preparations on the International Space Station on June 5, 2024. (Image credit: NASA)

The spacewalk had been running slightly behind its expected beginning at 8 a.m. EDT (1200 GMT) due to some small issues with tethers and other matters, but that was within normal range until the duo reported ice crystals (water) coming from the spacesuit.

"The spacewalk for today has been canceled due to a space suit cooling unit water loop leak that began right after the suits were put on internal battery power," an announcer on NASA Television said shortly after the spacewalk was canceled. "The crew is now moving back into the airlock and closing ... the hatch, then they will begin the repressurization process."

Conditions were frosty inside the hatch during repressurization. "It's a little snowy in here, but not as bad as it was ... I have ice on my gloves still and on my helmet a little bit," Dyson said.

Dyson added later she would remain on spacesuit battery power, as she was worried about the water leak affecting the umbilical connectors to the ISS. Mission Control told her there likely would not be an issue, but said she could remain on battery power if she liked.

The spacewalk was supposed to pick up faulty communications equipment, called a radio frequency group, and Dyson was expected to swab the ISS exterior to gather evidence of microorganisms in extreme microgravity environments. 

Monday's EVA was meant to be the first of two upcoming spacewalks geared toward ongoing science and maintenance of the orbital laboratory. (NASA originally planned three, but now plans on doing only two after the June 13 attempt.)

Coolant leaks have plagued planned spacewalks multiple times in recent years. In March 2022, water was found in an astronaut's helmet following an EVA, prompting a seven-month pause in spacewalks. And in 2013, Italian astronaut Luca Parmitano's helmet terrifyingly filled with water during an EVA.

This story was updated at 10:29 a.m. EDT with information about the water capacity in Dyson's suit.

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Elizabeth Howell
Staff Writer, Spaceflight

Elizabeth Howell (she/her), Ph.D., is a staff writer in the spaceflight channel since 2022 covering diversity, education and gaming as well. She was contributing writer for for 10 years before joining full-time. Elizabeth's reporting includes multiple exclusives with the White House and Office of the Vice-President of the United States, an exclusive conversation with aspiring space tourist (and NSYNC bassist) Lance Bass, speaking several times with the International Space Station, witnessing five human spaceflight launches on two continents, flying parabolic, working inside a spacesuit, and participating in a simulated Mars mission. Her latest book, "Why Am I Taller?", is co-written with astronaut Dave Williams. Elizabeth holds a Ph.D. and M.Sc. in Space Studies from the University of North Dakota, a Bachelor of Journalism from Canada's Carleton University and a Bachelor of History from Canada's Athabasca University. Elizabeth is also a post-secondary instructor in communications and science at several institutions since 2015; her experience includes developing and teaching an astronomy course at Canada's Algonquin College (with Indigenous content as well) to more than 1,000 students since 2020. Elizabeth first got interested in space after watching the movie Apollo 13 in 1996, and still wants to be an astronaut someday. Mastodon:

  • Gajh
    Just use the tech from the 60's, it worked perfectly.
  • ChrisA
    Gajh said:
    Just use the tech from the 60's, it worked perfectly.
    They are. THese suits are basically from the 1980s and are based on easier design. We have better batteries and electronics and these suits are modular but basically the same. Water cooling has been around for at least 50 years
  • tjmitche
    Should have been using the new Collins Aerospace EMU space suits. NASA can't get away from these old suits soon enough.
  • Rob77
    Seems like a few issues going on up there at the ISS....wondering if we are getting the full story?