A spacewalk scheduled for two astronauts outside the International Space Station was canceled by NASA about an hour before it was to begin Thursday morning.

“The spacewalk today, June 13, at the International Space Station did not proceed as scheduled due to a spacesuit discomfort issue,” NASA said on its blog. No other details were immediately given.

NASA said Tracy C. Dyson and Matt Dominick, the astronauts scheduled for the space walk, started taking off their spacesuits at approximately 7:25 am EDT, about an hour before the crew was anticipated to exit the ISS through an airlock.

Dyson and Dominick’s spacewalk was supposed to include station maintenance and science work.

In announcing the spacewalk, NASA said two astronauts would remove some communications equipment from one of the ISS’ laboratory modules with an assist from a robotic arm on the station. Dyson and Dominick were also going to swab surfaces on the ISS to “determine if microorganisms released through station vents can survive the external microgravity environment.”