Nasa has cancelled the first ever all female space walk outside the International Space Station after it emerged it did not have enough suits to fit women. A historic spacewalk was scheduled to occur this week, with only women operating outside the ISS for the first time ever.

The agency said it made the change after McClain found that she would be more comfortable wearing a suit with a medium-sized hard upper torso segment, rather than the large size she wore on the earlier spacewalk. Only one suit with a medium-sized torso is ready for use on the station, and station managers decided to have Koch use that suit.

There were no signs in the earlier spacewalk by McClain that the larger suit was a problem. An agency spokesperson said March 25 that McClain trained for the spacewalks on the ground in using medium and large torso segments, and initially thought that the larger suit would work, but concluded after the March 22 spacewalk that the smaller suit would be more comfortable.