All eyes were glued to their TV screens around the world yesterday (probably) as we all awaited the moment NASA inflated its first expandable habitat on the International Space Station (ISS). But, well, things didn’t quite go according to plan.

Unfortunately, NASA has had to postpone inflating the Bigelow Expandable Aerospace Module (BEAM) until an unspecified later date, due to unforeseen problems. We don’t quite know what went wrong yet, but the agency was getting some unusual readings while air was pumped into BEAM, so they decided to call it a day.

“During about two hours of expansion, BEAM’s length and diameter did not increase as expected with the increased internal pressure, and teams decided to stand down from operations for the day,” NASA said in a statement.

As disappointed as you might be, it’s important to note that this is very much an experimental technology. Bigelow Aerospace, the company who made BEAM, have tested inflatable technology in space before with their Genesis 1 and 2 missions in 2006 and 2007 respectively. But this is the first time an inflatable habitat has been attached to a manned spacecraft, so safety must be of the utmost concern.

During the event yesterday, NASA astronaut Jeff Williams gradually released air into BEAM, but mission controllers were not happy with how it was expanding. The agency will monitor how the module reacts to the air that has been pumped inside so far, before deciding to start the process again.

Once it has been inflated, astronauts will wait about a week before going inside. They will install sensors to monitor how BEAM copes with being in space, but otherwise it won’t be used for much other than demonstrating this technology is viable for space travel. If it is, it could one day be used on missions to Mars, or beyond.