Nasa has said a third spacewalk is now needed to restore a crucial cooling system at the International Space Station.
Space station astronauts did not make much progress during Saturday's urgent walk.
The crew had to hammer loose a stuck connector, then an ammonia leak erupted. In the end, Douglas Wheelock and Tracy Caldwell Dyson were unable to remove the ammonia coolant pump that failed last weekend.
Nasa originally estimated two spacewalks would be needed to replace the failed pump.
After Saturday's trouble, managers have said three will now be necessary. The next spacewalk will not be attempted until Wednesday at the earliest and engineers need to work out the next step.
Nasa said the space station remains in a stable condition.