Published: Aug 09, 2010 6:55 PM EDT
Updated: Aug 09, 2010 3:55 PM EDT

CAPE CANAVERAL, Fla. (AP) - NASA is scrambling to put together a new plan of attack to get the International Space Station back to full cooling.

A jammed connector and ammonia leak prevented two spacewalking astronauts from removing a broken pump Saturday. Until the pump is replaced, the space station has to limp along on only half its cooling power. The system keeps electronic equipment from overheating.

NASA is still targeting Wednesday for the next spacewalk. First, though, flight controllers need to relieve pressure in the ammonia line that is still attached to the failed pump, and get rid of any residual ammonia.

If the bathtub-sized pump is removed Wednesday, a spare would be installed during a third spacewalk Sunday.

The breakdown occurred more than a week ago.