Engineers responded with inspections of similar cabling on Atlantis, making repairs or replacements where necessary. The mission was targeted for a Jan. 19 lift off. But as they widened their inspections, engineers found potential problems with another kind of cable on the boosters that distributes electrical power and issues steering commands. As a result, Atlantis was hauled back to its hangar from the launching pad so three dozen cables could be disconnected and tested. No new difficulties were found, and the mission was re-scheduled for Wednesday.
Schedule is schedule.
It doesn't compete with safety.