Collins and Kelly had not already flown a mission as commander and pilot respectively. Collins advocated for at least one rookie astronaut to be assigned to the flight, and Charles Camarda was added. Rick Hauck, who had commanded the return to flight mission after the Space Shuttle Challenger disaster, advised her to visit the contractors where the Space Shuttle components were made. She visited the Rockwell International plant in Canoga Park, California, where the SSMEs were refurbished, the Thiokol factory in Brigham City, Utah, where the solid rocket boosters (SRBs) were made, and the Michoud Assembly Facility in New Orleans, Louisiana, where the Space Shuttle external tank was assembled. Asked if she felt afraid after the loss of Columbia, Collins replied: "I would have to say no. I want to fly again. I am very mentally ready to go fly again." Then pausing, noting that she wanted to be precise, she added "I am mentally ready to go fly again when the shuttle is cleared to fly." She expressed reservations about the studs that held the Space Shuttle in place on the launch pad. The bolts holding them were supposed to be ruptured by explosive charges on lift off, but not all had done so on every mission; nuts had failed to rupture on one in five missions. If too many failed to separate, the result could be catastrophic. A new detonator system was devised, but would not be available for STS-114. She also had concerns about the booster separation motors that separated the SRBs from the orbiter. These were redesigned for STS-114. Finally, she expressed concern about rudder/speed brake (RSB) actuators. An inspection of the RSB actuators on Discovery revealed problems; these were rectified by taking parts from Endeavour. Since it would take a month to inspect Atlantis, Discovery was substituted for Atlantis for the STS-114 mission. Discovery was rolled out to the launch pad on 6 April 2005, but problems with the sensors in the external tank led to it being taken back to the Vehicle Assembly Building at KSC to swap the external tank. This pushed the launch date back to 13 July. Then the same problem recurred, causing another postponement. The mission was launched on 26 July 2005, after a flawless countdown. Although Discovery was not damaged, video of the launch revealed that the problem with debris striking the Space Shuttle had not been resolved. Ten