be too hot. Instead, Lovell and Haise wore their lunar EVA boots and Swigert put on an extra coverall. All three astronauts were cold, especially Swigert, who had got his feet wet while filling the water bags and had no lunar overshoes (since he had not been scheduled to walk on the Moon). As they had been told not to discharge their urine to space to avoid disturbing the trajectory, they had to store it in bags. Water condensed on the walls, though any condensation that may have been behind equipment panels caused no problems, partly because of the extensive electrical insulation improvements instituted after the Apollo 1 fire. Despite all this, the crew voiced few complaints. Flight controller John Aaron, along with Mattingly and several engineers and designers, devised a procedure for powering up the command module from full shutdownsomething never intended to be done in flight, much less under Apollo 13's severe power and time constraints. The astronauts implemented the procedure without apparent difficulty: Kranz later credited all three astronauts having been test pilots, accustomed to having to work in critical situations with their lives on the line, for their survival. Recognizing that the cold conditions combined with insufficient rest would hinder the time critical startup of the command module prior to reentry, at 133 hours into flight Mission Control gave Lovell the okay to fully power up the LM to raise the cabin temperature, which included restarting the LM's guidance computer. Having the LM's computer running enabled Lovell to perform a navigational sighting and calibrate the LM's IMU. With the lunar module's computer aware of its location and orientation, the command module's computer was later calibrated in a reverse of the normal procedures used to set up the LM, shaving steps from the restart process and increasing the accuracy of the PGNCS-controlled reentry. Reentry and splashdown Despite the accuracy of the transearth injection, the spacecraft slowly drifted off course, necessitating a correction. As the LM's guidance system had been shut down following the PC+2 burn, the crew was told to use the line between night and day on the Earth to guide them, a technique used on NASA's Earth-orbit missions but never on the way back from the Moon. This DPS burn, at 105:18:42 for 14 seconds, brought the projected entry flight path angle back within safe limits. Nevertheless, yet another burn was needed at 137:40:13, using