The original crew of Apollo 13 was James A. Lovell, Thomas K. Mattingly II, and Fred W. Haise. Forty-eight hours before takeoff, Mattingly was exposed to German measles by LM pilot Charlie Duke, to be replaced by Jack Swigert. The entire crew had flight experience before boarding Apollo 13. Lovell, however, was the more qualified of the other two astronauts; he was the most traveled astronaut in the world at the time. He had flown three missions and had a total of 572 hours of flight experience. Lovell earned a Bachelor of Science degree from the United States Naval Academy in 1952 and was selected with the second group of astronauts in 1962. He participated in Apollo 8, the first mission to circumnavigate the Moon, and flew two Gemini missions, including a 14-day endurance race (Apollo 13: NASA Near-Disaster Facts). »Fred Haise was a journalist turned naval aviator. He was recognized as a lunar module specialist, having spent fourteen months at Grumman building the spacecraft. Haise earned a Bachelor of Science degree in aeronautical engineering in 1959 and was chosen in the fifth group of astronauts in 1966." He served as alternate lunar pilot for Apollo 8 and Apollo 11, lunar module pilot for Apollo 13, and alternate commander for Apollo 16 (Apollo13: NASA Near-Disaster Facts). Science degree in mechanical engineering in 1953, Master of Science in aerospace in 1965 and Master of Science in business administration in 1967. He was chosen in the fifth group of astronauts in 1966. “He was to be a backup commander. module pilot for Apollo 13 but was transferred to the main crew 48 hours before launch (Apollo13: NASA Near-Disaster Facts). » The Apo...... middle of paper ...... service module no. Cover 4 was also torn off in the process. All oxygen was lost in approximately three hours, along with loss of water, electrical power, and use of the propulsion system. During pre-flight testing, tank #2 was experiencing problems and was not emptying properly, likely due to the damaged fill line. “Scientists believe the switches may have been soldered, allowing the temperature inside the tank to exceed 1,000 degrees F. With the service module damaged beyond repair, the only source of power was the lunar module. The team had to preserve the command module's resources for re-entry to earth. As soon as it became apparent that the mission had to be aborted, the craft was maneuvered to return freely; the moon and would return to earth However, several changes were necessary to make the trip as quick and safe as possible...