Apollo 13 was designed as a lunar probe by NASA. The mission was launched at 13:13 CST, on April 11, 1970. However, only two days later, an explosion in one of the Service Module oxygen tanks led to the malfunction of both oxygen tanks and challenges with electrical power supply. Though the Command Module retained functionality, the battery power and oxygen supply were limited. Both were designed to support the crew landing, during the last mission hours. The emergency made the crew use the Lunar Module as a lifeboat instead. Luckily, despite the limited power, water shortage and loss of cabin heat, the crew managed to maneuver a safe return to Earth. The Apollo 13 mission thus, became one of the most successful NASA failures of all time.
Apollo 13 was manned by Commander James A. Lovell, Jr., Command Module Pilot John L. Swigert and Lunar Module Pilot Fred W. Haise, Jr. The entire mission seemed to have been shrouded with intrigue from the very beginning. Originally, Ken Mattingly was slated as Command Module pilot. However, he was diagnosed with rubella, which he had supposedly contracted from Charles Duke, the backup Lunar Module pilot. Mattingly was replaced by Swigert, a week prior to the launch, only to discover later that he had never contracted rubella! This NASA mission was designed and programed to explore the Fra Mauro formation on the lunar surface. The probe was supposed to bring back information on the Fra Mauro highlands, and the 80-kilometer-diameter crater by the same name. NASA planned to investigate the hilly selenological region that was thought to be composed of ejecta that was also responsible for the Mare Imbrium formation. Apollo 13 cost NASA approximately $4.4 billion, a mission that was subsequently completed as Apollo 14.
The mission faced the initial drawback with a second-stage boost malfunction. Luckily, the inboard or center engine shut down two minutes prior to pogo oscillations. These could have proved fatal otherwise, ripping the second stage apart. Nevertheless, the engine experienced violent vibrations recorded at 68g/16 hertz. The vibrations flexed the thrust frame by 76 mm, causing the four outboard engines to burn longer. The subsequent pressure fluctuations in the thrust chamber triggered an engine shutdown. A distance of 321,860 kilometers from Earth had been covered before an oxygen tank of the Service Module exploded. The mission control team asked the crew to destratify the contents of the hydrogen and oxygen tanks to increase accuracy of quantity readings. However, damaged insulation led to insulation ignition and increased pressure beyond the normal 1,000 PSI. The crew mistook the occurrence as a meteoroid collision with the Lunar Module. The failure caused the leakage of oxygen rapidly over the next few hours.
Since the basic functionality of the Service Module fuel cells (combining hydrogen and oxygen to generate water and electricity) was affected, they shut down completely. As suggested during training, the crew immediately shut down the Command Module and used the Lunar Module as a lifeboat. Apollo 13 was designed on a free return trajectory. The system was supposed to get automatically activated to return to Earth. The crew agreed upon free return trajectory, within the reservations of the descent propulsion system. After the closest approach to the lunar surface, the descent engine was fired to speed the return. The survival of the crew was largely due to the extensive coordination and ingenuity shown by the crew, support controllers and flight controlling panel. Clear thinking under extreme conditions enabled the crew to use the lifeboat consumables sparingly and maintain optimum functionality of the life support and communication systems.
The mission ended prematurely without touching the lunar surface, but the greatest satisfaction was that the crew returned to earth safely after all the hardship. The Apollo 13 Mission Operations Team and crew were awarded the Presidential Medal of Freedom on April 18,1970 by President Richard Nixon.