Apollo 13 (AS-508) was launched from Pad A, Launch Complex 39, KSC, at 2:13 p.m. EST April 11, with astronauts James A. Lovell, Jr., John L. Swigert, Jr., and Fred W. Haise, Jr., aboard. The spacecraft and S-IVB stage entered a parking orbit with a 185.5-kilometer apogee and a 181.5-kilometer perigee. At 3:48 p.m., onboard TV was begun for five and one-half minutes. At 4:54 p.m., an S-IVB burn placed the spacecraft on a translunar trajectory, after which the CSM separated from the S-IVB and LM Aquarius. (The crew had named lunar module 7 Aquarius and CSM 109 Odyssey.) The CSM then hard-docked with the LM. The S-IVB auxiliary propulsion system made an evasive maneuver after CSM/LM ejection from the S-IVB at 6:14 p.m. The docking and ejection maneuvers were televised during a 72-minute period in which interior and exterior views of the spacecraft were also shown.

At 8:13 p.m. EST a 217-second S-IVB auxiliary propulsion system burn aimed the S-IVB for a lunar target point so accurately that another burn was not required. The S-IVB/IU impacted the lunar surface at 8:10 p.m. EST on April 14 at a speed of 259 meters per second. Impact was 137.1 kilometers from the Apollo 12 seismometer. The seismic signal generated by the impact lasted 3 hours 20 minutes and was so strong that a ground command was necessary to reduce seismometer gain and keep the recording on the scale. The suprathermal ion detector experiment, also deployed by the Apollo 12 crew, recorded a jump in the number of ions from zero at the time of impact up to 2,500 shortly thereafter and then back to a zero count. Scientists theorized that ionization had been produced by 6,300 K to 10,300 K (6,000 degrees C to 10,000 degrees C) temperature generated by the impact or that particles had reached an altitude of 60 kilometers from the lunar surface and had been ionized by sunlight.

Meanwhile back in the CSM/LM, the crew had been performing the routine housekeeping duties associated with the period of the translunar coast. At 30:40 ground elapsed time a midcourse correction maneuver took the spacecraft off a free-return trajectory in order to control the arrival time at the moon. Ensuring proper lighting conditions at the landing site. The maneuver placed the spacecraft on the desired trajectory, on which the closest approach to the moon would be 114.9 kilometers.

At 10:08 p.m. EST April 13, the crew reported an undervoltage alarm on the CSM main bus B, rapid loss of pressure in SM oxygen tank No. 2, and dropping current in fuel cells 1 and 3 to a zero reading. The loss of oxygen and primary power in the service module required an immediate abort of the mission. The astronauts powered up the LM, powered down the CSM, and used the LM systems for power and life support. The first maneuver following the abort decision was made with the descent propulsion system to place the spacecraft back in a free-return trajectory around the moon. After the spacecraft swung around the moon, another maneuver reduced the coast time back to earth and moved the landing point from the Indian Ocean to the South Pacific.

About four hours before reentry on April 17, the service module was jettisoned and the crew took photographs and made visual observations of the damaged area. About one hour before splashdown the command module was powered up and the lunar module was jettisoned. Parachutes were deployed as planned, and the Odyssey landed in the mid-Pacific 6.4 kilometers from the recovery ship U.S.S. Iwo Jima at 1:07 p.m. EST April 17. The astronauts were picked up by helicopter and transported to the recovery ship less than an hour after splashdown.

Official NASA Account of the Mission from Where No Man Has Gone Before: A History of Apollo Lunar Exploration Missions, by W. David Compton, published as NASA SP-4214 in the NASA History Series, 1989.

Almost lost in the drama of the mission was the one piece of scientific information that Apollo 13 was able to provide. Shortly after command module pilot Jack Swigert had extracted the lunar module from atop the S-IVB stage, ground controllers fired the auxiliary propulsion system on the big rocket, putting it on a course to crash into the moon. Three days later the 30,700-pound (13,925 kilogram) hulk struck the lunar surface at 5,600 miles per hour (2.5 kilometers per second) some 74 miles (119 kilometers) west-northwest of the Apollo 12 landing site, releasing energy estimated as equivalent to the explosion of 7.7 tons (7,000 kilograms) of TNT. Half a minute later the passive seismometer left by Apollo 12 recorded the onset of vibrations that persisted for more than four hours. Another instrument, the lunar ionosphere detector, sensed a gas cloud that arrived a few seconds before the seismic signal and lasted for more than a minute. Seismologists were baffled by the moon's response to shock, but welcomed the new means of generating data.

In the year that it took to discover and correct the cause of the Apollo 13 failure, the scope of the remaining missions was altered. Apollo 14 would visit the site intended for exploration by Apollo 13, but it would go there as the last of the intermediate exploration missions. References: 1 , 2 , 5 , 6 , 16 , 26 , 27 , 33 , 60 .