All else seemed ready to go. The estimated engine reliability was 93%. The turbogenerators had achieved 100% reliability in test stands. There were still dissenting voices on the use of LH2 - the final vote was 7 for flying with it, and 2 against. References: 367.

All launch vehicle systems performed normally in achieving an earth parking orbit of 170 by 168 kilometers. After checkout, insertion into a lunar trajectory was begun at 3:46 a.m.; translunar coast time was shortened to compensate for the launch delay. CSM 114 transposition, docking with LM-12, and LM ejection from the launch vehicle stage were normal. The S-IVB stage was maneuvered for lunar impact, striking the surface about 13.5 kilometers from the preplanned point at 3:27 p.m. EST December 10. The impact was recorded by the passive seismometers left on the moon by Apollo 12, 14, 15, and 16.

The crew performed a heat flow and convection demonstration and an Apollo light-flash experiment during the translunar coast. The scientific instrument module door on the SM was jettisoned at 10:17 a.m. EST December 10. The lunar orbit insertion maneuver was begun at 2:47 p.m. and the Apollo 17 spacecraft entered a lunar orbit of 315 by 97 kilometers. After separation of the LM Challenger from the CSM America and a readjustment of orbits, the LM began its powered descent and landed on the lunar surface in the Taurus-Littrow region at 2:55 p.m. EST on December 11, with Cernan and Schmitt.

The first EVA began about 4 hours later (6:55 p.m.). Offloading of the lunar roving vehicle and equipment proceeded as scheduled. The Apollo Lunar Surface Experiment Package was deployed approximately 185 meters west northwest of the Challenger. Astronaut Cernan drove the lunar roving vehicle to the experiments deployment site, drilled the heat flow and deep core holes, and emplaced the neutron probe experiment. Two geological units were sampled, two explosive packages deployed, and seven traverse gravimeter measurements were taken. During the 7-hour 12-minute EVA, 14 kilograms of samples were collected.

The second extravehicular activity began at 6:28 p.m. EST December 12. Because of geological interest, station stop times were modified. Orange soil was discovered and became the subject of considerable geological discussion. Five surface samples and a double core sample were taken in the area of the orange soil. Three explosive packages were deployed, seven traverse gravimeter measurements were taken, and observations were photographed. Samples collected totaled 34 kilograms during the 7 hours and 37 minutes of the second EVA.

The third and final EVA began at 5:26 p.m. EST December 13. Specific sampling objectives were accomplished. Samples - including blue-gray breccias, fine-grained vesicular basalts, crushed anorthositic rocks, and soils - weighed 66 kilograms. Nine traverse gravimeter measurements were made. The surface electrical properties experiment was terminated. Before reentering the LM, the crew selected a breccia rock to dedicate to the nations represented by students visiting the Mission Control Center. A plaque on the landing gear of the lunar module, commemorating all of the Apollo lunar landings, was then unveiled. After 7 hours 15 minutes, the last Apollo EVA on the lunar surface ended. Total time of the three EVAs was approximately 22 hours; the lunar roving vehicle was driven 35 kilometers, and about 115 kilograms of lunar sample material was acquired.

While Cernan and Schmitt were exploring the lunar surface, Evans was conducting numerous scientific activities in the CSM in lunar orbit. In addition to the panoramic camera, the mapping camera, and the laser altimeter, three new scientific instrument module experiments were included in the Apollo 17 orbital science equipment. An ultraviolet spectrometer measured lunar atmospheric density and composition; an infrared radiometer mapped the thermal characteristics of the moon; and a lunar sounder acquired data on the subsurface structure.

Challenger lifted off the moon at 5:55 p.m. EST December 14. Rendezvous with the orbiting CSM and docking were normal. The two astronauts transferred to the CM with samples and equipment and the LM ascent stage was jettisoned at 1:31 a.m. December 15. Its impact on the lunar surface about 1.6 kilometers from the planned target was recorded by four Apollo 17 geophones and the Apollo 12, 14, 15, and 16 seismometers emplaced on the surface. The seismic experiment explosive packages that had been deployed on the moon were detonated as planned and recorded on the geophones.

During the coast back to earth, Evans left the CSM at 3:27 p.m. EST December 17 for a 1-hour 7-minute inflight EVA and retrieved lunar sounder film and panoramic and mapping camera cassettes from the scientific instrument module bay. The crew conducted the Apollo light- flash experiment and operated the infrared radiometer and ultraviolet spectrometer.

Reentry, landing, and recovery were normal. The command module parachuted into the mid-Pacific at 2:25 p.m. EST December 19, 6.4 kilometers from the prime recovery ship, U.S.S. Ticonderoga. The crew was picked up by helicopter and was on board the U.S.S. Ticonderoga 52 minutes after the CM landed. All primary mission objectives had been achieved. References: 2, 6, 16, 26, 27, 33,60.