Apollo 17 marked the end of the program that took 12 people to the surface of the moon. By the time the mission launched on Dec. 7, 1972, public interest had declined, the government had shifted its focus to the Vietnam War, and many other factors brought the program to a close, even though three more flights had been planned.
Though it was the last manned mission — so far — the moon still had some surprises for humanity to discover.
Apollo 17 was the first mission to include a scientist in its crew. Geologist Harrison "Jack" Schmitt was one of the first six scientist-astronauts selected in 1965 amid immense pressure to do so from the National Academy of Sciences, who were worried only test pilots would walk on the moon.
Schmitt's presence on the Apollo 17 crew as a lunar module pilot did not come easily. When it came time to select the final crew, Schmitt was chosen over Joe Engle, who was a backup pilot for Apollo 14 and ordinarily would have been next in the rotation to fly. Crewmates Ron Evans and Eugene Cernan were upset for Engle. However, they were pleased at the capabilities Schmitt — a geologic trainer for other moon-bound astronauts — showed on the job.
Evans, the command module pilot, was on his first mission to space. He was on combat duty in Vietnam in April 1966 when he found out he was selected as an astronaut. Evans had not only flown in combat, but also instructed others on how to do so.
Commander Cernan, a formal Navy pilot, faced many a crisis in space. On his first flight, Gemini 9, he did a spacewalk that exhausted him because there weren't enough handholds to perform his work in microgravity. On his second flight, Apollo 10, the lunar module briefly spun unpredictably as it did a practice descent to the surface. He was a seasoned pilot and felt ready to command his crew on the most challenging Apollo mission yet.
Assessing and accessing the landing site
With the latter Apollo missions so focused on science — and with a geologist on board — much consideration went into choosing Taurus-Littrow as Apollo 17's destination. It was geologic variety that tilted the decision to that location. Points of interest to scientists included Shorty Crater — believed to hold evidence of past volcanic vent — and several large boulders spotted in photographs taken by the Apollo 15 crew.
A minor technical error held up launch by almost three hours, but the crew lifted off as planned Dec. 7, 1972. Cernan and Schmitt landed on the surface on lunar module Challenger three days later without major incident, while Evans stayed in the command module, America.
Cernan's and Schmitt's first major challenge was when Cernan accidentally broke a wheel fender on their lunar rover. This meant the astronauts were showered in abrasive moon dust as they drove around the surface. Cernan made a partial repair with some duct tape, joking he would like a "mending award." The next day, he and Schmitt taped some maps in place of the fender to better fix the problem.
The astronauts also deployed several scientific experiments, most notably a traverse gravimeter. The astronauts carried this experiment on the rover and took it out at several sites to measure the relative gravity, which gave scientists an idea about the lunar substructure.
In lunar orbit, Evans made observations of the surface and kept Mission Control entertained by joking about how much he stunk.
Orange soil and a memorable ending
As Cernan and Schmitt worked near the rim of Shorty Crater on the second day, Schmitt exclaimed that he could see orange soil. In Cernan's autobiography, he said he feared Schmitt "has been up here too long and has overdosed on rocks."
But when Cernan clambered over to take a look, he could see the soil was indeed that color. Later examination on Earth showed the rocks were tiny spheres of colored glass that probably came from a surface vent.
After one more day racing the clock to do all the science they could, the lunar crew packed their gear and prepared to climb into Challenger for the last time. Alone on the surface, Cernan gave a short speech, concluding, "I'd just like to record that America's challenge of today has forged man's destiny of tomorrow ... Godspeed the crew of Apollo 17."
Evans got a chance to do a quick spacewalk on the way back to Earth, retrieving some film canisters mounted outside America. The crew splashed down Dec. 19 in the South Pacific Ocean.
The 22 hours of lunar exploration Apollo 17 performed, in the words of spaceflight author Andrew Chaikin, pushed Apollo to its limit. The astronauts drove around about 34 kilometers in the lunar rover. They brought back 108 kilograms of lunar rocks.
The Apollo 17 astronauts also left behind a plaque that read:
"Here Man completed his first exploration of the Moon, December 1972 A.D. May the spirit of peace in which we came be reflected in the lives of all mankind."
More importantly, the astronauts showed the possibilities of science to millions of Earthlings and inspired many youngsters to become scientists, engineers and astronauts themselves.