Apollo 17: The Final Lunar Journey and its Enduring Legacy

Apollo 17, which embarked on its historic journey from December 7 to December 19, 1972, stands as a monumental capstone to NASA's ambitious Apollo program. This mission represents not only the ninth and final crewed voyage to the Moon but also the most recent occasion humans have set foot on another celestial body or ventured beyond the protective confines of low Earth orbit. Its legacy continues to influence our understanding of lunar geology and space exploration.

The crew comprised Commander Eugene Cernan, who would become the last human to walk on the Moon; Lunar Module Pilot Harrison Schmitt; and Command Module Pilot Ronald Evans. While Cernan and Schmitt conducted extensive operations on the lunar surface, Evans meticulously managed scientific observations from lunar orbit in the Command and Service Module (CSM).

The Pioneering Geologist on the Moon

A distinctive aspect of Apollo 17 was the inclusion of Harrison Schmitt, a trained geologist. He holds the unique distinction of being the only professional scientist, specifically a geologist, to have ever landed on the Moon. His selection was pivotal, coming after considerable pressure on NASA to send a scientist-astronaut to the lunar surface. Originally, astronaut Joe Engle was slated for this role, but the scientific community advocated strongly for a trained researcher to maximize the geological insights from such a critical mission. Schmitt's expertise was instrumental in recognizing and interpreting the Moon's geological features in situ, a stark contrast to previous missions where astronauts received intensive geology training but were not professional geologists by background.

An Unprecedented Scientific Focus

Apollo 17 was specifically designated as a "J-type" mission, signifying an expanded scientific mandate that included a longer stay on the lunar surface, extended Extravehicular Activities (EVAs), and the utilization of the Lunar Roving Vehicle (LRV). This mission prioritized scientific exploration more heavily than any preceding Apollo flight. To this end, it incorporated a suite of new and advanced experiments. Notably, a biological experiment, known as Biostack III, was carried in the Command Module. This experiment contained five pocket mice (Perognathus longimembris), part of an effort to study the effects of cosmic radiation on living organisms during prolonged deep-space travel – a critical consideration for future human missions beyond Earth's magnetic field.

Strategic Landing Site: Taurus–Littrow Valley

Mission planners meticulously selected the Taurus–Littrow valley as the landing site, driven by two primary scientific objectives. The first was to sample ancient lunar highland material, specifically rocks older than the vast, dark plains of Mare Imbrium, to gain insights into the Moon's early crustal formation. The second objective was to investigate the possibility of relatively recent volcanic activity, which could challenge existing theories about the Moon's geological evolution. Taurus–Littrow was an ideal candidate because orbital observations and photographs had revealed formations, particularly the prominent massifs, that appeared to be volcanic in origin. The valley itself lies at the southeastern rim of Mare Serenitatis, offering access to both mare and highland terrains.

A significant advantage for the Apollo 17 crew was their prior experience. All three astronauts had served as backup crew members for previous Apollo lunar missions, making them intimately familiar with the intricate Apollo spacecraft systems. This foundational knowledge afforded them more dedicated time for rigorous geological training, which was essential for a science-intensive mission aiming to maximize discoveries on the lunar surface.

The Mission Unfolds: From Launch to Lunar Discoveries

A Unique Night Launch and Program's Only Delay

Apollo 17 launched spectacularly at 12:33 a.m. Eastern Standard Time (EST) on December 7, 1972. This marked the Apollo program's only scheduled night launch, creating a breathtaking visual spectacle. The launch was, however, preceded by the program's sole launch-pad delay, caused by a hardware problem involving an automatic sequencer in the ground support equipment. Despite this minor setback, the powerful Saturn V rocket successfully propelled the crew towards the Moon.

Lunar Surface Operations and the Discovery of Orange Soil

Upon reaching the Moon, Commander Cernan and Lunar Module Pilot Schmitt descended in the Lunar Module "Challenger" to the Taurus–Littrow valley. Over three extensive moonwalks, totaling 22 hours and 4 minutes of Extravehicular Activity, they deployed a comprehensive array of scientific instruments as part of the Apollo Lunar Surface Experiments Package (ALSEP). These instruments included a heat flow experiment, a lunar seismic profiling experiment, and a lunar surface gravimeter, designed to gather long-term data on the Moon's environment and internal structure. Utilizing the third Lunar Roving Vehicle (LRV), they traversed significant distances, collecting approximately 115 kilograms (254 pounds) of lunar samples – the largest sample return of any Apollo mission.

A particularly exciting discovery occurred near Shorty Crater: the presence of distinctive orange-colored soil. This material, initially a perplexing find, was later confirmed to be volcanic in origin, consisting of tiny glass beads formed during explosive "fire fountain" eruptions billions of years ago. This discovery provided crucial evidence of early, energetic volcanic activity on the Moon, contributing significantly to our understanding of lunar geological history.

Orbital Science and Return to Earth

While Cernan and Schmitt explored the lunar surface, Command Module Pilot Ronald Evans remained in lunar orbit aboard the Command and Service Module (CSM), "America." He meticulously conducted a range of scientific measurements and took high-resolution photographs from the Service Module's Scientific Instrument Module (SIM) bay. This suite of instruments included a mapping camera, a panoramic camera, a laser altimeter, and a lunar sounder, which provided invaluable data for mapping the Moon's surface and probing its subsurface structure. Evans even performed a deep-space EVA during the return journey to retrieve film cassettes from the SIM bay. The Apollo 17 spacecraft successfully returned to Earth, splashing down in the Pacific Ocean, on December 19, 1972.

Record-Breaking Achievements of Apollo 17

Apollo 17 etched its name in the annals of space exploration by setting numerous records for crewed spaceflight, many of which remain unbroken to this day:

• Longest Crewed Lunar Landing Mission: The mission lasted a total of 12 days and 14 hours.
• Greatest Distance Traveled from a Spacecraft During EVA: Astronauts ventured 7.6 kilometers (4.7 miles) from their Lunar Module, a record for any type of extravehicular activity that still stands.
• Longest Total Lunar Surface EVAs: The crew spent a combined 22 hours and 4 minutes exploring the lunar surface during their three moonwalks.
• Largest Lunar Sample Return: Apollo 17 brought back approximately 115 kilograms (254 pounds) of lunar rocks and soil, providing an unparalleled bounty for scientific analysis.
• Longest Time in Lunar Orbit: The Command Module orbited the Moon for 6 days and 4 hours.
• Most Lunar Orbits: The Command Module completed a remarkable 75 orbits around the Moon.

Frequently Asked Questions About Apollo 17

When was Apollo 17 launched?

Apollo 17 was launched at 12:33 a.m. Eastern Standard Time (EST) on December 7, 1972.

Who were the astronauts on Apollo 17?

The crew consisted of Commander Eugene Cernan, Lunar Module Pilot Harrison Schmitt, and Command Module Pilot Ronald Evans.

Why was Harrison Schmitt's inclusion unique?

Harrison Schmitt was the only professional geologist to land on the Moon, chosen to enhance the mission's scientific return under pressure from the scientific community.

What was the significance of the "orange soil" discovered on Apollo 17?

The orange soil, found near Shorty Crater, consisted of tiny volcanic glass beads. Its discovery provided definitive evidence of explosive "fire fountain" volcanism occurring early in the Moon's history, about 3.5 billion years ago.

What made Apollo 17 a "J-type" mission?

A "J-type" mission signified an extended stay on the lunar surface (up to three days), more extensive scientific capabilities, and the use of the Lunar Roving Vehicle (LRV) to explore wider areas and collect more diverse samples.

What records did Apollo 17 break?

Apollo 17 set several records, including the longest crewed lunar landing mission, the greatest distance traveled from a spacecraft during an EVA, the longest total lunar surface EVAs, the largest lunar sample return, the longest time in lunar orbit, and the most lunar orbits.

Is Apollo 17 the last time humans walked on the Moon?

Yes, as of now, Apollo 17 remains the most recent mission where humans have set foot on the Moon or traveled beyond low Earth orbit.