Taurus–Littrow

The selection of Taurus–Littrow as the landing site for Apollo 17 was a deliberate strategic decision driven by significant scientific objectives. Situated on the southeastern rim of Mare Serenitatis, this valley offered a unique geological context, bordering the highlands and a large mare. This juxtaposition promised a diverse array of rock types, including potential ejecta from distant impact events and materials from the Moon's ancient crust.

The presence of the prominent Mount Hadley and the surrounding 'Sculptured Hills' suggested a complex geological history, possibly involving ancient volcanic flows and significant impact cratering. The mission aimed to capitalize on this diverse terrain to gather comprehensive data on lunar differentiation, impact processes, and the timeline of volcanic activity, making it a prime target for the final human exploration of the Moon.

Apollo 17, launched in December 1972, represented the zenith of the Apollo program, culminating its lunar exploration endeavors at Taurus–Littrow. Commanded by Eugene Cernan and piloted by Harrison Schmitt, the mission’s Lunar Module 'Challenger' landed successfully, marking the final time humans would set foot on the lunar surface. Over their extended surface stay, Cernan and Schmitt conducted extensive geological traverses using the Lunar Roving Vehicle (LRV), covering approximately 30 kilometers.

Their activities focused on detailed geological mapping, sample collection from diverse locations including craters and mountain bases, and deploying scientific instruments. This mission was designed not only to gather more samples but also to conduct more in-depth scientific investigations, building upon the knowledge gained from previous Apollo missions.

One of the most significant scientific discoveries at Taurus–Littrow was the identification of bright orange soil, found unexpectedly within the rim of Shorty crater. This discovery was a profound revelation, providing compelling evidence for relatively recent volcanic activity on the Moon, far more recent than previously theorized. Analysis of these orange pyroclastic glass beads indicated that they were erupted from the Moon's interior within the last few hundred million years, a timescale considered 'young' in geological terms.

This finding challenged existing models of lunar thermal history and suggested that the Moon's internal heat engine may have persisted longer than anticipated, offering crucial insights into the Moon's ongoing geological evolution and differentiation processes.

Beyond the orange soil, the entire Taurus–Littrow valley served as an invaluable geological laboratory. The astronauts collected over 110 kilograms of lunar samples, including basalts, anorthosites, and breccias, representing a broad spectrum of lunar lithologies. The proximity to Mount Hadley, a massive mountain formed by tectonic uplift and impact processes, allowed for the study of deep lunar crustal materials.

Investigations into the composition and age of these samples have provided critical data for constructing detailed chronologies of lunar impact events, volcanic resurfacing, and the overall thermal and chemical evolution of the Moon. The diverse geological features and the extensive sample return from Taurus–Littrow continue to be a cornerstone for modern lunar science, informing research on planetary formation and evolution.