Playing the Moon Game

In preparing to visit the Moon’s surface, soon-to-be lunar explorers in NASA’s Apollo program first ventured into a variety of unfamiliar landscapes on Earth. A couple of these trips, in the summers of 1965 and 1966, took astronauts to Alaska’s remote Katmai National Park for simulations of field geology in Moon-like environments. In one exercise, which they called “playing the Moon game,” pairs of astronauts were placed at unfamiliar field sites and asked to pretend as if they were on the Moon. By the account of William Phinney, Apollo’s science training coordinator, they were tasked with collecting representative geologic samples and practicing how to communicate their observations to scientists. The Alaskan setting for the Moon game was an unusual volcanic landscape called the Valley of Ten Thousand Smokes. The valley is full of debris deposited by the 1912 eruption of Novarupta—the largest volcanic event on Earth in the 20th century. The images above, acquired on September 29, 2025, with the OLI (Operational Land Imager) on Landsat 9 , show the massive ash flow deposited by Novarupta. The layer measures up to 660 feet (200 meters) thick and was emplaced at a searing 1,380 degrees Fahrenheit (750 degrees Celsius). The Valley of Ten Thousand Smokes, shown in the 1917 photo below, is so named because of the abundance of fumaroles —gas and steam-emitting vents—that filled the valley for a decade after the eruption. …