STS039-096-065 White Sands National Monument, New Mexico, U.S.A. May 1991 The highly reflective white sand of south-central New Mexico is easily recognized from spacecraft. White Sands National Monument, established by the U.S. National Park Service, is recognized as the world's largest gypsum sand field with approximately 300 square miles (777 square kilometers). The southwest corner of White Sands National Monument, the lowest spot in the Tularosa Valley, changes from a dry lakebed into Lake Lucero when summer rain falls. This photograph shows no evidence of standing water in Lake Lucero. The sparse, scrub vegetation of the surrounding desert landscape contrasts with the dark, forested Sacramento Mountains, which form part of the eastern edge of the Tularosa Valley. Holloman Air Force Base (center of the photograph) and Alamogordo, northeast of Holloman, are barely discernible.