During the 1970s, James Turrell continued to expand upon the innovative approaches to light and space that he had begun exploring in the previous decade. This period marked a significant evolution in Turrell's work, moving from his early experiments with projection pieces to more ambitious projects that engaged directly with the landscape and architectural environments. One of Turrell's most ambitious and ongoing projects initiated in the 1970s is the Roden Crater, located in the Painted Desert region of Northern Arizona. This project, which began in 1977, involves the transformation of a natural cinder cone crater into a massive naked-eye observatory. Turrell's vision for Roden Crater is to create spaces within the crater that facilitate the observation of celestial phenomena, modifying the viewer's perception of the sky and integrating art with natural landscape on a grand scale. The project reflects Turrell's profound interest in celestial movements, geologic time, and the ways in which light affects human perception​ (The Art Story)​​ (Cambridge)​. The 1970s also saw Turrell engaging in various site-specific installations that explored the sensory effects of light and space. These works were designed to mediate the flow of natural light within constructed environments, challenging the viewers' perceptions and often inducing profound psychological and emotional responses. Turrell's work during this time was not just about the manipulation of light as a material; it was deeply concerned with the viewer's experience, transforming ordinary spaces into immersive sensory environments that question the very nature of seeing​ (The Art Story)​. Furthermore, Turrell's explorations during the 1970s were informed by his background in perceptual psychology, as well as his interest in the aerospace industry and the optimism of the space race era. These influences are evident in the way his art seeks to create spaces that transcend the immediate physical environment, inviting viewers to engage in a form of sensory exploration that borders on the spiritual​ (Cambridge)​. The 1970s were a period of significant experimentation and development for James Turrell, as he began to fully realize his vision of integrating light, space, and human perception in groundbreaking ways. His work from this decade laid the foundation for his subsequent projects and established him as a key figure in the Light and Space movement.