Today Andrews serves as the president of Skystone Foundation, a nonprofit organization that Turrell created to manage Roden Crater. One big part of Andrews’s job is to raise enough money to finish the crater. Finding donors in the recession has been a daunting task, so Andrews has spent the past five years preparing for a future drive. One of the first things he knew he would need, if he wanted to raise several million dollars, was to know exactly what “several” means. When you’re trying to solicit large amounts of cash, it’s helpful to explain where the money is going. Earlier this year, Andrews and Turrell completed the first full set of blueprints for the crater — detailing every screw, bolt, rod of reinforcing bar and cubic yard of concrete that the project will take.

Now that Andrews has the blueprints, he can estimate the costs; what remains is to grab the attention of the public and donors in a way that Turrell never has before. With so much of his work scattered across the globe, it can take years for a potential fan to discover Turrell. Even the best photography doesn’t begin to capture the immersive experience. For those inclined to travel for art, the exhibitions this summer present the first opportunity to take in so much of his work at once. For Turrell, what his newly raised profile allows, maybe, is a chance to complete the crater, his life’s work.

The afternoon sun was beginning to descend over Roden, and we left the lodge and followed a short path to the main entrance, a pair of high metal doors. As we stepped through, it was instantly apparent that none of my expectations had been right. For one thing, the room was several times larger than I had imagined. For another, it was as perfectly finished as the most elegant Midtown hotel.

We were in a circular room, with a slightly convex top, that Turrell calls the Sun and Moon Space. At the center of the room, a massive sheet of black stone rested on its edge. An eight-foot-diameter circle had been cut from the center and replaced with white marble. The seam where the two colors met was perfectly flush. One side of the slab faced the doors where we entered, which was precisely the direction of the rising sun at summer solstice. The other side faced the opening of a long tunnel, which rose gently into the distance. This was the direction of the moonset at its southernmost point in the lunar cycle. Every 18.61 years, the moon would align perfectly with the center of the tunnel, and Turrell had installed a five-foot diameter lens at the midpoint to refract its image onto the white circle. The next such occasion would be in 2025.

One by one, we walked up the tunnel. It was 854 feet long and 12 feet in diameter, with blue-black interior walls and ribs protruding every four feet. At the top, a great white circle of light beamed toward us. Or so it seemed. As we drew closer, the color changed from white to blue, and the shape began to shift, elongating from a circle to an oval and rising overhead, until it was clear that what had seemed to be a round opening at the far end of the tunnel was in fact an elliptical Skyspace in a large viewing room. A long, narrow staircase made of bronze ascended through it.

We climbed onto the top of the crater and stepped into the sun. Once again we were surrounded by a Martian landscape of crushed red stone. A cold wind blew across the caldera, and we lay down to view the sky, the clouds streaking overhead as the heavens vaulted.

Dusk was coming. We got up and followed a narrow ramp into another Skyspace. It was round, with a narrow bench around the perimeter. Turrell calls it “Crater’s Eye.” We took seats on the bench and stared through the opening in silence. The color of the sky was deepening. It was rich with blue and darkness. It seemed to hover on the ceiling close enough to touch. No one spoke for 30 minutes. I glanced over at Turrell. His hands were folded in his lap, his eyes smiling at the sky. Whatever else the crater had become for him — a job, a dream, an office, a persistent reminder of his own mortality — it was clear that the Skyspace still had the power to lift him up from earth.