Next year, the Department of Energy will start building the Dark Energy Spectroscopic Instrument (DESI), which will 3D map millions of galaxies across the universe. The agency-backed project has passed "Critical Decision 3" almost a year after it went through the second phase of approval. That means DOE has OK'd its construction and will provide the funding needed to finish manufacturing its camera's 5,000 10-inch-long cylindrical robots. See that pizza slice-like contraption in the image above? It's one of the camera's ten "petals." Each hole in a petal houses a robot, and the ten petals will carry a total of 5,000. All those machines will point fiber-optic cables to the sky to gather light from distant worlds.