The Nuclear Spectroscopic Telescope Array, or NuSTAR, is a X-ray observatory. It was designed to look at some of the most energetic and mysterious places in the universe through X-ray light. In order to focus these very short-wavelength, high-energy light rays, the telescope must separate its light-gathering optics from a focal point a distance away.
This is where the mast comes in. The mast is 33 feet long, and made up of stack-able cubes. These cubes are made of carbon fiber rods. They serve to distance the telescope’s two X-ray optics from the focal point where its camera is placed.
“The mast has deployed! We are on our way to getting the best views yet of high-energy X-rays in our universe!” the telescope’s team wrote on Twitter after the event.