The NuSTAR black hole telescope unfolded its giant mast in orbit on Thursday, June 21. This is one of the final steps before it begins to look into deep space.

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.