The IXPE observatory features three identical telescopes, each with a mirror assembly and a polarization-sensitive detector. To focus X-rays, IXPE’s mirrors need to be about 13 feet (4 meters) away from the detectors. That’s too large to fit inside some rocket fairings. So IXPE’s boom had to fold up, like origami, into a 12-inch (0.3-meter) cannister and stretch out again in orbit. With the boom now deployed, mission specialists are ready to focus on commissioning the telescopes, preparing them for the spacecraft’s first science.