Boeing technicians meticulously lower its CST-100 Starliner’s upper dome to the lower dome before bolting and sealing the pressure vessel on March 11. This is the Starliner spacecraft slated to fly in the company’s Orbital Flight Test (OFT). The mate was completed at Boeing’s Commercial Crew and Cargo Processing Facility at NASA’s Kennedy Space Center in Florida. Starliner uses an innovative weldless design where the main structure is made of two domes, each spin-formed and machined from a solid piece of aerospace-grade aluminum. The two domes then undergo outfitting with avionics, cooling systems, wire harnesses, fuel and life support lines, and other critical systems before being mated together. This is one of the last major milestones ahead of final processing and closeouts for flight. OFT is Boeing’s uncrewed flight test of Starliner and part of NASA’s Commercial Crew Program, which will return human spaceflight launches into low-Earth orbit from U.S. soil.