NASA’s Commercial Crew Program partners laid out their plans Monday for flights tests leading up to operational missions taking astronauts to the International Space Station. Both Boeing and SpaceX anticipate uncrewed flight tests followed by crewed flight tests with at least one NASA astronaut aboard the CST-100 and Crew Dragon spacecraft, respectively. After their systems are certified by NASA, they will begin transporting crews to the station. Because of lead time requirements established by the companies in their proposals, they will receive what is known as Authority to Proceed (ATP) when they have met established development-related criteria, and NASA has determined the need for a mission. The Authority to Proceed marks the start of lead time needed to purchase hardware and process their systems for those missions. Boeing may receive the Authority to Proceed before SpaceX, though that does not necessarily mean that Boeing’s CST-100 will fly before the SpaceX Crew Dragon.