Even in the era of private spaceflight companies, the process of getting a rocket into space is glacially slow: it can take months or years to schedule and prepare for a mission. That was fine when launching any rocket was a special occasion, but DARPA thinks the industry can do better. The military research agency recently kicked off a Launch Challenge that encourages companies to cut these launch timetables to "days, not years." Teams will have to develop systems that can launch two low Earth orbit rockets at different sites within days of each other, and with little advance notice. They'll only know where the first launch site will be within a "few weeks," and they'll learn about the payload mere days before blastoff.