Photos: Most powerful Atlas 5 puts 15,000-pound satellite in orbit

A series of unprecedented back-to-back test-firings of a rocket engine originally developed for NASA’s space shuttle concluded earlier this month, giving engineers data crucial to achieving rapid 24-hour turnarounds planned for a U.S. military-funded reusable winged booster under construction at Boeing, government and industry officials said.

Hours after calling off a launch of a different rocket from a nearby launch pad, SpaceX’s launch team loaded a Falcon 9 rocket with propellant Saturday and fired its nine main engines on pad 40 at Cape Canaveral Air Force Station, setting the stage for a liftoff with a South Korean military satellite as soon as Tuesday amid a busy stretch of missions for the California-based rocket company.

The Falcon Heavy is lifted upright at launch pad 39A at the Kennedy Space Center on April 10, 2019, in this time-lapse video.