Military scientists with Australia and the United States successfully launched a hypersonic rocket from Australia’s Woomera Test Range March 22, the Australian Defence Science and Technology Organisation (DSTO) said in a press release.

The flight was the second of up to 10 planned under the Hypersonic International Flight Research Experimentation program, a joint effort of DSTO and the U.S. Air Force Research Laboratory.

“Today’s flight represents a significant scientific milestone, enabling scientists to collect fundamental data critical to the design and development of an engine capable of sustained hypersonic flight,” Greg Combet, Australia’s minister for defence personnel, materiel and science, said in a prepared statement.

Hypersonic flight is flight through the atmosphere at speeds of Mach 5.5, or more than five times the speed of sound. Hypersonic vehicles have potential applications as weapons delivery systems and low-cost reusable launch vehicles.

One of the challenges to hypersonic flight is the development of air-breathing engines that can sustain operation at such high speeds. During testing, these so-called supersonic combustion ramjet, or scramjet, engines, typically are accelerated to hypersonic or near-hypersonic speeds by conventional rockets before being ignited to take over the propulsion job.