Image copyright NASA Image caption The hypervelocity suborbital vehicle reached an altitude of 855 miles, according to a mock-up of the test vehicle in a pre-launch presentation
The US military has successfully launched three hypersonic missiles in tests on 4 July.
A hypersonic vehicle built by the US Air Force National Reconnaissance Office (NRO) reached hypersonic speeds of over 5,000 miles per hour – or 6,000 km per hour.
The X-37B technology demonstrator vehicle flew at an altitude of 770 miles and then plunged into the Pacific Ocean, the US military said.
The launches marked the first time the X-37B has completed two consecutive flights.
hitherto, the Air Force has used this experimental vehicle, originally designed for intelligence, surveillance and reconnaissance (ISR) missions, for test flights at an altitude of approximately 50,000 ft.
The mission, which began on 29 January, is on track to return to Earth at the end of August.
The X-37B launches vertically from a Vandenberg Air Force Base in California.
Image copyright US Air Force Image caption The vehicle has been responsible for over a dozen test flights since 2010
Other companies are using similar concepts for hypersonic testing but the X-37B is believed to be the most technically advanced and technologically versatile vehicle in production, reports say.
Hypersonic flight is more than three times the speed of sound (Mach 5) and operates at altitudes of over 20km.
The test flights have ended with the drone crashing into the Pacific.
US Defense Secretary James Mattis and the head of US Strategic Command, General John Hyten, hailed the launch tests in a joint statement as “the culmination of two years of persistence.”
This previous US Air Force X-37B flight test in 2017 re-offered a concept of reusable vehicles used in robotics testing and operational military operations.
According to National Post, the flight testing of hypersonic technology is particularly important at the moment, as China is investing heavily in the space of weapons developments.