After separating from the booster, the scramjet engine was ignited, accelerating the aircraft to Mach 5.1 at 60, 000 feet.

NPR: Experimental Air Force Aircraft Goes Hypersonic

The Atlas 5 rocket that launched today stands 191.2 feet (58.3 meters) tall and includes one main booster powered by the RD AMROSS RD-180 engine.

MSN: Shhh �� Air Forces launches secret US spy satellite