The Chinese military is apparently using an abandoned NASA design to develop a 6,000-mph hypersonic nuclear missile engine. A prototype of the engine has been built and tested using a "radical" American design first proposed over 20 years ago as the country competes to outperform the West in a contemporary arms race, according to a report . The design was presented by Ming Han Tang, a Chinese American and former chief engineer of NASA's hypersonic program. Tang's Two-Stage Vehicle X-plane is driven by two different engines and can travel faster than five times the speed of sound. It was initially...