Computational Fluid Dynamics Analysis of the Infrared Emission From a Generic Hypersonic Glide Vehicle

Hypersonic boost-glide vehicles are designed to fly long distances in the upper atmosphere. They are reported to have the potential to evade ballistic missile early warning systems and to maneuver as they fly toward their target. A recent analysis by Tracy and Wright in Science & Global Security claimed to show that typical boost-glide vehicles produce significant infrared signatures that would be readily detectable with existing U.S. satellites and therefore questioned the potential advantages of hypersonic weapons over existing missiles. The prior analysis is revisited and several inconsistencies in the underlying assumptions are described. A detailed computational fluid dynamics analysis predicts typical infrared signatures to be significantly lower than those predicted by Tracy and Wright. As a result, these signatures would fall below the detection threshold of legacy U.S. Defense Support Program satellites but remain detectable by the more modern sensors from the Space-Based Infrared System. There are two significant issues with the prior analysis: an incorrect aerodynamic angle of attack was used, and the turbulent heat transfer rate correlation used to predict the surface temperature is inaccurate at the conditions studied.