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This Defense Intelligence Reference Document was prepared by the Defense Intelligence Agency's Defense Warning Office in fiscal year 2010 as part of the Advanced Aerospace Weapons System Applications program. It reviews how air flows around objects at subsonic, supersonic and hypersonic speeds, covering shock waves, wakes and ionization. It then compares ways to detect and track hypersonic vehicles, including radar, optical, infrared, LIDAR, infrasound and seismic methods. The report makes four recommendations, among them building a database of aircraft wake signatures and developing novel detectors.
From the source:Release of 2026-09-18 Incident: 11/20/10, Las Vegas, Nevada. Released with redactions. This document is a Defense Intelligence Reference Document (DIRD), a technical reference format used by the Defense Intelligence Agency (DIA) to capture baseline knowledge on a specific topic for later analytic use. DIRDs are best understood as reference and synthesis products rather than as original research. It is one of 38 DIRDs produced under the Advanced Aerospace Weapon System Applications Program (AAWSAP) between 2009 and 2011. Because AAWSAP’s scope permitted a broad range of supporting topics, not every DIRD in the series directly concerns aerospace systems or future threat assessment. The following summary reflects the DIRD’s scope and framing at the time of writing and should not be read as implying current validation of the concepts discussed. This DIRD surveys how hypersonic vehicles may be detected and tracked by exploiting the physical effects they create in flight, especially shock waves, ionized gas, hot surfaces, and turbulent atmospheric wakes. The report reviews a broad set of detection methods, including radar, infrared sensing, optical imaging, LIDAR, passive radio reflection, infrasound, and seismic techniques, and argues that the most effective systems will likely combine multiple sensor types, because each captures different features of a high-speed vehicle’s passage through the atmosphere. It presents radar and infrared sensing as the strongest existing tools for operational detection, while giving particular attention to wake-based methods such as LIDAR and passive radio techniques for improving tracking, identification, and discrimination of future hypersonic aircraft. The paper identifies hypersonic vehicles as an evolving surveillance problem in which future progress will depend on better multi-sensor integration, improved wake characterization, and novel signature-exploitation techniques.
UNCLASSIFIED/fFOR. QFFIEIA.L: Ulii Qt!! X European Fireball Network16 uses cameras at severa l stations separated by distances of about 100 km and covering an area of about 1,000,000 km 2 . Fisheye lenses all ow each station to observe the sky every night to monitor meteors and other nebular objects. The network is operated by the German Aerospace Center (DLR) and the I nstitute of Planetary Research in Prague .17 Other networks include the Meteorite Observation and Recovery Project (MORP) in Canada and the Prairie Network in the United States; all have been in operation since the 1960s and 70s. Another recent meteorite recovery was made when asteroid 2008 TC3 entered the Earth's atmosphere on 7 October 2008 over Sudan .18 The meteor's path left a wake that was visible through dawn. A total of 280 fragments weighing 11 pounds were collected in the Sudanese desert. The photographic evidence of this hypersonic reentry was interesting. The 4.2- meter William Herschel Telescope in the Canary Islands optically recorded the spectrum of this asteroid 2 hours before it burned up in the Earth's atmosphere. This information can be used to identify the chemical makeup of the surface of the object or of the vaporized products in its wake. A sequence of photographs taken at 4-second intervals over a period of about 50 seconds provided information on its velocity as it reentered the atmosphere and its brig htness as a function of t ime . Although these photographic methods have been applied to meteors, data from the European Fireball Network and similar camera systems can be used to monitor the flig ht of hypersonic aircraft that produce a visible wake t hrough the ionization of air. The photograph ic methods described here are limited to nighttime use. Multiple stations recording the same event have been used to measure both position and velocity of objects moving at hypersonic velocities through the Earth's atmosphere and the computed trajectories have been used to successfully predict meteorite impact points on at least two occasions . Optical systems are constantly monitoring the Earth for possible missile launches. Two KH -11 satellites are constantly in orbit 250 to 500 km above the Earth's surface with multispectral cameras that resolve objects to within 2 to 3 meters. Big-Bird, at an orbit 160 to 280 km above the Earth, can take video or photographs with a resolution of 250 mm. The photos must be sent back to Earth for processing. Close-Look, operating from 130 to 300 km, has a resolution of 50 to 150 mm. Landsat, with an orbit of 800 km, can transmit multispectral video of the Earth with a resolution of 20 to 30 meters. The space shuttle, the U-2 aircraft, and the SR-71 have all been used to provide high-resolution images of objects from high altitude. Infrared Detection Infrared detection of reentry vehicles and ICBMs by satellites has been available since the early 1960s, with the United States leading the effort through detection of possible missile launches from the Soviet Union. In addition to RADAR, infrared detection is one of the best techniques for the detection of hypersonic vehicles. Theory of Infrared Detection Systems. All objects emit radiation that is a function of their temperature according to equation 17, the Stefan-Boltzmann Law: 19 q=BCY AT4 (17) UNCLASSIFIED//FOR QliliiliEili.t.L: W&li ONL'l 17
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Official release, from the pursue collection. The PDF is mirrored here; the original link is above. 46 pages are in the text index: search them above, or from the library's search.