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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.
“Anderson”2 pages
UNCLASSIFIED/fFOR. QFFIEl.t.L: Uii QD:I! X red penalty at close range would be significantly offset by the high speed of the flight." Th is discussion about the AJAX engine concerned the generation of ion combustion products that would be further accelerated by an MHD (magnetohydrodynamic drive) . The increased number of various carbon -based molecules in the wake of this aircraft could be detected using LIDAR. The increased temperature near the surface of this aircraft would also increase its detectabi lity due to increased emission of infrared radiation. For AJAX (AYAK) vehicles, development of enhanced LIDAR systems and IR detectors should proceed over the next 30 years to in crease their detection and tracking. Recommendation #4 - Explore the Development of Novel Detectors One characteristic of hypersonic flight (M > 5) is the ionization of air in the region downstream of the bow shock and the disassociation of oxygen and nitrogen at very high speeds. When electrons recombine with ions generated by the shock, they emit electromagnetic radiation that can be detected. This radiation extends from the visible range, as evidenced by the glowing trail left by meteors entering the Earth's atmosphere, but the emitted radiation also extends into the ultraviolet and x-ray range. Although such electro-optical sensors are likely part of the existing DARPA/USAF space surveillance system, telescope systems that monitor the UV range should be developed, along with x-ray detectors capable of monitoring the atmosphere. Hypersonic objects passing through the atmosphere disassociate nitrogen and oxygen which recombine in the object's turbu lent wake. During recombination, new molecules are created, including NO, NO2, ionized O and N, and combustion products. 32 LIDAR can detect the presence and concentration of these compounds in veh icle wakes and improved LIDAR systems should be a priority. As hyperson ic objects pass through the atmosphere, the object becomes ionized with a significant positive charge. Technology shou ld be developed to sense the flight of objects with an electrostatic charge as they pass through the atmosphere. SUMMARY Each detection system discussed in the previous section has both benefits and problems. A comparison of the various detection techniques is shown in Figure 19 based on their ability to detect specific properties, re lative cost, and accuracy. Infrared detection systems and multispectral cameras installed on satellites, such as the KH- 11, provide surveillance of large portions of the Earth for possible missile launches, reentry vehicle trajectories, meteor wakes, and hypersonic vehicles. RADAR systems based on satellites, ships, and aircraft can detect the position and velocity of such hypersonic objects at varying range. AWACS, for example, can detect objects at up to 370 km with a resolution of 0.5 meters. TRADEX can track up to six objects at a distance of 1,400 km with an accuracy of 3 meters and a velocity resolution of 0.01 m/s. UNCLASSIFIED//EQA: QlililEl.t.L: W&&: O,.L'l 31
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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.