DOW-UAP-D148, AAWSAP DIRD, Detection and High-Resolution Tracking of Vehicles at Hypersonic Velocities, November 2010
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.
The summary above is sourced from the released file metadata as published to war.gov. The analysis sections below are original to this tracker.
Text of the document
Machine-extracted from the PDF war.gov published (its text layer or OCR), so expect errors, especially in names, numbers and handwriting; the PDF is the authoritative copy. Lines that did not extract as readable text are left out. Showing about 986 words from pages 2, 3, 4, 5 of 46.
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Detection and High Resolution Tracking of Vehicles at Hypersonic Velocities The Defense Intelligence Reference Document provides nonsubstantive but authoritative reference information related to iutelli ence to ics or methodolo ies. Prepared by: Technology Warning Division (DW0-4) Defense Warning Office Directorate for Analysis Defense Intelligence Agency AAP Person 83 {U) COPYRIGHT WARNING: Further dissemination of the photographs in this publication is not authorized. This product is one of a series of advanced technology reports produced in FY 2010 under the Defense Intelligence Agency, Defense Warning Office's Advanced Aerospace Weapons System Applications (AAWSA) Program. Comments or questions pertaining to this document should be addressed to !AAP Person 1 f AWSA Program Manager, Defense Intelligence Agency,
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Chapter 1: Theory Governing Objects in Flight ............................................................... 3 RADAR (Reflected Energy) .................................................................................. 13 Radio Reflection Detection .................................................................................. 15 Sky Cameras and Photographic Methods ............................................................... 16 Acoustic and Seismic Methods ................................................................................ 25 Chapter 4: Vision of Progress Over the Next 30 Years ................................................... 28 Detectability of New Hypersonic Aircraft ................................................................... 29 Recommendation #1 - Build a Database of the Wake Characteristics for Existing Aircraft Recommendation #2 - Exploit the Detectability of Hypersonic Aircraft Based on the Features That Allow Them To Fly Efficiently at High Speeds ..................................... 30 Recommendation #3 - Explore the Detection of Vehicles Designed To Be Undetectable30 Recommendation #4 - Explore the Development of Novel Detectors ......................... 31
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Figure 1. Boundary Layer Development in Subsonic Flow about a Projectile........................ 4 Figure 2. Subsonic Flow Past a Projectile....................................................................... 5 Figure 3. Strauhal Frequency as a Function of Reynolds Number for Flow over a Figure 4. Supersonic Flow Past a Wedge-Shaped Body .................................................... 8 Figure 5. Supersonic Flow Past a Blunt Body (Spheroid) .................................................. 8 Figure 6. Ratios of Mach Number, Temperature, and Pressure Across a Normal Shock ....... 10 Figure 7. Hypersonic Vehicle Detection Techniques ....................................................... 11 Figure 8. Laser-Based Chronograph............................................................................ 12 Figure 9. Electromagnetic Spectrum as a Function of Wavelength................................... 13 Figure 10. Schematic of a RADAR System................................................................... 14 Figure 12. Energy Spectrum of the Sun at 5,778 K....................................................... 19 Figure 13. Hypersonic Flow Past a Sphere................................................................... 20 Figure 14. Infrared Energy Spectra for Mach 3 and Mach 3.5......................................... 21 Figure 15. Peak Wavelength of the Infrared Radiation Emitted by Hypersonic Objects ........ 22 Figure 16. Peak Shock Layer Temperature for Hypersonic Objects .................................. 22 Figure 17. Schematic of a Pulsed LIDAR System ........................................................... 24 Figure 18. Mach Cone Generated by a Supersonic Object .............................................. 26 Figure 19. Comparison of Detection Technology for Hypersonic Objects ........................... 32 Table 1: Normal Shock Values for Mach 3 Flow ...............................................................9
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An object is supersonic when its speed through the atmosphere is greater than the local speed of sound. The Mach number is defined as the speed of the object divided by the local speed of sound . For Mach numbers greater than 1 (supersonic flow), shock waves develop in the flowfield and near the surface of the object due to the air's compressibility. Traditionally, the lower Mach number limit for the so-called hypersonic speed regime is about Mach 5 (1. 7 km/sec). "Low hypersonic" values range between Mach 5 to about Mach 10, while "high hypersonic" values range between approximately Mach 10 to Mach 30 or above. Mach 30 (10 km/s), for example, is close to Space Shuttle reentry velocity. Few objects can travel at hypersonic velocities. The most common object that we see moving at these speeds are meteors entering the Earth's atmosphere. As meteors fall to the Earth's surface, their velocities may reach 30 miles per second (48 km/s),1 and their corresponding Mach number as they enter the upper layers of the atmosphere will exceed 150. Meteors are preceded by a bow shockwave as they compress the air immediately in their path. Temperatures and pressures increase dramatically across the shockwave to a point where the gases in air ionize and disassociate, leading to the emission of visible light and radio waves. These conditions also lead to rapid heating of the meteor surface causing them to fracture and break up as they enter the atmosphere. Optical and RADAR-based surveillance systems are now used to scan outer space to detect asteroids and other objects with orbits that may lead them to collide with Earth. A second class of hypersonic objects includes reentry vehicles moving into the Earth's atmosphere from orbit. In the case of a reentry vehicle returning from low-Earth orbit at 100 km altitude, the velocity of the vehicle will reach 8 km/s (about 5 miles per second). The Mach number of this vehicle will exceed 26.5 in the upper atmosphere. As the vehicle moves through the atmosphere, flow-induced drag forces will slow down the vehicle; if the vehicle has sufficient thermal protection, it can survive reentry and be recovered. A third class of hypersonic vehicles includes the reentry payload used in ICBMs (intercontinental ballistic missiles). The payload in these missiles is launched using a rocket that boosts them above the atmosphere to a suborbital velocity. The payload velocity may exceed 7 km/s as they reenter the atmosphere, equating to M > 23. The coupled high velocity and high kinetic energy of these objects creates an ionized wake and shock wave that can be used to detect their position and to determine their velocity. This information, along with their ballistic trajectory, is used to locate their target and the time to impact. A fourth class of hypersonic vehicles includes manned and unmanned rockets and aircraft. The North American X-15, for example, exceeded a speed of 7,274 km/hr in 1964, equating to about M = 6.5. This aircraft also exceeded 100 km in altitude on two occasions, qualifying the X-15 as a spacecraft. The SR-71 Blackbird, an air-breathing strategic reconnaissance aircraft, has exceeded Mach 3.2 at 80,000-ft altitude, and its actual maximum speed may have reached into the hypersonic flow regime. Other real and conceptual aircraft capable of reaching hypersonic speeds include the alleged Aurora SR-91 (Mach 4 to 6), the Boeing X-
Where this file fits in the PURSUE archive
This file is one of DoD's 282 files in the Trump PURSUE disclosure. Within the DoD agency block it ranks #264 of 282 by Anomalousness Index. Across the entire 478-file archive it ranks #439 of 478.
That places it in the lower-scoring band of the archive (439 of 478 by score), typical of investigative-record style files where the report is paper-based rather than instrumented.
Anomalousness Index: 53/100
This is a reference document, not an encounter report, so the index has no encounter to measure here. The value above is the rubric's default for a document that describes no event, shown so every file in the archive can be ranked the same way. Not a probability of extraterrestrial origin - that number is not honestly computable from the released files and this tracker refuses to publish it.
🤖 AI-ASSISTED SCORING · methodology
The six rubric components break down for this file as follows. Each component has a weighted contribution to the final score; the per-component explanation below describes what this file's particular value on that component means in the rubric's framework.
This file is a reference document, not an observation, so no sensor, camera, or witness captured anything. The rubric's sensor axis has no not-applicable option, so a document with no instrument record sits on its lowest tier by default.
There is no witness: this is a document released by the Department of War, not a first-hand account. The rubric assigns this axis from the originating body, so the value reflects the source of the record, not anyone's testimony.
Nothing is being corroborated, because the file does not report an event. Like every file in the archive it takes the rubric's single-source default.
The file describes no object and no motion, so the kinematic axis takes the archive-wide 'no kinematic data' default.
Every file in the archive scores this tier. For a document that describes no event it carries no information about the record at all.
The rubric's default for the file's release status (files released with redactions are catalogued as unresolved, unredacted ones as open). For a document that reports no event this describes how the file was released, not anything that happened.
Bottom line on the score: the 53/100 is the rubric's default for a document that reports no encounter, so it is not a finding about any event and should not be compared with the scores of sighting reports. For the full per-axis weights and the rubric JSON, see /methodology.
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DOW-UAP-PR108, Unresolved UAP Report, Western United States, 2020
DOW-UAP-PR109, Unresolved UAP Report, Eastern United States, 2015
DOW-UAP-PR110, Unresolved UAP Report, Eastern United States, 2020
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