Historical research guide · 0307 · 2010

DIRD Detection and High Resolution Tracking of Vehicles at Hypersonic Velocities

DIA / AAWSAP contractor

In one minute

This is the AAWSAP volume on how you find something moving faster than Mach 5. Writing for the Defense Intelligence Agency in 2010, the author first lays out the fluid mechanics — boundary layers, shed eddies, the bow shock and the abrupt jumps in pressure, density and temperature across it — then walks the whole sensor catalogue: radar and Doppler radar, over-the-horizon radio reflection, all-sky cameras, infrared satellites, LIDAR, infrasound and seismic arrays. Two findings carry well beyond the brief. The first is that at hypersonic speed the air itself ionises, which both blinds radio and lights the object up: the glow, the radio echoes and the recombination chemistry in the wake are all readable signals. The second is the Russian AYAKS concept, in which lasers and radio-frequency generators deliberately ionise the air ahead of the craft to break up its own bow shock, halving its drag and, the cited authors say, wrapping it in a film of ionised gas impervious to radar. The report closes with four research recommendations for the following thirty years.

Connection

It is the government’s own account of what a sensor can and cannot see when a craft outruns its own shock wave — the practical floor under chapter 1’s evidence ladder. And it treats a deliberately generated plasma sheath as a working engineering technique for both drag reduction and radar transparency, which is exactly the mechanism chapters 8 and 9 read into transmedium craft and glowing plasmoids.

From the source

A rule of thumb for hypersonic flight is that the peak shock layer temperature in kelvin is about 1,000 times the vehicle speed in km/s, so a reentry vehicle at 8 km/s (Mach 26.5) reaches a maximum shock layer temperature near 8,000 K.Chapter 2: Hypersonic Compressible Flow Theory, p. 10
The perfect-gas Rankine-Hugoniot relations fail above about 550 degrees Celsius: they predict 29,787 degrees Celsius at the surface of a blunt object at Mach 26.5, where the actual temperature only reaches 7,600, because energy is consumed ionising the air and dissociating oxygen and nitrogen above 2,000 K.Chapter 2: Hypersonic Compressible Flow Theory, p. 10
That same ionisation is what makes a hypersonic object visible: recombining electrons release x-rays and visible light, which produces the glowing wake, interferes with radio transmissions, and provides a convenient way to identify the object.Chapter 2, p. 10; Chapter 3, Radio Reflection Detection, pp. 15–16
An ordinary receiver tuned to an over-the-horizon transmitter hears the bow shock and the ionised wake of a hypersonic object as pings and whistles; the technique separates reflections from the shock and from the wake, is at present employed only by hobbyists, and should be developed into a triangulating receiver network.Chapter 3, Radio Reflection Detection, pp. 15–16
In the Russian AYAKS concept, lasers and radio-frequency generators ionise the air ahead of the aircraft to disrupt its own bow shock, reducing drag enough to double the vehicle’s maximum speed, and the cited authors state that the resulting film of ionised gas would be impervious to radar pulses, rendering the vehicle electronically invisible.Chapter 4, Recommendation 2, p. 30; Recommendation 3, pp. 30–31
Although an aircraft may be designed for stealth, its wake cannot be hidden: the turbulent wake carries the vehicle’s bearing, its velocity and hydraulic diameter through the shed-eddy frequency, and its fuel chemistry through LIDAR, so a database of wake signatures should be built for existing aircraft.Chapter 4, Recommendation 1, pp. 29–30

The way in

https://documents2.theblackvault.com/documents/dia/AAWSAP-DIRDs/DIRD_31-DIRD_Detection_and_High_Resolution_Tracking_of_Vehicles_at_Hypersonic_Velocities.pdf

Historical source-access record. This guide links to the original; it does not reproduce the paper text.

Defense Intelligence Reference Document, Defense Futures. DIA-08-1012-001, 20 November 2010 (ICOD: 30 August 2010), produced in FY 2010 under the Defense Intelligence Agency Advanced Aerospace Weapons System Applications (AAWSA) Program. Released under FOIA and published by The Black Vault. AUTHOR. The author’s name is withheld under FOIA exemption (b)(6). Internal evidence only: the report is written from a mechanical-engineering and compressible-flow teaching perspective, leans on J. D. Anderson’s and F. M. White’s textbooks, and includes a MathCad worksheet as its appendix — that points to an academic fluid-mechanics author rather than a radar specialist, which is an inference from the text and not an attribution. TEXT. Full text below, introduction through Chapter 4, pages 1 to 32. The document carries a copyright warning against further dissemination of its photographs, so the nineteen figures are not reproduced; their captions are kept because they carry information. Appendix A (the MathCad worksheet used to estimate hypersonic vehicle surface temperature, pages 33 to 40) and the endnote list (endnotes 1 to 32, pages 41 to 42) are omitted; both are at the source. EQUATIONS. Several equations did not survive text extraction from the scan and are described in place rather than restored; superscripts, subscripts and Greek symbols elsewhere were rebuilt from the surrounding definitions.

How to cite it

DIA / AAWSAP contractor (2010) DIRD Detection and High Resolution Tracking of Vehicles at Hypersonic Velocities https://documents2.theblackvault.com/documents/dia/AAWSAP-DIRDs/DIRD_31-DIRD_Detection_and_High_Resolution_Tracking_of_Vehicles_at_Hypersonic_Velocities.pdf

In one minute

From the source

The way in

How to cite it

Where it sits in the curriculum