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Brian M. Kent


Dr. Brian M. Kent

Aerospace Consultant and Adjunct Professor (Michigan State University)
C/O 385 Lightbeam Dr, Dayton, OH 45458-3632
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Dr. Brian M. Kent, a member of the scientific and professional cadre of senior executives, is Chief Scientist, Sensors Directorate, Air Force Research Laboratory, Wright-Patterson Air Force Base, Ohio. He serves as the directorate's principal scientific and technical adviser and primary authority for the technical content of the science and technology portfolio. He evaluates the total laboratory technical research program to determine its adequacy and efficiency in meeting national, Department of Defense, Air Force, Air Force Materiel Command and AFRL objectives in core technical competency areas. He identifies research gaps and analyzes advancements in a broad variety of scientific fields to advise on their impact on laboratory programs and objectives.

He recommends new initiatives and adjustments to current programs required to meet current and future Air Force needs. As such, he is an internationally recognized scientific expert, and provides authoritarian counsel and advice to AFRL management and the professional staff as well as to other government organizations. He also collaborates on numerous interdisciplinary research problems that encompass multiple AFRL directorates, customers from other DOD components, as well as the manned space program managed by NASA. 

Dr. Kent joined the Air Force Avionics Laboratory in 1976 as cooperative engineering student through Michigan State University. He began his career performing research in avionics, digital flight displays and radar signature measurements. Through a career broadening engineering assignment with the Directorate of Engineering, Aeronautical Systems Division, he modeled a number of foreign threat missile systems and performed offensive and defensive electronic combat systems assessments. He received a National Science Foundation Fellowship in 1979, working at both the Air Force Wright Aeronautical Laboratories and the Ohio State University Electroscience Laboratory until the completion of his doctorate. Dr. Kent spent two years in the Passive Observables Branch of the Avionics Laboratory, later transferring to the AFWAL Signature Technology Office. From 1985 to 1992, Dr. Kent was involved with classified research efforts, managed through the Air Force Wright Laboratory, now the AFRL. During his tenure with AFRL and its predecessor organizations, Dr. Kent held a variety of positions. He has made pioneering and lasting contributions to the areas of signature measurement technology, and successfully established international standards for performing radar signature testing.

Dr. Kent has authored and co-authored more than 85 archival articles and technical reports and has written key sections of classified textbooks and design manuals. He has delivered more than 200 lectures, and developed a special DOD Low Observables Short Course that has been taught to more than 2,000 scientists and engineers since its inception in 1989. Dr. Kent has provided technical advice and counsel to a wide range of federal agencies, including the Department of Transportation, the Department of Justice and NASA's Space Shuttle Program. He is also an international technical adviser for the DOD and has provided basic research guidance to leading academic institutions.


Contributions of the US Air Force Laboratory’s Sensor’s Directorate to the Columbia Accident Investigation - shedding light on the mystery of the flight day two object and our role in returning the Shuttle to safe flight.

In the wake of the Columbia tragedy, Air Force Space Command carefully reviewed records of all radar objects in space during the time the Shuttle was on orbit. To everyone’s surprise, a post accident review revealed that a mysterious object separated from the Orbiter on Flight Day 2 and subsequently de-orbited 60 hours later, burning up on re-entry. Reentry ballistics revealed an estimate of the object’s area to mass. Four ground based tracking radars gave a hint of the objects radar cross section at the UHF frequency of 433 MHz. The Columbia Accident Investigation Board (CAIB) wanted to know what the object was, and whether it could be related to the accident.  Three weeks after the accident, the CAIB eventually contacted Dr Brian Kent of the Air Force Research Laboratory Multi-spectral Advanced Compact Range measurement facility, for their help in assessing the mysterious object.  For the next two months, RCS measurements performed at the AFRL advanced compact range ultimately narrowed the mystery of the Flight Day 2 object to a very few possibilities. Their work became so visible that Dr Kent provided public testimony to the CAIB on May 6, 2003.  In light of the accident cause, NASA made many changes to the Shuttle system and supporting ground sensors. Dr Kent was involved in the fielding of a debris radar system that allows NASA to closely monitor ascent debris from ascending rockets, including the Shuttle. Come hear how a solid engineering analysis, good teamwork, and a bit of sleuthing shed light on what turned out to be one of the most intriguing issues in the Columbia investigation, leading eventually to returning the Shuttle to operational flight status.

Air Force Research Laboratory Sensors Directorate: An Update on the organization, Our Major Research Interests, and On-going Laboratory Construction and Modernization Activities

The AFRL Sensor Directorate mission is to “Lead the discovery, development, and integration of affordable sensor and countermeasure technologies for our warfighters.” Sensors is being transformed by a $45M military construction office and laboratory modernization effort related to consolidating our research workforce and laboratories from Rome, New York and Hanscom AFB, Massachusetts. This talk will outline Sensors vision for the future work in antenna design, multi-input/multi-output passive and active RF systems, and other research interests of the US Air Force. We will also describe the major new Sensors laboratory facilities recently completed, and provide insight into collaborative research opportunities.

Electro-Magnetic Interference Measurements on the Shuttle Orbiter "Discovery" in Preparation for Return to Flight - A Case Study

As NASA prepared the Space Shuttle for its first return to flight mission (STS-114) in the July 2005 timeframe, a number of new visual and radar sensors were used during the critical ascent phase of the flight to assess whether any unintentional debris was liberated from the Shuttle as it raced into orbit. New high-resolution C-Band and X-Band radars were used to help ascertain the location and speed of any released debris, and were also used to monitor routine flight events such as Solid Rocket Booster (SRB) separation. To assure these new radars did not interfere with flight-critical engine subsystems, an Electromagnetic Interference (EMI) measurement was performed on the Shuttle Orbiter "Discovery" in January 2005, using the Air Force Research Laboratory's Mobile Diagnostic Laboratory (MDL). This portable EM Measurement system performed a large number of attenuation measurements the night of January 17-18, 2005. This paper describes how the attenuation data was acquired, and the methodology used to reduce the data to predict average attenuation of the radar energy from the outside world to the inside of the aft engine bay of the Orbiter. This data, when combined with a separate NASA performed equipment level EMI analysis, demonstrated the new C and X-Band Debris Radars could be operated without adversely interfering with the Orbiter electronic systems in the aft avionics and engine bays.

Characterization of Space Shuttle Ascent Debris Based on Radar Scattering and Ballistic Properties --Evolution of the NASA Debris Radar System told in two parts

This is a two-part presentation (with break) that introduces the NASA Debris Radar (NDR) system developed to characterize debris liberated by the space shuttle (and any follow-on rocket system) during its ascent into space.  Radar technology is well suited for characterizing shuttle ascent debris, and is especially valuable during night launches when optical sensors are severely degraded.  The shuttle debris mission presents challenging radar requirements in terms of target detection and tracking, minimum detectable radar cross-section (RCS), calibration accuracy, power profile management, and operational readiness.  In Part I, I describe the NDR system consists of stationary C-band radar located at Kennedy Space Center (KSC) and two X-band radars deployed to sea during shuttle missions.  To better understand the signature of the shuttle stack, Xpatch calculations were generated at C and X band to predict the radar signature as a function of launch time.  These calculations agreed very well with measured data later collected.  Various sizes, shapes, and types of shuttle debris materials were characterized using static and dynamic radar measurements and ballistic coefficient calculations.  After a break, Part II discusses the NASA Debris Radar (NDR) successes, which led to a new challenge of processing and analyzing the large amount of radar data collected by the NDR systems and extracting information useful to the NASA debris community.  Analysis tools and software codes were developed to visualize the shuttle metric data in real-time, visualize metric and signature data during post-mission analysis, automatically detect and characterize debris tracks in signature data, determine ballistic numbers for detected debris objects, and assess material type, size, release location and threat to the orbiter based on radar scattering and ballistic properties of the debris. Future applications for space situational awareness and space-lift applications will also be discussed.

Dynamic Radar Cross Section and Radar Doppler Measurements of Commercial General Electric Windmill Power Turbines -- Predicted and Measured Radar Signatures

Commercial windmill driven power turbines (“Wind Turbines”) are expanding in popularity and use in the commercial power industry since they can generate significant electricity without using fuel or emitting carbon dioxide “greenhouse gas”.  In-country and near-off shore wind turbines are becoming more common on the European continent, and the United States has recently set long term goals to generate 10% of national electric power using renewable sources. In order to make such turbines efficient, current 1.5 MW wind turbine towers and rotors are very large, with blades exceeding 67 meters in diameter, and tower heights exceeding 55 meters.    Newer 4.5 MW designs are expected to be even larger. The problem with such large, moving metallic devices is the potential interference such structures present to an array of civilian air traffic control radars. A recent study by the Undersecretary of Defense for Space and Sensor Technology acknowledged the potential performance impact wind turbines introduce when sited within line of site of air traffic control or air route radars. In the Spring of 2006, the Air Force Research Laboratory embarked on a rigorous measurement and prediction program to provide credible data to national decision makers on the magnitude of the signatures, so the interference issues could be credibly studied. This paper will discuss the calibrated RCS and Doppler measurement of the turbines and compare this data (with uncertainty) to modeled data.