TECHNOLOGY AREA(S): Chem Bio_defense OBJECTIVE: Develop remote optical sensor receiver for the non-contact detection and geospatial mapping of chemical contaminants on surfaces. DESCRIPTION: Surface contamination by chemical warfare agents presents a serious threat both to the civilian and military sectors and an adequate defense against these weapons will require rapid detection and identification of both known and unknown agents. Methods of detecting and localizing chemical contamination on operational surfaces is limited to contact sampling and analysis by colorimetric or molecular analysis, forcing a time- and resource-intensive reconnaissance mission that places personnel or systems into direct contact with the hazardous materials in order to interrogate the surface. Recent advances in laser-based optical spectroscopy demonstrate the efficacy of non-contact remote methods for the sensing of chemical on surfaces. Ultraviolet Raman spectroscopy affords one demonstrable means for non-contact optical detection of hazardous materials on surfaces, but the standoff range is limited by atmospheric attenuation of the laser source. An alternative to standoff illumination and sensing of the spectral signature would be the application of remotely-piloted unmanned systems fitted with the laser and spectrometer; however, unmanned ground vehicles have limited maneuverability and would become contaminated on contact with the contaminated surface in order to map the contaminated area. Unmanned aerial systems (UAS) have much greater maneuverability, but a limited mission life and payload size, weight, and power (SWAP) budget. A possible compromise to minimize the SWAP of the UAS payload would be to mount a laser source on the base platform (e.g. the Nuclear Biological Chemical Reconnaissance Vehicle) and mount an optical receiver/analyzer on the UAS. An integrated system that mounts a receiver on a UAS and synchronizes the flight path of the UAS to follow the laser spot on the surface would enable the detection of contaminants without necessarily contaminating the UAS platform. A standoff range from the NBCRV of 50 meters (threshold) to 100 meters (objective) with a 1-meter (threshold) to 2-meter (objective) standoff range for the UAS-mounted receiver would enable the rapid remote interrogation and geospatial mapping of contaminants on surfaces while protecting the reconnaissance platforms from contamination due to contact with the chemical hazard. PHASE I: Conduct a feasibility study of detecting liquid contaminants on the ground using a remote, autonomous UAS-mounted receiver paired with a larger, vehicle-mounted laser illumination source. Perform laser-illuminated spectral measurements of a contaminant deposited on concrete, asphalt, grass, and sand surfaces using a static (laboratory bench) system in order to prove the detection concept. Appropriate simulant or toxic industrial chemical targets for this study would include the insecticides malathion and parathion, representing solid and liquid state hazards, respectively. Measurements should be performed using liquid droplets of mission-relevant sizes (~500 m, micron) on the various relevant surfaces at aerial concentrations of 10 grams/square meter or less. Using the proof-of concept results, develop a system model and conceptual design of a fast hyperspectral line imaging detection system for on-the-move detection. PHASE II: Develop a prototype demonstration system using the results of the Phase I study. The remotely operated unmanned aerial vehicle should travel at speeds up to 45 mph with a standoff distance of 1-2 meters from the surface while tracking the laser spot projected onto the surface from 50 meters (threshold) to 100 meters (objective) at slant angles approaching 180 degrees. The system should be able to detect 10 grams per square meter (threshold) to less than 1 gram per square meter (objective) of solid or liquid contaminants. Develop necessary data acquisition, telemetry, and analytic signal processing system to provide real-time detection of chemical agents and toxic industrial chemicals in real time. Size, weight, and power constraints impose a limit of 50,000 cm3, 50 lbs, 350 watts on the laser source and 1000 cm3, 6 lbs, 150 watts on the remote optical sensing platform. Dual-use functionality of the laser source to provide light detection and ranging capabilities are desired, but not required. PHASE III: Further research and development during Phase III efforts will be directed towards refining a final deployable design, incorporating design modifications based on results from tests conducted during Phase II, and improving engineering/form-factors, equipment hardening, and manufacturability designs to meet the operational requirements of the Joint Chemical and Biological Defense Program, U.S. Army CONOPS and end-user requirements. PHASE III DUAL USE APPLICATIONS: There are many environmental applications for a sensitive remote chemical detector/identifier. A rugged, sensitive, and flexible remotely operated chemical detector will benefit precision agriculture by providing accurate validation of crop chemical applications and plant health. Environmental remediation industries would benefit from the sensitive detection, localization, and mapping of chemical spills and fugitive emissions from industrial incidents. Homeland security and environmental regulation offices can use the technology to characterize and remediate domestic crises such as natural disasters. REFERENCES: 1: S. Michael Angel, Nathaniel R Gomer, Shiv K Sharma, and Chris McKay, "Remote Raman Spectroscopy for Planetary Exploration: A Review", Applied Spectroscopy, Vol. 66, Issue 2, pp. 137-150 (2012).2: Christopher A. Kendziora, Robert Furstenberg, Michael Papantonakis, Viet Nguyen, Jeff Byers, and R. Andrew McGill, "Infrared photothermal imaging spectroscopy for detection of trace explosives on surfaces", Applied Optics, Vol. 54, Issue 31, pp. F129-F138 (2015).3: Clayton S.-C. Yang, Eiei Brown, Eric Kumi-Barimah, Uwe Hommerich, Feng Jin, Yingqing Jia, Sudhir Trivedi, Arvind I. D'souza, Eric A. Decuir, Priyalal S. Wijewarnasuriya, and Alan C. Samuels, "Rapid long-wave infrared laser-induced breakdown spectroscopy measurements using a mercury-cadmium-telluride linear array detection system", Applied Optics, Vol. 54, Issue 33, pp. 9695-9702 (2015).4: Anupam K. Misra, Tayro E. Acosta-Maeda, John N. Porter, Genesis Berlanga, Dalton Muchow, Shiv K. Sharma, Brian Chee, "A Two Components Approach for LoKEYWORDS: Chemical Detection, Surface Detection, Remote Sensing, Laser Spectroscopy, Unmanned Aerial Vehicle Sensing, Non-contact Optical Interrogation
