FT-IR spectroscopy is the technology of choice to identify solid and liquid phase unknown samples. The challenges of
ConOps (Concepts of Operation) in emergency response and military field applications require a significant redesign of
the stationary FT-IR bench-top instruments typically used in laboratories. Specifically, field portable units require high
levels of resistance against mechanical shock and chemical attack, ease of use in restrictive gear, quick and easy
interpretation of results, and reduced size. In the last 20 years, FT-IR instruments have been re-engineered to fit in small
suitcases for field portable use and recently further miniaturized for handheld operation. This article introduces the
advances resulting from a project designed to overcome the challenges associated with miniaturizing FT-IR instruments.
The project team developed a disturbance-corrected permanently aligned cube corner interferometer for improved
robustness and optimized opto-mechanical design to maximize optical throughput and signal-to-noise ratios. Thermal
management and heat flow were thoroughly modeled and studied to isolate sensitive components from heat sources and
provide the widest temperature operation range. Similarly, extensive research on mechanical designs and compensation
techniques to protect against shock and vibration will be discussed. A user interface was carefully created for military
and emergency response applications to provide actionable information in a visual, intuitive format. Similar to the
HazMatID family of products, state-of-the-art algorithms were used to quickly identify the chemical composition of
complex samples based on the spectral information. This article includes an overview of the design considerations, tests
results, and performance validation of the mechanical ruggedness, spectral, and thermal performance.
The SOAR Telescope developed by NOAO and sited on Cerro Pachon, Chile is a 4.1-meter Ritchey-Chretien design incorporating active optics (AO). The AO system is composed of PC-hosted control software, a solid primary mirror supported by 120 electro-mechanical actuators, a lightweighted 600 mm secondary mirror supported by a six degree-of-freedom hexapod mechanism, and a lightweighted 600 mm tertiary mirror controllable over a range of ±100 μrad in two axes with a bandwidth of 50 Hz. The tertiary mirror assembly is in turn mounted on an azimuthal bearing that allows the output bundle of the telescope to be directed to one of five science instruments located at nasymth and bent-cassegrain foci. This paper discusses the active tertiary mirror assembly from the perspective of a control system designer. After a brief overview to establish the tertiary mirror's place in the overall AO system architecture, the paper presents the requirements that drove the design and some of the design’s salient electrical and mechanical features. A model representing electrical and mechanical aspects of the mirror and controller is presented and observed performance metrics such as frequency response, NEA, and measures of servo robustness are compared with values predicted by this model. The paper discusses a number of the design challenges which arose from the requirement to control a massive load with great precision and over a relatively large bandwidth and concludes with the "lessons learned."
The SOAR Telescope project has embarked on the development of a very high quality 4.2-meter diameter optical telescope to be sited on Cerro Pachon in Chile. The telescope will feature an image quality of 0.18 arc seconds, a moderate field of 11 arc minutes, a very large instrument payload capacity for as many as 9 hot instruments, and an Active Optical System optimized for the optical to near IR wavelengths. The active optical system features a 10 cm thick ULETM primary mirror supported by 120 electro- mechanical actuators for a highly correctable surface. the 0.6 meter diameter secondary is articulated by a hexapod for real time optical alignment. The 0.6-meter class tertiary will provide fast beam steering to compensate for atmospheric turbulence at 50 hertz and a turret for directing the light to either of two nasmyth or three-bent cassegrain ports. Both the secondary and tertiary are light- weighted by machining to achieve cost-effective low weight mirrors. This paper discusses the unique features of this development effort including many commercial products and software programs that enable its technical feasibility and high cost efficiency.
Hughes Danbury Optical Systems (HDOS) has developed several concepts for hyperspectral remote sensing of the earth and major and minor planets. The basic instrument is an imaging prism spectrometer located on an orbiting platform. The spectrometer slit is imaged by a telescope on the planetary surface and pushbroom scanned across it. The prism spectrometer disperses the observed slit image and reimages it in the multiple spectral bands onto a 2D focal plane array. Extensive use is made of Application Specific Integrated Circuits (ASICs) for signal processing in order to reduce power and weight. The baselined focal plane array is a 320 (image) X 210 (spectral) InSb detector. This detector provides high quantum efficiency for photons spanning the spectral range from the band gap limit of 5.4 micrometers to the ultraviolet. Various spectral ranges and spectral resolutions may be selected by appropriate choice of the prism and design of the spectrometer optics. These concepts for a spaceborne imaging prism spectrometer rely heavily on HDOS's HYDICE heritage. HYDICE (HYperspectral Digital Imaging Collection Experiment) is a prism imaging spectrometer being developed by HDOS for the Naval Research Laboratory. HYDICE will fly in a Convair aircraft and pushbroom scan the earth in 210 spectral colors between 0.4 micrometers and 2.5 micrometers . The heritage for the miniaturized electronics in the HDOS Miniature Star Tracker program.