The NASA Earth Science Technology Office (ESTO) selected the Pyro-atmosphere Infrared Sounder (PIRS) airborne demonstration as part of its FireTech program in May of 2023. Upon completion, the PIRS will be flown in an aircraft to measure temperature and water vapor profiles, and total column carbon monoxide, above and in the vicinity of wildfires to support fire prediction and suppression efforts and scientific investigations of the meteorology of wildfires. The PIRS incorporates a wide field all refractive grating spectrometer operating in the MWIR region of the spectrum with 640 spectral channels from 4.08-5.13μm. The PIRS optics assembly was developed by BAE SYSTEMS for the CubeSat Infrared Atmospheric Sounder (CIRAS) project, as part of an earlier NASA and NOAA technology maturation program in support of reducing the size of infrared sounding instruments for space applications. Through the PIRS airborne flight development and demonstration, the full performance capabilities of the CIRAS instrument will have been demonstrated and build confidence in the performance expected from a future CIRAS spaceflight mission.
Optical alignment of the Coronagraph Instrument (CGI) was completed in time to begin its full-functional and environmental testing in late 2023 and its integration into the Roman Space Telescope (RST) in summer 2024. The optics of the CGI relay the optical pupil of the RST five times so that science operations, such as coronagraphy and wavefront control, can be conducted in the different internal pupil and image planes. Within the pupil relays, the CGI has multiple active optical assemblies, including a fast-steering mirror, a focus-control mirror, two deformable mirrors, and six precision alignment mechanisms that articulate different masks and apertures into the beam.
Initial alignment of the CGI optics was completed in the reverse direction, using a commercial dynamic Twyman-Green interferometer to measure the wavefront error through each relay as optics were added sequentially from back to front. The end-to-end wavefront error was initially verified using surrogate optics in place of the active optical assemblies, to allow their simultaneous development and test. Throughout alignment, pupil and image planes were referenced and coaligned optically using fiducials, including spherically mounted retroreflectors (SMRs) that were positioned by a laser tracker and measured by the interferometer camera.
Upon end-to-end alignment of the pupil-relay optics, the active optical assemblies were integrated and aligned individually, and the entire CGI alignment was then optimized. The CGI optical subsystem was also mapped to SMR fiducials, which will later be used to integrate CGI into the RST observatory and verify its alignment to the Telescope’s line of sight. This paper details the many alignment steps required to successfully achieve the performance criteria of the CGI.
The next generation of space telescopes will require large, segmented apertures for observations in the near ultraviolet through mid- and far-infrared regions to enable new science ranging from exoplanet characterization to precision astronomical observations that refine astrophysics models. To meet these challenges, we are developing instrumented (strain gauge) surface parallel actuators (SPAs) that are robust and can meet the stringent requirements of mass and cost per m2. We have developed a surface parallel mirror test piece and a set of flexured actuators that maintain compression in the piezoelectric stack elements at all times. The characterization work of these actuators is directed at understanding the performance of flexure piezoelectric multilayer stack actuator operation when embedded in the mirror. To determine the influence functions for each actuator position, we will report the measured stroke/strain and charge/capacitance versus voltage curves for all 42 preloaded actuators. Although designed to operate under close loop control via feedback from the strain gauge initial testing on bare lead zirconate titanate (PZT) stack actuators suggests that by driving the stack to a known domain state we could perform open loop control in the actuators to levels of ± 0.3 μm. We will also report on creep for the actuators and cross actuation for each unique actuator position as well as discuss approaches to mitigating the effect on open loop control error. Thermal studies of flextensional actuators embedded in analog rib structures down to 100K will also be presented.
KEYWORDS: Equipment, Gas cells, Dark current, Fabry–Perot interferometers, Signal to noise ratio, Black bodies, Vacuum chambers, Thermography, Infrared radiation
Hyperspectral infrared sounders measure the profiles of temperature and water vapor in the atmosphere and the concentration of trace gas species. Instruments such as NASA Atmospheric Infrared Sounder (AIRS) on the Aqua spacecraft have proven their value for weather and climate research, atmospheric composition research, and high impact to the operational forecast at NWP centers worldwide. Reducing the size, weight and power of these instruments is key to enabling more rapid revisit when deployed in Low Earth Orbit (LEO), enabling new measurements such as 3D Atmospheric Motion Vector (AMV) winds, and reducing the cost of these instrument for future deployment in LEO, Geostationary Earth Orbit (GEO) and aircraft platforms. NASA and NOAA have sponsored technology maturation at JPL of the CubeSat Infrared Atmospheric Sounder (CIRAS) to demonstrate the use of wide field grating spectrometer optics and large format FPA technologies included in CIRAS for infrared sounding. These include a 2D format High Operating Temperature-Barrier Infrared Detector (HOT-BIRD), a silicon Immersion Grating, and Black Silicon for the CIRAS entrance slit and blackbody. Thermal Vacuum (TVac) performance testing of CIRAS has been completed achieving TRL 5 for a full scale brassboard of the instrument. Testing included spatial, spectral, and radiometric response of the instrument including measurements of the transmission in a gas cell. Results show excellent performance from the system with the exception of a high background flux from the Integrated Dewar Cryocooler Assembly (IDCA). The IDCA is not planned for flight use and projections of the performance in the flight configuration are discussed. Through this testing the instrument has reached TRL 5. Recently, the NASA Earth Science Technology Office (ESTO) awarded JPL a contract to fly the CIRAS in an aircraft, called the Pyro-atmosphere Infrared Sounder (PIRS), to measure the convective environment around wildfires.
The Nancy Grace Roman Space Telescope Coronagraph Instrument is a critical technology demonstrator for NASA’s Habitable Worlds Observatory. With a predicted visible-light flux ratio detection limit of 10−8 or better, it will be capable of reaching new areas of parameter space for both gas giant exoplanets and circumstellar disks. It is in the final stages of integration and test at the Jet Propulsion Laboratory, with an anticipated delivery to payload integration in the coming year. This paper will review the instrument systems, observing modes, potential observing applications, and overall progress toward instrument integration and test.
The Nancy Grace Roman Space Telescope is NASA’s flagship astrophysics mission planned for launch in 2026. The Coronagraph Instrument (CGI) on Roman will demonstrate the technology for direct imaging and spectroscopy of exoplanets around nearby stars. It will work with the 2.4-meter diameter telescope to achieve starlight suppression and point source detection limits that are 2–3 orders of magnitude deeper than previous space-based and groundbased coronagraphs by using active wavefront control with deformable mirrors. CGI has passed its Critical Design Review (CDR) in April of 2021, and System Integration Review (SIR) in June of 2022. We describe the status of CGI’s development and plans for the upcoming integration and testing phase.
Hyperspectral infrared measurements of Earth’s atmosphere from space have proven their value for weather forecasting, climate science and atmospheric composition. The CubeSat Infrared Atmospheric Sounder (CIRAS) instrument will demonstrate a fully functional infrared temperature, water vapor and carbon monoxide sounder in a CubeSat sized volume for at least an order of magnitude lower cost than legacy systems. Design for a CubeSat significantly reduces cost of access to space and enables flight in a constellation to reduce revisit time and enable new measurements including 3D winds. A technology demonstration of CIRAS is currently under development at JPL. The effort has completed integration and ambient testing of a high fidelity brassboard, complete with the flight configured optics assembly developed by Ball Aerospace with a JPL Immersion Grating and Black Silicon Entrance Slit. The brassboard includes a flight-configured High Operating Temperature Barrier Infrared Detector (HOT-BIRD) mounted in an Integrated Dewar Cryocooler Assembly (IDCA), enabling testing in the ambient environment. Ambient testing included radiometric testing of the system to characterize the instrument operability and NEdT. Spatial testing was performed to characterize the system line spread function (LSF) in two axes and report FWHM of the LSF. Spectral testing involved an air path test to characterize the spectral/spatial transformation matrix, and an etalon was used to measure the Spectral Response Functions (SRFs). Results of the testing show the CIRAS performs exceptionally well and meets the key performance required of the system. The end result of testing is the CIRAS instrument now meets TRL 4 with confidence in a brassboard configuration ready for thermal vacuum (TVac) testing necessary to achieve TRL 5 for the system.
An Associate of Science Degree is essential for technical students who seek applied, hands-on employment in the technical workforce after education at a community college. Pasadena City College administration has stepped up to work with experienced faculty to create a program in Laser Technology that is based on tested, industrial skill-driven curricula. This paper will discuss the foundation of this Laser Tech Program and its guidance by its many industrial advisors.
Irvine Valley College was the first school in the United States to have both HeNe and Nd:YAG open-cavity laser educational kits from eLas (formerly PI miCos Campus) successfully integrated into their extensive hands-on Laser Technology program. This paper is presented from two students’ perspective, describing the students’ experiences and including comments from the professors who integrated the laser kits into the curriculum. The main benefits these laser education kits provide for both students and faculty include their specific industrial-quality design for intensive hands-on education. Students learn about laser components and the techniques required to align a laser cavity. Theses laser systems come with lesson plans and experiments that faculty may use as is, or modify to suit a particular emphasis in their curriculum. Once alignment is achieved on a repeatable basis, then many experiments can be performed successfully, such as studying laser mode structure, input current versus output power, and wavelength stability.
Over the past decade, Southern California has seen informal optics education and outreach programs grow substantially,
mainly due to efforts from members of the Optical Society of Southern California (OSSC) and more recently the Optical
Society of America, UC Irvine, Student Chapter. Also, the Optics Institute of Southern California (OISC) has served as a
focal point for many of these programs, as an independent organization working closely with society members and other
partners. This paper provides an update of these programs, including a new OSSC website that provides a new platform
for significantly expanding the member participation efforts.
A test procedure is developed for an infrared laser scene projector, and applied to a projection system that we develop based on digital micromirror technology. The intended use will be for simulation and target training. Resolution and noise are significant parameters for target perception models of infrared imaging systems. System resolution is normally measured as the modulation transfer function (MTF), and its noise modeled through an appropriate signal standard deviation metric. We compare MTF measurements for both mid-wave (MWIR) and long-wave IR (LWIR) bands for an infrared laser scene projector based on the digital micromirror device (DMD). Moreover, we use two complimentary models to characterize imaging camera noise. This provides a quantitative image-quality criterion of system performance.
Two designs for antenna-coupled Ni-NiO-Ni diodes are fabricated and tested for dual-band detection in the millimeter-wave (MMW), 94-GHz, and infrared (IR), 28.3-THz, frequencies. The detector noise, antenna receiving properties, and noise equivalent power (NEP) are measured. The simultaneous dual-band response is verified.
Missile Defense Agency/Advanced Systems, in partnership with both EUTECUS/University of Notre Dame (UND) and ITN Energy Systems/University of Central Florida (UCF) has embarked on developing a multispectral imaging IR sensor. This technology, when matured, could revolutionize IR sensor technology by reducing the need for cooling, eliminating lattice matching and avoiding epitaxial fabrication processes. This paper describes the approaches employed by both EUTECUS/UND and ITN/UCF teams to integrate nano-antenna technology with the existing cellular neural network (CNN) processor to produce multispectral IR sensors. This effort is a leap into the performance realm where biological systems operate.
IR lasers are widely used in electro-optical applications, especially in detector characterization systems. These lasers can be extremely sensitive to fluctuations in the operational temperature of their cavity and other environmental factors. Due to these influences, the laser output signal normally fluctuates randomly. These variations make it difficult to characterize the laser waist position and exact focus, which in turn causes difficulty with detector measurement. We apply a multivariate statistical approach to characterize and filter these variations and to calculate the "best focus" of a carbon dioxide laser operating at 10.6 µm. Using this method, the "best focus" can be calculated with great accuracy and can be easily implemented during postsignal processing. Also, this technique can potentially be applied to other situations in which laser signal instability is significant.
Wavelength tuning is demonstrated in an antenna-coupled infrared microbolometer. With a 300-mV control voltage, we observed a tuning range of 0.5 µm near 10 µm. A metal-oxide-semiconductor capacitor underneath the antenna arms causes the shift of resonance wavelength with applied voltage. We develop a device model that agrees well with measured results.
A frequency selective surface (FSS) is designed and fabricated to resonate in the infrared. This IR FSS is designed using Periodic Method of Moments (PMM) software and is based on circuit-analog resonance of square loop conducting elements. The FSS is fabricated via electron beam lithography. The spectral characteristics of this surface are studied in the mid-infrared employing a spectral radiometer. The IR FSS may operate as an emissive narrowband source or reflective bandpass filter centered at a wavelength of 6.5μm, sharply cutting off short wavelength radiation and gradually filtering longer wavelengths. The addition of a superstrate layer, intended to further shape the FSS spectral signature, is also studied and the results discussed.
We present a design for an IR scene projector for live-fire training applications, based on modification of a commercial-off-the-air laser-light-scene scanner retrofitted with a CO2 laser and associated IR optics. Design goals include a reusable or at least very inexpensive shoot- through projection screen. This application calls for a wide projection field as compared to typical IR scene-projection systems intended for hardware in the loop testing.
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