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.
Space imagery provides a unique resource for addressing environmental challenges associated with land cover change, land use, disaster relief, deforestation, regional planning and global change research. At Ball Aerospace, we are developing the Compact Hyperspectral Prism Spectrometer (CHPS) as a candidate imaging spectrometer technology for insertion into future Sustainable Land Imaging missions. The 2013 NRC report Landsat and Beyond: Sustaining and Enhancing the Nations Land Imaging Program recommended that the nation should “maintain a sustained, space-based, land-imaging program, while ensuring the continuity of 42-years of multispectral information.” In support of this, NASA’s Sustainable Land Imaging-Technology (SLI-T) program aims to develop technology for a new generation of smaller, more capable, less costly payloads that meet or exceed current Landsat imaging capabilities. CHPS is designed to meet these objectives, providing high-fidelity visible-to-shortwave spectroscopic information. CHPS supports continuity of legacy Landsat data products, but also, provides a path to enhanced capabilities in support of land, inland waters, and coastal waters science. CHPS features full aperture full optical path calibration, extremely low straylight, and low polarization sensitivity; all crucial performance parameters for achieving the demanding SLI measurement objectives. In support of our space-borne instrument development, we have developed an airborne instrument to provide representative spectroscopic data and data products. Now in the final year of this 3-year development program, we have completed our initial engineering airborne flights and are beginning science flights. We present initial results from laboratory characterization and calibration and from our engineering flights and close with an overview of instrument performance.
REMI (Reduced Envelope Multispectral Imager) is a new instrument developed by Ball Aerospace specifically for the Sustained Land Imaging (SLI) program. The goal of REMI is to meet the current Landsat mission requirements with a much smaller volume, lower cost payload. A lower single unit recurring cost enables economies of scale on multiple builds by leveraging non-recurring engineering costs. This lower cost enables multiple copies on-orbit at the same time for improved temporal sampling, an innovative approach to space segment reliability, and more frequent technology onramps. REMI achieves miniaturization through use of a common aperture for all spectral bands. REMI features a pointing mechanism that compensates for platform and ground motion while using cross-track, step-stare pointing to produce contiguous ground coverage in all spectral bands. The status of the REMI development and airborne flight testing will be presented.
The Geostationary Environmental Monitoring Spectrometer (GEMS) and the Tropospheric Emissions: Monitoring of Pollution (TEMPO) instruments will provide a new capability for the understanding of air quality and pollution. Ball Aerospace is the developer of these UV/Vis Hyperspectral sensors. The GEMS and TEMPO instrument use proven remote sensing techniques and take advantage of a geostationary orbit to take hourly measurements of their respective geographical areas. The high spatial and temporal resolution of these instruments will allow for measurements of the complex diurnal cycle of pollution driven by the combination of photochemistry, chemical composition and the dynamic nature of the atmosphere.
The GEMS instrument was built for the Korea Aerospace Research Institute and their customer, the National Institute of Environmental Research (NIER) and the Principle Investigator (PI) is Jhoon Kim of Yonsei University. The TEMPO instrument was built for NASA under the Earth Venture Instrument (EVI) Program. NASA Langley Research Center (LaRC) is the managing center and the PI is Kelly Chance of the Smithsonian Astrophysical Observatory (SAO).
Optical Autocovariance Wind Lidar (OAWL) is a new direct-detection interferometric Doppler lidar approach that
inherently enables simultaneous acquisition of multiple-wavelength High Spectral Resolution Lidar calibrated aerosol
profiles (OA-HSRL). Unlike other coherent and direct detection Doppler systems, the receiver is self referencing; no
specific optical frequency lock is required between the receiver and transmitter. This property facilitates frequency-agile
modalities such as DIAL. Because UV laser wavelengths are accommodated, a single transmitter can simultaneously
support winds, Raman, fluorescence, DIAL, and HSRL receiver channels, each sampling identical spatial and temporal
volumes. LOS species flux measurements are acquired without the usual spatial and temporal sampling errors (or cost,
volume, mass, power, and logistical issues) incurred by separate lidar systems, or lidars in combination with other
remote or in-situ sensors. A proof of concept (POC) OAWL system has been built and demonstrated at Ball, and OAHSRL
POC is in progress. A robust multi-wavelength, field-widened OAWL/OA-HSRL system is under development
with planned airborne demonstration from a WB-57 in late 2010. Detailed radiometric and dynamic models have been
developed to predict performance in both airborne and space borne scenarios. OA theory, development, demonstration
status, advantages, limitations, space and airborne performance, and combined measurement synergies are discussed.
Interferometric testing of large-sized optics in a thermal vacuum environment poses challenges not normally found in an optical metrology lab. Unless the test equipment is thermal-vacuum compatible, it must be installed in an ambient environment with the test item viewed through a window in the thermal-vacuum chamber. Limitations in chamber port size preclude normal-incidence viewing of the full aperture of large-sized optical elements. This necessitates the use of a mechanical translation of the test item to acquire multiple overlying interferograms. The interferograms are then concatenated in order to produce a full-aperture surface map of the test item. This is then used to confirm surface deformation of the entire test mirror. This paper will discuss the challenges, solutions, and results of a series of thermalvacuum tests performed on a large-scale (>40cm) silicon carbide mirror at ambient temperatures.
We present a method for measuring an optical system’s effective focal length with a single mode fiber array and a wedge prism. Light emitted by the input fiber near the focal plane is collimated, reflected back in two angularly separated beams, and detected by the output fibers in the auto-collimation configuration. Measurement precision of a micron can be achieved due to the precision of fiber spacing and the position sensitivity of single-mode coupling. Absolute accuracy depends on factors such as optical design configuration, metrology, aberrations, and environmental control, and can be better than 10 micron. By varying input wavelength and field angle, this technique can be utilized to precisely characterize chromatic dispersion and distortion of the optics. Furthermore, because the technique only requires compact opto-mechanical accessories and electronic apparatus, it can be readily carried out on large optical systems in the field.
The Multicenter Airborne Coherent Atmospheric Wind Sensor instrument is an airborne coherent Doppler laser radar (Lidar) capable of measuring atmospheric wind fields and aerosol structure. Since the first demonstration flights onboard the NASA DC-8 research aircraft in September 1995, two additional science flights have been completed. Several system upgrades have also bee implemented. In this paper we discuss the system upgrades and present several case studies which demonstrate the various capabilities of the system.
The first Multi center Airborne Coherent Atmospheric Wind Sensor (MACAWS) field experiment demonstrated an airborne high energy TEA CO2 Doppler lidar system for measurement of atmospheric wind fields and aerosol structure. The system was deployed on the NASA DC-8 during September 1995 in a series of checkout flights to observe several important atmospheric phenomena, including upper level winds in a Pacific hurricane, marine boundary layer winds, cirrus cloud properties, and land-sea breeze structure. The instrument, with its capability to measure 3D winds and backscatter fields, promises to be a valuable tool for climate and global change, severe weather, and air quality research. In this paper, we describe the airborne instrument, assess its performance, discuss future improvements, and show some preliminary results from the September experiments.
A very compact, transportable differential absorption lidar (DIAL) for ozone and aerosol profiling in the lower troposphere (from near surface to about 3 km) has been developed at the National Oceanic and Atmospheric Administration's Environmental Technology Laboratory. The ozone lidar has been employed in two field experiments in California. the first was in intercomparison experiment of the lidar and an airborne ozone analyzer carried out in the Sacramento valley of northern California during July 1993. The second field experiment involving the ozone lidar was the Free Radical Study, carried out in the Los Angeles basin during September 1993, where the highest ozone episode of the year was observed during the experiment. The system will be described and examples of ozone profiles during the high- ozone episode in inland Los Angeles will be shown.
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