This PDF file contains the front matter associated with SPIE Proceedings Volume 8516, including the Title Page, Copyright information, Table of Contents, and the Conference Committee listing.

The Climate Absolute Radiance and Refractivity Observatory (CLARREO) mission addresses the need to observe highaccuracy, long-term climate change trends and to use decadal change observations as the most critical method to determine the accuracy of climate change. One of the major objectives of CLARREO is to advance the accuracy of SI traceable absolute calibration at infrared and reflected solar wavelengths. This advance is required to reach the on-orbit absolute accuracy required to allow climate change observations to survive data gaps while remaining sufficiently accurate to observe climate change to within the uncertainty of the limit of natural variability. While these capabilities exist at NIST in the laboratory, there is a need to demonstrate that it can move successfully from NIST to NASA and/or instrument vendor capabilities for future spaceborne instruments. The current work describes the test plan for the Solar, Lunar for Absolute Reflectance Imaging Spectroradiometer (SOLARIS) which is the calibration demonstration system (CDS) for the reflected solar portion of CLARREO. The goal of the CDS is to allow the testing and evaluation of calibration approaches, alternate design and/or implementation approaches and components for the CLARREO mission. SOLARIS also provides a test-bed for detector technologies, non-linearity determination and uncertainties, and application of future technology developments and suggested spacecraft instrument design modifications. The end result of efforts with the SOLARIS CDS will be an SI-traceable error budget for reflectance retrieval using solar irradiance as a reference and methods for laboratory-based, absolute calibration suitable for climate-quality data collections.

The Visible Infrared Imager Radiometer Suite (VIIRS) is the next-generation imaging spectroradiometer for the NOAA/NASA Joint Polar Satellite System (JPSS). Flight unit 1 (F1) was successfully launched onboard the Suomi NPP spacecraft in 2011. Measured performance shows that VIIRS F1 offers important new capabilities for a wide range of weather and Earth science applications. VIIRS replaces four different sensors with a single instrument built into a flight proven rotating telescope scene scanning architecture first used in the highly successful SeaWiFS ocean color imager starting in the 1990s. This flexible VIIRS architecture can be adapted and enhanced to respond to a wide range of requirements and to incorporate new technology as it becomes available. Possible VIIRS improvements include adding water vapor and temperature sounding bands, improving spatial resolution near nadir by transmitting all unaggregated data to Earth thus avoiding aggregation of saturated or corrupted pixels with good measurements and improving sensitivity especially at the longest wavelength bands by replacing the passive radiative cooler with an active mechanical cooler. This paper extends previous work that showed that the VIIRS design can accommodate adding three water vapor bands by describing an even simpler modification to VIIRS that would involve replacing one of the current VIIRS spectral bands with a single water vapor band. Two cases are considered. The first involves replacing a redundant spectral filter and associated microlenses for the VIIRS M16 band at 12.0 μm with a water vapor band filter and microlenses based on MODIS Band 27 (MB27) at 6.7 μm, while making no changes to the detector material or ROIC. The second case involves making the same spectral filter and microlens replacements, while also improving optimization of the detector material and ROIC for operation at MB27. Expected radiometric sensitivity performance of MB27 in VIIRS is excellent in both cases and compares favorably with flight performance in the corresponding band operating today in MODIS for the optimized performance case.

Since 1991, along track scanning radiometers (A)ATSR have been flown on a series of satellite platforms. These instruments use an along-track scanning design that provides two views of the same earth target through different atmospheric paths. Dual-view multispectral measurements can be used to derive an accurate atmospheric correction when retrieving geophysical parameters such as Sea Surface Temperature (SST). In addition, the (A)ATSR family of instruments use actively cooled detector systems and two precision calibration blackbody targets to maintain and manage on-board calibration. Visible channel calibration is implemented using a solar diffuser viewed once per orbit. As a consequence of these design features, resulting data derived from (A)ATSR instruments is both accurate and well characterized. After 10 years of Service the ENVISAT platform was lost in early 2012 asnd AATSR operations stopped. The Global Monitoring for Environment and Security (GMES) Sentinel-3 “Sea Land Surface Temperature Radiometer“ (SLSTR) instrument is the successor to the AATSR family of instruments and is expected to launch in April 2014. The challenge for SLSTR is to develop and deliver a new instrument with identical or improved performance to that of the (A)ATSR family. The SLSTR design builds on the heritage features of the (A)ATSR with important extensions to address GMES requirements. SLSTR maintains the main instrument principles (along-track scanning, a two point infrared on-board radiometric calibration, actively cooled detectors, solar diffuser). The design also includes more spectral channels including additional bands at 1.3 and 2.2 μm providing enhanced cloud detection, dedicated fire channels, an increase of dual view swath from 500 to 740 km, an increase in the nadir swath of 1400 km. The increase in swath has led to, a new optical front-end design incorporating two rotating scan mirrors (with encoders to provide pointing knowledge) and an innovative flip mechanism to select a specific optical chain. Unavoidably, these improvements introduce complexity, risk, increased mass and power. Bearing these aspects in mind, this paper reviews the design and performance of the Sentinel-3 SLSTR.

The potential for a significant improvement in the spatial resolution of the Visible Infrared Imager Radiometer Suite (VIIRS) is discussed. VIIRS continuously samples a 3000 km-wide swath from its low-earth orbit in support of NASA/NOAA’s weather, climate and environmental science missions. In order to provide superior spatial resolution across the swath compared with previous sensors, VIIRS samples the earth at very high angular resolutions and then aggregates up to three samples per pixel in order to reduce the raw data rate presented to the spacecraft for downlink. As additional downlink capacity becomes available, science data users may consider if utilization of the native rectangular resolution provided by the VIIRS detectors can improve any of the JPSS Environmental Data Records. The impacts to this potential improvement would be largely limited to increasing capacity for data handling and processing. The VIIRS sensor would still meet its sensitivity requirements in spite of this elimination of detector averaging.

The Commercially Hosted Infrared Payload (CHIRP) Flight Demonstration (FD-CHIRP) launched 21 Sept 2011 was designated a "resounding success" as the first Wide Field-of-View (WFOV) staring infrared (IR) sensor flown in geostationary earth orbit (GEO) with a primary mission of Missile Warning (MW). FD-CHIRP was an Air Force research and development project initiated in July 2008 via an unsolicited industry proposal aimed to mature and reduce the risk of WFOV sensors and ground processing technologies. Unlike the Defense Support Program (DSP) and the Space Based Infrared System (SBIRS) which were acquired via traditional integrated sensor and satellite design, FDCHIRP was developed using the "commercially hosted" approach. The FD-CHIRP host spacecraft and sensor were independently designed, creating significant development risk to the industry proposer, especially under a Firm Fixed Price contract. Yet, within 39 months of contract initiation, FD-CHIRP was launched and successfully operated in GEO to 30 June 2012 at a total cost of $111M including the $82.9M CHIRP commercial-hosting contract and a $28M sensor upgrade. The commercial-hosting contract included sensor and spacecraft modifications, integration and test, design and development of secure Mission Operations and Analysis Centers, launch, and nearly a year of GEO operations with 70 Mbps secure data acquisition. The Air Force extended the contract for six months to continue operations through the end of calendar 2012. This paper outlines system engineering challenges FD-CHIRP overcame and key lessons to smooth development of future commercially hosted missions.

The scientific benefits generated from the synergy of the satellites in the AM and PM (A-Train) Constellations are unprecedented. Constellation Flying in this context refers to each satellite flying independently in their own control box with acceptable minimum buffers ensuring that the control boxes do not intersect each other. Recently it is has been realized that rather than two separate constellations, they should be considered as one entity called the “705-km Fleet” named for their common nominal altitude over the equator. This realization partly comes from the recent events with the USGS satellite Landsat-5 which is in the AM Constellation, but for a period of time was overlapping with the A-Train. A fundamental concept is the Triad consisting of Alongtrack Phasing, Groundtrack and Mean Local Time of Ascending Node. Another related lesson learned is that to maintain the buffers, phasing at the two intersection points where each pair of orbits cross near the poles should be considered, as opposed to the relative phasing of the times they cross the equator. These types of geometric considerations are presented after presenting an introduction and history of the constellations. Other topics include: reference ground tracks, the process of handling the growing concern of conjunctions with other orbiting bodies, CloudSat and CALIPSO satellites performing Formation Flying, and the general ascent and exit methods for satellites entering/leaving a constellation.

NASA operates a fleet of piloted and UAV aircraft to perform a variety of Earth Science and emergency observation [1]. NASA's recent move toward sensor-web mission architectures requires a corresponding upgrade to its payload systems. NASA Airborne Science payloads will now interface to a new standard Experimenter Interface Panel (EIP), presented here. This discussion will cover the standard interface from the payload perspective. Details are provided on payload interface, cockpit control (for manned aircraft), technical design, network physical layer, qualification, and maintenance. Analyses are provided to support high-altitude design 'rules of thumb' and design decisions.

This paper describes an approach for addressing potential gaps in continuity of critical weather and other Earth observations begun by SeaWiFS, MODIS and MISR with single band CubeSat imagers that could be used in combination either onboard a single host satellite or in a constellation of small satellites to provide stable, high SNR multispectral measurements. These wide field of view, high SNR imagers are enabled by large format (~4000 element long) ultraviolet-near infrared focal plane assemblies and achromatic wide field of view telescopes. This new class of wide field of view pushbroom imagers offers capability to continue SeaWiFS, MODIS, MISR and, as discussed in a companion paper, DMSP OLS measurements in support of operational weather observations, Earth imaging and Earth science studies. In addition, extension of the spectral response to 350 nm enables supplementing existing and future systems with multispectral observations at near ultraviolet wavelengths of importance to aerosol and ocean color measurements. The large format size of the array and high optical quality wide field of view telescope enable an entire ~3000 km wide MODIS or VIIRS swath to be collected simultaneously by a pushbroom imaging radiometer in polar sun synchronous orbit. The increase in effective integration time made possible by a pushbroom approach versus the whiskbroom imaging approaches of AVHRR, MODIS and VIIRS enables measurements with the required SNR using a telescope aperture so small that the entire instrument can fit on a 3U CubeSat. Small single purpose imager modules like this could be used to supplement much larger systems like VIIRS by providing measurements of scientifically important bands not in VIIRS like the MODIS chlorophyll fluorescence and near-infrared water vapor bands and fill possible gaps in measurement continuity not provided by future systems or resulting from program delays.

Day/Night Band (DNB) earth sensing and meteorological systems like the Defense Meteorological Satellite Program (DMSP) Operational Line Scanner (OLS) provide visible wavelength imagery 24 hours a day that is used primarily for cloud imaging in support of weather forecasting. This paper describes a compact pushbroom imager that meets low light imaging requirements for DMSP OLS and the NOAA/NASA Joint Polar Satellite System (JPSS) as documented in the Integrated Operational Requirements Document (IORD). The presentation describes the imager design, including system level concepts of operation for data collection, radiometric and spatial calibration, and data transmission to Earth. This small, lightweight imager complies with the low mass, low power CubeSat standard, and could be built into a variety of different satellites, for example, as a payload on Iridium NEXT, DMSP, or the International Space Station (ISS). Depending on power generation capabilities, the imager could be implemented as a free flyer in formation with other CubeSats or as a free flyer operating on its own. The imager's volume will fill about half of a 3U CubeSat; roughly measuring 170x80x80 mm3 and having mass less than 1.5 kg. Considering an estimated 3U CubeSat average core avionic power usage of 0.8W and total orbit average power of 4W, the available average power for the payload imager is 3.2W.

Multispectral imaging is a powerful tool in remote sensing applications. Recently， a micro-arrayed narrow-band optical mosaic filter was invented and successfully fabricated to reduce the size and cost of multispectral imaging devices in order to meet the requirements for low- or mid- altitude remote sensing. Such a filter with four narrow bands is integrated with an off-shelf CCD camera, resulting in an economic and light-weight multispectral imaging camera with the capacity of producing multiple images at different center wavelengths with a single shot. The multispectral imaging camera is then integrated with a wireless transmitter and battery to produce a remote sensing multispectral imaging system. The design and some preliminary results of a prototyped multispectral imaging system with the potential for remote sensing applications with a weight of only 200 grams are reported. The prototyped multispectral imaging system eliminates the image registration procedure required by traditional multispectral imaging technologies. In addition, it has other advantages such as low cost, being light weight and compact in design.

The polarization lidar technique requires that the transmitted laser beam in the atmosphere is linearly polarized so that a depolarization ratio from hydrometeors and aerosol particles can be detected. This is easily achieved in vertically pointing lidars used to study clouds. However, in scanning lidars, which are of interest for wind and pollution studies, stand-off detection and biodefense, the state of polarization of the laser beam is modified upon reflection by the mirrors of the scanner. We study experimentally the effect of a two-mirror scanner, or beam steering unit (BSU), on the polarization state of a linearly polarized beam at 1.54 micron wavelength. We built a miniature BSU in the lab and used a polarimeter to map the state of polarization (SOP) for all combinations of azimuth-elevation angles. We found that the linear polarization is preserved for a horizontal scan (elevation angle is 0°) but it rotates as a function of azimuth angle. There are a few more pointing directions in which the SOP is linear. Overall, the transmit beam is elliptically polarized for a non-zero elevation angle. The ellipticity and orientation of the ellipses is not constant. However, we found a period of repeatability of 180° in both azimuth and elevation angles. When comparing two different coatings, we note that the ellipticity is a function of the type of coating. We propose a method to eliminate the induced ellipticity by the BSU mirrors for all scan directions by means of altering the incident SOP on the BSU.

The pulse from a transversely excited atmospheric CO2 laser consists of a sharp spike followed by a long, drawn out tail region spanning about 2-5 μs caused by the nitrogen gas in the laser cavity. The nitrogen tail is undesirable in many applications because it decreases the average power of the laser pulse. High stability and energy-efficient laser-induced plasma shutter to clip the nitrogen tail of CO2-TEA based DIAL is built. Optimum shutter gases pressures and laser breakdown intensities are reported. Clipped laser pulses are also field tested.

The paper introduces photonic service as a new type of multi-domain, end-to-end network service, that besides traditional data transmission enables also non-data or real-time communication, e.g. the remote control and sharing of different, typically unique, devices. We proved the concept of photonic services on a specialized metrology application - comparison of time scales, where time offset between atomic clock is measured. The experiment has been conducted over distance of 550 km (342 miles).

This paper describes measured performance of VIIRS Flight unit 1 (F1) in response to variations in linearly polarized light input into the instrument. Measurements and analysis show that VIIRS F1 meets specified polarization sensitivity requirements with maximum measured degree of linear polarization (DoLP) ranging from 0.5% for the M7 band (865 nm) to 2.8% for the M1 band at 412 nm. Estimated uncertainty in the DoLP ranges from 0.l7% for the M6 band at 746 nm up to 0.37% for I2 at 865 nm. Detailed tables of measured polarization sensitivity characteristics for all spectral bands, all detectors and both sides of the VIIRS de-rotation mirror are provided to help the VIIRS users’ community with analysis of measured spectral radiances in the solar reflectance channels.

In normal operation mode, RSI is not exposed to direct Sun irradiation, as long on-ground nominal procedure for Mission Programming is respected. The Spacecraft contingency mode is the so-called Safe Mode, in Safe mode, RSI can be exposed for a short time to direct Sun irradiation, as shown by AOCS detailed simulations. This may happen only during the initial transient phase of ASH mode, when attitude has not yet fully converged. The aim of this paper is to discuss that if Sun exposure periods are compatible with RSI constraints. There are two factors to be taken into consideration; one is the Sun exposure period (duration), the other is the Sun direct illumination in sensor and filter.

The bonding positions of three isostatic mounts on the primary mirror of a Cassegrain telescope under self-weight loading have both been studied in the paper. Finite element method and Zernike polynomial fitting are complementarily applied to the ZERODUR® primary mirror with a pre-designed lightweight configuration on the back. Eight bonding positions of isostatic mounts with respect to the center of gravity of the mirror have been chosen to investigate the mirror surface deforms as well as the induced optical aberrations. It is found that astigmatism becomes remarkably higher than other optical aberrations under self-weight loading. The optimum bonding position with the least astigmatism value has also been obtained.