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PROBA-3 is an ESA mission aimed at the demonstration of formation flying performance of two satellites that will form a giant coronagraph in space. The first spacecraft will host a telescope imaging the solar corona in visible light, while the second, the external occulter, will produce an artificial eclipse. This instrument is named ASPIICS (Association of Spacecraft for Polarimetric and Imaging Investigation of the Corona of the Sun). To accomplish the payload's scientific tasks, PROBA-3 will ensure sub-millimeter reciprocal positioning of its two satellites using closed-loop on-board metrology. Several metrology systems will be used and the Shadow Position Sensors (SPS) subsystem senses the penumbra around the instrument aperture and returns the 3-D displacement of the coronagraph satellite, with respect to its nominal position, by running a dedicated algorithm. In this paper, we describe how the SPS works and the choices made to accomplish the mission objectives.

PROBA-3 is a two-spacecraft ESA mission carrying the space-based diluted coronagraph ASPIICS. The imaging instrument is hosted on the first spacecraft with the second acting as external occulter. In order to accomplish the payload’s scientific tasks, PROBA-3 will ensure sub-millimeter reciprocal positioning of its two satellites by means of closedloop on-board metrology. The Shadow Position Sensors (SPS) sense the penumbra around the instrument aperture and return the 3-D displacement of the coronagraph satellite with respect to its nominal position by running a dedicated algorithm. In this paper we describe how the SPS works and the choices made in order to accomplish the mission objectives.

This project was an initial effort to investigate the feasibility of an instrument combining real-time atmospheric particle composition measurements using an ATOFMS (Atmospheric Time-Of-Flight Mass Spectrometer) such as those performed by Prather’s group at the University of California, San Diego (UCSD) with multi-wavelength scattering measurements of the type investigated by Sorensen et al., of Kansas State University (KSU). In this Phase I effort we proposed to investigate near-angle scattering and the possibility of integration of a multi-wavelength scattering instrument into the UCSD ATOFMS. After an initial optical design and calculations, we discovered issues with the theory of measurement and with mechanical integration. Evidence emerged that the method of multi-wavelength scattering is only efficacious for spherical particles, while most atmospheric particles are non-spherical fractal aggregates. We also determined that the integration of the detector into existing ATOFMS instruments would be severely limited by volume constraints, and additional volume would require prohibitive additional pumping compared with the existing ATOFMS systems. Based on this evidence, we decided not to pursue a Phase II effort.

The Air Force Research Laboratory/Space Vehicles Directorate (AFRL/RV) is developing a satellite structural architecture in support of the Department of Defense's Operationally Responsive Space (ORS) initiative. Such a structural architecture must enable rapid Assembly, Integration, and Test (AI&T) of the satellite, accommodate multiple configurations (to include structural configurations, components, and payloads), and incorporate structurally integrated thermal management and electronics, while providing sufficient strength, stiffness, and alignment accuracy. The chosen approach will allow a wide range of satellite structures to be assembled from a relatively small set of structural components. This paper details the efforts of AFRL, and its contractors, to develop the technology necessary to realize these goals.

The Air Force Research Laboratory/Space Vehicles Directorate (AFRL/RV) is developing Structural Health Monitoring (SHM) technologies in support of the Department of Defense's Operationally Responsive Space (ORS) initiative. Such technologies will significantly reduce the amount of time and effort required to assess a satellite's structural surety. Although SHM development efforts abound, ORS drives unique requirements on the development of these SHM systems. This paper describes several technology development efforts, aimed at solving those technical issues unique to an ORS-focused SHM system, as well as how the SHM system could be implemented within the structural verification process of a Responsive satellite.

The United States is striving to develop an Operationally Responsive Space capability. The goal is to be able to deliver tailored spacecraft capabilities to the warfighter as needs arise. This places a premium on the timespan between generating that requirement and having a functioning satellite performing its mission on orbit. Although there is lively debate regarding how to achieve this responsive space capability, one thing remains undeniable; the satellite flight qualification and launch vehicle integration process needs to be dramatically truncated. This paper describes the Air Force Research Laboratory's attempts to validate the use of Structural Health Monitoring (SHM) in lieu of traditional structural flight qualification testing schemes (static and shock loads, random vibration, coupled loads analysis, thermal vacuum testing, etc.) for potential Responsive Space (RS) satellites.

Recent experiments in upward burning flame spread over solid materials have shown the importance of lateral entrainment in the dynamics of the flame evolution. The traditional 2-D solution proposed by ~mmons(1956)~ with extensions by Kodson, Williams and Buman (1968); Pagni and Shih (1976); and Annamalai and Sibulkin (1974); does not take lateral entrainment into account. For this reason, empirically determined B numbers from experimental measurements do not yield consistent values when plotted as a function of distance normalized by the pyrolysis length. A numerical model and experiments over PMMA are used to evaluate the main assumptions used in the Emmons solution. Flow characteristics (2-D Boundary Layer) and surface thermal balance are identified as the critical assumptions to be evaluated. Comparison of experiments, numerical results and the theoretical model serve to validate the assumptions leading to the definition of a mass transfer number but establish the need to model all three-dimensional features of the flow. B = C, = u g = Gr , = J Lv = Pr = Q = Qp = GI' = .,I qs,r 4; = Re = T = TiE, = Nomenclature

The Space Shuttle is an inexpensive, reliable vehicle for small satellite launch for the Air Force Space Test Program (STP). Unfortunately, typical Shuttle orbits have a limited lifetime due to their low altitudes. One way to allow the STP to take advantage of the low Shuttle space lift cost is to employ a small propulsion module to boost the STP satellite from the relatively low Shuttle orbit to a higher orbit. Current Propulsion Module (PM) technologies are expensive and have difficulties conforming to the man-rating requirements of the Shuttle. The Space Vehicles Directorate of the Air Force Research Laboratory (AFRL/VS) seeks to solve this problem by developing PM technologies that will lower costs, improve performance, and increase the reliability of these systems, facilitating approval to fly on the Shuttle. The AFRL/VS will fund the development of several innovative technology efforts to design this proposed propulsion system to meet the STP requirements. It must be a lightweight, maneuverable vehicle that also meets Shuttle safety requirements. This system will also be compatible with current Space Shuttle Hitchhiker Experiment Launch System (SHELS) configuration for mounting in the Space Shuttle cargo bay, i.e. weight and volume requirements. The PM will also have a re-startable motor and appropriate avionics to provide flexible orbit transfer support.

In order to increase the number of satellites that can be flown with reduced costs, Multiple Payload Adapters (MPAs) are needed to take advantage of excess payload capability on launch systems. This paper will discuss the development of several MPAs at the Air Force Research Laboratory Space Vehicles Directorate in support of current and future Air Force and Department of Defense requirements. The adapters are being designed using state-of-the-art manufacturing processes, launch vibration isolation, and low-shock separation technology that can accommodate multiple satellite configurations. The MPAs can deploy multiple satellites, in a large range of sizes (15 kg to 1000 kg), depending on the design configuration. The MPAs are being developed to support the Minuteman and Peacekeeper derived space launch vehicles, the Evolved Expendable Launch Vehicle, and the Space Shuttle. The successful development of these adapters will greatly reduce the cost of launching satellites into orbit by allowing for the efficient use of currently unused payload margins. These MPA concepts maximize the opportunity for low-budget satellites to be manifested for launch, and are being proposed to fly as early as 2003. Additionally, work has begun to standardize adapter configurations and connections across multiple launch vehicles to provide reduced flight integration costs and greater opportunities for inclusion of small experiments on larger missions.

Small satellites require a variety of release devices to accomplish mission-related functions such as separation from the launch vehicle, separation from each other, and deployment of instruments. This paper summarizes low-shock non-pyrotechnic separation efforts that are being managed by the Air Force Research Laboratory Space Vehicles Directorate (AFRL/VS). The AFRL/VS has been actively developing low-shock, non-pyrotechnic spacecraft release devices to mitigate problems associated with traditional pyrotechnic release devices. Specifically, pyrotechnic devices produce high shock, create unnecessary contamination, and have costly handling requirements due to their hazardous nature. Small satellites are particularly susceptible to shock related failure because of the close proximity of sensors and instruments to the shock source. Reducing shock-induced loads on the spacecraft dramatically lowers the overall cost of a spacecraft's design, testing, and operation. Lower loads allow spacecraft components, such as solar arrays and other flexible structures, to be made lighter and use less expensive materials. This results in both smaller mass and reduced production costs. The AFRL/VS is sponsoring the development of several innovative technologies that can provide solutions to these problems. The devices are being designed to replace existing separation and deployment systems.

The critical pathway methodology of assigning and timing staff interventions and expected patient outcomes has developed worldwide recognition, but is less likely to be used in psychiatry than in other medical fields. 2 At St. Mary's in Rochester, New York, an interdisciplinary team adapted the critical pathway concept to meet the needs of an acute inpatient population with relative success. Although staff education needs continue and plans to modify the pathway are in progress, all staff feel that the critical pathway is a viable tool for enhancing patient care and optimizing resources use. Benefits, obstacles, and suggestions are discussed.

The Western United States is expected to undergo both extended periods of drought and longer wildfire seasons under forecasted global climate change and it is important to understand how these disturbances will interact and affect recovery and composition of plant communities in the future. In this research paper we describe the temporal response of grassland communities to drought and fire in southern Arizona, where land managers are using repeated, prescribed fire as a habitat restoration tool. Using a 25-year atlas of fire locations, we paired sites with multiple fires to unburned control areas and compare satellite and field-based estimates of vegetation cover over time. Two hundred and fifty Landsat TM images, dating from 1985–2011, were used to derive estimates of Total Vegetation Fractional Cover (TVFC) of live and senescent grass using the Soil-Adjusted Total Vegetation Index (SATVI) and post-fire vegetation greenness using the Normalized Difference Vegetation Index (NDVI). We also implemented a Greenness to Cover Index that is the difference of time-standardized SATVI-TVFC and NDVI values at a given time and location to identify post-fire shifts in native, non-native, and annual plant cover. The results highlight anomalous greening and browning during drought periods related to amounts of annual and non-native plant cover present. Results suggest that aggressive application of prescribed fire may encourage spread of non-native perennial grasses and annual plants, particularly during droughts.