Large space antennas: A systems analysis case history

The value of systems analysis and engineering is aptly demonstrated by the work on Large Space Antennas (LSA) by the NASA Langley Spacecraft Analysis Branch. This work was accomplished over the last half-decade by augmenting traditional system engineering, analysis, and design techniques with computer-aided engineering (CAE) techniques using the Langley-developed Interactive Design and Evaluation of Advanced Spacecraft (IDEAS) system. This report chronicles the research highlights and special systems analyses that focused the LSA work on deployable truss antennas. It notes developmental trends toward greater use of CAE techniques in their design and analysis. A look to the future envisions the application of improved systems analysis capabilities to advanced space systems such as an advanced space station or to lunar and Martian missions and human habitats

Radiometer requirements for Earth-observation systems using large space antennas

Requirements are defined for Earth observation microwave radiometry for the decade of the 1990's by using large space antenna (LSA) systems with apertures in the range from 50 to 200 m. General Earth observation needs, specific measurement requirements, orbit mission guidelines and constraints, and general radiometer requirements are defined. General Earth observation needs are derived from NASA's basic space science program. Specific measurands include soil moisture, sea surface temperature, salinity, water roughness, ice boundaries, and water pollutants. Measurements are required with spatial resolution from 10 to 1 km and with temporal resolution from 3 days to 1 day. The primary orbit altitude and inclination ranges are 450 to 2200 km and 60 to 98 deg, respectively. Contiguous large scale coverage of several land and ocean areas over the globe dictates large (several hundred kilometers) swaths. Radiometer measurements are made in the bandwidth range from 1 to 37 GHz, preferably with dual polarization radiometers with a minimum of 90 percent beam efficiency. Reflector surface, root mean square deviation tolerances are in the wavelength range from 1/30 to 1/100

A transmitting and reflecting diffuser for ultraviolet light

Fabrication of ultraviolet radiation diffusing layer in configuration that uses ultraviolet properties of fused silica condensate is discussed. Construction and operation of the device are described. Diagram of reflecting diffuser to show construction and method of operation is included

Tropospheric Passive Remote Sensing

The long term role of airborne/spaceborne passive remote sensing systems for tropospheric air quality research and the identification of technology advances required to improve the performance of passive remote sensing systems were discussed

Transmitting and reflecting diffuser

An ultraviolet grade fused silica substrate is coated with vaporized fused silica. The coating thickness is controlled, one thickness causing ultraviolet light to diffuse and another thickness causing ultraviolet light to reflect a near Lambertian pattern

Red Tides in Inshore and Offshore Casco Bay and Their Relationship to Local and Gulf of Maine Physical and Biological Conditions

The objective of this report focuses on the secondary goal of the overall program – to develop a better understanding of A. fundyense bloom dynamics in Casco Bay – by examining bloom origin and development (outside Casco Bay, within Casco Bay or both) and correlations between water quality data, location, and bloom intensity. We analyzed the IPSP monitoring program 2006-2008 data to characterize the blooms (spatially and temporally), and examine correlations between water quality, toxicity and A. fundyense data. Using the IPSP data along with data from other studies, we have examined the role of local and regional physical and biological factors in the larger Gulf of Maine and their potential impact on the onset and temporal and spatial extent of red tide blooms in Casco Bay. We have also examined the role of nutrient availability in the spatial and temporal extent of Casco Bay blooms

Development and disease of opakapaka (Pristiopomoides filamentosus) larvae in culture

Opakapaka (Pristipomoides filamentosus) is a snapper (family Lutjanidae) native to the waters around Hawaii. Recent population declines of this commercially important species have increased interest in the culture of this fish. Survival of this fish through the larval period in culture has been consistently low, usually not exceeding 2%. The aim of this thesis was to provide an extensive diagnostic report of diseases affecting opakapaka larvae in culture. Opakapaka larvae mortality was found to be the result of a synergy of factors including larvae development stage, larvae nutrition, environmental conditions, and the presence of infectious agents. During culture, high larval mortalities occur around first feeding and around a period of rapid development. Crucial periods of development in both the digestive system and the respiratory system coincided with these catastrophic mortality events. It is therefore suspected that failure to complete the progression of development from one stage to the next is partially responsible for low larvae survival. A large proportion of opakapaka surviving to the juvenile stage had deformed jaws and/or vertebral columns. Therefore, the development of the jaw and other skeletal elements was investigated. Lower jaw deformities were found to occur as early as 2 days post hatch and larvae with some deformity represented roughly 30% of the population. Given the severity of these deformities, it is likely that this results in increased larvae mortality. Due to the identified risk of ammonia toxicity, experiments were designed to determine the concentration of ammonia lethal to opakapaka larvae. The 50% lethal dose for post-hatch opakapaka larvae was found to be 1.4 mg/L total nitrogen. Ammonia toxicity could have been a factor in opakapaka larvae mortality, because this concentration was lower than that observed in larvae rearing tanks. The evaluation of the role of infectious disease in opakapaka culture showed that current infections are primarily opportunistic. Observed infections included bacterial gill disease and external lungal infection. Although infectious disease is not currently a significant cause of mortality, continued surveillance for infectious disease introduction is recommended. The success of intensive opakapaka culture hinges on the ability to culture a large number of opakapaka to the juvenile stage. As a result of this study, major issues of concern in opakapaka culture were identified. This information could provide direction for culturists in the refinement of opakapaka culture and subsequent improvement of larvae survival

Radiometer mission requirements for large space antenna systems

Requirements are defined for Earth observational microwave radiometry using large space antenna systems with apertures in the 50 to 200 meter range. General Earth observational needs, specific measurement requirements, orbital mission guidelines and constraints, and general radiometric requirements are defined. Specific measurements include soil moisture, water surface temperature, water roughness, ice boundaries, salinity, and water pollutants. Measurements with 10 to 1 km spatial resolution and 3 to 1 day temporal resolution are required

Improving the accuracy and utility of harmful algal bloom forecasting systems

Author Posting. © The Author(s), 2006. This is the author's version of the work. It is posted here by permission of Geological Society for the Micropalaeontological Society for personal use, not for redistribution. The definitive version was published in Biological and Geological Perspectives of Dinoflagellates, edited by Jane Lewis, F. Marret, L.Bradley, :141-147. London: Geological Society for the Micropalaeontological Society, 2013. ISBN: 9781862393684.One of the goals of harmful algal bloom (HAB) research has been to develop predictive capabilities for blooms. Major steps have been made towards this goal, including the development of physical-biological models of HAB species that simulate bloom dynamics in specific regions. In the Gulf of Maine region of the northeastern U.S., models have been developed that have considerable skill in simulating blooms of Alexandrium fundyense, the causative organism for paralytic shellfish poisoning (PSP) outbreaks in the region. This model is now being used for both short-term and long-term forecasts. This paper describes several ongoing activities that will improve the accuracy and usefulness of the model and forecasts. These include efforts to streamline or minimize the sampling and analysis requirements of annual A. fundyense cyst surveys, efforts to quantitatively describe or characterize the severity of predicted outbreaks, and plans to obtain real-time data on Alexandrium cell abundance and toxicity that can be assimilated into the models. Together, these and other activities are moving us towards an operational forecasting system for Alexandrium blooms in the region.Woods Hole Center for Oceans and Human Health, National Science Foundation (NSF) Grants OCE-0430724, and OCE-0911031; and National Institute of Environmental Health Sciences (NIEHS) Grant 1-P50-ES012742-01, the ECOHAB Grant program through NOAA Grants NA06NOS4780245 and NA09NOS4780193, and the MERHAB Grant program through NOAA Grant NA11NOS4780025

Technology needs assessment of an atmospheric observation system for tropospheric research missions, part 1

The technology advancements needed to implement the atmospheric observation satellite systems for air quality research were identified. Tropospheric measurements are considered. The measurements and sensors are based on a model of knowledge objectives in atmospheric science. A set of potential missions and attendant spacecraft and sensors is postulated. The results show that the predominant technology needs will be in passive and active sensors for accurate and frequent global measurements of trace gas concentration profiles