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A Bread Board Model of a spaceborne hydrogen maser atomic clock for the satellite positioning system using Quasi-Zenith Satellites has been developed. Analysis and experiments for technical problems such as miniaturization, achievement of long life, mechanical vibration proofing, and space environment characteristics have been performed, and technical data necessary for EM development have been obtained., See also ADM001784. Presented at the Annual Precise Time and Time Interval (PTTI) Systems and Applications Meeting (36th) held in Washington, DC on 7-9 Dec 2004. Published in the Proceedings of the Annual Precise Time and Time Interval (PTTI) Systems and Applications Meeting (36th), p423-430, 2004. The original document contains color images.

There are two imagers on NASA's EO-1 satellite: Hyperion and Advanced Land Imager (ALI). Hyperion is a hyperspectral sensor with about 45 bands covering the spectral range of 430-900 nm, while ALI has only six (wide width) bands for the same range. Past studies have shown that data from both kinds of sensors can provide observations of important environmental properties, such as bathymetry and water turbidity. However, in the derivation of bathymetry using data from multi-band sensors (e.g., LANDSAT), usually bathymetry data at a few locations are required to be known first. Recently, a semi-analytical spectral optimization algorithm has been developed for remote-sensing of shallow-water environments. Using data from hyperspectral airborne and space-borne sensors, it has been demonstrated that bathymetry of optically shallow waters can be derived without a priori knowledge of depths at a few locations, and properties of water column and bottom can be retrieved simultaneously from remotely sensed data. In this study, the authors extend the optimization approach to ALI data with retrieved water and bottom properties compared with that from Hyperion data. From these results, they discuss the advantages/disadvantages of Hyperion and ALI sensors, and their potential applications for coastal observations., Presented at the International Conference on Remote Sensing for Marine and Coastal Environments (8th) held in Halifax, Nova Scotia (Canada), on 17-19 May 2005. The original document contains color images.

ELECTRONIC FILE CHARACTERISTICS: 37 files; HyperText Markup Language (.HTML), MS PowerPoint (.PPT), and MS Word (.DOC). PHYSICAL DESCRIPTION: 1 computer laser optical disc (CD-ROM); 4 3/4 in.; 25.1 MB. SYSTEMS DETAIL NOTE: ABSTRACT: This is a report of an occupational survey of the Missile and Space Systems Electronic Maintenance (AFSC 2MOX1) specialty (OSSN 2555, May 04), conducted by the Occupational Analysis Flight, AFOMS. The OSR reports the findings of current data that are available for use in guiding the development and evaluation of training and support planned changes within these fields. In addition, the data are used to support SKT development for the enlisted member promotion system. The previous OSR was completed in September 2000.

A vectorial Fourier-based technique for electromagnetic (EM) wave reconstruction with application to polarimetric airborne and spaceborne radar data exploitation is presented. The approach provides a comprehensive picture of scattering through an electromagnetic-based formulation of equivalent sources and introduction of vector scattering functions. The method is different from conventional modeling techniques for SAR applications as result of the full electromagnetic treatment of field interaction with the scatterer, the possibility of introducing new and controllable feature classes for target classification, and the accurate decomposition of source impulse response function that avoids potential errors (e.g., loss of coherent information) associated with the spherical phase approximations. In addition to including the potential for high quality image formation, the capability of extracting target or scatterer information, such as coherent radar cross section (RCS) is explored. It is highlighted how target image and information processing can be optimized and tailored for a desired scenario (e.g., the required information type, the nature of the targets) by applying the developed model and devising appropriate inversion techniques to aid data processing in support of exploitation., and Summary in English and French.

Modern theories of gravity predict ripples in space and time, which are known as gravitational waves. Very large interacting masses, such as binary systems of neutron stars or black holes, are predicted to generate gravitational waves that may be intense enough to bevvv detected. This study presents a response analysis for the proposed gravitational wave experiment known as the Laser Interferometer Space Antenna (LISA). The analysis focuses on the gravitational wave distortion patterns, or polarizations, predicted by the Brans-Dicke Scalar-Tensor Theory of Gravity (BD). LISA, a cooperative venture between the National Aeronautics and Space Administration (NASA) and the European Space Agency (ESA), is a proposed space-based gravitational wave experiment with the potential to distinguish between polarizations of gravitational waves. LISA is scheduled for launch in 2012; so much of the current work for LISA involves the development and design of systems and procedures that will allow LISA to attain its desired performance. For a gravitational wave experiment, the projected sensitivity is determined by an instrument response function, which relates the disturbance generated by the gravitational wave to the disturbance that can be measured by the instrument. This study compares the response functions for BD polarizations to the published response functions for GR. Response functions co-responding to several different methods of data collection were analyzed. To numerically evaluate and compare the response functions, two programs were generated in the MATLAB programming language. The first program computes the response functions averaged over all source directions for each gravitational wave polarization and data collection method. The second program calculates the instrument response at each point in LISA s orbit to gravitational waves originating from the galactic center., The original document contains color images.

The global ocean surface wind vector is a key parameter for short-term weather forecasting, the issuing of timely weather warnings, and the gathering of general climatological data. In addition, it affects a broad range of naval missions, including strategic ship movement and positioning, aircraft carrier operations, aircraft deployment, effective weapons use, underway replenishment, and littoral operations. WindSat is a satellite-based multifrequency polarimetric microwave radiometer developed by the Naval Research Laboratory for the U.S. Navy and the National Polar-orbiting Operational Environmental Satellite System Integrated Program Office. It is designed to demonstrate the capability of polarimetric microwave radiometry to measure the ocean surface wind vector from space. The sensor provides risk reduction for the development of the Conical Microwave Imager Sounder, which is planned to provide wind vector data operationally starting in 2010. WindSat is the primary payload on the Department of Defense Coriolis satellite, which was launched on January 6, 2003. It is in an 840-km circular sun-synchronous orbit. The WindSat payload is performing well and is currently undergoing rigorous calibration and validation to verify mission success., The original document contains color images. Pub. in IEEE Transactions on Geoscience and Remote Sensing, v42 n11, p2346-2361, Nov 2004.

This document is a report of the work performed during the period 10 Aug 1999 - 31 Aug 2003 in the areas of: (1) research, evaluation and adaptation of particle transport simulation programs for modeling the detection and measurement of space radiation by space-borne sensors; (2) the transfer of this particle transport simulation capability to the Air Force Research Laboratory, Space Weather Center of Excellence (AFRL/VSBXR); (3) construction of realistic flight sensor computer models; (4) performance of particle transport calculations; (5) space-borne dosimeter simulation studies; and (6) studies of scattering of grazing incidence protons from surfaces of material constituents of space-borne X-ray telescopes. The computer programs ITS-ACCEPT and MCNPX were applied to the modeling of the CEASE and HEP sensors, and the CRRES dosimeter. This document also summarizes our collaboration in research leading to the publication of two technical papers., The original document contains color images. All DTIC reproductions will be in black and white.

As the world of flight enters its second century, in-space propulsion nears the end of its first 50 years. The field is progressing rapidly, with a diversification of propulsion technologies that enable space missions that were previously untenable. This paper will summarize the state of the art and current development efforts for the major classes of spacecraft propulsion: chemical, electric, and solar thermal. Chemical propulsion systems remain the backbone of spacecraft architectures. Work continues to improve the performance, storability, and environmental friendliness of liquid monopropellant, bipropellant, cold gas, and gel systems for orbital insertion, stationkeeping, orbital maneuvering, and attitude control. Electric propulsion, once the "technology of tomorrow" has entered the mainstream of in-space propulsion, establishing operability for stationkeeping and orbital insertion and being baselined for next generation scientific deep space and interferometry missions. Research efforts are now concentrated primarily on expanding the applicable power range for electric propulsion systems in order to enable large orbit transfer vehicle applications and micro/nano spacecraft propulsion systems. Solar thermal propulsion is also discussed. A comprehensive research and development effort is ongoing in the United States and Europe in industrial, academic, and national laboratory settings to advance the state of the art for spacecraft propulsion systems. Apart from technological developments in these various fields, the economic pressure on both commercial and scientific missions is increasing and customers require an industrialization of space businesses. Improvements in these areas have been achieved within the Astrium EUROSTAR and Alcatel SPACEBUS series., Prepared in collaboration with Astrium GmbH Space Infrastructure, Lampoldshausen, Germany.

Space-time adaptive processing (STAP) is a signal processing technique for detection of moving targets buried in ground clutter by means of a moving (air- or spaceborne) radar. No future military air- or spaceborne radar will be designed without this feature. This Lecture Series gives a comprehensive overview of the broad field of STAP, starting with fundamentals, clutter characteristics, application to synthetic aperture radar (SAR), and issues in over-the-horizon radar (OTH). Beside the principles and underlying fundamentals special aspect are covered, such as economic STAP architectures, limiting effects, algorithms for real-time processing, and special applications such as bistatic radar configurations and terrain scattered jamming., Text in English. Summaries in English and French. The original document contains color images. ISBN 92-837-1064-9. Presented at RTO SET Lecture Series held in Istanbul, Turkey on 16-17 Sep 2002; in Wachtberg, Germany on 19-20 Sep 2002; and in Moscow, Russia on 23-24 Sep 2002. For individual articles, see ADP014040 thru ADP014047

Spaceborne radiometric measurements of the L band brightness temperature over the oceans make it possible to estimate sea surface salinity. However, Faraday rotation in the ionosphere disturbs the signals and must be corrected. Two different ways of assessing the disturbance directly from the radiometric measurements, and hence enabling a correction for the effect, are being discussed. Also, a method, which aims at circumventing the problem by using the first Stokes parameter in the salinity retrieval, is being discussed.

This is a report of technical progress made during 1 Aug 00 to 31 Jul 01 in the areas of: (1) research and evaluation of particle transport simulation programs for modeling the detection and measurement of space radiation by space-borne sensors; (2) construction of realistic flight sensor computer models; (3) performance of particle transport calculation; (4) analysis of transport simulation results, including single particle tracking; (5) addition of new capabilities such as single particle tracking and specialized source geometry to an existing particle transport simulation program; (6) space-borne dosimeter simulation studies; (7)three-dimensional visualization of ITS-ACCEPT and MCNPX were applied to the modeling of the geometry files. The computer programs ITS-ACCEPT and MCNPX were applied to the modeling of the CEASE and HEP sensors. Shown in this report are listings of input files with geometry/materials drawings for the various simulation programs, annotated computer code listings showing program modifications and partial listings of computer code outputs for individual particle tracking and coincidence event identifications.

In most recent years, both high-resolution imagery systems and images were only available to military and national security organizations. Distinctive changes within the commercial image industry allowed space-borne pioneers to provide high-resolution images. Space-borne Image Company's Ikonos satellite provides a 1-meter resolution for the past 3 years. Current development of .5-meter resolution will be offered in the near future. Access of these images is available in ground stations located worldwide in different regions. Studies have shown that these high quality images are eye-catching and may serve a purpose through its design; on contrary high cost and accessibility does not met all the requirements of a nation or a region. A nation certainly cannot rely on a foreign commercial company for reconnaissance needs in times of crisis. The best frequency of coverage for a single point on earth is available once every 2.9 days on an average with high resolution. This study seeks a commercial imaging solution for regional applications. Mission requirements are set well above the existing commercial imaging systems including; continuous coverage during daylight hours, and daily re-visitation; service 5 to 25 'simultaneous' customers in addition to competitive resolution and cost. Alternatives considered included satellites, small satellites, UAV's and mixed systems. Inflatable technologies that permit higher orbit attitude and solar-powered UAV's with extended on-station times are also evaluated in this study., The original document contains color images.

This research develops an adaptive controller that actively suppresses a single frequency disturbance source at a remote position and tests the system on the NPS Space Truss. The experimental results are then compared to those predicted by an ANSYS finite element model. The NPS space truss is a 3.7-meter long truss that simulates a space-borne appendage with sensitive equipment mounted at its extremities. One of two installed piezoelectric actuators and an Adaptive Multi-Layer LMS control law were used to effectively eliminate an axial component of the vibrations induced by a linear proof mass actuator mounted at one end of the truss. Experimental and analytical results both demonstrate reductions to the level of system noise. Vibration reductions in excess of 50dB were obtained through experimentation and over 100dB using ANSYS, demonstrating the ability to model this system with a finite element model. This report also proposes a method to use distributed quartz accelerometers to evaluate the location, direction, and energy of impacts on the NPS space truss using the dSPACE data acquisition and processing system to capture the structural response and compare it to known reference Signals.

The scientific aims of this project are to investigate, develop and apply methods based solidly on scattering physics and inverse theory to estimate vertical distributions of water vapor and aerosol properties from hyperspectral observations of scattered sunlight. We seek especially to advance methods for the lower troposphere, where water vapor and aerosols are concentrated and affect naval systems strongly. We are presently working on a method applicable over the sea surface. The current focus of the project is on physics and inverse theory for retrieval of water vapor profiles very near sea and littoral land surfaces (from roughly 0 - 500 mB) using high spectral resolution near- IR observations of scattered sunlight, such as are expected from the NEMO/COIS sensor. We are working to quantify the fidelity and altitude ranges of inversion based on clear-air aerosol scattering, and to test alternative methods for this inversion using existing (airborne) hyperspectral observations, to the degree possible., Prepared in collaboration with the Department of Mathematics, University of Washington, Seattle.

An increasing amount of interest has evolved in VHF/UHF SAR applications. These types of radars have proven to be a very powerful method for underground and obscured object detection. In this paper we analyze the possibility of a spaceborne P-band SAR system, based on the experience gained from the analysis of the experimental airborne P-band SAR (E- SAR)system of DLR. We address possible methods and filters for effective Radio Frequency Interference (RFI) suppression, polarimetric and radiometric calibration procedures. We also assess the problems concerning the image quality degradation due to ionospheric propagation effects based on several simulation models., Pres. at the RTO Sensors and Electronics Tech. Panel (SET) Symposium, Island of Samos Greece, 16-18 Oct 2000. This article is from ADA391327 Space-Based Observation Technology

COSMO/SkyMed is a spaceborn program primarily dedicated to Earth observation, remote sensing and data exploitation for risks management, defense and intelligence applications and coastal zone monitoring. This program is going on under a contract of Agenzia Spaziale Italiana (ASI) that foresees also the development of critical technologies., Pres. at the RTO Sensors and Electronics Tech Panel (SET) Symposium, Island of Samos Greece, 16-18 Oct 2000. This article is from ADA391327 Space-Based Observation Technology

This final technical report summarizes the research performed by the Colorado Center for Astrodynamics Research (CCAR) for the Naval Research Laboratory (NRL) on Spaceborne Differential GPS Applications over the period Ol September 1997 through 31 August 1999. The primary focus of our work was on relative state estimation using GPS data from two vehicles. Data from a spaceborne experiment conducted by NASA was used for algorithm development and performance analysis. An auxiliary area of research was the identification and reduction of multipath errors in GPS observations. This effort is key to full utilization of GPS for high precision applications such as attitude determination, differential GPS, and relative navigation. The report comprises three documents descrIbing the research. The first two are conference papers presented at ION GPS 99 describing the relative navigation and multipath research. The third is a doctoral dissertation research proposal written by Dolan Highsmith, summarizing his research on this project and plans for future work.

This thesis created an analytical model for active vibration control of the NPS space truss using ANSYS. The NPS space truss is a 3.7-meter long truss that simulates a space-borne appendage with sensitive equipment at its extremities. With the use of a dSPACE data acquisition and processing system, quartz force transducer and piezoelectric actuator, active controls using an integral plus double integral control law were used to damp out the vibrations caused by a linear proof mass actuator. Vibration reductions on the order of 15-20 dB were obtained with experiment. The ANSYS finite element model used SOLIDS elements to model the piezoelectric characteristics and ANSYS Parametric Design Language to provide for an iterative approach to an active controls analysis. Comparative data runs were performed with the ANSYS model to determine its similarity to experiment. The analytical model produced power reductions of 18-22 (B, demonstrating the ability to model the control authority with a finite element model. This technique can be used and modified to enhance its flexibility to many types of controls and vibration reduction applications. An analytical model for active control of the NPS space truss using MATLAB/Simulink was also developed as an alternative to the ANSYS model.

The scientific aims that motivate our work on this project are: (1) to understand quantitatively the multiple-scattering physics underlying spaceborne hyperspectral and lidar observations of atmospheric aerosols and surface reflectivity; (2) to develop rigorous, stable (i.e., genuinely useful) inverse methods to interpret such observations in terms of geophysical quantities, based on the mathematics of inverse radiative transfer; and (3) to apply such methods to gain otherwise unavailable insight into geophysical interactions of the ocean, the atmosphere, and land surfaces. The specific objectives of this project are: (1) to understand quantitatively how the accuracy of dust parameter and ocean color estimates from hyperspectral data depend on knowledge of vertical aerosol distributions and dust particle absorption; (2) to develop improved methods for estimating dust aerosol properties and water-leaving-radiance (WLR) from hyperspectral and limited vertical profile data, including data from the newest generations of NASA (SeaWIFS, MODIS, MISR, and spaceborne lidar) and DoD (COIS/NEMO) sensors; and (3) to demonstrate the initial use of such methods in investigation of dust outbreaks over littoral seas., See also ADM002252.

The long-term goal for this project is threefold: (1) to develop remote sensing procedures for determining aerosol loading and optical properties over land and ocean, (2) to use these properties for atmospheric corrections over coastal regions, and (3) to assess what combination of hyperspectral information can lead to the best results. In preparation for the era of hyperspectral sensors in remote sensing, we need to establish a climatology of aerosol properties and of spectral reflectance for land, ocean and coastal regions. These specific features will be used to develop aerosol remote sensing capability and in the future corrections of remote sensing data., See also ADM002252.

The long term goal of this work is specify long ocean wave spatial coherence in a way that is useful for designers of Mobile Offshore Bases (MOBs). The proposed sizes of MOBs are on the order of a kilometer or more and pose unique design challenges. In particular, we intend to generate a statistical database of wave "long-crestedness" and "groupiness" from spaceborne synthetic aperture radar (SAR) imagery of the ocean surface. We will place emphasis on those SAR images in high sea states, the environmental conditions that will pose the greatest challenge to MOBs. SAR images from hurricanes will likely prove the most useful., See also ADM002252.

In this paper, the authors describe a demonstration using a Multiple Quantum Well modulator combined with an optical retroreflector that supported a high-speed, free space optical data link. Video images were transmitted over an 859-nanometer link at a rate of 460 kilo bits per second, where rate of modulation was limited by demonstration hardware, not the modulator. Reflection architectures for the modulator were used; transmission architectures also were investigated but are not discussed in this paper. The modulator was a GaAs/Al(sub 0.3)Ga(sub 0.7)As quantum well that was designed and fabricated for use as a shutter at the Naval Research Laboratory. These may be the first results reported demonstrating a high-speed, free space optical data link using multiple quantum well shutters combined with retroreflectors for viable free space optical communications., Pub. in Applications of Photonic Technology 3: Closing the Gap between Theory, Development, and Application, SPIE v3491, p581-586, 1998.

The density of data output from spaceborne altimeters is an impressive 7-km alongtrack. This is an excellent data source to the study of global and regional wind and wave conditions. A technical evaluation of constructing regional climatologies of winds and waves is presented. The accuracy of the measurements is summarized from several earlier comparison studies. The results indicate that the wind speeds and wave heights measured by satellite altimeters are of outstanding quality. For the construction of a regional climatology, the spatial resolution (grid size) and temporal resolution (time bin) are important considerations. Our analysis indicates that from a single satellite seasonal statistics with 1 degree resolution can be achieved. With combined satellite output, monthly climatologies with 0.25 degree resolution is possible. A demonstration study is presented for the region of Yellow and East China Seas using the TOPEX output. The results show significant temporal and spatial structure of the wind and wave distributions in the region. Four distinct domains of winds and waves can be defined for the area defined by (115 degree E, 20 degree N) and (130 degree E, 42 degree N): the Yellow Sea, the East China Sea, the Kuroshio, and South of Ryukyu Islands. The distinction of each area is outlined.

The feasibility of using a Fourier Transform Infrared (FTIR) spectrometer from an airborne platform for remote sensing of air pollution was investigated. Air Force Phillips Laboratory mounted a FTIR spectrometer into a small twin engine aircraft and obtained the data used in this investigation. The aircraft was flown over sections of New York and New England. The spectrometer was operated two different configurations, a passive configuration where the spectrometer viewed the warm ground and atmosphere below the aircraft, and an extractive mode where outside air was flushed through a 100 meter optical path gas cell. The spectral data were analyzed at AIL Systems Inc. for the presence of atmospheric pollutants.

The FY97 Space and Missiles Technology Mea Plan describes Phillips Laboratory's exploratory and advanced technology development strategy for Boost and Orbit Transfer Propulsion Technology, Tactical and Spacecraft Propulsion Technology, Space vehicle Structures and Controls. Advanced Technology Integration and Demonstration, Space Power and Thermal Management Space Sensors and Satellite Communications, Space Vehicle Electronics and Satellite Control, Space Vehicle and Missile Dynamics Technology.

This report summarizes the progress for the first quarter of FY'96-97 by the Colorado Center for Astrodynamics Research (CCAR) on the application of GPS based attitude determination techniques to near-Earth spacecraft. Two areas are addressed - application of an open architecture receiver for spaceborne attitude determination and coarse spacecraft attitude determination based on GPS signal to noise ratios. We have started work with the GEC Plessey GPSBuilder 2 receiver and identified modifications required to use the receiver for attitude determination functions. In particular we made arrangements for the addition of a second RF section to be added to the receiver and determined that the receiver tracking loop must be modified from a frequency lock loop to a phase lock loop (PLL) design. In the area of coarse attitude determination based on SNR, we have made improvements to a fuzzy estimation algorithm which provide attitude estimates at the 7 deg RMS level for flight data sets from CRISTA SPAS and GANE. We have also begun work on a maximum likelihood estimation technique using these same observables. Two research papers funded under this grant were presented at the ION GPS-96 meeting in Kansas City.

With PASP Plus as its primary payload, the APEX satellite was launched by a standard Pegasus rocket released from a NASA B-52 aircraft on 3 August 1994. A 70 deg inclination, 363 km X 2550 km orbit was achieved, allowing both investigation of space plasma effects on high-voltage operation in the perigee region and investigation of space radiation effects on array power output from passage through the inner radiation belt in the apogee region. Data gathering by PASP Plus was begun on 7 Aug 94 and ended on 11 Aug 95. In one year, PASP Plus collected an order of magnitude more data on environmental interactions on solar arrays than all previous space-borne photovoltaic experiments combined. The test arrays flown and the interactions-measuring and space-environment sensors of PASP Plus are described. The results of measurements of leakage current under test-array positive biasing and arc rates under negative biasing as a function of bias voltage, plasma density, array orientation, and other conditions are presented. The results of measurements of test-array power-output degradation caused by space radiation are also examined.

This report summarizes the activities sponsored by the Office of Naval Research for the Magnetospheric Atmospheric X-ray Imaging Experiment (MAXIE). The MAXIE instrument was developed as a joint activity of Lockheed, The Aerospace Corporation, and the University of Bergen, Norway. Lockheed was responsible for the overall management of the program, interfacing with the appropriate government agencies, the overall electrical and mechanical design, flight software, environmental testing, spacecraft integration activities, on orbit checkout, and data processing activities. The Magnetospheric Atmospheric X-ray Imaging Experiment (MAXIE), the ONR 401 experiment, is the first in a new class of satellite-borne remote sensing instruments. The primary innovation is the ability to obtain rapid, sequential, images with high sensitivity of the earth's X ray aurora from a low altitude polar orbiting satellite. These images can be used to identify dynamic temporal variations in the three-dimensional (energy and position) distribution of electron precipitation into the atmosphere. MAXIE was launched on the TIROS NOAA-13 satellite on 9 August 1993. The experiment performed well during its turn-on sequence; however, the spacecraft bus failed on 21 August 1993. New spacebased technologies successfully used in MAXIE were mixed-mode ASIC microcircuits, a zero torque scanning system with associated viscoelastic damping, a paraffin stow release mechanism, a parallel integrating PHA processor, a low noise Si(Li) seruor telescope, and an advanced thermal cooling system. MAXIE's on orbit operation, control of penetrating particle backgrounds, and scientific data indicated good overall performance.

The FY 96 Space and Missiles Technology Area Plan describes Phillips Laboratory's exploratory and advanced technology development for missile propulsion technology, space systems propulsion technology, space vehicle structures and controls, advanced technology integration and demonstration, space power and thermal management, space sensors and satellite communications, space vehicle electronics and software, and space vehicle and missile dynamics technology. Specifically, each thrust is discussed in terms of its goals, major accomplishments, and changes from last year.

This report provides a context in which questions put forth by NASA's Office of Mission to Planet Earth (OMPTE) regarding the next steps in spaceborne synthetic aperture radar (SAR) science and technology can be addressed. It summarizes the state-of-the-art in theory, experimental design, technology, data analysis, and utilization of SAR data for studies of the Earth, and describes potential new applications. The report is divided into five science chapters and a technology assessment. The chapters summarize the value of existing SAR data and currently planned SAR systems, and identity gaps in observational capabilities needing to be filled to address the scientific questions. Cases where SAR provides complementary data to other (non-SAR) measurement techniques are also described. The chapter on technology assessment outlines SAR technology development which is critical not only to NASA's providing societally relevant geophysical parameters but to maintaining competitiveness in SAR technology, and promoting economic development.

Eight years ago the AFOSR awarded us a grant to study the solar activity cycle both to understand its physical nature, and to forecast the timing and magnitude of future maxima with as much anticipation as possible. Because solar activity affects so many processes on Earth, from the reliability of solid state components on satellites, to electric power grids, to the orbital lifetime of low Earth orbit satellites, etc., such information is important to the DoD in general, and to the USAF in particular. The specific components of this study were three different tasks. The first consisted in developing an empirical forecasting scheme based on general but sound physical principles whose only objective was to provide the timing and magnitude of the following activity maximum both half a cycle and, hopefully, one and a half cycle in advance. The second task involved a realistic modeling of the magnetized flow in the solar convective envelope with the ultimate objective of producing a dynamo model sufficiently solid to allow detailed forecasting of the behavior of future cycles. The third task involved partial support for the development of the Solar Disk Sextant, a space-borne experiment which measures variations of the size and shape of the Sun with milli arc s accuracy. (AN)

This thesis outlines the theoretical underpinnings used for the software designed to meet Detailed Technical Objectives 700-6 and 700-7 for the Space Shuttle Discovery mission STS-5 1. The primary goal was to compare state vector information produced by an on board GPS receiver and Discovery's computers, and provide real time display of the results. Because state vector information for the ORFEUS/SPAS payload was also available, relative position and rendezvous information between Discovery and ORFEUS/SPAS was made possible. Analysis of the various state vectors was used to produce a graphical display, in an operationally meaningful format, to the flight crew of Discovery. Fast relative position display and prediction, Terminal rendezvous algorithms.

The main principal of this microwave multiband phased array antenna is the use of optically controlled photonic delay line for beam forming and steering. This system is suitable for spaceborne and airborne phased array applications. it also has a potential to perform frequency hopping of transmitting signals since it is a dual band transmitter (L and X-band) and the dual band system is controlled by one set of frequency independent delay lines. The L-band (1 to 2.6 GHz) array and the X-band (8 to 12 HGz) array, each has the same physical length. Each is split into four subarrays and use a common time delay generator for each subarray on both bands. True time delay with wideband radiating elements permits large transmit and receive frequency excursions without beam wander (beam squint) as the frequency is changed, and also permits the use of wideband waveforms. The advantage also extends to both communications and surveillance applications where the beam wanders off target could occur without the use of the optically controlled true time delay beam forming and steering.

Because of their higher switching speeds, power MOSFETs are favored over power BJTs in spaceborne and military applications where size and weight are important. However, power MOSFETs are subject to degradation and failure mechanisms in radiation environments, including single event burnout, reduction of breakdown voltage, threshold shifts, and loss of current drive. This report discusses radiation-effects research in the areas of single event burnout of power MOSFETs and power BJTS, simulation of the effect of ionizing radiation on power-MOSFET breakdown voltage, charge buildup in field oxides, and 1/f noise in power MOSFETS. A model for single event burnout is presented and structural changes to reduce susceptibility are provided. A simulation tool for designing high-voltage termination structures is presented and applied to field-ring and field-plate terminations. Guidelines to minimize breakdown-voltage degradation are given. A method of correlating charge buildup in field oxides to that in test devices is discussed. The use of 1/f noise as a radiation-effects characterization tool in power MOSFETs is examined. This work is intended to: (1) facilitate selection of appropriate power MOSFETs for radiation environments and (2) provide design techniques to improve the radiation hardness of power MOS FETs.... Power MOSFETs, Radiation Effects, 1/f Noise in MOSFETs, Single Event Burnout, Simulation of Power MOSFETs, Breakdown Voltage.

Complexity of future manned space flight mission control can be significantly reduced by integrating GPS, the PTTI source, into telemetry, tracking and command (TT&C). Future telecommunications, space tracking electronic intelligence, metrology, navigation, and data acquisition will thereby be sewed, including: (1) On-board ephemeris determination, (2) Reduced synchronization time for time division muUiple access (TDMA) links, and (3) In-flight clock calibration, increasing on-board autonomy and reducing ground support costs. Manned space transportation through the first quarter of the 21st century will probably depend on a mix of vehicles, including the Advanced Manned Launch System (AMLS), the Personnel Launch System (PLS), and continued use of the Shuttle Fleet. Precise Ephemeris is important on-board for mission success, status monitoring, also for rendezvous and docking. Use of GPS can eliminate ground based tracking/processing, enhancing autonomy and reducing communications bandwidth. GPS time can simplify complicated functions used in bandwidth efficient time division multiple access (TDMA) communications, such as: (1) Precise and real-time synchronization of receive reference timing, (2) nansmit-timing and acquisition control, (3) Unique synchronization word (UW) detection, and (4) Elastic buffering. High clock accuracy provides increased signal-to-noise (S/N) ratio during acquisition, permitting narrower acquisition frequency and time windows. Spaceborne systems requirements to provide capabilities such as: (1) Refinement of the GEM-72 gravity model based on satellite tracking observations from ATS-6 to GEOS-3, (2) Relativistic clock experiments, (3) NASA crustal dynamics program for developing space geodetic techniques to study the earth's crust, its gravity field, and earthquake mechanisms, and (4) Multi-disciplinary space geodetic tracking for studying global climatic changes are also reviewed., See also ADA267301. Presented at the Annual Precise Time and Time Interval (PTTI) Applications and Planning Meeting (24th) Held in McLean on VA, 1-3 Dec 1992.

The Lecture Series will cover the field of airborne and spaceborne SAR with respect to its technical realisation in order to convey the participants' ideas and know-how on SAR, on its capabilities and on the technology necessary for the successful construction and application of airborne and spaceborne SAR systems. The basic principles of SAR will be explained and SAR will be compared to airborne and spaceborne radar with real aperture. The influence of the antenna parameters on specification and capabilities of SAR and the advantages, necessities and limits will be considered. Digital SAR processing Is indispensible for SAR. Theories and special algorithms will be given along with basic processor configurations and different processing techniques on a hardware and software basis. The simulation of SAR-systems as well as SAR-products will also be a topic of the Lecture Series. A presentation of the present state of the art, giving examples of presently planned and realised airborne and spaceborne SAR with its foreseen applications will conclude the Lecture Series. This Lecture Series, sponsored by the Avionics Panel of AGARD, has been implemented by the Consultant and Exchange Programme.

The Ada implementation described above was tested according to the Ada Validation Procedures Pro90 against the Ada Standard Ada83 using the Current Ada Compiler Validation Capability (ACVC). This Validation Summary Report (VSR) gives an account of the testing of this Ada implementation. For any technical terms used in this report, the reader is referred to Pro90.

For the calibration of air- and spaceborne radars commonly used in remote sensing a PARC(Polarimetric Active Radar Calibrator) can be used. This report presents measurement results of the radar cross section, crosstalk level etc. Of a PARC developed at TNO-FEL the results are used to infer guidelines for the use of this PARC. Remote sensing, Polarimetric active radar calibrator, Radar, Calibration, Antenna polarization.

This report summarizes results of a basic research program to investigate and develop advanced techniques for obtaining and applying meteorological parameters from spaceborne lidars. The focus of this program was to identify potentially inexpensive lidar sensor concepts which provide maximum paybacks in improvements to numerical weather prediction (NWP) model performance. As the result of a trade-off of potential lidar systems for measuring meteorological parameters such as temperature, moisture, and winds, it was determined that maximum payback for NWP could be achieved by improving the accuracy and coverage of wind observations. Since they will be available from a polar orbiter, coverage will be increased, especially for extratropical areas. The lidar will produce winds wherever there is a cloud and will likely provide boundary layer winds from maritime aerosol backscatter. The assessment of the impact of candidate satellite lidar observation concepts on numerical weather analysis and prediction models was performed through a series of observing system simulation experiments (OSSEs). In addition to NWP model impacts, the fusion of potential lidar sensor system data with that from the current Defense Meteorological Satellite Program (DMSP) suite of passive sensors was considered. Special emphasis was placed on investigating active/passive data fusion approaches for improving the retrieval of atmospheric temperature and moisture profiles and the analysis of clouds (i.e. nephanalysis) in support of tactical and strategic operations.

The National Aeronautics and Space Administration (NASA) is undertaking one of its most ambitious projects ever-Space Station Freedom. As part of this effort, NASA has started developing computer software that will drive the station's 10 main on-board computer systems. This software will perform critical functions ranging from keeping the station in its proper orbit to maintaining life support of the crew. In contrast with the space shuttle, software development for the station will be highly dispersed, with three prime contractors and scores of subcontractors across the country developing millions of lines of computer software code. This software is meant to last for the station's entire life-three decades. Given the risks inherent in such a large, complex undertaking, the House Committee on Science, Space, and Technology asked GAO to determine (1) if independent verification and validation techniques are being used to ensure that critical software meets specified requirements and functions; (2) if NASA has incorporated software risk management techniques into the program; (3) whether standards are in place that will prescribe a disciplined, uniform approach to software development; and (4) if software support tools will help, as intended, to maximize efficiency in developing and maintaining the software., Report to the Chairman, Committee on Science, Space and Technology, House of Representatives.

We examine the system design issues associated with the use of adaptive jammer rejection in the context of possible specifications for a space- based surveillance radar. We show that the adaptive nulling requirements of the system cannot be considered in isolation. Adaptive processing has implications for the entire system, from design of the antenna array, through to the choice of ADCs and the requirements of subsequent coherent integration and detection processing. Three different classes of adaptive processing architecture are considered: the sidelobe canceller, the fully adaptive array, and the generalized sidelobe canceller. These are shown to achieve different trade-offs between inherent complexity, requirements upon the system specification, flexibility and performance.

Our existing Sky Model for the point source infrared sky is extended to make predictions for any filter lying wholly within the range 2, 0 to 35.0 microns. To support this extension we have developed a library of complete 2-35 microns low-resolution (0.1 micron step size) spectra to represent the 87 categories of Galactic object and 4 types of extragalactic source implicit in the Model. This library is based upon the technique of the spectral template whereby existing spectral fragments for individual sources (from ground-based, airborne, and satellite-borne instruments) are combined into complete spectra. Templates provide a natural way of representing the complete spectral energy distributions of celestial sources for which only infrared photometry or partial spectroscopy exists, provided that such sources can be classified by the scheme inherent in the Sky Model which is essentially based upon the combination of optical and mid-infrared attributes. Consequently, templates bear upon the important general problem of establishing mid-infrared calibration sources. The new Model is validated by comparison with broadband K (2.2 microns) source counts.

A study conducted previously at the Space Physics Research Laboratory, University of Michigan (Hays et al., 1988) has concluded that measurement of the spectral intensity of the O sub 2 atmospheric band is the most feasible technique. The basic determination of the temperature can be accomplished using the optically thin transition from O sub 2(Sigma1) to O sub 2(Sigma3) in the (0-1) band; here local atmospheric temperature is determined uniquely by the rotational development of the emission band since the band is in the thermal dynamic equilibrium. The density of molecular oxygen is determined from the (0-0) band of the same system; here self absorption by molecular oxygen is responsible for a reduction in intensity of the stronger lines in the system. This remote sensing technique has been proven to be feasible by rocket spectroscopic measurements during this funding period. This report describes the remote sensing techniques and the optical instrument used. The results obtained from the rocket experiment are presented with evaluation of the magnitude of all the possible sources of error. A conceptual design of the instrument to implement this remote sensing technique from a satellite platform is also prepared which identifies the major hardware elements required.

We have simulated the wind measurements which might be obtained from a low power doppler wind lidar (DWL) sensor. Wind profiles obtained from such an instrument will not be as complete as those expected from planned higher energy sensors (e.g.LAWS), with measurements only from cirrus clouds, the tops of other clouds, and from marine boundary layer aerosol. The potential impact of such a scaled down DWL system has been assessed by inserting the simulated measurements into the Air Force Phillips Laboratory Global Data Assimilation System (GDAS). Results from the observing system simulation experiment (OSSE) indicate that significant improvement in the analysis and forecast of geopotential height, horizontal wind, and relative humidity may be expected in the southern hemisphere extratropics. Comparison of impacts with those obtained in a previously conducted OSSE which assumed a full blown DWL instrument (WINDSAT) indicate that the low energy lidar yields improvements which are 1/2 to 3/4 magnitude of improvements with WINDSAT. Thus, if the development cost of a simple lidar is found to be substantially less than a LAWS-type sensor, such an instrument may warrant consideration in the planning of future space-based observing systems.

This report describes the first year efforts to develop a miniature, high speed superconducting bearing system suitable for cryogenic turbomachines such as miniature turboexpanders used in spaceborne cryocoolers for surveillance sensors. A bearing breadboard was designed, fabricated, and tested to a rotational speed of 450,000 rpm. Numerical models were developed to predict levitation focus between superconductors and permanent magnets, and validated with experimental data. The design of the turbomachine was initiated, including the conceptualization of a novel bearing system.

A review of the principles of spaceborne Synthetic Aperture Radar (SAR) is given, and its application in the maritime environment is discussed, with reference to several specific systems. The requirement for calibration is discussed, as are some of the more advanced techniques expected to be incorporated in future missions. The paper was written as a dissertation submitted in partial fulfillment of the requirements for the award of an MSc degree in Microwave Solid State Physics undertaken in the Department of Applied Physics and Physical Electronics, University of Portsmouth., Original contains color plates: All DTIC/NTIS reproductions will be in black and white.

This paper gives an overview over the field of airborne MTIsystems (AMTI). For introduction, the problems of airborne MTI is pointed out. Well-known techniques such as conventional MTI and DPCA (displaced phase center antenna) are briefly described. Then the authors give a prospective view of future AMTI-techniques, including an overview of their own work on novel algorithms (TASTE = Techniques for Airborne Slow Target Extraction). Although airborne radar is particularly addressed in this paper, the results may, with some modifications, be applied to other moving sensor configurations, such as active sonar, spaceborne radar, and Synthetic Aperture Radar (SAR). The paper is intended to be tutorial and gives an overview over the state of the art in AMTI techniques. Readers interested in more details are referred to the references given below., This article is from Target and Clutter Scattering and Their Effects on Military Radar Performance (Diffraction par les Cibles et le Fouillis et ses Effets sur les Performances des Radars Militaires ), AD-A244 893, p18-1 thru 18-7.

This report presents the results of research carried out by Space Computer Corporation under the U.S. government's Small Business Innovation Research (SBIR) Program. The work was sponsored by the Strategic Defense Initiative Organization and managed by the Office of Naval Research under Contracts N00014-87-C-0801 (Phase I) and N00014-89-C-0015 (Phase II). The basic purpose of this research was to develop and demonstrate a new approach to the detection of, and initiation of track on, moving targets using data from a passive infrared or visual sensor. This approach differs in very significant ways from the traditional approach of dividing the required processing into time dependent, object-dependent, and data-dependent processing stages. In that approach individual targets are first detected in individual image frames, and the detections are then assembled into tracks. That requires that the signal to noise ratio in each image frame be sufficient for fairly reliable target detection. In contrast, our approach bases detection of targets on multiple image frames, and, accordingly, requires a smaller signal to noise ratio. It is sometimes referred to as track before detect, and can lead to a significant reduction in total system cost. For example, it can allow greater detection range for a single sensor, or it can allow the use of smaller sensor optics. Both the traditional and track before detect approaches are applicable to systems using scanning sensors, as well as those which use staring sensors.

The most successful approaches to both machine target recognition and robot arm manipulation have been those where tasks are completely pre-specified. In such systems there is little room for deviations in robot path motion or target location and orientation. A novel approach to robotic implementation such as spaceborne assembly of SDI platforms are too difficult for existing robots because random occurrences and large numbers of external variables preclude the complete specification of tasks off-line. The proposed system has strong adaptability due to the following innovations: Registered video and range laser radar sensing (i.e.,a one-to-one correspondence between visual and range data). This allows fast, accurate 3D target recognition as part of an autonomous CAD model based recognition system for Phase II, or as input to teleoperator control in Phase I. Closed loop range and video feedback for grasper guidance using the pose matching concept where target and grasper are both in the field of view, and CAD derived track points are used for position and orientation error signals. Adaptive control systems; Manipulators; Computer aided design; Computer vision/recognition; Data bases; Optical radar tracking., Original contains color plates: All DTIC and NTIS reproductions will be in black and white.