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Resolution 91-7-F - Student Picket To Support President Meredith, Wku Student Government Association
Resolution 91-7-F - Student Picket To Support President Meredith, Wku Student Government Association
Student Government Association
Resolution in support of President Meredith's contract being renewed by the Board of Regents.
Resolution 91-5-F - Vacuum Cleaners For Residence Halls, Wku Student Government Association
Resolution 91-5-F - Vacuum Cleaners For Residence Halls, Wku Student Government Association
Student Government Association
Resolution to provide vacuum cleaners for student use in each dormitory.
Resolution 91-3-F - Freshman Council, Wku Student Government Association
Resolution 91-3-F - Freshman Council, Wku Student Government Association
Student Government Association
Resolution to create a freshman council.
Resolution 91-2-F - Modified Shuttle Fare, Wku Student Government Association
Resolution 91-2-F - Modified Shuttle Fare, Wku Student Government Association
Student Government Association
Resolution requesting change in Big Red Shuttle fees.
Resolution 91-4-F - Student Health Service, Wku Student Government Association
Resolution 91-4-F - Student Health Service, Wku Student Government Association
Student Government Association
Resolution to increase student health fee in order to provide basic health care for students.
Resolution 91-8-F - Soap Dispensers In Residence Hall Bathrooms, Wku Student Government Association
Resolution 91-8-F - Soap Dispensers In Residence Hall Bathrooms, Wku Student Government Association
Student Government Association
Resolution requesting the installation of soap dispensers in dormitory restrooms.
Surfsat: Supporting Deep-Space-Network Research And Development With A Student-Designed Small Satellite, Jonathan Chow
Surfsat: Supporting Deep-Space-Network Research And Development With A Student-Designed Small Satellite, Jonathan Chow
Small Satellite Conference
SURFSAT is a small satellite designed primarily by students at the California Institute of Technology under Caltech's Summer Undergraduate Research Fellowship (SURF) program and is sponsored by the Telecommunications and Data Acquisition Office at JPL, the research and development arm for the Deep Space Network (DSN). The project was initiated in the summer of 1987 and has involved several dozen undergraduate students. SURFSAT is designed to radiate at either the milliwatt or microwatt level in four bands: Sband (2.29 GHz), X-band (8.45 GHz), Ku-band (15.33 GHz) and Ka-band (32 GHz). The signals will be received by a new 34-meter DSN …
A Comparison Of Digital Modulation Methods For Small Satellite Data Links, Daniel Mulally, Don Lefevre
A Comparison Of Digital Modulation Methods For Small Satellite Data Links, Daniel Mulally, Don Lefevre
Small Satellite Conference
The selection of a good modulation scheme for a satellite data link should involve careful consideration of several factors. Bit-error-rate (BER), initial cost, power consumption, circuit complexity, channel linearity, reliability, and bandwidth must be considered and weighed in the selection process. This paper examines and compares various modulation methods applicable to small satellite data links. The performance of frequency-shift keying (FSK), bi-phase-shift keying (BPSK), quadrature-phase-shift keying (QPSK), offset QPSK (OQPSK), minimum-shift keying (MSK), and on-off keying (OOK) are compared. The use of a non-linear transmitter amplifier is normally desirable because of its power efficiency. Because of this, a near constant …
Tracking Small Satellites Using Translated Gps, Don Lefevre, Daniel Mulally
Tracking Small Satellites Using Translated Gps, Don Lefevre, Daniel Mulally
Small Satellite Conference
This paper discusses using translated GPS for tracking small satellites, the technical trade-offs involved, and the position and timing accuracies which are achievable using translated GPS. The Global Positioning System (GPS) uses the relative times-of-arrival of multiple spread-spectrum signals at an antenna to determine the position of the antenna. The system can also determine the time the antenna was at that position. The direct sequence spread spectrum signals are transmitted from GPS satellites whose orbital position and timing (the ephemeris data) are accurately known. Once the GPS signals are received at the antenna, their relative timings are fixed, and are …
Earth-Space Leosat Communication Using Optical Frequencies, Kenneth Baker, Timothy Pratt
Earth-Space Leosat Communication Using Optical Frequencies, Kenneth Baker, Timothy Pratt
Small Satellite Conference
This paper introduces the concept of a high bit rate burst type communications system as a means of increasing the communications throughput on LEO spacecraft. The discussion concerns the use of optical frequencies due to the decrease in size, weight and prime power of LEO satellite communication packages at these wavelengths. The penalty is an increase in pointing and tracking complexity. An example link design is presented.
Soesat Low Cost Telemetry Ground Station, David Horton
Soesat Low Cost Telemetry Ground Station, David Horton
Small Satellite Conference
The School Of Engineering SATellite (SOESAT) will be fabricated and donated by American-Microsat Inc. of Sunnyvale, California. SOESAT will carry a radiation sensor that will measure the secondary emission internal to the satellite caused by the impinging of external primary radiation. At the time of this abstract SOESAT has not been manifested on a launch vehicle. A fourth quarter '92 launch into a geotransfer orbit on a European Space Agency Ariane is being investigated. Low earth orbit launch alternatives on various boosters are also being investigated. Command and control of SOESAT will be accomplished using the telemetry ground station built …
Spaceborne Application Multiprocessor Operating System, Gary Grisbeck, Wesley Webber
Spaceborne Application Multiprocessor Operating System, Gary Grisbeck, Wesley Webber
Small Satellite Conference
Control Data Corporation, as part of a joint development program with the Boeing Electronics Company, built a nine node, three active module multiprocessor called SPA-l or Spaceborne Processor Array-I. (SPA was the processing system concept proposed as the heart of a multi-mission autonomous surveillance satellite in a paper presented at the 4th Annual AIAA/Utah State Small Satellite Conference in 1990). Since then, an operating system called the Operational Kernel, or OK, has been completed, tested, and functionally validated in a demonstration using the SPA-l. This demo featured fully autonomous on-board control of data movement, fault detection, fault isolation, hardware reconfiguration, …
Single Event Upset Error Protection For Solid State Data Memory On Microsatellites, M.S. Hodgart, C.I. Underwood, J.W. Ward
Single Event Upset Error Protection For Solid State Data Memory On Microsatellites, M.S. Hodgart, C.I. Underwood, J.W. Ward
Small Satellite Conference
Many microsatellite missions rely upon large arrays of CMOS static RAM for data storage. Even a satellite with strict power and volume limitations can carry several Mbytes of SRAM. Experience has shown that these memory arrays are useful for scientific data collection image storage, store and- forward message switching and spacecraft telemetry monitoring. This paper describes the authors' design and implementation of error protection codes which protect large CMOS RAM arrays from radiation-induced single event upsets.
Protocols For Store-And-Forward Message Switching Via Microsatellites, J.W. Ward, H.E. Price
Protocols For Store-And-Forward Message Switching Via Microsatellites, J.W. Ward, H.E. Price
Small Satellite Conference
The authors have developed a suite of protocols specifically optimized for use on store-and-forward microsatellite communications missions. The protocols support networks in which user terminals directly access the store-and-forward satellite to transfer electronic mail. The authors' PACSAT Protocol Suite includes a message format standard, a virtual-circuit directory and file transfer service, and a datagram based point-to-multipoint "broadcast" protocol. An implementation of this suite has been operating on the UoSAT-3 PACSAT Communications Experiment (PCE) for twelve months and on the AMSAT Microsats for seven months. During this period, hundreds of small and medium-sized ground terminals in all parts of the world …
Dataware; A Graphical Approach For Decoding And Displaying Small Satellite Data And Telemetry, George Starcher
Dataware; A Graphical Approach For Decoding And Displaying Small Satellite Data And Telemetry, George Starcher
Small Satellite Conference
Today's small satellites are capable of producing vast quantities of data from experiments and engineering telemetry. The requirements of the small satellite operator define how science and engineering data is treated. The small satellite operator typically does not have the financial resources for a worldwide network of downlink ground stations. These constraints require that the satellite's status must be ascertained within a relatively short window during a pass over a single or a few ground stations. Any anomalous operation needs to be quickly identified so that corrective action may be taken. In addition, the satellite operator is often the end …
Optical Processing Of Microwave Signals For Small Satellite Payloads, Dan Sullivan
Optical Processing Of Microwave Signals For Small Satellite Payloads, Dan Sullivan
Small Satellite Conference
For low altitude small satellite applications performing electronic surveillance or communication transponding missions highly capable payloads are needed. Generally these spacecraft have low dwell times over the areas of interest and must receive, or search for, signals over a wide frequency band. This paper presents an approach to the implementation of optical processing in complex electronic systems intended to receive and operate on multiple radio frequency (or microwave) signals. The goal is to exploit the rapidly expanding field of linear and nonlinear optics to synthesize transponders and receiving systems for satellites and other platforms. The inputs are assumed to be …
Autonomous Data Acquisition Using The Actel 1020 Fpga, Ron Novick
Autonomous Data Acquisition Using The Actel 1020 Fpga, Ron Novick
Small Satellite Conference
The Actel 1020 Field Programmable Gate Array (FPGA) is a low power CMOS device equivalent to 2000 logic gates. It is a one-time programmable device utilizing non-volatile PLICETM anti-fuse programming. The 2-micron, two level metal CMOS process has been tested Rad Hard to 400K Rad total dose Si making it suitable for space applications. In the Barnes Dual Cone Scanner Earth Horizon Sensor, it has been used (with an A/D converter) to autonomously sample radiance data and store it in pseudo-dual port memory. The Actel chip is also used to control bus access to the memory. The Barnes implementation replaces …
Space Science And Microsatellites - A Case Study Observations Of The Near-Earth Radiation Environment Using The Cosmic-Ray Effects And Dosimetry (Credo) Payload On-Board Uosat-3, C.J. Underwood., J.W. Ward, C.S. Dyer., A.J. Sims, J. Farren, J. Stephen
Space Science And Microsatellites - A Case Study Observations Of The Near-Earth Radiation Environment Using The Cosmic-Ray Effects And Dosimetry (Credo) Payload On-Board Uosat-3, C.J. Underwood., J.W. Ward, C.S. Dyer., A.J. Sims, J. Farren, J. Stephen
Small Satellite Conference
The University of Surrey's technology demonstration microsatellite: UoSAT-3 launched in January 1990. carries on-board a Cosmic-Ray Effects and Dosimetry (CREDO) payload for characterizing the low-Earth orbit (LEO) radiation environment. Measurements made with this payload are correlated with radiation effects observed in the spacecraft's microelectronics, in particular, the occurrence of single event upsets (SEUs) in solid-state memory devices. The CREDO payload consists of two Sub-systems, the Cosmic Particle Experiment (CPE) and the Total-Dose Experiment (TDE). The CPE houses an array of large-area PIN diode detectors, connected to a pulse-height analysis network. Particles incident on the detector are counted and logged according …
A Spacecraft Computer For High-Performance Applications, John Stone, Joseph Kroesche
A Spacecraft Computer For High-Performance Applications, John Stone, Joseph Kroesche
Small Satellite Conference
A high-performance processor circuit called the SC-3 has been developed to meet the requirements of advanced experiment and attitude control applications. It is based on the 16 MHz Intel 80386/80387 chip set and implements a dual bus system configuration which allows high-speed, 32-bit wide memory and low-speed. 16-bit wide Input Output(I/O) circuits to be separated. This separation maintains compatibility with a wide range of current I/O circuit designs while exploiting the high-bandwidth memory access capabilities of the 80386. Performance is further enhanced by means of a cache on the 32-bit bus. Gibson, Whetstone, and Dhrystone instruction mixes have been used …
Brem-Sat Attitude Control At Low Altitudes, Hans Koenigsmann, H. Rath, H. Oelze, A. Ginatii
Brem-Sat Attitude Control At Low Altitudes, Hans Koenigsmann, H. Rath, H. Oelze, A. Ginatii
Small Satellite Conference
The German University satellite BREM-SAT (scheduled for launch in early 1993) carries two experiments which require attitude control down to 150 km altitude and aerodynamic stabilization between 150 and 100 km altitude. These contradicting requirements and new ways to change the satellite's attitude and to keep it stable and controlled at very high disturbance torque levels. Complex numerical attitude simulation has shown the feasibility to maintain the required attitude with a momentum wheel and a single torque coil down to 150 km when optimized algorithms are used. To achieve the aerodynamic stabilization, the momentum wheel has to be ejected and …
Flexible Booms, Momentum Wheels, And Subtle Gravity-Gradient Instabilities, J.W. Hunt, J.C. Ray
Flexible Booms, Momentum Wheels, And Subtle Gravity-Gradient Instabilities, J.W. Hunt, J.C. Ray
Small Satellite Conference
A gravity-gradient boom and a momentum wheel provides a passive, three-axis attitude control system for a small satellite requiring 10° Earth-oriented pointing In a low Earth orbit. The Polar BEAR satellite Is a small satellite using just such a system that has experienced unexpected attitude instabilities during some of Its full-sun orbit periods. This paper examines the attitude dynamles and disturbances associated with gravlty-gradientlmomentum-wheel systems In an attempt to identify potential destabilizing mechanisms common to the configuration. Polar BEAR is not the only such configuration to experience problems In full sun. and several other examples are briefiy discussed. Although we …
A Deployable Stiffened Biconvex Mast, Nancy Holt, Emery Reeves
A Deployable Stiffened Biconvex Mast, Nancy Holt, Emery Reeves
Small Satellite Conference
Deployable structures are a common spacecraft configuration feature. Deployables are used to configure spacecraft inertia properties, provide expanded antenna aperture and solar array area, or to provide separation between spacecraft components. Lightsat design would be especially enhanced by small size lightweight deployable structures. A review of the state of the art of deployable structures has been conducted and shows that these devices can be divided into two categories: one, rollable mast of the stem, bistem, or stacer types; and two, folding trusses. The rollable masts are generally of open section and susceptible to thermal excitation. Folding trusses are not available …
The Commandable Rate Scanner: Precision Attitude Sensing For Spinning Spacecraft, David Skulsky
The Commandable Rate Scanner: Precision Attitude Sensing For Spinning Spacecraft, David Skulsky
Small Satellite Conference
High performance Earth sensing for spin-stabilized vehicles can be achieved through a straightforward modification to a flight-proven conical Earth horizon sensor. The necessary hardware and therefore, cost and weight is essentially identical to hardware used by three-axis stabilized satellites making precision attitude sensing available to the entire spacecraft community, including small satellite builders. The Barnes Engineering Commandable Rate Scanner uses a rotating sensor on a spinning spacecraft to provide full-sky (4x steradian) Earth coverage with a single sensor. The sensor provides data for any spacecraft attitude and altitude from LEO to above GEO. In LEO, a data rate of several …
Electrical, Electronic, And Electro-Mechanical Parts For Space Flight Use, A Review, Gerard Kiernan
Electrical, Electronic, And Electro-Mechanical Parts For Space Flight Use, A Review, Gerard Kiernan
Small Satellite Conference
This paper will review the various philosophies (e.g., established reliability, Class S) used in developing the military and NASA specifications for the various types of electrical, electronic, and electromechanical parts. The paper will show how the specification requirements can be combined with applications guidelines, such as derating tables given in various NASA and military documents, to choose appropriate parts to meet the reliability goal of the particular space flight project.
The Webersat Camera: An Inexpensive Earth Imaging System, Stephen Jackson, Jeffrey Raetzke
The Webersat Camera: An Inexpensive Earth Imaging System, Stephen Jackson, Jeffrey Raetzke
Small Satellite Conference
WEBERSAT, a 27 pound LEO satellite launched by the Ariane 40 on January 21, 1990 into a 500 mile polar orbit, carries several payload experiments that were developed as a learning experience for engineering students at Weber State University. The experiments include a modified color CCD camera and video flash digitizer. Operational command and control of the spacecraft and its payloads is performed by students in the College of Applied Science & Technology, from a ground station located on the WSU campus. Here, the students and their advisor's monitor on-board systems, plan & execute experiments, and observe test results. This …
Sedsat 1 Advanced Photovoltaic Power System Technology Demonstration Flight, Dennis Wingo, Cheryl Bankston, Steve Tesney, Namsoo Kim, Ronald Gale
Sedsat 1 Advanced Photovoltaic Power System Technology Demonstration Flight, Dennis Wingo, Cheryl Bankston, Steve Tesney, Namsoo Kim, Ronald Gale
Small Satellite Conference
The University of Alabama in Huntsville Students for the Exploration and Development of Space, in cooperation with the NASA Marshall Space Flight Center, Boeing Defense & Space, and the Kopin Corporation, are designing an advanced electrical power system for a small satellite. This system incorporates recent advances in three areas: photovoltaic cell design, battery energy storage design, and DC·DC power conversion technology. Introducing these advances into a flight power system will produce a satellite power system with double the capability of similar systems utilizing current technology.
Yaw Control - A Simple Way To Enhance Solar Array Performance, Emery Reeves
Yaw Control - A Simple Way To Enhance Solar Array Performance, Emery Reeves
Small Satellite Conference
Solar cell arrays are used on substantially all earth orbiting spacecraft to produce electric power. Solar arrays are of three geometric types: planar, cylindrical, and omnidirectional oriented planar arrays have a geometric efficiency (ratio of solar energy capture area to total array area) of one and are used on most large spacecraft. Cylindrical arrays which have a geometric efficiency of l/π are common on spinners while most small spacecraft including those that are earth pointed use omnidirectional arrays which have a geometric efficiency of only 1/4. An earth oriented spacecraft with a body fixed planar array can achieve a geometric …
Common-Pressure-Vessel Nickel-Hydrogen Battery Development, Burton Otzinger, James Wheeler
Common-Pressure-Vessel Nickel-Hydrogen Battery Development, Burton Otzinger, James Wheeler
Small Satellite Conference
The dual-cell, common-pressure vessel, nickel-hydrogen configuration has recently emerged as an option for small satellite nickel-hydrogen battery application. An important incentive is that the dual-cell, CPV configured battery presents a 30 percent reduction in volume and nearly 50 percent reduction in mounting footprint, when compared with an equivalent battery of individual pressure- vessel (IPV) cells. In addition energy density and cost benefits are significant. Eagle-Picher Industries and Rockwell International have collaborated on the development and test evaluation of a 40 Ampere-hour, nickel-hydrogen, dual-cell, CPV battery module. The module was committed to a cycle life test in Rockwell's advanced battery test …
Six Channel Spaceborne Gps Receiver, Richard Sfeir, Roger Weninger
Six Channel Spaceborne Gps Receiver, Richard Sfeir, Roger Weninger
Small Satellite Conference
Rockwell International Corporation is developing a lightweight, compact GPS receiver for low earth-orbiting space vehicles. The effort is sponsored by the Defense Advanced Research Projects Agency (DARPA) and monitored by the Air Force Phillips Laboratory. Three flight receivers are scheduled for delivery prior to the end of CY 1991. The first receiver will fly on a technology for autonomous operational survivability satellite planned for launch in 1992. The receiver has six channels that continuously track four primary GPS satellites and sequentially acquire and track all other visible and healthy satellites on the fifth and sixth channels. It performs pseudorange and …
Miniaturized, Low-Power Parallel Processor For Space Applications, W.J. Jacobi, N.J. Teneketges, L.A. Wadsworth
Miniaturized, Low-Power Parallel Processor For Space Applications, W.J. Jacobi, N.J. Teneketges, L.A. Wadsworth
Small Satellite Conference
A miniaturized, low-power parallel processor for space applications is under development by Space Computer Corporation for DARPA's Advanced Space Technology Program. The basic goal of this project is the reduction, by an order of magnitude or more, of on-board processor weight, size and power consumption for space-based sensor systems. Our approach for achieving this goal is to use low power VLSI devices which maximize throughput per watt, together with three dimensional hybrid wafer-scale integration and packaging technology. In its prototype version, a l2-node processor will have a peak throughput greater than 1.2 GFLOPS and occupy a volume less than 15 …