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Articles 129511 - 129540 of 136246

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Remote Access Observatories In Low Earth Orbit -A Low-Cost Concept For A Small Scientific Spacecraft, Kenneth Kissell, Russell Genet, Donald Hayes, Francois Martel, Bruce Rafert Sep 1989

Remote Access Observatories In Low Earth Orbit -A Low-Cost Concept For A Small Scientific Spacecraft, Kenneth Kissell, Russell Genet, Donald Hayes, Francois Martel, Bruce Rafert

Small Satellite Conference

In parallel with the evolution of large observatory spacecraft such as the Einstein, Copernicus, and IUE, and the yet-to-be-Iaunched Hubble Space Telescope and Gamma Ray Observatory, Increasingly large ground telescopes are in construction which will allow ground astronomy to compete favorably with elaborate and expensive space systems in the quest for new discoveries. Sometimes overlooked in this pursuit of new discoveries, with the limited observational time on the space Instruments, or the oversubscribed large ground Instruments, Is the recent development of smaller, low-cost robotic ground observatories designed for routine - but vital - collection of synoptic data. High-quality stellar observations …

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Vibration Testing For Small Satellites, Delbert Wilson Sep 1989

Vibration Testing For Small Satellites, Delbert Wilson

Small Satellite Conference

Most people involved in the design and construction of small satellites are unfamiliar with vibration testing. Yet most satellites undergo vibration testing to qualify them for flight. Some familiarity with the basic aspects of vibration testing is needed to insure that a vibration test on a satellite is valid. This paper sets forth the basic equipment, practices and concepts of vibration testing. It provides guidelines for specifying a vibration test, designing fixtures, attaching instrumentation, acquiring data and data interpretation for a satellite vibration test.

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High Quality Image Compression For Rockets And Satellites, Richard Harris, Scott E. Budge, Paul Israelson, William Roark, Jan Sojka Sep 1989

High Quality Image Compression For Rockets And Satellites, Richard Harris, Scott E. Budge, Paul Israelson, William Roark, Jan Sojka

Small Satellite Conference

Installed communication systems for the more recent imagery rockets and satellites generally do not have sufficient data link bandwidth to allow imagery transmission. High quality image compression can alleviate this problem since 5 to 10 times more image data can be transmitted over existing communication systems. Researchers at Utah State University have developed a high quality image compression algorithm which has been denoted as "Statistically Lossless". This algorithm combines the good features of the well known vector quantization (VQ) compression and lossless compression. Results are presented in this paper in which different scientific imagery collection systems have been processed using …

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Qrm, Packet Satellites And Spread Spectrum, Stewart Cobb Sep 1989

Qrm, Packet Satellites And Spread Spectrum, Stewart Cobb

Small Satellite Conference

Digital messaging satellites designed for general use may attract considerable user interest. High interest will mean heavy interference on the satellite uplink channels, which could make the satellite useless. This paper discusses the characteristics of this interference, and proposes a solution using spread-spectrum technology.

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A Power-Efficient Bpsk Communications System For Small Satellites, Don Lefevre Sep 1989

A Power-Efficient Bpsk Communications System For Small Satellites, Don Lefevre

Small Satellite Conference

Many of the small satellites which have been launched or designed to date have used Frequency Shift Keyed (FSK) modulation for the communications link. FSK necessarily suffers a best-case signal to-noise ratio (SNR) loss of 3 dB for coherent demodulation. Many, if not most, of the FSK systems in use today employ non coherent demodulation which suffers additional SNR loss. This means that small satellites using FSK must use two or more times the minimum power required for the communications link. A small satellite using two watts for an FSK communications link could save at least 1 watt by using …

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Development Of The Naval Postgraduate School Solid State Data Recorder Project, Capt James O'Donnell, Ronald Phelps Sep 1989

Development Of The Naval Postgraduate School Solid State Data Recorder Project, Capt James O'Donnell, Ronald Phelps

Small Satellite Conference

Tile Naval Postgraduate School Solid State Data Recorder for space applications has been an ongoing project for the Space Systems Academic Group. Tile current status of the project is discussed, including developments in the software, redesign of the enclosure and test plans to flight certify the device. The proposed mission to test tile experiment as a Get Away Special payload aboard the Space Shuttle is also discussed.

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Performance Of Lips Iii Attitude Control System, Robert Conway, Robert Burdett Sep 1989

Performance Of Lips Iii Attitude Control System, Robert Conway, Robert Burdett

Small Satellite Conference

The LIPS III satellite is a spin stabilized sun tracking space platform who's primary mission is to test new space power sources. The attitude control system has two modes of operation, hydrazine gas jet for large attitude errors and an electromagnetic torque rod for nominal operations. The control law will be discussed and examples of inflight data will be given.

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The Tubsat-1 Attitude Control And Stabilization System, Amnon Ginati Sep 1989

The Tubsat-1 Attitude Control And Stabilization System, Amnon Ginati

Small Satellite Conference

TUBSAT-1 (Technical University Berlin Satellite) is an experimental low-cost satellite being financed by the German BMFT. The dimensions and weight are determined by the NASA Gas-Program and it will be ejected from the Space Shuttle within the German spacelab mission D2 by December 19, 1991, into a 298 km circular orbit and at a 28.5° inclination. To enable a large variety of useful experiments to fly with TUSSAT, it was necessary to develop a rather precise attitude control and stabilization (ACS) system. The ACS should be low cost, flexible (in view of changing ACS modes and parameters during the mission …

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Amsat Phase Iv Propulsion And Attitude Control Systems Conceptual Design, Doug May Sep 1989

Amsat Phase Iv Propulsion And Attitude Control Systems Conceptual Design, Doug May

Small Satellite Conference

Amateur Radio Satellite Corporation (AMSAT) is developing a satellite designated Phase IV for operation in geosynchronous orbit. Conceptual development of the primary propulsion system and the attitude and velocity control system (AVCS) is described with an approach outlined for hardware selection. A launch opportunity in Ariane will provide insertion into a transfer orbit and spin stabilization. The primary propulsion system, which will provide the orbit insertion burn only, will be designed around a Messerschmitt-Bolkow-Blohm (MBB) 400 newton engine. Two subsystems will comprise the AVCS, a momentum storage system for countering small external perturbations to maintain attitude control and a reaction …

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Power System For The Alexis Satellite, Bob Dill, Greg Huffman Sep 1989

Power System For The Alexis Satellite, Bob Dill, Greg Huffman

Small Satellite Conference

ALEXIS is a 250 Ibm satellite being built for the Department of Energy through Los Alamos National Laboratory. Its primary payload is an array of low energy x-ray telescopes. ALEXIS will be a sun pointer with a daily averaged power draw of 57 W. The ALEXIS power system provides electrical power for the operation of the various satellite subsystems including payloads, guidance and control systems, and telemetry systems. The goal of the ALEXIS power system is to provide efficient power regulation with low mass, low cost and reasonable reliability.

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Autonomous Magnetic Navigation For Earth Orbiting Spacecraft, Mark Psiaki, Francois Martel Sep 1989

Autonomous Magnetic Navigation For Earth Orbiting Spacecraft, Mark Psiaki, Francois Martel

Small Satellite Conference

The strength and orientation of the Earth's magnetic field varies as a function of the location of the observations, which means that the magnetic field measurements contains position information. Many artificial satellites carry a magnetometer on-board. The local magnetic field measurements could be used to provide navigation information. Such a navigation method has the advantage of requiring only data from low cost on-board instruments and has applications in low budget operation of satellite systems. Furthermore if processing can be performed on-board, this method leads to the possibility of fully autonomous long term navigation. In many systems magnetic navigation could be …

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Small Satellite Power System Design, Abbas Salim, George Dakermanji Sep 1989

Small Satellite Power System Design, Abbas Salim, George Dakermanji

Small Satellite Conference

Recently, there has been extensive interest in Special Purpose Inexpensive Satellite’s (SPINSAT) that perform cost effective space oriented missions. Reduced reliability and short delivery schedules are two key issues relating to the design of such satellites for minimizing acquisition costs. These issues are important factors in the design of a spacecraft power system which can be considered to be the heart of the entire satellite. The power system constitutes a substantial portion of the overall satellite system cost that must be reduced for SPINSAT missions. Minimum cost or inexpensive satellite implies prudent power system design with minimal redundancy, inexpensive energy …

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Meeting Minutes, Wku Student Government Association Sep 1989

Meeting Minutes, Wku Student Government Association

Student Government Association

Meeting to discuss elections, master plan committee, campus improvements and legislation.

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The Insurance Climate For Small Satellites And Elvs, Peter Stark Sep 1989

The Insurance Climate For Small Satellites And Elvs, Peter Stark

Small Satellite Conference

The space insurance industry provides coverage for physical damage and liability risks to which space ventures are exposed as part of their business. The Insured party obtains insurance coverage through a Broker, who represents the Insured in soliciting coverage from the various Insurers in the world market. Physical damage insurance is designed to cover the value of an asset or the revenue it may provide, while liability insurance covers damage to the person or property of parties unrelated to those involved in launch activities. Under the Commercial Space Act of 1988, U.S. commercial ELV operators are required to obtain a …

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Amsat-Na Phase Iv Project Lessons In Distributed Engineering, Dick Jansson Sep 1989

Amsat-Na Phase Iv Project Lessons In Distributed Engineering, Dick Jansson

Small Satellite Conference

The academic year 1988-89 has provided AMSAT with some really new experiences in engineering and fabricating a moderately large "small satellite". While most of the AMSAT engineering forces were engaged in a truly small "small satellite" - the Microsat Project - a few of us have been engaged in the Phase IV project in conjunction with Weber State College, a new working environment for AMSAT. This experience has provided us with insights on what kinds of tasks that we can expect to assign and be completed. We know that the basic planning, task descriptions, people interfaces and organizational interfaces are …

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Naval Postgraduate School Petite Amateur Navy Satellite (Pansat), Daniel Sakoda Sep 1989

Naval Postgraduate School Petite Amateur Navy Satellite (Pansat), Daniel Sakoda

Small Satellite Conference

The Naval Postgraduate School's (NPS) Space Systems Academic Group (SSAG) is designing and developing a small communications satellite. The objectives of PANSAT are three-fold. First, PANSAT will provide an ideal educational tool for the officer students at NPS supporting Space Systems Engineering and Space Systems Operations with hands-on hardware development. Secondly, the satellite will provide digital store-and-forward communications, or Packet Radio, for the amateur radio community. The third objective is to provide a low-cost, space-based platform for small experiments. PANSAT will be launched into Low Earth Orbit (LEO) for NPS coverage. The satellite weight is 150 lbs. Since there is …

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Microsat: A New, Small Satellite Bus Concept, Courtney Duncan Sep 1989

Microsat: A New, Small Satellite Bus Concept, Courtney Duncan

Small Satellite Conference

The Radio Amateur Satellite Corporation of North America (AMSAT-NA) is pioneering a new, small satellite bus concept known as "Microsat." The product is roughly a nine inch cube, exclusive of antennas, with five sub-assemblies. Four are standard: radio transmitter(s), radio receiver(s), power system, and onboard computer. The fifth module is reserved for payload or special application hardware. Design goals dictate that the cost of the satellites and the cost and complexity of ground terminals be minimized. Satellite software is also standardized. Applications can be prototyped on common personal computers. The four development Microsats will be in the Amateur Radio Service. …

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The Spinsat Bus: New And Old In A Small Package, Donald Mcmillen, Kurt Krabbe Sep 1989

The Spinsat Bus: New And Old In A Small Package, Donald Mcmillen, Kurt Krabbe

Small Satellite Conference

The SPINSAT Bus is a three axis stabilized, light weight, inexpensive spacecraft capable of orbit changing (elliptic to circular, co-planar, plus inclination adjustment), orbit maintenance (altitude adjustment to assure ground trace repeatability) and, in final operational orbit, accurate earth pointing (± 0.5 degrees). The Bus also provides thermal control, telecommunication, data storage and electrical power for modest sized payloads to perform a variety of low-earth orbit (LEO) missions of up to three years duration. The baseline Bus version is a cylindrical shape (914.4 mm [36 inch] diameter by 902.2 mm [35.52 inch] height). The outer surface is covered with solar …

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Nasa Standard Gas Can Satellite, Patrick Cudmore, W. Mcintosh, M. Edison, S. Nichols, E. Mercier, J. Wise, A. Mangassarian Sep 1989

Nasa Standard Gas Can Satellite, Patrick Cudmore, W. Mcintosh, M. Edison, S. Nichols, E. Mercier, J. Wise, A. Mangassarian

Small Satellite Conference

This paper describes a new direction in small low cost spacecraft. This 150 pound satellite provides access to conduct experiments in space on an economical and short term basis. It can be used by commercial as well as scientific institutions. Currently called the XSAT, it was developed by NASA in cooperation with Defense Systems Inc. (DSI) of McLean, Virginia. XSAT provides for experimental payloads up to 50 pounds, 50 watt hours per day, one megabyte data storage, three day command memory and packetized protocol. Structural and thermal designs can handle worst case loads of the STS manned launch vehicle. XSAT …

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A Single Geostationary Satellite For Mobile Terrestrial Transmitter Tracking, Chris Le Marshall, Donald Mcmillen, Robert Twiggs Sep 1989

A Single Geostationary Satellite For Mobile Terrestrial Transmitter Tracking, Chris Le Marshall, Donald Mcmillen, Robert Twiggs

Small Satellite Conference

This paper will describe the Energetics Satellite Locating Service (ESLS) which is a unique, patented, proprietary satellite based geolocation system. This system called SAT/TRAC for Satellite Tracking, Ranging and Communications may be used to quickly determine the present location within 50 feet of any person, vehicle or object that is equipped with a ESLS low power transmitter. This technology represents a novel approach to radio tracking. The single point location system uses a single satellite with a 165 foot inflatable antenna.

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An Imaging Satellite System For Tactical Applications, Kent Backman, Vince Tate Sep 1989

An Imaging Satellite System For Tactical Applications, Kent Backman, Vince Tate

Small Satellite Conference

The Tactical Imaging Experiment and Demonstration System (TIDES) goal is to develop a small imaging satellite for tactical applications where the field commander controls the satellite and achieves a launch on demand at a reasonable cost. The TIDES imaging payload is two modified Schmidt cameras, coupled with linear charged couple devices capable of producing 5 meter resolution at a 700 km polar sun synchronous orbit. Innovations such as Vector Quantization (VQ) technology with a new developed codebook processing chip (CPC) demonstrates the ability to compress images at ratios of 12 to 1 or greater reducing satellite to ground datalink bandwidth, …

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Monitoring The Ocean With Navy Radar Altimeter Lightsats, Charles Kilgus, Eric Hoffman, William Frain Sep 1989

Monitoring The Ocean With Navy Radar Altimeter Lightsats, Charles Kilgus, Eric Hoffman, William Frain

Small Satellite Conference

A system of three radar altimeter LightSats would provide optimum temporal and spatial sampling of the sea surface height signatures of ocean features at mid latitudes and above. Merging this data with satellite infrared images would provide a robust, affordable, all-weather, global ocean monitoring system in support of the Navy Tactical Oceanography mission. The present Navy system for mapping ocean features uses sea surface temperature maps from NOAA satellite radiometers and sea surface height profiles from the Navy GEOSA T radar altimeter satellite. GEOSAT is a 1450-pound, completely redundant satellite with a 207-pound, 165-watt radar altimeter. GEOSAT was developed by …

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Measurement Of Surface Reactions In The Space Environment, Wedad Abdou, Lawrence Megill, David Brinza, Roger Hart, Gilbert Moore, Andrew Sexton, Ali Siahpush Sep 1989

Measurement Of Surface Reactions In The Space Environment, Wedad Abdou, Lawrence Megill, David Brinza, Roger Hart, Gilbert Moore, Andrew Sexton, Ali Siahpush

Small Satellite Conference

Serious degradation is experienced by the external surfaces of spacecraft that operate in low earth orbits for extended periods of time, as a result of the ablative effects of atmospheric atomic oxygen, possibly catalyzed by solar ultraviolet radiation. Improved base materials and surface coatings are being developed by government, university and industry teams to combat the effects of this degradation. A small spacecraft and a suite of associated instruments, designed to measure the performance of improved, atomic-oxygen-resistant materials and coatings in orbit and to telemeter the resulting data and video images to earth at intervals during a one-year mission, have …

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The Mini Metsat: A Small Low-Cost Advanced Technology Weather System, David Thompson, William Knorr, Jeff Sechrist Sep 1989

The Mini Metsat: A Small Low-Cost Advanced Technology Weather System, David Thompson, William Knorr, Jeff Sechrist

Small Satellite Conference

Spectrum Research, the ITT Aerospace Optical Division and the E-Systems Garland Division describe a system design concept for a 350-lb class small weather satellite system which includes a high-performance meteorological imaging instrument and a completely mobile satellite command, control and weather data processing terminal. The system can be made compatible with either civil or military weather data collection and processing systems, and it is interoperable with existing ground terminals. The system permits collection of high-resolution weather imagery in five spectral bands, and can be launched on a variety of lower-cost small space boosters. Applications discussed include cloud imagery, determination of …

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Single Purpose Satellite Systems, Warren Watkins Sep 1989

Single Purpose Satellite Systems, Warren Watkins

Small Satellite Conference

This paper examines the need for tactically responsive space systems capable of supporting battlefield and fleet commanders. Terminology used to describe this category of satellite system varies according to organization or agency. The Defense Advanced Research Projects Agency's Lightsat, the Naval Space Command's SPINSAT, and the Air Force Space Command s TACSAT, are reviewed. The United State Space Command's space support mission IS addressed and the role single-purpose satellites can play in fulfilling requirements for operationally responsive satellite systems is described. The United States and Department of Defense space policies are discussed. The position taken by Secretary of Defense, Frank …

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An Assessment Of The Market For Small Satellites, Larry Stern Sep 1989

An Assessment Of The Market For Small Satellites, Larry Stern

Small Satellite Conference

This study was sponsored by a grant from the Virginia Center for Innovative Technology's Space Research Fund, to provide an assessment of current activities in the design and development of small satellites and potential commercial markets for these satellites and the services they could provide. Our research methods included a review of: a) the history of the satellite industry, b) current activities of satellite manufacturers, c) complementary inputs to small satellites such as launchers and ground control, d) functional requirements that could be met using small satellites, e) potential users of small satellites, f) availability of various technologies, g) existing …

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Small Orbited Payloads: A Demand Assessment, Michael Stancati Sep 1989

Small Orbited Payloads: A Demand Assessment, Michael Stancati

Small Satellite Conference

Experimenters and sponsor organizations continue to express interest in flying small, often low cost payloads to orbit. Government procurement in the last several months have focused attention on prospects for expanding commercial activity in space. The interests and activity span many disciplines and applications, so a "payload" may be anything from an experiment apparatus that requires full spacecraft support (power, pointing, thermal protection, etc.) to a complete, self-contained satellite. Small packages fly now as secondary payloads on Shuttle or other large vehicles. Soon, however, these payloads may have several new options for rapid, low-cost access to orbit. The stated interest …

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Nasa's Initial Flight Missions In The Small Explorer Program, Nickolus Rasch, William Brown Sep 1989

Nasa's Initial Flight Missions In The Small Explorer Program, Nickolus Rasch, William Brown

Small Satellite Conference

The National Aeronautics and Space Administration (NASA) Office of Space Science and Applications has initiated a new component of the Explorer Program to provide research opportunities characterized by small, quick turn-around, and frequent space missions. The objective is to launch one to two payloads per year, depending on mission cost and availability of funds and launch vehicles. The first Small Explorer Announcement of Opportunity, released in May 1988, invited proposals in Astrophysics, Space Physics, and Upper Atmospheric Science disciplines. From the 51 proposals received, four missions were selected for flight. The initial flight missions described in this paper, in order …

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Space Test Program Small Satellite Initiatives, Major Stanley Sneegas Sep 1989

Space Test Program Small Satellite Initiatives, Major Stanley Sneegas

Small Satellite Conference

The Department of Defense (DOD) Space Test Program (STP) has been and will continue to provide spaceflight for DOD experiments on small satellites. STP past, present and future small satellite missions will be described. The currently planned small satellite missions, P87-2 STACKSAT, P89-1 Independent Space Experiment System (lSES). P89-A Profile and SIlO on Scout (PASS), and P90-1 Space Test Experiments Platform (STEP) will be highlighted.

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The Role Of Small Satellites In Our National Defense, Major R.J. Bonometti, Lieutenant Colonel E.D. Nicastri Sep 1989

The Role Of Small Satellites In Our National Defense, Major R.J. Bonometti, Lieutenant Colonel E.D. Nicastri

Small Satellite Conference

Highly capable small satellites may play a significant role in the future of our national defense space architecture. Such capable small satellites are generically referred to as "LightSats." In this paper, we examine the logical motivation behind the utilization of LightSats to support military operations and national defense requirements. To complement LightSats, new cost-effective and responsive launch vehicles are also needed. We present an overview of the DARPA Advanced Space Technology Program (ASTP), which seeks to develop high-payoff advanced enabling technologies to enhance space system operational support to military forces and to assure availability of space assets in wartime. The …

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