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Magnetic And Momentum Bias Attitude Control Design For The Hete Small Satellite , Daniel Chang
Magnetic And Momentum Bias Attitude Control Design For The Hete Small Satellite , Daniel Chang
Small Satellite Conference
A design study of the attitude control system for the High Energy Transient Experiment (RETE) small satellite is presented. The satellite is 3-axis stabilized and sun pointing, with stringent pointing stability requirements. For actuation, magnetic torquers and a momentum wheel are chosen for their technological maturity and lack of consumables. One science instrument (CCD UV camera) and sun sensors provide attitude measurement. Two complimentary control strategies are implemented to maximize controllability given the expected wide variation in Earth field direction. As this actuator complement is particularly suitable for a variety of small satellite missions, the design guidelines presented here should …
Populating The Abyss-Investigating More Efficient Orbits -Or- "Getting More Miles To The Gallon For Your (Space) Vehicle" , John Draim, Thomas Kacena
Populating The Abyss-Investigating More Efficient Orbits -Or- "Getting More Miles To The Gallon For Your (Space) Vehicle" , John Draim, Thomas Kacena
Small Satellite Conference
Most satellites operating in orbit are spatially distributed in one of the following regions: LEO (below 600 nm and below), MEO (Molniya and GPS), and GEO (synchronous circular). Other than Molniya and a few similar systems, little use has been made of either elliptic orbits or the 'middle-ground' orbits lying between 600 nm and synchronous altitude. This paper explores the potential for exploiting these less populated regions and demonstrates that analyzing system optimization parametrically may in fact, also dictate an increasing interest in this new territory. A non-dimensional coverage parameter is presented which indicates that the 'efficiency' of an orbit …
The Space Test Program Apex Mission Satellite , Frank Knight
The Space Test Program Apex Mission Satellite , Frank Knight
Small Satellite Conference
An overview is presented of the Air Force Space Test Program's Advanced Photovoltaic and Electronic Experiments (APEX) Mission. APEX will provide spaceflight for three military experiments on the fourth flight of the Pegasus Air-Launched Vehicle in ready 1993. The APEX spacecraft is Orbital Sciences Corporation's "PegaStar" integrated third stage, in which components of the final stage of the launch vehicle are augmented to provide a fully-functional, 3-axis stabilized experiment platform. The spacecraft configuration and capabilities are described. The mission development history to date is outlined, as is the vehicle processing prior to launch. Finally, plans for the distribution of experiment …
Technologies For Future High Capability Micro-Milsatcom Systems, B. Steele, R.J. Bonometti, A. Wallace, K. Brandt
Technologies For Future High Capability Micro-Milsatcom Systems, B. Steele, R.J. Bonometti, A. Wallace, K. Brandt
Small Satellite Conference
Satellite communications systems are a vitally important component of our Defense infrastructure for both tactical and strategic missions. In particular, satellite communications (whether military or commercial) have become increasingly important to support tactical operations, as was clearly demonstrated during Operations Desert Shield and Desert Storm. In the emerging doctrinal shift to a CONUS-based force structure with capabilities for rapidly responsive lethal power projection to meet global crises, the vital necessity for SATCOM to provide an omnipresent communications infrastructure for immediate support of the developing theater will become a key element in the successful realization of our new warfighting strategy. This …
Near Earth Asteroid Rendezvous, Edward Reynolds, Robert Farquhar
Near Earth Asteroid Rendezvous, Edward Reynolds, Robert Farquhar
Small Satellite Conference
The Johns Hopkins University Applied Physics Laboratory recently completed a pre-Phase A study to design a spacecraft to rendezvous and go into orbit around a near earth asteroid. The spacecraft would map the asteroid's surface and collect other science data for a one year period. The primary mission would be a rendezvous with either asteroid Anteros or with asteroid 1982XB. Presently, the APL NEAR spacecraft is beginning Phase A study. This paper identifies the science objectives and mission goals, outlines the mission scenario, and concludes with a description of the APL NEAR pre-Phase A spacecraft.
Exploration Of Fuel Objects In Space Very Near Earth, Anthony Zuppero, Michael Jacox
Exploration Of Fuel Objects In Space Very Near Earth, Anthony Zuppero, Michael Jacox
Small Satellite Conference
A prospecting plan is presented to assay near Earth objects (NEO) for their potential to yield rocket fuel. The plan calls out small satellites as the near-term means to achieve low cost surveys and deep subsurface sampling of NEO composition. The water bearing classes of NEO to be considered are limited to those accessible in short time and with small thrusters. These include the water bearing clay objects (phylosilicates) at nearly trivial distances from Earth, and the recently identified water ice objects such as comet (#4015) 1979 VA. These objects are evaluated as small satellite prospecting and assay vehicle targets.
Exploration Of Pluto: Search For Applicable Small Satellite Technology, Robert Staehle, John Carraway, Christopher Salvo, Richard Terrile, Stacy Weinstein, Elaine Hansen
Exploration Of Pluto: Search For Applicable Small Satellite Technology, Robert Staehle, John Carraway, Christopher Salvo, Richard Terrile, Stacy Weinstein, Elaine Hansen
Small Satellite Conference
Pluto is the last known planet in our Solar System awaiting spacecraft reconnaissance. In its eccentric orbit taking it 50 AU from the Sun, Pluto presently has a thin atmosphere containing methane, which is projected to "collapse" back to the icy planet's surface in about three decades, following Pluto's 1989 perihelion pass at 30 AU. Based on ground and Earth-orbit-based observing capabilities limited by Pluto's small size and extreme distance, present top-priority scientific questions for the first mission concern Pluto and Charon's surface geology, morphology and composition, and Pluto's neutral atmosphere composition. Budgetary realities preclude a large, many-instrument flyby spacecraft, …
Copernicus - Lunar Surface Mapper, Frank Redd, Shaun Anderson
Copernicus - Lunar Surface Mapper, Frank Redd, Shaun Anderson
Small Satellite Conference
The Utah State University (USU) 1991-92 Space Systems Design Team has designed a Lunar Surface Mapper (LSM) to parallel the development of the NASA Office of Exploration lunar initiatives. USU students named the LSM "Copernicus" after the 16th Century Polish astronomer, for whom the large lunar crater on the face of the moon was also named. The top level requirements for the Copernicus LSM are to produce a digital map of the lunar surface with an overall resolution of 12 meters (39.4 ft). It will also identify specified local surface features/areas to be mapped at higher resolutions by follow-on missions. …
The Space System For The High Energy Transient Experiment, Bob Dill, Rick Fleeter, Richard Warner, Francois Martel, George Ricker
The Space System For The High Energy Transient Experiment, Bob Dill, Rick Fleeter, Richard Warner, Francois Martel, George Ricker
Small Satellite Conference
The High Energy Transient Experiment (HETE) is an astrophysics project funded by NASA and led by the Center for Space Research (CSR) at the Massachusetts Institute of Technology (MIT). It has for principal goal the detection and precise localization of the still mysterious sources of gamma ray bursts. The project is original in many respects. HETE will provide simultaneous observations of bursts in the gamma, X-ray and UV ranges from the same small (250 Ibms) space platform. A network of ground stations around the world will diffuse in real time key information derived from HETE observations to many ground observatories, …
Mapping Of Earth's Magnetic Field With The Ørsted Satellite, W.R. Baron, K. Leschly, P.L. Thomsen
Mapping Of Earth's Magnetic Field With The Ørsted Satellite, W.R. Baron, K. Leschly, P.L. Thomsen
Small Satellite Conference
The Danish Ørsted satellite will carry three science experiments with the objectives of mapping the Earth's magnetic field and measuring the charged particle environment from a 7801an altitude sun-synchronous polar orbit. The science data generated during the planned one year mission will be used to improve geomagnetic models and study the auroral phenomena. Comprehensive and accurate mapping of the geomagnetic field every 5 to 10 years is of particular interest to geophysical studies. As such, the Ørsted science data return will complement the Magsat (1979-80) and Aristoteles (=2000) mission objectives. Two magnetometers will be mounted on an 8 meter long …
Space Test Program Activities And Lessons Learned, Lt. David Spackman, Elmer Witte
Space Test Program Activities And Lessons Learned, Lt. David Spackman, Elmer Witte
Small Satellite Conference
The Space Test Program (STP) was established in 1966 to provide space flight for Department of Defense (DOD) space experiments which had no other means of space flight. This paper discusses STP's capabilities and achievements as a provider of space services. STP is now part of a new organization with expanded capabilities to include on-orbit support, launch operations and planning, and sub-orbital launches. With extensive experience acquiring, launching, and operating small satellites, lessons learned from recent missions are presented.
Marine Corps Tactical Satellite Communications, Walter Daniel, Gavino Rivas, Robert Bruninga
Marine Corps Tactical Satellite Communications, Walter Daniel, Gavino Rivas, Robert Bruninga
Small Satellite Conference
A tactical satellite communications exercise using the DARPA Microsats was conducted by Naval Academy personnel at the Quantico Marine Corps Base in Virginia. Midshipmen used a military UHF radio, a modified amateur radio transmitter, and scanner receivers while a station in Annapolis communicated with them. Voice communications were clear and understandable even when the tactical teams were in the woods. Amateur radio operators and scanner enthusiasts around the eastern half of the United States and Canada successfully monitored the Microsat downlinks during the demonstration.
Navy/Marine Corps Demonstrations Of The Darpa Microsats, Walter Daniel, Robert Bruninga
Navy/Marine Corps Demonstrations Of The Darpa Microsats, Walter Daniel, Robert Bruninga
Small Satellite Conference
Demonstrations of the DARPA Microsats with an emphasis on Navy and Marine Corps applications were conducted by personnel at the United States Naval Academy. These satellite communications demonstrations used the analog FM mode of the Microsats. Radios used were military transceivers, transmitters composed of laboratory signal generators with broadband power amplifiers, a modified amateur radio UHF transmitter, and commercially-available scanner receivers. Voice demonstrations included equipment checks with DARPA personnel, a tactical exercise at a Marine Corps base, and communications with a U.S. Navy destroyer. Position and status report data beacons were relayed through the Microsats from training vessels to Annapolis. …
Restoration And Enhancement Of Earth Images From A Low Cost Sampled Video System, Jay Smith
Restoration And Enhancement Of Earth Images From A Low Cost Sampled Video System, Jay Smith
Small Satellite Conference
The WEBERSAT microsat has been in a 800 Km polar orbit of Earth since January of 1990. During this time an on board, low cost, color CCD camera has logged several dozen video images of Earth and heavens. Each new image has presented a unique challenge in restoration and image enhancement.
Microsat Constellation Control Techniques, Keith Reiss
Microsat Constellation Control Techniques, Keith Reiss
Small Satellite Conference
The first air-launched constellation of seven small experimental communications satellites into an unexpectedly low earth orbit (246 nmi X 192 nmi) resulted in a set of tough flight control demands. In the abbreviated demonstration mission the flight operations team was challenged in rapidly propelling the spacecraft into a useful uniform distribution about the orbit plane and in maintaining the "stations" under adverse conditions. The constellation was injected in perfect order and began mission operations immediately. However, each spacecraft's attitude control system coupled with the force of heavy atmospheric drag to produce variable in-plane phase drifts that required constant observation and …
Chemical Release Observation Program Description And Flight Results , Stephen Nichols, Jeffrey Wise, Ian Strong
Chemical Release Observation Program Description And Flight Results , Stephen Nichols, Jeffrey Wise, Ian Strong
Small Satellite Conference
The Chemical Release Observation (CRO) program developed three small satellites that were deployed from the Shuttle on flight STS-39. These were small experimental satellites built with a minimum of paperwork. While meeting all the necessary NASAISTS requirements. Each satellite contained a chemical (either hydrazine or an oxidizer) which was released on ground command. The satellites were approximately 18" diameter and 31" high. and weighed 160 to 195 pounds when loaded. The satellites carried 60 pounds of MMH (MonoMethyl Hydrazine), 52 pounds of UDMH (Unsymmetrical DiMethyl Hydrazine) and 11 pounds of N10 4 (Nitrogen Tetroxide). The satellites were designed and built …
Integrated Space Experiment Satellite (Ises) Low Cost Stabilization Subsystem Performance , George Sebestyen
Integrated Space Experiment Satellite (Ises) Low Cost Stabilization Subsystem Performance , George Sebestyen
Small Satellite Conference
On June 29, 1991 the ISES satellite was launched into a 450 nm polar orbit. The 183 lbs satellite is a 30 inch diameter, 16 inch high, 16-sided cylinder to provide Nadir-pointing stabilization for a helix antenna associated with the Radiation Experiment (REX) payload of the satellite. The stabilization system uses a 20 ft gravity gradient boom, hysteresis rod damping, a 3-axis magnetometer, a sun sensor and torque coils. Through careful design of the gravity gradient boom and magnetic grooming of the satellite, excellent stability was achieved. The U.S. Air Force commended ISES as the best gravity gradient stabilized satellite. …
Attitude Determination By Image Processing Algorithms, Hans Konigsmann, Hans Rath, Hartmut Renken
Attitude Determination By Image Processing Algorithms, Hans Konigsmann, Hans Rath, Hartmut Renken
Small Satellite Conference
To determine attitude or direction with star constellations is perhaps the oldest method in the field of navigation and control. Besides its accuracy, star constellations can give three axis information by using just a single sensor, a digital CCD camera. What is very easy for men looking at the stars turns out to be complex if done by an onboard computer. The process of star identification can be divided into two parts: object segmentation and, needing much more calculation time, the matching process. Matching can be explained as comparing a star catalog stored in a computer memory with identified objects …
The Effects Of Momentum Bias On A Gravity Gradient Stabilized Spacecraft With Active Magnetic Control , Parimal Pal, Stephen Fox
The Effects Of Momentum Bias On A Gravity Gradient Stabilized Spacecraft With Active Magnetic Control , Parimal Pal, Stephen Fox
Small Satellite Conference
The improvements achieved by adding a momentum bias wheel to a Gravity Gradient (GG) stabilized spacecraft are evaluated. Mass, power, and computational processing requirements, as well as performance, are compared for three Attitude Determination and Control Subsystem (ADACS) scenarios. Spacecraft which require low mass and power have long Incorporated GG torques as a passive stabilization technique. The spacecraft is oriented in the general direction required by the mission, but the overall attitude and attitude rate errors are not exceptionally tight. In order to improve the spacecraft pointing accuracies the GG stabilized ADACS .can be augmented by an active control technique. …
The Development Of A Small Satellite Attitude Control Simulator, Rees Fullmer, Glen Peterson, Walter Holmans, Jay Smith, Jim Nottingham, Shaun Anderson, Tanya Olsen, Frank Redd
The Development Of A Small Satellite Attitude Control Simulator, Rees Fullmer, Glen Peterson, Walter Holmans, Jay Smith, Jim Nottingham, Shaun Anderson, Tanya Olsen, Frank Redd
Small Satellite Conference
Utah State University has developed an air bearing table to simulate the attitude dynamics of a small satellite. The Small Satellite Attitude Control Simulator (SSACS) table includes attitude sensors, a control computer, movable mass units and gas jet thrusters. This paper describes the design of the SSACS table and provides preliminary experimental results from 3 axis control tests.
Ultraviolet Three Axis Attitude Sensor, James Billing-Ross, Teresa Fritz, Douglas Pledger
Ultraviolet Three Axis Attitude Sensor, James Billing-Ross, Teresa Fritz, Douglas Pledger
Small Satellite Conference
It is becoming increasingly obvious that satellite bus technologies, which have been developed for traditional larger satellite platforms, are not always suitable for use with smallsats. This is due to the intrinsic limitations in size, weight, available power, and cost associated with the latter. The problem is particularly obvious for attitude reference sensors of both the earth and star viewing type. In response to the lack of suitable sensors for this purpose, Honeywell is developing a system that determines three axis attitude through ultraviolet imaging of the earth's limb and adjacent stars. A non-conventional wide angle optics assembly and intensified …