Digital Commons Network^™

Mars Relay Spacecraft Low-Cost Approach, T. Svitek, J. King, R. Fulton, R. Mcomber, R. Hastrup, A. Miller

Small Satellite Conference

The next phase of Mars exploration will utilize a network of small low-cost landers, penetrators, microrovers and other surface devices to provide site-diversity. Direct Earth communications link, if required for these landers, will drive the lander design for two reasons: a) mass and complexity of a steerable high-gain antenna and b) electric power supply for high-power X-band amplifier (solar panel and battery mass). Total mass of the direct-Earth-link hardware for several recent small-lander designs exceeded mass of scientific payload. Alternatively, local UHF communication link via a relay spacecraft can be used. Resource requirements of this link are comparatively trivial; a …

Whale Ecology Observation Satellite, Tomonao Hayasid, Gendai Etoh, Takeshi Orii, Ken Maeda, Yoshinari Masumoto

Small Satellite Conference

Catching whales has long been discussed internationally among the specialists and organizations concerned. The ecology of whales, however, is not sufficiently clear yet. Since Japan has been assigned at the International Whale Committee as the responsible country for monitoring ecology of blue whales in the antarctic ocean, we have started a study on a Whale Observation Satellite System. This system comprises of three elements: a small satellite on a polar orbit, ecological sensor probes attached to whales, and a ground station. In each probe, a receiver of GPS, several sensors to collect ecological data of a whale, a memory to …

On The Practicality Of A Family Of Pop-Up Parabolic Reflectors, G. Greschik

Small Satellite Conference

The transformation of doubly curved surfaces, without affecting their geometric integrity, into quasifoldable mechanisms via surface discontinuities is a recently proposed approach to self-deploying ("popup") reflectors. The marriage of surface accuracy and kinematic simplicity this concept represents may be especially attractive for small satellite antenna applications, once certain questions of practicality are answered. This paper is to summarize these questions and to quantitatively examine one of them - stowage efficiency - in the context of parabolic reflectors. First, a structural classification of deployable antenna dishes is put forth and the concerned pop-up concept is introduced. Some of the mechanical and …

Microelectromechanical Systems (Mems) Technology Integration Into Microspacecraft, Lilac Muller

Small Satellite Conference

The need to significantly reduce the mass, power, and volume of future scientific spacecraft has resulted in an increased interest on the part of NASA in the relatively new technology of microelectromechanical systems (MEMS). In addition to being light, compact and low-power-consuming, MEMS technology offers other advantages to space applications. Chief among these are robust performance with solid-state reliability. In addition, the ability to array many identical MEMS devices allows for very large scale integration (VLSI), fault tolerant, and distributed architectures. These micromachined, chip-level systems have been in the research stage for over a decade and are currently being developed …

Abstract For Low Cost/High Reliability Rotary Actuator For Space Satellites, Dave Koehler

Small Satellite Conference

Honeywell is nearing completion of the development program for the antenna positioning rotary actuators to be used on the Iridium® Space Vehicle. The program's goal has been to develop and qualify, within a relatively short period of time, a set of low cost, high performance and highly reliable rotary actuators which can be produced efficiently in large quantities. These actuators will be utilized to point communication antennas but could also be used to point cameras or tum and position solar arrays.

Performance Measurements Of The Submillimeter Wave Astronomy Satellite (Swas) Solar Array Deployment System, Gary Sneiderman

Small Satellite Conference

This paper discusses some unique features of the solar array deployment system used on the Submillimeter Wave Astronomy Satellite (SWAS). The mechanism system is highly optimized, incorporates no single-use components, and is fully testable in a one-"g" environment. A single High Output Paraffin (HOP) linear actuator drives the mechanisms used to deploy and lock each wing of solar array panels. The solar arrays open slowly, requiring only enough force to overcome inefficiencies and friction. Load cells measure the force required to open the solar arrays. The system's margin is easily determined by comparing the maximum capability of the HOP actuator …

Systems Engineering And Integration Of Advanced Technologies For Small Satellites At Phillips Laboratory Directorate Of Space And Missiles Technology, Col. Henry Pugh, Robert Vacek, Lt. Michael Hopkins, William Macpherson, Kevin Bell

Small Satellite Conference

This paper will review some of the satellite technology developments and the system engineering approaches in use at the Phillips Laboratory Directorate of Space and Missiles Technology (PL/VT), which are relevant to increasing the capability of small satellites. The paper will cover structures, materials and controls, space power technology, thermal management, and electronics developments that enable high performance small satellites. In the last section of the paper we will cover some mass and performance advantages that can be obtained by integrating technologies at the system level and developing new concepts that cross the bounds of traditional spacecraft subsystems.

Pulsed Plasma Thruster Technology For Small Satellite Missions, Roger Myers, Steven Oleson, Melissa Mcguire, Nicole Meckel, Joseph Cassady

Small Satellite Conference

Pulsed plasma thrusters (PPTs) offer the combined benefits of extremely low average electric power requirements (1 to 150 W), high specific impulse (~ 1000 s), and system simplicity derived from the use of an inert solid propellant. Potential applications range from orbit insertion and maintenance of small satellites to attitude control for large geostationary communications satellites. While PPTs have been used operationally on several spacecraft, there has been no new PPT technology development since the early 1970's. As a result of the rapid growth in the small satellite community and the broad range of PPT applications, NASA has initiated a …

Deep Space Network Support Of Small Missions, G.K. Noreen

Small Satellite Conference

Spacecraft to be used in future missions supported by the Deep Space Network (DSN) will be much smaller than in previous missions, resulting generally in lower radiated power. These missions are expected to be launched more frequently than previous missions and to require an ever increasing number of tracking hours, while the funds available to track these future missions are declining. This paper briefly describes the DSN. It then characterizes performance limits of smaller spacecraft and the tracking challenges these limits present. It reviews new techniques and technologies the DSN is developing to meet these challenges. Finally, it recommends guidelines …

The Engineering Of Cost Efficient Operations, G.E. Cameron, G.A. Herbert

Small Satellite Conference

The Thermosphere • Ionosphere • Mesosphere • Energetics and Dynamics (TIMED) program, being developed at The Johns Hopkins University Applied Physics Laboratory for NASA's Space Physics Division, is the first in mission in the Solar Connections program. The TIMED mission, in its present form, was engineered to reduce life cycle costs. This paper describes the operations concept planned for TIMED and shows how this novel approach to operations has resulted in a lower overall cost. TIMED relies on a combination of simplified operations, enhanced automation, and event-based commanding to provide a mission operations system that is less expensive to operate, …

"Faster, Better, Cheaper" Mission Operations - Employing A Reusable Object Methodology, Donald Hei, Rhoda Hornstein, Hong Liu, Frank Lopinto, Raymond Miller, Jacqueline Todd

Small Satellite Conference

This paper presents a systematic approach for changing the process of engineering and operating one-of-a-kind solutions and start-from-scratch systems for similar mission operations functions. The approach employs an object methodology to specify end-to-end mission operations with reusable objects and actions. Through this technique, which resembles design of custom electronic circuit assemblies from standard components, objects that appear in different parts of mission operations, and which were viewed previously as unique, are now recognized to be similar, allowing for reduction of unique implementations. Unlike conventional data flow methods which concentrate on function uniqueness and the detailed data flows necessary to interconnect …

Uars And Toms-Ep Project Operations Control Centers Collocated And Reengineered, E.J. Macie, A.H. Maury, R. Horne, J. Speer

Small Satellite Conference

At NASA's Goddard Space Flight Center (GSFC), we are reengineering Project Operations Control Centers (POCCs) based on workstation network technologies and lessons learned from the current complex Upper Atmosphere Research Satellite (UARS) mission and the impending generation of low-cost satellites such as the Total Ozone Mapping Spectrometer-Earth Probe (TOMS-EP) mission. UARS is supported in a multimission institutional environment by Concurrent Computer Corporation computers; TOMS-EP is supported independently by networked workstations using embedded processing techniques tailored to small systems. To maintain data continuity until follow-on instruments can be launched, NASA wants to extend the UARS mission (currently in its fourth year …

An Evolutionary Approach To Small Satellite Technology Development: A Status Report On Sstl Platforms, Payload And Missions, Jeffrey Ward

Small Satellite Conference

Between 1989 and 1995, 10 micro satellites were constructed using SSTL' s 50 kg modular micro satellite design. Eight are presently in orbit, while two are scheduled for launches during summer 1995. Each satellite has incorporated design enhancements, which can be grouped roughly into six distinct design generations. This rapid design and test cycle, combined with in-orbit operational experience, has fostered rapid advancement of technology within the basic modular design. When measured between the two extremes, the technological advance is startling. UoSAT-3 (launched 1990) contained three on-board computers and just over four megabytes of solid-state data storage. FaSAT-Alfa (to be …

The Taos/Step Satellite, David Edwards, Robert Hosken

Small Satellite Conference

The Technology for Autonomous Operational Survivability / Space Test Experiments Platform (TAOS/STEP) satellite was launched on a Taurus booster from Vandenberg Air Force Base into a nearly circular, 105 degree inclined orbit on March 13, 1994. The purpose of this satellite is twofold: 1) to test a new concept in multiple procurements of fast-track modular satellites and 2) to test a suite of Air Force Phillips Laboratory payloads in space. The TAOS payloads include the Microcosm Autonomous Navigation System (MANS), two Barnes Engineering Dual Cone Scanners, two Honeywell Generic VHSIC Spaceborne Computers, a Rockwell Global Positioning System receiver, a MIL-STD …

The Space Technology Research Vehicles Strv-1a And -1b: One Year In Gto, N.S. Wells

Small Satellite Conference

On 17th June 1994, Ariane flight V64 placed into geostationary transfer orbit (GTO) two 52 kg 'Space Technology Research Vehicles' built by the UK Defence Research Agency (DRA). The major objective of the STRV-1a/b one year mission was to evaluate in orbit, new technologies which have application to future space missions. The GTO provides a very harsh space environment, particularly in terms of radiation dose. The two spacecraft not only carry a suite of fourteen experiments between them, including experiments from the Ballistic Missile Defence Organisation, European Space Agency, the DRA and various universities, but they also incorporate many new …

Astrid: An Attempt To Make The Microsatellite A Useful Tool For Space Science, Sven Grahn, Anna Rathsman

Small Satellite Conference

The ASTRID microsatellite (27 kg) was built and launched to demonstrate that "good science" can be done with a microsatellite. It has deployable solar panels to provide plenty of power, a high downlink data rate and a flexible structure design to provide a good field-of-view for the scientific sensors. The satellite was developed and launched in 15 months at a total cost of $1.4 million and has provided pioneering imagery of energetic neutral particles in the earth's magnetisphere.

Proceedings From The 32nd Marschall Italian And Specialty Cheese Seminar, Various Authors

Cheese Industry Conference

No abstract provided.

Endoarticular Loose Bodies And Calcifications Of The Disk Of The Temporomandibular Joint: Morphological Features And Chemical Composition, C. Piacentini, C. Marchetti, A. Callegari, M. Setti, G. Bernasconi, U. Baciliero, P. Menghini, C. Brusotti

Scanning Microscopy

We studied articular disks and endoarticular loose bodies taken from patients suffering from different types of temporomandibular joint (TMJ) pathology. The scanning electron microscopy (SEM) analysis of the disks and the endoarticular loose bodies was followed by a chemical-compositional analysis using an energy dispersive spectrometer (EDS) and by characterization of the crystalline phases by X-ray powder diffraction (XRD). The articular disks were composed of a central radio-opaque area lacking any evident structural features, surrounded by compact bundles of collagen fibers. EDS and XRD analyses showed that endodiscal radio-opaque areas were hydroxyapatite. By SEM, we observed a fibrous network only in …

Atomic Force Microscopy Of Neuron Networks, A. Cricenti, G. De Stasio, R. Generosi, P. Perfetti, M. T. Ciotti, D. Mercanti

Scanning Microscopy

We imaged uncoated neuron networks by an atomic force microscope in the repulsive regime of contact mode. Images of granule cells and their axons have been clearly revealed with details smaller than 20 nm. The good stability of the sample and the mechanical reproducibility of the microscope allowed the imaging of a neuron culture area of several square microns. By combining tens of images, we were able to reconstruct a highly defined neuronal network. Furthermore, the images were very reproducible over repeated scanning acquisition, demonstrating the mechanical and thermal stability of the instrument-sample system.

Human Skin Physiology Studied By Particle Probe Microanalysis, B. Forslind, M. Lindberg, K. G. Malmqvist, J. Pallon, G. M. Roomans, Y. Werner-Linde

Scanning Microscopy

Particle probe methods (electron probe and proton probe X-ray microanalysis) have been applied to investigate the distribution of elements and water over the different layers of the epidermis. For major elements, electron probe X-ray microanalysis (XRMA) provides the advantage of superior spatial resolution, but for trace element analysis the more sensitive proton probe (particle induced X-ray emission, PIXE) analysis has to be used. On a dry weight basis, the concentration of S is rather constant across the epidermis, whereas the concentrations of P, K, Cl and Na show gradients with high levels in stratum germinativum (basale) and stratum spinosum but …

Cells Are Not Just Bags Of Water: A Personal Appreciation Of The Work Of Dr. Brij L. Gupta And His Contribution To Biological X-Ray Microanalysis, Alice Warley

Scanning Microscopy

This paper surveys the contribution made by the work of Dr. B.L. Gupta to the science of biological X-ray microanalysis. A brief biographical sketch of Brij's early years is given, this is followed by considerations about the models for water transport across epithelia. The ultrastructural and histochemical studies carried out by Brij Gupta and colleagues are reviewed to introduce the historical need for the use of EPXMA for the study of ion and water transport in epithelia. The outstanding contribution made by Brij Gupta's work in this field is outlined, and his understanding of the subcellular distribution ions in other …

Comparative Analysis Of Patch Lesions In The Chick Inner Ear Following Acoustic Trauma: Optical Versus Scanning Electron Microscopy, H. J. Adler, J. Mantooth, Y. Raphael

Scanning Microscopy

Neonatal chicks were exposed to an octave band noise with a center frequency of 1.5 kHz at 116 dB SPL for 4 hours. Seven days following overstimulation, the birds were sacrificed. Their basilar papillae were re-moved, fixed in 4% paraformaldehyde, and processed in two steps. First, the ears were immunostained with a supernatant of mouse anti-tectorial membrane antibodies, followed by a diaminobenzidine process. Examinations of the papillae under an optical stereo microscope revealed a patch site with a partially regenerated tectorial membrane (referred to as the honeycomb).

After the optical studies, the same ears were post-fixed in 1% osmium tetroxide, …

Finite Thermal Diffusivity At Onset Of Convection In Autocatalytic Systems: Discontinuous Fluid Density, D. A. Vasquez, Boyd F. Edwards, J. W. Wilder

All Physics Faculty Publications

A linear convective stability analysis for propagating autocatalytic reaction fronts includes density differences due to both thermal and chemical gradients. Critical parameters for the onset of convection are calculated for an unbounded geometry, a vertical slab, and a vertical cylinder. Thermal effects are important at unstable wavelengths well above the critical wavelength for the onset of convection.

Utah State University Commencement, 1995 – Main Campus, Utah State University

Commencement Programs

102nd Annual Commencement of Utah State University

The Effect Of Arf-Excimer Laser Irradiation Of The Human Enamel Surface On The Bond Strength Of Orthodontic Appliances, U. Stratmann, K. Schaarschmidt, M. Schürenberg, U. Ehmer

Scanning Microscopy

This study investigated enamel laser conditioning as an alternative to acid etching in bracket therapy. In preliminary experiments optimal laser parameters for achieving a bond strength of 6-10 N/mm² were defined. Enamel surface morphology was assessed and the ablation depth was measured on serial enamel sections. Thirty human molars were exposed to 193 nm ArF-excimer laser radiation (energy density: 260 mJ/cm²) by single pulse application of 23 nanoseconds. Thirty molars were etched with phosphoric acid (37%) for 60 seconds. The brackets from the treated molars and 30 untreated molars were debonded vertically for tensile bond strength measurement. …

The Nighthawk Review, 1995, Usu Eastern English Department

Nighthawk Review

An annual publication featuring student work from Utah State University Eastern Campus.

Introgression Between Colorado River Cutthroat Trout And Rainbow Trout In An Isolated Drainage System, Catherine M. Bischoff

Biology

Fishes of the western United States, in particular native salmonids, are at risk of extinction as a result of human activities. One major threat to native fishes is hybridization with exotic species introduced by humans. Enzyme electrophoresis was used to determine the degree of hybridization between native Colorado River cutthroat trout (Oncorhynchus clarki pleuriticus) and introduced rainbow trout (Oncorhynchus mykiss) in ten streams located across five drainages on the north slope of the Uinta Mountains in Utah, USA. To assess the level of hybridization in each individual, I constructed a hybrid index using 10 diagnostic loci …

Expression Of Hamster Retinoic Acid Receptor Β2 And Β4 During Development And The Effect Of Retinoic Acid, Dolores Diaz

Biology

The retinoic acid receptors (RARs) constitute a group of nuclear proteins that belong to the steroid and thyroid-hormone receptor superfamily. They act as ligand-inducible transcriptional regulatory factors and provide a model for the molecular mechanism of action of retinoids (vitamin A derivatives). The objective of this study was to identify one or more isoforms of the retinoic acid receptor β (RARβ) in hamster embryos, and to study their expression during development and after retinoic acid (RA) treatment. Total RNA was extracted from a 12-day-old hamster embryo, reverse transcribed and tailed with dGTP. The resulting cDNA was subjected to anchored-polymerase chain …

Gene Regulation In Maize Silk During Pollen Tube Growth, Chalapathi Rao V. Koka

Biology

The objective of this research was to evaluate whether genes encoding certain classes of cell wall protein and pathogenesis-related protein are regulated in response to pollen tube growth, in maize silk. In Northern blot analysis of total RNA isolated from maize silk at different time periods after pollination, there was an increase in the transcripts for extensin, a cell wall protein. However, there was an increase in transcripts for mock pollinated samples, albeit to a lesser extent, indicating that there is a wound response as well. In contrast, PR-4, a pathogenesis-related protein gene, was induced only 24 hr after pollination, …

Undergraduate Writing In The Sciences: A Case Study, Susan Browning, Jon Bruce Obray

Undergraduate Honors Capstone Projects

This research project is an attempt to understand the role of writing in undergraduate science education, including the development of writing's current role in scientific education, the present nature of writing in the scientific disciplines, and its value. With this understanding, we feel it is possible to successfully improve the communication skills of undergraduates students in the scientific disciplines, which in turn will benefit both the scientific community and society itself. A case study of undergraduate writing in the sciences was conducted at Utah State University, both to assess the present attitude of faculty toward this subject and to investigate …