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Chemical And Electric Propulsion Options For Small Satellites, Roger Myers, Steven Oleson, Francis Currant, Steven Schneider

Small Satellite Conference

Advanced chemical and low power electric propulsion systems offer attractive options for near-term small satellite propulsion. Applications include orbit raising, orbit maintenance, attitude control, repositioning, and deorbit of both Earth-space and planetary spacecraft. Potential propulsion technologies for these functions include high pressure Ir/Re bipropellant engines, very low power arcjets, Hall thrusters, and pulsed plasma thrusters, all of which have been shown to operate in manners consistent with currently planned small satellites. The broad range of small satellite missions, capabilities, and constraints dictates that multiple technologies be considered for these spacecraft. Arcjets, Hall thrusters, and pulsed plasma thrusters have been used …

The Peacekeeper Post Boost Vehicle For Civil Space Applications, Paul Phillips, Stephen Hoffman, James Moore

Small Satellite Conference

Ownership of several Peacekeeper fourth stages has been transferred from the USAF to NASA for use in the civil space program. The production of Peacekeeper missiles was discontinued although several of the fourth stages known as Post Boost Vehicles or PBV's were in production and in various stages of completion. This paper examines the potential use of these PBV's for small civil space missions, especially Discovery class missions. Several configurations of the PBV with small interplanetary missions are examined. The delivered configuration of the PBV is described along with modifications necessary to make them flight ready. This paper examines the …

To The Moon From A B-52: Robotic Lunar Exploration Using The Pegasus Winged Rocket And Ballistic Lunar Capture, Edward Belbruno, Rex Ridenoure, Jaime Fernandez

Small Satellite Conference

A subset of the presently-defined NASA robotic lunar exploration objectives may be achievable with a new mission architecture involving the Pegasus winged rocket, small satellites, and a new class of Earth-Moon trajectories incorporating ballistic lunar capture. Enabling this potentially low-cost method of lunar exploration - perhaps for a few tens of millions of dollars per mission - is the application of the Weak Stability Boundary Theory developed by Belbruno during 1987-89, which leads to ballistic ("maneuverless") Earth-Moon trajectories. On such a path, a spacecraft could be orbited at the Moon for little additional ∆ V (< 50 m/s for minor trajectory correction maneuvers) beyond that supplied by the Pegasus for the initial Earth departure burn, resulting in a significant propellant savings. (Additional maneuvers would then be required to establish a more useful lunar orbit.) The price for this savings is an extended trip time to the Moon of 3-5 months. This type of trajectory is presently being demonstrated for the first time by the Japanese Hiten spacecraft, using an …

Auroral Cluster: A Space Physics Mission For Multiple, Electronically Tethered Small Satellites, J.P. Andrews, J.R. Scherrer, J.H. Waite, J.L. Burch

Small Satellite Conference

Auroral Cluster is a space physics mission that has been identified by the NASA Space Physics Strategic Implementation Study as a candidate for flight in the next decade. Auroral Cluster will employ multiple spacecraft outfitted with similar complements of science instruments allowing simultaneous multipoint plasma measurements in the Earth's auroral regions. Co-orbiting small satellites (mass < 400 kg each) that are electronically "tethered" to share distributed spacecraft systems represent an efficient approach for achieving the science goals of the Auroral Cluster mission. Multisatellite missions represent a new trend in gathering space science data and pose many new and difficult challenges for the space systems engineer. The results of an Auroral Cluster feasibility study, which discusses a variety of mission trade-offs, are presented. A discussion of the science background and mission goals is used to identify the technical drivers for the design of the multiple spacecraft system. A mission plan and some considerations for a Auroral Cluster satellite design are presented. Special consideration is given to the spacecraft subsystems that will allow the system to be operated as a network of electronically tethered interdependent small satellites. These subsystems include attitude determination, spatial separation knowledge and control, data storage, and intersatellite communication.

Design Of An Electrically-Propelled Asteroid Rendezvous Probe Launched As A Secondary Payload, Ralph Lorenz

Small Satellite Conference

This paper summarises a design study undertaken as a final year project for the author’s B.Eng in Aerospace Systems Engineering. A spacecraft design is outlined for a vehicle to perform a rendezvous with a near earth asteroid after being launched as a secondary payload into Geosynchronous Transfer Orbit. The 380 kg (dry) spacecraft would use a bipropellant chemical propulsion system to manoeuvre in, and escape from Earth orbit. Interplanetary maneuvering would be accomplished with an ion propulsion system.

Small Satellite Design For Inner Solar System Exploration, Walter Daniel, Commander Vernon Gordon

Small Satellite Conference

This paper describes a study that examined using the Pegasus launch vehicle and small spacecraft for missions to the atmospheres of Venus and Mars. The launch vehicle can deliver approximately 820 lb (371.9 kg) into a 0° inclination circular orbit of 200 nm (370.4 km) altitude. With convential solid propellant rocket motors, a spacecraft of 73.8 kg (162.7 lb) would be delivered to Venus or Mars. A spacecraft using a currently existing 10 kW xenon-ion engine system with specific impulse of 3500 sec would deliver 143.4 kg (316.2 lb) to Venus or Mars. The spacecraft can fit inside the Pegasus …

An Approach To The Design Of A Lightweight Lunar Spacecraft, G.E. Sevaston, D.H. Lehman, K.T. Nock

Small Satellite Conference

The Quicksat study, undertaken at the Jet Propulsion Laboratory (JPL), had as its goal the development of low mass, low cost spacecraft that can be implemented within a relatively short time span. As part of this effort, JPL studied a lunar mission referred to as Lunar Prospector (LP). The LP spacecraft carries a spare Apollo gamma ray spectrometer (GRS) in a 100 km polar orbit about the moon in order to obtain a global map of surface composition. The primary mission objective is to search for water in the form of ice trapped within polar craters; this is viewed as …

The Uosat Spacecraft Programme, M. N. Sweeting

Small Satellite Conference

Spacecraft-designed, built and operated by traditional means-have proved extremely costly, thus limiting access to space to large organizations work within enormous budgets. The Amateur Satellite Service, over a period of 20 years, has demonstrated that small spacecraft can be built very inexpensively, and as a low-cost stimulus to technology. The UoSAT Programme at the University of Surrey (UK) has developed highly sophisticated yet inexpensive small satellites through adopting imaginative, cost effective spacecraft engineering techniques. Two UoSAT spacecraft, UoSAT 1 & 2, have been in orbit since 1981 and 1984 respectively supporting active space engineering research, space science and space education …

Changes In The Market Structure Of The Grocery Retailing Industry Of Four Selected Utah Retail Selling Areas, 1960-1969, Michael H. Salsibury

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

An analysis of four Utah retail selling areas was made to determine the changes in the market structure of the retail grocery industry of these markets. The study markets were Logan, Ogden, Salt Lake, and Provo-Orem. This study was an ex tension of the National Commission Food Marketing study of the retail food marketing industry.

The major changes observed in the study markets were increasing population, dollar food sales, supermarket saturation levels and concentration ratios. The number of retail food outlets was decreasing. The barriers to entry in the study markets increased during the study period.

There was substantial economic …

Studies In Transmission In Ovine Vibriosis, William H. Rose

Biology

Vibrio fetus, Smith and Taylor, is the principle etiological agent of ovine infectious abortion in the United States. During the 1952 lambing season, the lamb abortions were estimated at 50,000 in Colorado, 30,000 to 40,000 in Idaho, and from 10,000 to 15,000 each in Utah and Wyoming. A conservative estimate of premature lamb losses due to V. fetus infections in the western states for this year was 100,000. In infected flocks the incidence of mortality in aborting ewes may be as high as 10 percent. Since 1952 the incidence of vibrosis among sheep has remained high.

Studies In Transmission In Ovine Vibriosis, William H. Rose

Biology

Vibrio fetus, Smith and Taylor, is the principle etiological agent of ovine infectious abortion in the United States. During the 1952 lambing season, the lamb abortions were estimated at 50,000 in Colorado, 30,000 to 40,000 in Idaho, and from 10,000 to 15,000 each in Utah and Wyoming. A conservative estimate of premature lamb losses due to V. fetus infections in the western states for this year was 100,000. In infected flocks the incidence of mortality in aborting ewes may be as high as 10 percent. Since 1952 the incidence of vibrosis among sheep has remained high.

Studies In Transmission In Ovine Vibriosis, William H. Rose

Biology

Vibrio fetus, Smith and Taylor, is the principle etiological agent of ovine infectious abortion in the United States. During the 1952 lambing season, the lamb abortions were estimated at 50,000 in Colorado, 30,000 to 40,000 in Idaho, and from 10,000 to 15,000 each in Utah and Wyoming. A conservative estimate of premature lamb losses due to V. fetus infections in the western states for this year was 100,000. In infected flocks the incidence of mortality in aborting ewes may be as high as 10 percent. Since 1952 the incidence of vibrosis among sheep has remained high.

Resistance To And Transmission Of Witches' Broom And Comparative Yields Of Alfalfa Varieties In The Uintah Basin, Utah, David Val Glover

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Alfalfa is the most important forage crop in Utah. It is of particular importance to the Uintah Basin, Utah area where alfalfa hay and seed production are major sources of agricultural income. This crop owes much of its popularity to the fact that it will normally produce large yields of good forage on land which is unsuited to more intensive cultivation. In many cases it is impractical to advocate disease control practices which involve extra labor or expense and as a result most diseases of alfalfa, if controlled at all, are controlled by the use of resistant varieties.

During the …