Power needs for electric propulsion.
Power needs for electric propulsion systems suited to auxiliary, intermediate and primary propulsion missions application
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Power needs for electric propulsion systems suited to auxiliary, intermediate and primary propulsion missions application
NASA orbital space station mission application program on solar activity, plasma physics, and space environment effect on biological systems
An evaluation of the precise linear sun sensor relating to future mission applications was performed. The test procedures, data, and results of the dual-axis, solid-state system are included. Brief descriptions of the sensing head and of the system's operational characteristics are presented. A unique feature of the system is that multiple sensor heads with various fields of view may be used with the same electronics.
The present day knowledge is reported of comets and asteroids and recommendations for a development program needed to provide instruments to achieve certain scientific objectives are also presented. Discussions include reports on the primary experiments and instruments, the instruments of potential applicability, mission classes and parameters, mission opportunities, and vehicular technology. An annotated bibliography and recommendations for flight projects, propulsion systems, and experiment development are included.
The technology status of 8 cm diameter electron bombardment ion thrusters is presented. Much of the technology resulting from the 5 cm diameter thruster has been adapted and improved upon to increase the reliability, durability, and efficiency of the 8 cm thruster. Technology discussed includes: dependence of neutralizer tip erosion upon neutralizer flow rate; impregnated and rolled-foil insert cathode performance and life testing; neutralizer position studies; thruster ion beam profile measurements; high voltage pulse ignition; high utilization ion machined accelerator grids; deposition internal and external to the thruster; thruster vectoring systems; thruster cycling life testing and thruster system weights for typical mission applications.
The technology status of 8-cm diameter electron bombardment ion thrusters is presented. Much of the technology resulting from the 5-cm diameter thruster has been adapted and improved upon to increase the reliability, durability, and efficiency of the 8-cm thruster. Technology discussed includes: dependence of neutralizer tip erosion upon neutralizer flow rate; impregnated and rolled-foil insert cathode performance and life testing; neutralizer position studies; thruster ion beam profile measurements; high voltage pulse ignition; high utilization ion machined accelerator grids; deposition internal and external to the thruster; thruster vectoring systems; thruster cycling life testing and thruster system weights for typical mission applications.
The feasibility was studied of using adaptive multibeam multi-frequency antennas on the spacelab, and to define the experiment configuration and program plan needed for a demonstration to prove the concept. Three applications missions were selected, and requirements were defined for an L band communications experiment, an L band radiometer experiment, and a Ku band communications experiment. Reflector, passive lens, and phased array antenna systems were considered, and the Adaptive Multibeam Phased Array (AMPA) was chosen. Array configuration and beamforming network tradeoffs resulted in a single 3m x 3m L band array with 576 elements for high radiometer beam efficiency. Separate 0.4m x 0.4 m arrays are used to transmit and receive at Ku band with either 576 elements or thinned apertures. Each array has two independently steerable 5 deg beams, which are adaptively controlled.
Alternatives to all-propulsive manned Orbit Transfer Vehicles (OTV) are presented that utilize aeromaneuvering in combination with propulsive maneuvering. A summary of the results of feasibility and concept definition studies is induced along with a discussion of the advantages and disadvantages of aeromaneuvering as compared with all-propulsive vehicles. Manned aeromaneuvering OTV concepts are described, including the Aeromaneuvering Orbit-to-Orbit Shuttle (AMOOS) for future orbital transportation and the Aeromaneuvering Recovery System (AMRS) for emergency recovery of crewmen from high-altitude orbits. Data are provided regarding aeromaneuvering OTV configurations, performance, systems, tradeoffs, mission applications, and major design parameters, such as dynamic pressure, heating rates, and guidance.
A prototype Electric Power Management and Thruster Control System for a 30 cm ion thruster has been built and is ready to support a first mission application. The system meets all of the requirements necessary to operate a thruster in a fully automatic mode. Power input to the system can vary over a full two to one dynamic range (200 to 400 V) for the solar array or other power source. The Power Management and Control system is designed to protect the thruster, the flight system and itself from arcs and is fully compatible with standard spacecraft electronics. The system is designed to be easily integrated into flight systems which can operate over a thermal environment ranging from 0.3 to 5 AU. The complete Power Management and Control system measures 45.7 cm x 15.2 cm x 114.8 cm and weighs 36.2 kg. At full power the overall efficiency of the system is estimated to be 87.4 percent. Three systems are currently being built and a full schedule of environmental and electrical testing is planned.
A long-lived space-based system that converts on-orbit solar and/or nuclear energy to a suitable form for distribution to using space systems is described. Mission applications, requirements, issues, problems, benefits, and technology thrusts are identified for the multipurpose power platform. Power levels of at least 10-100Kw are required for space manufacturing, satellites, and space station operations. Two Mw are needed for a proposed passive radar system. Propulsion system requirements are in the 100Kw-100Mw range.
A program involving the development of one or more free-flying platforms for earth orbit to provide accommodations and operational services to space science and applications payloads is described. An overview is presented of studies carried out to select a specific platform and utilities module concept, its subsystems, and the means by which services are supplied to dependent science and applications mission equipment. Some examples are given of candidate research and technology programs that support development of the platform system.
The NASA Applications Data Service (ADS), which is being developed to provide timely, affordable access to readily usable multisource data products and services for NASA-affliliated space-technology applications researchers, is presented. The system concept of a decentralized information network, which retrieves data from existing data bases and provides it to the user, has been adopted, and feasibility studies of the compatibility of the ADS with other existing or planned network data systems are under way. Other current efforts include the definition of the requirements and services necessary to support NASA applications experiments and encourage private industry to design the system and commercially implement it, as well as applications scenarios support, commercialization potential, standards identification, and concept justification with respect to future applications missions.
During the timeframe from 1980 to the year 2000, optics technology and applications experiments will require spacecraft that yield the maximum benefit at minimum cost. Current NASA plans include Spacelab, Power Extension Package (PEP), 25 kW Power System (PS), and a Science Applications and Space Platform (SASP), to satisfy the user needs in low earth orbit (LEO) and geosynchronous orbit (GEO). The purpose of this paper is to acquaint the optics technology user with NASA planning applicable to his future needs. This paper identifies current NASA concepts, including Spacelab hardware, that can be utilized to achieve a broad spectrum of optics scientific and application missions. Evolving configurations of Spacelab hardware elements will be shown that can be utilized as an orbital test platform in LEO and GEO.
Regenerative life support systems for future space missions will require closure of the waste-food loop. Each mission application will generate specific requirements for the waste management system. However, there are generic input and output requirements that can be identified when a probable scenario is chosen. This paper discusses the generic requirements when higher plants are chosen as the primary food source. Attention is focused on the quality and quantity of nutrients necessary for culturing higher plants. The types of wastes to be processed are also discussed. In addition, requirements generated by growing plants on three different substrates are presented. This work suggests that the mineral composition of waste materials may require minimal adjustment to satisfy the plant requirements.
A logical next step after shuttle is a manned orbital service system (MOSS) consisting of a two-man crew module mated with a propulsion module. The resulting spacecraft would remain in low Earth orbit for months or years at a time conducting civil or military satellite servicing, experimental, or applications missions while being periodically supplied and refueled by Shuttle flights from the ground. The system would accumulate experience invaluable to the design of future large and more expensive spacecraft. Key features of the vehicle are versatility and mobility. With Centaur-type propulsion and a large payload, the MOSS could leave an initial orbit of 370 km (200 nmi) altitude and inclinations up to 56 deg, make a plane change of up to + or - 14 deg, reach altitudes to 5500 km (2970 nmi), and then return the payload to the original orbit altitude and inclination. Obviously, the size of the performance envelope varies with the payload and propulsion-unit selected. The MOSS can reach orbits and perform tasks not possible with Shuttle alone or with the much larger space stations currently being proposed.
The development of novel electro-optic spatial light modulators (both one and two dimensional) which allows real-time coherent optical SAR processors to be implemented is outlined. It is suggested that the availability of such processors may initiate new mission applications not presently envisioned due to current digital processor limitations.
A historical review is presented of some monoplanar missile systems in which the vehicle flight control was similar to that for a conventional aircraft. The review is essentially chronological, beginning prior to World War I, and includes worldwide programs. Illustrative examples of aerodynamic research with monoplanar missiles are presented including some comparisons with cruciform missiles. Some examples of current programs are presented and some particular mission applications for monoplanar systems are discussed.
A modularized, standardized spacecraft bus, known as MESA, suitable for a variety of science and applications missions is discussed. The basic bus consists of a simple structural arrangement housing attitude control, telemetry/command, electrical power, propulsion and thermal control subsystems. The general arrangement allows extensive subsystem adaptation to mission needs. Kits provide for the addition of tape recorders, increased power levels and propulsion growth. Both 3-axis and spin stabilized flight proven attitude control subsystems are available. The MESA bus can be launched on Ariane, as a secondary payload for low cost, or on the STS with a PAM-D or other suitable upper stage. Multi-spacecraft launches are possible with either booster. Launch vehicle integration is simple and cost-effective. The low cost of the MESA bus is achieved by the extensive utilization of existing subsystem design concepts and equipment, and efficient program management and test integration techniques.