Engineering Papers⌕ Search

SEARCH · Engineering Papers

Results for “orbit maintenance”

Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 271 records · Page 15
All sourcesNASA NTRSDOE OSTI
NASA NTRS1971

Crew operations

The requirements for the activities involved, and the procedures used by the crew in the operations of the modular space station are presented. All crew-related characteristics of the station and its operations are indicated. The interior configuration and arrangement of each of the space station modules, the facilities and equipment in the module and their operation are described as related to crew habitability. The crew activities and procedures involved in the operation of the station in the accomplishment of its primary mission are defined. The operations involved in initial station buildup, and the on-orbit operation and maintenance of the station and its subsystems to support the experimental program are included. A general description of experiment operations is also given.

Source record↗
NASA NTRS1973

Payloads.

Approaches to payload definition, design, and planning adopted in the Space Shuttle Program are described. The Space Shuttle offers many new modes of operation featuring reuse of spacecraft, on-orbit checkout and maintenance, sortie experiment missions, and opportunities to trade launch weight and volume for cost savings. In order to take advantage of these new approaches and to accommodate the varying missions, new payload elements have been identified, and new low-cost design approaches are being developed to utilize standardized components and modularized subassemblies that reduce spacecraft buildup and maintenance costs. A new payload planning technique makes use of the computer to provide large-scale planning, scheduling, and costing required for various program options.

Marshall, W. R.↗
NASA NTRS1975

Atmosphere explorer /AE-C/ adaptive mission design and trajectory performance

The preflight mission design and in-flight execution are presented to illustrate the actual utilization of the adaptive nature of this mission. Spacecraft systems (propulsion, attitude, accelerometer) and software (maneuver program) features which contribute to the adaptive trajectory flexibility are discussed. Descriptions of procedures used to handle low perigee maneuver operations (to 130 km), for achieving ground track control and orbit phasing, for making a transition from elliptical to circular orbits, and for circular orbit restoration and maintenance are presented in detail. The 85 maneuvers made during the first 17 months of the mission are summarized.

Barbieri, R. W.↗
NASA NTRS1976

The preliminary design of an orbiting observatory - The Space Telescope

The systems and subsystems of the Space Telescope proposed for an orbiting observatory to be launched by the Space Shuttle in the 1980s are described. The structural design is simple and based on existing technologies for high reliability. Provisions are made for on-orbit servicing and maintenance. All deployable appendages are designed for manual override to insure retrieval and return of the Space Telescope to earth for major refurbishing, which should occur at intervals of not less than six years. Low performance risk, passive techniques are used in the thermal control subsystem to provide a cold-biased design with thermostatically controlled heaters to adjust temperature. The electrical power system utilizes NASA Standard Hardware - 50 ampere hour nickel-cadmium battery cells, a standard power regulator unit, and a flight-proven flexible rollup solar array with high-efficiency (12.5 per cent) silicon solar cells. The communication subsystem is designed for compatibility with the Tracking and Data Relay Satellite System. The pointing control system will have a maximum line of sight variation of 0.007 arc seconds. The telescope optics are a Ritchey-Chretien version of the Cassegrain configuration.

Timmons, K. P.↗
NASA NTRS1977

Alternative approaches to space-based power generation

Satellite Power Stations (SPS) would generate electrical power in space for terrestrial use. Their geosynchronous orbit location permits continuous microwave power transmission to ground receiving antenna farms. Eight approaches to the generation of the electrical power to be transmitted were investigated. Configurations implementing these approaches were developed through an optimization process intended to yield the lowest cost for each. A complete program was baselined for each approach, identifying required production rates, quantities of launches, required facilities, etc. Each program was costed, including the associated launches, orbital assembly, and maintenance operations. The required electric power charges to amortize these costs were calculated. They range from 26 to 82 mills/kWh (ground busbar).

Gregory, D. L.↗
NASA NTRS1980

Satellite power system concept development and evaluation program. Volume 1: Technical assessment summary report

Candidate satellite power system (SPS) concepts were identified and evaluated in terms of technical and cost factors. A number of alternative technically feasible approaches and system concepts were investigated. A reference system was defined to facilitate economic, environmental, and societal assessments by the Department of Energy. All elements of the reference system were defined including the satellite and all its subsystems, the orbital construction and maintenance bases, all elements of the space transportation system, the ground receiving station, and the associated industrial facilities for manufacturing the required hardware. The reference conclusions and remaining issues are stated for the following topical areas: system definition; energy conversion and power management; power transmission and reception; structures, controls, and materials; construction and operations; and space transportation.

Source record↗
NASA NTRS1981

Manned geosynchronous mission requirements and systems analysis study extension

Turnaround requirements for the manned orbital transfer vehicle (MOTV) baseline and alternate concepts with and without a space operations center (SOC) are defined. Manned orbital transfer vehicle maintenance, refurbishment, resupply, and refueling are considered as well as the most effective combination of ground based and space based turnaround activities. Ground and flight operations requirements for abort are identified as well as low cost approaches to space and ground operations through maintenance and missions sensitivity studies. The recommended turnaround mix shows that space basing MOTV at SOC with periodic return to ground for overhaul results in minimum recurring costs. A pressurized hangar at SOC reduces labor costs by approximately 50%.

Source record↗
NASA NTRS1985

Gamma-Ray Observatory

The Gamma-Ray Observatory (GRO) will be placed in orbit by the Space Shuttle in the latter part of 1988. This large observatory weighs approximately 34,000 pounds, and the main body measures 25-feet long and 15-feet high and wide. The GRO will carry four scientific instruments that measure the gamma-ray spectrum from the end of the X-ray spectrum to the very high energy gamma. This paper primarily discusses the GRO's design and the procedures that relate to on-orbit servicing and maintenance. The original design of GRO was based on using some of the multimission modules from the Solar-Maximum Mission (SMM). The use of these modules and the increased use of astronauts in space activities has resulted in designs that, hopefully, will make GRO a more versatile observatory.

Madden, J. J.↗
NASA NTRS1987

An overview of the artificial intelligence and expert systems component of RICIS

Artificial Intelligence and Expert Systems are the important component of RICIS (Research Institute and Information Systems) research program. For space applications, a number of problem areas that should be able to make good use of the above tools include: resource allocation and management, control and monitoring, environmental control and life support, power distribution, communications scheduling, orbit and attitude maintenance, redundancy management, intelligent man-machine interfaces and fault detection, isolation and recovery.

Feagin, Terry↗
NASA NTRS1994

ASI's space automation and robotics programs: The second step

The strategic decisions taken by ASI in the last few years in building up the overall A&R program, represent the technological drivers for other applications (i.e., internal automation of the Columbus Orbital Facility in the ESA Manned Space program, applications to mobile robots both in space and non-space environments, etc...). In this context, the main area of application now emerging is the scientific missions domain. Due to the broad range of applications of the developed technologies, both in the in-orbit servicing and maintenance of space structures and scientific missions, ASI foresaw the need to have a common technological development path, mainly focusing on: (1) control; (2) manipulation; (3) on-board computing; (4) sensors; and (5) teleoperation. Before entering into new applications in the scientific missions field, a brief overview of the status of the SPIDER related projects is given, underlining also the possible new applications for the LEO/GEO space structures.

Dipippo, Simonetta↗
NASA NTRS1995

Pulsed Plasma Thruster Technology for Small Satellite Missions

Pulsed plasma thrusters (PPT's) offer the combined benefits of extremely low average electric power requirements (1 to 150 W), high specific impulse (approximately 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 PPT's have been used operationally on several spacecraft, there has been no new PPT technology development since the early 1970's. As result of the rapid growth in the small satellite community and the broad range of PPT applications, NASA has initiated a development program with the objective of dramatically reducing the PPT dry mass, increasing PPT performance, and demonstrating a flight ready system by October 1997. This paper presents the results of a series of near-Earth mission studies including both primary and auxiliary propulsion and attitude control functions and reviews the status of NASA's on-going development program.

Myers, Roger M.↗
NASA NTRS1996

Pulsed Plasma Thruster Technology

The continuing emphasis on reducing costs and downsizing spacecraft is forcing increased emphasis on reducing the subsystem mass and integration costs. For many commercial, scientific, and Department of Defense space missions, onboard propulsion is either the predominant spacecraft mass or it limits the spacecraft lifetime. Electromagnetic-pulsed-plasma thrusters (PPT's) offer the combined benefits of extremely low average electric power requirements (1 to 150 W), high specific impulse (approx. 1000 sec), 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.

Source record↗
NASA NTRS2005

CHAMP (Camera, Handlens, and Microscope Probe)

CHAMP (Camera, Handlens And Microscope Probe)is a novel field microscope capable of color imaging with continuously variable spatial resolution from infinity imaging down to diffraction-limited microscopy (3 micron/pixel). As a robotic arm-mounted imager, CHAMP supports stereo imaging with variable baselines, can continuously image targets at an increasing magnification during an arm approach, can provide precision rangefinding estimates to targets, and can accommodate microscopic imaging of rough surfaces through a image filtering process called z-stacking. CHAMP was originally developed through the Mars Instrument Development Program (MIDP) in support of robotic field investigations, but may also find application in new areas such as robotic in-orbit servicing and maintenance operations associated with spacecraft and human operations. We overview CHAMP'S instrument performance and basic design considerations below.

robotic field investigations↗
NASA NTRS1988

Development of an automated checkout, service and maintenance system for a Space Station EVAS

The development of a new operational system for the Space Station will minimize the time normally spent on performing on-orbit checkout, servicing, and maintenance of an extravehicular activity system of the Space Station. This system, the Checkout, Servicing, and Maintenance System (COSM), is composed of interactive control software interfacing with software simulations of hardware components. The major elements covered in detail include the controller, the EMU simulator and the regenerative life support system. The operational requirements and interactions of the individual elements as well as the protocols are also discussed.

Abeles, Fred J.↗
NASA NTRS1972

Space shuttle maintenance program planning document

A means for developing a space shuttle maintenance program which will be acceptable to the development centers, the operators (KSC and AF), and the manufacturer is presented. The general organization and decision processes for determining the essential scheduled maintenance requirements for the space shuttle orbiter are outlined. The development of initial scheduled maintenance programs is discussed. The remaining maintenance, that is non-scheduled or non-routine maintenance, is directed by the findings of the scheduled maintenance program and the normal operation of the shuttle. The remaining maintenance consists of maintenance actions to correct discrepancies noted during scheduled maintenance tasks, nonscheduled maintenance, normal operation, or condition monitoring.

Brown, D. V.↗
NASA NTRS1992

Operability of Space Station Freedom's meteoroid/debris protection system

The design of Space Station Freedom's external structure must not only protect the spacecraft from the hazardous environment, but also must be compatible with the extra vehicular activity system for assembly and maintenance. The external procedures for module support are utility connections, external orbital replaceable unit changeout, and maintenance of the meteoroid/debris shields and multilayer insulation. All of these interfaces require proper man-machine engineering to be compatible with the extra vehicular activity and manipulator systems. This paper discusses design solutions, including those provided for human interface, to the Space Station Freedom meteoroid/debris protection system. The system advantages and current access capabilities are illustrated through analysis of its configuration over the Space Station Freedom resource nodes and common modules, with emphasis on the cylindrical sections and endcones.

Kahl, Maggie S.↗
NASA NTRS2013

Seven Years of Permanent Running of MELFI-1 on Board the ISS and Utilisation of the Three MELFI Units Refrigeration Pool

The pool of three Minus Eighty Laboratory freezer for ISS (MELFI) units continues providing the scientific community with robust and permanent freezer and refrigeration capabilities for life science experiments on the International Space Station (ISS). Launched in 2006, the first unit will complete, by summer 2013, seven years of continuous operations without intervention on the internal Nitrogen gas cycle, while all necessary hardware and operations were initially planned for preventive maintenance every two years. This unit has demonstrated outstanding performance on orbit and proved the technical decisions made during the development program. Current utilization of MELFI units in the ISS is taking full benefit of the initial specifications, which allows for wide adaptations to cope with the mission scenario imposed by the life extension in orbit. The two other MELFI units, launched respectively in 2008 and 2009, are supporting the first unit providing additional conditioned volume necessary for the science on board, and also for preparing thermal mass used to protect the samples on their way down to earth. The MELFI pool is outfitted with all supporting hardware to allow for extended operation on orbit including preventive and corrective maintenance. The internal components were designed to allow for easy on board maintenance. Spare equipment was installed in the MELFI rack on ISS and specific maintenance means were developed which required crew training before the cold gas cycle could be accessed. The paper will present first how the design choices made for the initial missions are identifying features necessary for extended duration missions, and will then give highlights on the utilization of the MELFI refrigeration pool during the recent years in ISS.

Chegancas, Jean↗
NASA NTRS1988

Space station mobile transporter

The first quarter of the next century will see an operational space station that will provide a permanently manned base for satellite servicing, multiple strategic scientific and commercial payload deployment, and Orbital Maneuvering Vehicle/Orbital Transfer Vehicle (OMV/OTV) retrieval replenishment and deployment. The space station, as conceived, is constructed in orbit and will be maintained in orbit. The construction, servicing, maintenance and deployment tasks, when coupled with the size of the station, dictate that some form of transportation and manipulation device be conceived. The Transporter described will work in conjunction with the Orbiter and an Assembly Work Platform (AWP) to construct the Work Station. The Transporter will also work in conjunction with the Mobile Remote Servicer to service and install payloads, retrieve, service and deploy satellites, and service and maintain the station itself. The Transporter involved in station construction when mounted on the AWP and later supporting a maintenance or inspection task with the Mobile Remote Servicer and the Flight Telerobotic Servicer is shown.

Renshall, James↗