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At least 19 records

Concepts for space maintenance of OTV engines

Concepts for space maintainability of OTV engines are examined. The advanced efforts are based on work recently completed for NASA Lewis Research Center Space Propulsion Technology Division. An engine design is developed which is driven by space maintenance requirements and by a failure modes and effects analysis. Modularity within the engine is shown to offer cost benefits and improved space maintenance capabilities. Space-operable disconnects are conceptualized for both engine change-out and for module replacement. Through FME mitigation the modules are conceptualized to contain the most often replaced engine components. A preliminary space maintenance plan is developed around a controls and condition monitoring system using advanced sensors, controls, and conditioning monitoring concepts.

Martinez, A.

Concepts for space maintenance of OTV engines

Concepts for space maintainability of the Orbital Transfer Vehicle (OTV) engines are examined. An engine design is developed which is driven by space maintenance requirements and by a failure modes and effects analysis (FMEA). Modularity within the engine is shown to offer cost benefits and improved space maintenance capabilities. Space-operable disconnects are conceptualized for both engine change-out and for module replacement. A preliminary space maintenance plan is developed around a controls and condition monitoring system using advanced sensors, controls, and condition monitoring concepts.

Martinez, A.

Concepts for space maintenance of OTV engines

In this paper, concepts for space maintainability of Orbital Transfer Vehicles engines are examined. An engine design is developed which is driven by space maintenance requirements and by a Failure Modes and Effects Analysis (FMEA). Modularity within the engine is shown to offer cost benefits and improved space maintenance capabilities. Space-operable disconnects are conceptualized for both engine change-out and for module replacement. Through FME mitigation the modules are conceptualized to contain the most often replaced engine components. A preliminary space maintenance plan is developed around a Controls and Condition Monitoring system using advanced sensors, controls, and conditioning monitoring concepts.

Martinez, A.

Multisensor robotic system for autonomous space maintenance and repair

The feasibility of realistic autonomous space manipulation tasks using multisensory information is demonstrated. The system is capable of acquiring, integrating, and interpreting multisensory data to locate, mate, and demate a Fluid Interchange System (FIS) and a Module Interchange System (MIS). In both cases, autonomous location of a guiding light target, mating, and demating of the system are performed. Implemented visio-driven techniques are used to determine the arbitrary two-dimensional position and orientation of the mating elements as well as the arbitrary three-dimensional position and orientation of the light targets. A force/torque sensor continuously monitors the six components of force and torque exerted on the end-effector. Both FIS and MIS experiments were successfully accomplished on mock-ups built for this purpose. The method is immune to variations in the ambient light, in particular because of the 90-minute day-night shift in space.

Abidi, M. A.

Diagnosing anomalies of spacecraft for space maintenance and servicing

Very often servicing of satellites is necessary to replace components which are responsible for anomalous behavior of satellite operations due to adverse interactions with the natural space environment. A major difficulty with this diagnosis is that those responsible for diagnosing these anomalies do not have the tools to assess the role of the space environment causing the anomaly. To address this issue, we have under development a new rule-based, expert system for diagnosing spacecraft anomalies. The knowledge base consists of over two-hundred rules and provides links to historical and environmental databases. Environmental causes considered are bulk charging, single event upsets (SEU), surface charging, and total radiation dose. The system's driver translates forward chaining rules into a backward chaining sequence, prompting the user for information pertinent to the causes considered. When the user selects the novice mode, the system automatically gives detailed explanations and descriptions of terms and reasoning as the session progresses, in a sense teaching the user. As such it is an effective tutoring tool. The use of heuristics frees the user from searching through large amounts of irrelevant information and allows the user to input partial information (varying degrees of confidence in an answer) or 'unknown' to any question. The system is available on-line and uses C Language Integrated Production System (CLIPS), an expert shell developed by the NASA Johnson Space Center AI Laboratory in Houston.

Lauriente, Michael

Space Station maintenance studies using plaid graphics

The Graphics Analysis Facility (GRAF) has been used frequently to study extravehicular activity (EVA) maintenance scenarios on Space Station Freedom. The ability to use 3-dimensional visualization gives one a more accurate estimate of the Space Station environment. Moreover, human EVA and robotic kinematics can be accurately simulated for columetric reach and collision detection analysis. An animation of this kind was developed for a research group at JSC to study and discover problem areas involved with doing external Space Station maintenance tasks. On the EVA side, it was discovered that items such as handholds and temporary restraint mechanisms should more effectively facilitate EVA movement about the Space Station structure for the suited personnel. Issues concerning CETA cart configuration, PWP storage locations, and locations of EVA storage areas were also identified by use of the animation. In the area of EVA versus robotics, it was found that there is a strong desire to make EVA and robotics interfaces compatible on items such as replacement units and unpressurized logistics carriers. The animation also showed that the use of robotics within an EVA task increases the difficulty and duration of the task setup, leaving less time available for the maintenance task itself. Graphics animation provides a mechanism to simultaneously analyze several mission parameters (i.e., EVA reach, volumetric analysis, and task timelines), and thus, it has proven to be an effective method for mission evaluation.

Helm, Mary E.

Space Telescope maintenance and refurbishment

The Space Telescope (ST) represents a new concept regarding spaceborne astronomical observatories. Maintenance crews will be brought to the orbital worksite to make repairs and replace scientific instruments. For major overhauls the telescope can be temporarily returned to earth with the aid of the Shuttle. It will, thus, be possible to conduct astronomical studies with the ST for two decades or more. The five first-generation scientific instruments used with the ST include a wide field/planetary camera, a faint object camera, a faint object spectrograph, a high resolution spectrograph, and a high speed photometer. Attention is given to the optical telescope assembly, the support systems module, aspects of mission and science operations, unscheduled maintenance, contingency orbital maintenance, planned on-orbit maintenance, ground maintenance, ground refurbishment, and ground logistics.

Trucks, H. F.

Evaluation of Hands-Free Devices for Space Habitat Maintenance Procedures

Currently, International Space Station (ISS) crews use a laptop computer to display procedures for performing onboard maintenance tasks. This approach has been determined to be suboptimal. A heuristic evaluation and two studies have been completed to test commercial off-the-shelf (COTS) "near-eye" heads up displays (HUDs) for support of these types of maintenance tasks. In both studies, subjects worked through electronic procedures to perform simple maintenance tasks. As a result of the Phase I study, three HUDs were down-selected to one. In the Phase II study, the HUD was compared against two other electronic display devices - a laptop computer and an e-book reader. Results suggested that adjustability and stability of the HUD display were the most significant acceptability factors to consider for near-eye displays. The Phase II study uncovered a number of advantages and disadvantages of the HUD relative to the laptop and e-book reader for interacting with electronic procedures.

Hoffman, R. B.

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.

Space Station maintenance concept study

The relationships among NASA Space Station operational constraints and logistical requirements are presently investigated. The concepts studied locate organizational, intermediate, and depot maintenance at the Space Station, at the Kennedy Space Center (KSC), and at a depot remote from the KSC. Measures of reliability, maintainability, and availability were selected; a life-cycle study was then conducted to ascertain the optimum Space Station system maintenance concept. The results obtained indicate that orbital replacement unit MTBFs should not be less than 36,000 hours.

Nelson, Eric E.

Innovative Robot Archetypes for In-Space Construction and Maintenance

The space environment presents unique challenges and opportunities in the assembly, inspection and maintenance of orbital and transit spaceflight systems. While conventional Extra-Vehicular Activity (EVA) technology, out of necessity, addresses each of the challenges, relatively few of the opportunities have been exploited due to crew safety and reliability considerations. Extra-Vehicular Robotics (EVR) is one of the least-explored design spaces but offers many exciting innovations transcending the crane-like Space Shuttle and International Space Station Remote Manipulator System (RMS) robots used for berthing, coarse positioning and stabilization. Microgravity environments can support new robotic archetypes with locomotion and manipulation capabilities analogous to undersea creatures. Such diversification could enable the next generation of space science platforms and vehicles that are too large and fragile to launch and deploy as self-contained payloads. Sinuous manipulators for minimally invasive inspection and repair in confined spaces, soft-stepping climbers with expansive leg reach envelopes and free-flying nanosatellite cameras can access EVA worksites generally not accessible to humans in spacesuits. These and other novel robotic archetypes are presented along with functionality concepts

Rehnmark, Fredrik

Orbit Transfer Rocket Engine Technology Program: Advanced engine study, task D.1/D.3

Concepts for space maintainability of OTV engines were examined. An engine design was developed which was driven by space maintenance requirements and by a failure mode and effects (FME) analysis. Modularity within the engine was shown to offer cost benefits and improved space maintenance capabilities. Space operable disconnects were conceptualized for both engine change-out and for module replacement. Through FME mitigation the modules were conceptualized to contain the least reliable and most often replaced engine components. A preliminary space maintenance plan was developed around a controls and condition monitoring system using advanced sensors, controls, and condition monitoring concepts. A complete engine layout was prepared satisfying current vehicle requirements and utilizing projected component advanced technologies. A technology plan for developing the required technology was assembled.

Martinez, A.

Space Assembly, Maintenance, and Servicing Study (SAMSS)

The goal is to define and establish Space Assembly, Maintenance, and Servicing (SAMS) capabilities to meet requirements for improved space systems. Consolidated requirements, hardware/tool concepts, systems analysis, related studies interaction, and schedule/milestones are outlined. This presentation is represented by charts and figures only.

Wong, Joseph