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At least 1,045 records · Page 58

Water-propellant resistojets for man-tended platforms

The selection of a propulsion system for a man-tended platform has been influenced by the planned use of resistojets for drag make-up on the manned space station. For that application a resistojet has been designed that is capable of operation with a wide variety of propellants, including water. The reasons for the selection of water as the propellant and the performance of water as a propellant are discussed. The man-tended platform and its mission requirements are described.

Louviere, Allen J.↗

Use of the Orbital Maneuvering Vehicle (OMV) for placement and retrieval of spacecraft and platforms

This paper describes the Orbital Maneuvering Vehicle (OMV) and its intended role as a key element of NASA's space infrastructure. Status, plans, and operational modes are summarized. Typical mission scenarios supporting the servicing of spacecraft and platforms from both the Shuttle and the Space Station are described. Particular emphasis is placed on the orbital mechanics associated with the placement and retrieval of spacecraft and platforms. For example, the optimum placement of a Space Station co-orbiting spacecraft in order to maximize the time interval during which it can be retrieved by a Space Station based OMV is shown as a function of the ballistic coefficient of the spacecraft.

Snoddy, William C.↗

Trace gas measurements from tethered balloon platforms

Instrumentation and chemical sampling and analysis procedures are described for making measurements of atmospheric carbon disulfide in the concentration range 1-1000 pptv from tethered balloon platforms. Results of a study on the CS2 composition of air downward of a saltwater marsh are reported. A method for obtaining the necessary data for solving the budget equations for surface fluxes, chemical formation rates and chemical destruction rates using data acquired from tethered balloon platforms is presented.

Bandy, Alan R.↗

A test-bed for space interferometry: Space Platform Interferometer (SPI)

The Space Platform Interferometer (SPI), a 20-m two-mirror Michelson interferometer, which can reach magnitude 14 at UV and visible wavelengths, is described. The SPI is attached to a platform serviced from the space station. In addition to its ability to produce unique science in the UV, SPI is intended to demonstrate the feasibility of larger projects in the field. Dynamical behavior of the structure in the gravity gradient environment and fringe stabilization at low photon rate are studied by picking up an adjacent bin (in the near IR) on the same object and using it to track the white light fringe in a separate differential interferometer. The same subsystem also corrects for tilt. Active control of critical parameters ensures optical rigidity. Performances are evaluated in low orbit.

Faucherre, M.↗

Carbon Dioxide Observational Platform System (CO-OPS), feasibility study

The Carbon Dioxide Observational Platform System (CO-OPS) is a near-space, geostationary, multi-user, unmanned microwave powered monitoring platform system. This systems engineering feasibility study addressed identified existing requirements such as: carbon dioxide observational data requirements, communications requirements, and eye-in-the-sky requirements of other groups like the Defense Department, the Forestry Service, and the Coast Guard. In addition, potential applications in: earth system science, space system sciences, and test and verification (satellite sensors and data management techniques) were considered. The eleven month effort is summarized. Past work and methods of gathering the required observational data were assessed and rough-order-of magnitude cost estimates have shown the CO-OPS system to be most cost effective (less than $30 million within a 10 year lifetime). It was also concluded that there are no technical, schedule, or obstacles that would prevent achieving the objectives of the total 5-year CO-OPS program.

Bouquet, D. L.↗

Orbiter processing facility service platform failure and redesign

In a high bay of the Orbiter Processing Facility (OPF) at the Kennedy Space Center, technicians were preparing the space shuttle orbiter Discovery for rollout to the Vehicle Assembly Building (VAB). A service platform, commonly referred to as an OPF Bucket, was being retracted when it suddenly fell, striking a technician and impacting Discovery's payload bay door. A critical component in the OPF Bucket hoist system had failed, allowing the platform to fall. The incident was thoroughly investigated by both NASA and Lockheed, revealing many design deficiencies within the system. The deficiencies and the design changes made to correct them are reviewed.

Harris, Jesse L.↗

Water-propellant resistojets for man-tended platforms

The selection of a propulsion system for a man-tended platform has been influenced by the planned use of resistojets for drag make-up on the manned Space Station. For that application a resistojet has been designed that is capable of operation with a wide variety of propellants, including water. The reasons for the selection of water as the propellant and the performance of water as a propellant are discussed. The man-tended platform and its mission requirements are described.

Louviere, Allen J.↗

Flight simulator platform motion and air transport pilot training

The effect of a flight simulator platform motion on the performance and training of a pilot was evaluated using subjective ratings and objective performance data obtained on experienced B-727 pilots and pilots with no prior heavy aircraft flying experience flying B-727-200 aircraft simulator used by the FAA in the upgrade and transition training for air carrier operations. The results on experienced pilots did not reveal any reliable effects of wide variations in platform motion design. On the other hand, motion variations significantly affected the behavior of pilots without heavy-aircraft experience. The effect was limited to pitch attitude control inputs during the early phase of landing training.

Lee, Alfred T.↗

Space station Platform Management System (PMS) replanning using resource envelopes

One of the responsibilities of the Space Station Platform Management System (PMS) is to maintain constraint-free, short-term plans for platform and free-flyer activities. Both the replanning function and the associated constraint-checking function are viewed as potentially requiring expert system assistance. The PMS Resource Envelope Scheduling System (PRESS) expert system, which is currently under development, is described. The PRESS capabilities will include the following: plan, replan, and perform constraint checking using resource envelopes resembling those required for telescience; initialize itself using the results fo a previous run; infer the replanning needs associated with a change in resource availability; allow the user to determine the level of interaction (including an advisory capability) with the system during execution; and generate both a graphic timeline and a report as output. The PRESS is being developed on an IBM PC/AT using TeKnowledge, Inc.'s M.1 expert system shell. The PRESS activity definitions and constraints are based on those defined for the Cosmic Background Explorer (COBE) mission scheduled for launch in early 1989.

Bush, Joy Lee↗

Space Station Freedom electrical power system hardware commonality with the United States Polar Platform

The National Aeronautics and Space Administration has adopted the policy to achieve the maximum practical level of commonality for the Space Station Freedom program in order to significantly reduce life cycle costs. Commonality means using identical or similar hardware/software for meeting common sets of functionally similar requirements. Information on how the concept of commonality is being implemented with respect to electric power system hardware for the Space Station Freedom and the U.S. Polar Platform is presented. Included is a historical account of the candidate common items which have the potential to serve the same power system functions on both Freedom and the Polar Platform.

Rieker, Lorra L.↗

Robotic mobile servicing platform for space station

The semi-autonomous inspection and servicing of the Space Station's major thermal, electrical, mechanical subsystems are critical needs for the safe and reliable operation of the station. A conceptual design is presented of a self-intelligent, small and highly mobile robotic platform. Equipped with suitable inspection sensors (cameras, ammonia detectors, etc.), this system's primary mission is to perform routine, autonomous inspection of the Station's primary subsystems. Typical tasks include detection of leaks from thermal fluid or refueling lines, as well as detection of micro-meteroid damage to the primary structure. Equipped with stereo cameras and a dexterous manipulator, simple teleoperator repairs and small On-orbit Replacement Unit (ORU) changeout can also be accomplished. More difficult robotic repairs would be left to the larger, more sophisticated Mobile Remote Manipulator System (MRMS). An ancillary function is to ferry crew members and equipment around the station. The primary design objectives were to provide a flexible, but uncomplicated robotic platform, one which caused minimal impact to the design of the Station's primary structure but could accept more advanced telerobotic technology as it evolves.

Lowenthal, S. H.↗

U.S. Space Station platform - Configuration technology for customer servicing

Features of the Space Station coorbiting and polar orbiting platforms (COP and POP, respectively) are described that will allow them to be configured optimally to meet mission requirements and to be assembled, serviced, and modified on-orbit. Both of these platforms were designed to permit servicing at the Shuttle using the remote manipulator system with teleoperated end effectors; EVA was planned as a backup and for unplanned payload failure modes. Station-based servicing is discussed as well as expendable launch vehicle-based servicing concepts.

Dezio, Joseph A.↗

Space Station Freedom as an earth observing platform

The Space Station manned base is discussed, focusing on the use of the base as a science platform for earth observation. The program elements of the Space Station are described, including the manned base, the international elements, the Polar Platform, and the Man-tended Frequent Flyer. The accommodation and operational requirements for the earth observation payloads are examined. Candidate missions for the manned base earth observation program are presented, including observations of tropical regions, the Tropical Rainfall Measuring Mission, the tropical regions imaging spectrometer, the Earth Radiation Budget Experiment, and commercial remote sensing.

Snyder, Richard E.↗

Space Station Freedom electrical power system hardware commonality with the United States Polar Platform

Information is presented on how the concept of commonality is being implemented with respect to electric power system hardware for the Space Station Freedom and the U.S. Polar Platform. Included is a historical account of the candidate common items which have the potential to serve the same power system functions on both Freedom and the Polar Platform. The Space Station program and objectives are described, focusing on the test and development responsibilities. The program definition and preliminary design phase and the design and development phase are discussed. The goal of this work is to reduce the program cost.

Rieker, Lorra L.↗

The GEO platform

NASA plans for a Geostationary Earth Observatory (GEO) platform meant to operate in conjunction with the polar orbiting Earth Observing System (EOS) are discussed. The scientific goals of the GEO platform are summarized, and the facility's instruments are examined, including the microwave precipitation radiometer, atmospheric profiler, earth processes spectrometer, advanced lightning mapper, high resolution earth processes imager, operational instrument suite, solar constant and spectrum monitors, earth climate sensor, and trace gas imager. The GEO system to provide data and information to users is addressed.

Koczor, R. J.↗

Distributed planning and scheduling for instrument and platform operations

Distributed planning and scheduling for instruments and platform operations in resource constrained environments are discussed. NASA has repeatedly faced the situation of multiple users having differing goals, objectives, and requirements interacting with a planning and scheduling system. Current examples include the Hubble Space Telescope and Space Station Freedom. The paper provides a brief description of the instrument and platform operations domain, discusses both traditional and distributed planning and scheduling in the context of this domain, and looks at examples of NASA environments in which planning and scheduling is or will be performed in a distributed system.

Hull, Larry G.↗

The Space Shuttle as a polarization observation platform

The advantages and constraints on using the Space Shuttle as a polarization observation platform are discussed. Recommendations made by a workshop to upgrade the Space Shuttle as such a platform are examined, including the location of an imaging system in the cargo bay (using a pointing system controlled by the astronaut or a ground operator). The present status of funding to make such improvements is addressed.

Whitehead, V. S.↗

Simulation of cooperating robot manipulators on a mobile platform

The dynamic equations of motion for two manipulators holding a common object on a freely moving mobile platform are developed. The full dynamic interactions from arms to platform and arm-tip to arm-tip are included in the formulation. The development of the closed chain dynamics allows for the use of any solution for the open topological tree of base and manipulator links. In particular, because the system has 18 degrees of freedom, recursive solutions for the dynamic simulation become more promising for efficient calculations of the motion. Simulation of the system is accomplished through a MATLAB program, and the response is visualized graphically using the SILMA Cimstation.

Murphy, Steve H.↗