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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.
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This paper proposes the use of a new tool more quickly develop initial cost and risk estimates of alternative flight options for both single missions and the partnering of missions into a single space flight. this work is particularly useful for small missions that require low-cost opportunities for accessing space.
This guide is written for the space experimenter seeking an understanding of the issues which will drive a large part of the design of a space experiment - the method of access to space.
The yourSky custom astronomical image mosaicking software has a web portal architecture that allows access via ordinary desktop computers with low bandwidth network connections to high performance and highly customizable mosaicking software deployed in a high performance computing and communications environment.
An aerodynamic database for the crew access arm during deployment is generated. While initial attempts used data derived from wind tunnel testing, limitations lead to the use of computational fluid dynamics to improve analysis. This computational data compared favorably to the experimental data increasing confidence in both. Further analysis lead to simplification showing the ability to build the database with a single relative wind variable which takes into account both arm deployment angle and wind direction. Eventually geometric simplifications and conservative results lead to the use of simulations of the CAA alone to build the database.Finally these static conditions are then compared to a dynamic simulation where the CAA rotates into position to test the quasi-steady state assumptions used to generate the database. The dynamic case showed an increase in the moment of interest but within acceptable bounds for now.
An aerodynamic database for the crew access arm during deployment is generated. While initial attempts used data derived from wind tunnel testing, limitations lead to the use of computational fluid dynamics to improve analysis. This computational data compared favorably to the experimental data increasing confidence in both. Further analysis lead to simplification showing the ability to build the database with a single relative wind variable which takes into account both arm deployment angle and wind direction. Eventually geometric simplifications and conservative results lead to the use of simulations of the CAA alone to build the database.Finally these static conditions are then compared to a dynamic simulation where the CAA rotates into position to test the quasi-steady state assumptions used to generate the database. The dynamic case showed an increase in the moment of interest but within acceptable bounds for now.
Multiple access satellite communication systems
Latching mechanism that is securely locked by the movement of the operating handle in one direction is used in limited access areas. This mechanism is operated by a force applied to the handle at small angles.
Double door provides an extreme high vacuum seal as well as access to a vacuum chamber for insertion of test devices into the vacuum environment. This arrangement is applicable to any vacuum chamber and could be of value in cryopumping or mechanically pumped chambers.
Multistation random access satellite communication technique for use with surface systems to meet global needs - routing and economic aspects
Accessible regions method for delineating generalized low thrust trajectory energy requirements and payload capabilities of vehicle systems for exploration of solar system
Comparison of modulation techniques for multiple access synchronous satellite voice communications
Computer memory access commutator and steering gate configuration produces bipolar current pulses while still employing only the diodes and magnetic cores of the classic commutator, thereby appreciably reducing the complexity of the memory assembly.
Managanese bismuthide films are used in the development of a random access memory device of high packing density and nondestructive readout capability. Memory entry is by Curie point switching using a laser beam. Readout is accomplished by microoptical or micromagnetic scanning.
Multiple access techniques for communications satellites - digital modulation, time division multiplexing, and related signal processing
Codes for multiple-access communication satellite systems using time-frequency multiplexing
Analog modulation, frequency-division multiplexing and signal processing for multiple-access satellite communication
Accessibility of solar system regions to earth launched spacecraft using Jupiter gravity- assisted trajectories
Multiple access communication utilizing small ground stations for satellite communication modulation - multiplexing techniques