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  • 1
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    Security Policy for a Generic Space Exploration Communication Network Architecture (2016)
    In:  CASI
    Details
    Publication Date: 2019-07-12
    Description: This document is one of three. It describes various security mechanisms and a security policy profile for a generic space-based communication architecture. Two other documents accompany this document- an Operations Concept (OpsCon) and a communication architecture document. The OpsCon should be read first followed by the security policy profile described by this document and then the architecture document. The overall goal is to design a generic space exploration communication network architecture that is affordable, deployable, maintainable, securable, evolvable, reliable, and adaptable. The architecture should also require limited reconfiguration throughout system development and deployment. System deployment includes subsystem development in a factory setting, system integration in a laboratory setting, launch preparation, launch, and deployment and operation in space.
    Keywords: Computer Systems; Space Communications, Spacecraft Communications, Command and Tracking
    Type: NASA/TM-2016-219123 , E-19246 , GRC-E-DAA-TN32924
    Format: application/pdf
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    NASA TECHNICAL REPORTS
  • 2
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    High-Data-Rate Quadrax Cable Microwave Characterization at the NASA Glenn Structural Dynamics Laboratory (2012)
    In:  CASI
    Details
    Publication Date: 2019-07-12
    Description: An experiment was performed to determine the degradation in the bit-error-rate (BER) in the high-data-rate cables chosen for the Orion Service Module due to extreme launch conditions of vibrations with a magnitude of 60g. The cable type chosen for the Orion Service Module was no. 8 quadrax cable. The increase in electrical noise induced on these no. 8 quadrax cables was measured at the NASA Glenn vibration facility in the Structural Dynamics Laboratory. The intensity of the vibrations was set at 32g, which was the maximum available level at the facility. The cable lengths used during measurements were 1, 4, and 8 m. The noise measurements were done in an analog fashion using a performance network analyzer (PNA) by recording the standard deviation of the transmission scattering parameter S(sub 21) over the frequency range of 100 to 900 MHz. The standard deviation of S(sub 210 was measured before, during, and after the vibration of the cables at the vibration facility. We observed an increase in noise by a factor of 2 to 6. From these measurements we estimated the increase expected in the BER for a cable length of 25 m and concluded that these findings are large enough that the noise increase due to vibration must be taken in to account for the design of the communication system for a BER of 10(exp -8).
    Keywords: Communications and Radar
    Type: NASA/TM-2012-217609 , E-18193
    Format: application/pdf
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    NASA TECHNICAL REPORTS
  • 3
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    Secure Network-Centric Aviation Communication (SNAC) (2017)
    In:  CASI
    Details
    Publication Date: 2019-07-13
    Description: The existing National Airspace System (NAS) communications capabilities are largely unsecured, are not designed for efficient use of spectrum and collectively are not capable of servicing the future needs of the NAS with the inclusion of new operators in Unmanned Aviation Systems (UAS) or On Demand Mobility (ODM). SNAC will provide a ubiquitous secure, network-based communications architecture that will provide new service capabilities and allow for the migration of current communications to SNAC over time. The necessary change in communication technologies to digital domains will allow for the adoption of security mechanisms, sharing of link technologies, large increase in spectrum utilization, new forms of resilience and redundancy and the possibly of spectrum reuse. SNAC consists of a long term open architectural approach with increasingly capable designs used to steer research and development and enable operating capabilities that run in parallel with current NAS systems.
    Keywords: Communications and Radar; Computer Systems
    Type: E-19379 , GRC-E-DAA-TN42728 , Digital Avionics Systems Conference (DASC''17); Sep 17, 2017 - Sep 21, 2017; Saint Petersburg, FL; United States
    Format: application/pdf
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    NASA TECHNICAL REPORTS
  • 4
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    REP Concept Feasibility Study (2004)
    In:  CASI
    Details
    Publication Date: 2019-07-13
    Description: Radioisotope Electric Propulsion (REP) may have the potential to provide certain advantages, over conventional chemical propulsion, for outer planetary exploration involving small bodies and long term investigations for medium class missions requiring power comparable to past outer planetary exploration missions. This paper describes a study that investigates the concept s feasibility by performing a preliminary conceptual design of an REP-based spacecraft for a design reference mission. The mission utilizes a spacecraft with a radioisotope power supply less than one kilowatt while operating for a minimum of 10-years. A key element of the REP spacecraft is to ensure sustained science return by orbiting or flying in formation with selected targets. Utilizing current and impending technological advances, this study finds that at a conceptual design level a small body REP orbiter/explorer appears to be feasible for the design reference mission selected for this study.
    Keywords: Spacecraft Propulsion and Power
    Type: E-14845 , IAC-04-IAA.3.6.P.01 , 55th International Astronautical Congress; Oct 04, 2004 - Oct 08, 2004; Vancouver; Canada
    Format: text
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    NASA TECHNICAL REPORTS
  • 5
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    Non-Maximally Decimated Filter Banks Enable Adaptive Frequency Hopping for Unmanned Aircraft Vehicles (2017)
    In:  CASI
    Details
    Publication Date: 2019-07-13
    Description: In the last few years, radio technologies for unmanned aircraft vehicle (UAV) have advanced very rapidly. The increasing need to fly unmanned aircraft systems (UAS) in the national airspace system (NAS) to perform missions of vital importance to national security, defense, and science has pushed ahead the design and implementation of new radio platforms. However, a lot still has to be done to improve those radios in terms of performance and capabilities. In addition, an important aspect to account for is hardware cost and the feasibility to implement these radios using commercial off-the-shelf (COTS) components. UAV radios come with numerous technical challenges and their development involves contributions at different levels of the design. Cognitive algorithms need to be developed in order to perform agile communications using appropriate frequency allocation while maintaining safe and efficient operations in the NAS and, digital reconfigurable architectures have to be designed in order to ensure a prompt response to environmental changes. Command and control (C2) communications have to be preserved during "standard" operations while crew operations have to be minimized. It is clear that UAV radios have to be software-defined systems, where size, weight and power consumption (SWaP) are critical parameters. This paper provides preliminary results of the efforts performed to design a fully digital radio architecture as part of a NASA Phase I STTR. In this paper, we will explain the basic idea and technical principles behind our dynamic/adaptive frequency hopping radio for UAVs. We will present our Simulink model of the dynamic FH radio transmitter design for UAV communications and show simulation results and FPGA system analysis.
    Keywords: Air Transportation and Safety; Space Sciences (General); Communications and Radar
    Type: GRC-E-DAA-TN30791 , Integrated Communication Navigation Systems (ICNS 2016); Apr 19, 2017 - Apr 21, 2017; Herndon, VA; United States
    Format: application/pdf
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    NASA TECHNICAL REPORTS
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