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At least 19 records

Availability of the DSN Telemetry Data System and Its Major Elements, Including the TWM Assemblies

The DSN discrepancy report system which records all outages of DSN data systems that occur during mission support operations is described. The recorded outages of the telemetry data system for 1981 through 1983 were tabulated and availability characteristics of the telemetry data system and several of its major elements, including the traveling wave maser (TWM) Assemblies were developed. Availability characteristics of the TWM assemblies are compared with those of other DSN subsystems and assemblies. It is found that for a three year period, the availability of the telemetry data system is 99.0%, and its mean time to restore service is 0.9 hours; the availability of the TWM assemblies is 99.83%, and their mean time to restore service is 2.5 hours.

Stevens, R.↗

New Directions in Space Operations Services in Support of Interplanetary Exploration

To gain access to the necessary operational processes and data in support of NASA's Lunar/Mars Exploration Initiative, new services, adequate levels of computing cycles and access to myriad forms of data must be provided to onboard spacecraft and ground based personnel/systems (earth, lunar and Martian) to enable interplanetary exploration by humans. These systems, cycles and access to vast amounts of development, test and operational data will be required to provide a new level of services not currently available to existing spacecraft, on board crews and other operational personnel. Although current voice, video and data systems in support of current space based operations has been adequate, new highly reliable and autonomous processes and services will be necessary for future space exploration activities. These services will range from the more mundane voice in LEO to voice in interplanetary travel which because of the high latencies will require new voice processes and standards. New services, like component failure predictions based on data mining of significant quantities of data, located at disparate locations, will be required. 3D or holographic representation of onboard components, systems or family members will greatly improve maintenance, operations and service restoration not to mention crew morale. Current operational systems and standards, like the Internet Protocol, will not able to provide the level of service required end to end from an end point on the Martian surface like a scientific instrument to a researcher at a university. Ground operations whether earth, lunar or Martian and in flight operations to the moon and especially to Mars will require significant autonomy that will require access to highly reliable processing capabilities, data storage based on network storage technologies. Significant processing cycles will be needed onboard but could be borrowed from other locations either ground based or onboard other spacecraft. Reliability will be a key factor with onboard and distributed backup processing an absolutely necessary requirement. Current cluster processing/Grid technologies may provide the basis for providing these services. An overview of existing services, future services that will be required and the technologies and standards required to be developed will be presented. The purpose of this paper will be to initiate a technological roadmap, albeit at a high level, of current voice, video, data and network technologies and standards (which show promise for adaptation or evolution) to what technologies and standards need to be redefined, adjusted or areas where new ones require development. The roadmap should begin the differentiation between non manned and manned processes/services where applicable. The paper will be based in part on the activities of the CCSDS Monitor and Control working group which is beginning the process of standardization of the these processes. Another element of the paper will be based on an analysis of current technologies supporting space flight processes and services at JSC, MSFC, GSFC and to a lesser extent at KSC. Work being accomplished in areas such as Grid computing, data mining and network storage at ARC, IBM and the University of Alabama at Huntsville will be researched and analyzed.

Bradford, Robert N.↗

A Study of DSN Traveling Wave Maser System Reliability

Reliability and availability characteristics of the DSN traveling wave maser (TWM) Assemblies are reported for the years 1981 through 1983, the charcteristics determined are: mean time between failures (MTBF) - 1200 hours; mean time to restore service (MTTRS) - 2.5 hours; and availability - 99.83%. The TWM MTBF is very good as compared to other DSN subsystems and assemblies. The TWM MTTRS is currently about three times as long as the average of other DSN subsystems. The dominant cause of TWM failures is contamination of the helium gas in the closed cycle refrigerators. Station configurations that do not provide TWM redundancy are subject to reception outages for long periods of time. Recommendations are made to improve the TWM Assembly availability characteristics for future mission support operations.

Stevens, R.↗

Determining Availability Characteristics of DSN Data Systems Using Discrepancy Report Data

A reasonably economical way was developed to determine availability characteristics of Deep Space Network (DSN) data systems, subsystems, and assemblies using the DSN discrepancy report (DR) data base and DSN operating schedule and history data bases. Operating mean time between failures (OMTBF), operating mean time to restore service (OMTTRS), and operating functional availability (OFA) can be computed by year, by system, by subsystem, by assembly, and by station. The effort required to produce the desired reports is described, specific data on the telemetry, command, and tracking systems are presented, and major contributors to system outages are identified. Future improvements in preparing and analyzing DR data are also outlined to enhance their use in correcting conditions that lead to outages.

Ruskin, A. M.↗

Availability analysis of the traveling-wave maser amplifiers in the deep space network. Part 1: The 70-meter antennas

The results of the reliability and availability analyses of the individual S- and X-band traveling-wave maser (TWM) assemblies and their operational configurations in the 70-meter antennas of NASA's Deep Space Network (DSN) are described. For the period 1990 through 1991, the TWM availability parameters for the Telemetry Data System are: mean time between failures (MTBF), 930 hr; mean time to restore services (MTTRS), 1.4 hr; and the average availability, 99.85 percent. In previously published articles, the performance analysis of the TWM assemblies was confined to the determination of the parameters specified above. However, as the mean down time (MDT) for the repair of TWM's increases, the levels of the TWM operational availabilities and MTTRS are adversely affected. A more comprehensive TWM availability analysis is presented to permit evaluation of both MTBF and MDT effects. Performance analysis of the TWM assemblies, based on their station monthly failure reports, indicates that the TWM's required MTBF and MDT levels of 3000 hr and 36 to 48 hr, respectively, have been achieved by the TWM's only at the Canberra Deep Space Station (DSS 43). The Markov Process technique is employed to develop suitable availability measures for the S- and X-band TWM configurations when each is operated in a two-assembly standby mode. The derived stochastic expressions allow for the evaluation of those configurations' simultaneous availability for the Antenna Microwave Subsystem. The application of these expressions to demonstrate the impact of various levels of TWM maintainability (or MDT) on their configurations' operational availabilities is presented for each of the 70-m antenna stations.

Issa, T. N.↗

An Approach for the Assessment of System Upset Resilience

This report describes an approach for the assessment of upset resilience that is applicable to systems in general, including safety-critical, real-time systems. For this work, resilience is defined as the ability to preserve and restore service availability and integrity under stated conditions of configuration, functional inputs and environmental conditions. To enable a quantitative approach, we define novel system service degradation metrics and propose a new mathematical definition of resilience. These behavioral-level metrics are based on the fundamental service classification criteria of correctness, detectability, symmetry and persistence. This approach consists of a Monte-Carlo-based stimulus injection experiment, on a physical implementation or an error-propagation model of a system, to generate a system response set that can be characterized in terms of dimensional error metrics and integrated to form an overall measure of resilience. We expect this approach to be helpful in gaining insight into the error containment and repair capabilities of systems for a wide range of conditions.

Torres-Pomales, Wilfredo↗

Restore-L Satellite Servicing Internship Final Report

This paper reviews the Restore-L mission purpose and the necessary research and simulations to meet mission specification for the Propellant Transfer Subsystem (PTS). It is essential the PTS undergoes functionality testing, environmental testing, and calculations to understand the capabilities of the system. For the testing of components from PTS, a proper test setup is required. It is vital for test hardware, such as hoses and valves, to stay in place while the test is being performed. For the test hardware to operate correctly, positioning, orientation, and alignment are critical as well. In addition to the testing, calculations for pressure drop were explored. To meet requirements for test setups, designs for test hardware mounts were sketched, 3D modeled, and manufactured. Using fluid mechanics for calculations, a pressure drop equation was applied with known variables from mission specification. With the test hardware mounts designed and manufactured, the test setup was assembled with mounts installed. Test hardware mounts met all design requirements. Calculation for pressure drop were concluded and an answer was achieved. Meeting design requirement, mission specification, and calculating correct results allow the Restore-L mission to make further progress and help understand the effectiveness of the Propellant Transfer Subsystem.

PTS↗

Service Lives Of Restored Bearings

Rebuilt units last almost as long as new ones. Report describes theoretical and experiemental studies of lifetimes of restored ball and cylindrical-roller bearings. Results of this and related studies have implications of economy and safety in modern high-speed machinery, especially in aircraft industry, where inspection and rejection or replacing of bearings are new standard practice.

Zaretsky, Erwin V.↗

Restore-L Satellite Servicing Internship Final Report

An experiment was conducted to determine whether a sample of shorter flexible metal hoses could sustain tensile loads of up to 200 lbf and continue to meet the minimum mission requirements. The purpose of this experiment was to determine if tension loads during the processing of the hoses compromise performance. With this information, it will be decided whether the flight flex-hose manufacturer should proceed with the testing of the full-scale flex-hoses. To reduce the time and funding required for this test, a test fixture was designed and assembled in the Engineering Development & Operations (EDO) test facility. In this test fixture, two Engineering Development Unit (EDU) flex-hoses were loaded with free floating weights up to 350 lbf. A load of 200 lbf equates to the maximum expected loading with a margin of safety, thus all data recorded after 200 lbf was purely for reference. Measurements were taken using a tape measure and a custom datum measurement system to record the loaded and unloaded length of each flex-hose at various loads. Any permanent stretching beyond a 1/8th of an inch was indicative of inelastic yielding. The loading of each flex-hose was done with an initial weight 80 lbf and was increased to 100 lbf. Additional loading up to 350 lbf was done by 50 lbf increments thereafter. During the performance of the test, slippage occurred in the mounting of the flex-hoses in the test fixture. The first slippage occurred during the testing of the first flex-hose due to the collar of the flex-hose slipping within the collet of the top Kellem. As a result, the first flex-hose test was terminated early to modify the fixture. Due to the flex-hose not inelastically yielding, the test was repeated on the first flex hose. This test resulted in another instance of slippage in the upper collar of the Kellem due to tape interfering with the securing of a collet around the collar of the flex-hose. The test was then continued with one more slippage of the flex-hose within the collet of the bottom Kellem. Preventive measures were taken for future slippage, and the second hose remained secure during testing.Once the tests were concluded, the elongation of each hose was analyzed for inelastic yielding. Both flex-hoses stretched a measurable and repeatable amount under loading, however, this stretching was recovered once each hose was unloaded. As a result, both EDU flex-hoses did not experience any inelastic yielding during the tension testing. Once received, one additional flex-hose will be tested for yielding, but at the time of this paper, the recommendation is to proceed with testing of the full-scale flex-hoses at the flex-hose manufacturer.

Dziekan, Joseph↗

HST image restoration: A comparison of pre- and post-servicing mission results

A variety of image restoration techniques (e.g., Wiener filter, Lucy-Richardson, MEM) have been applied quite successfully to the aberrated HST images. The HST servicing mission (scheduled for late 1993 or early 1994) will install a corrective optics system (COSTAR) for the Faint Object Camera and spectrographs and replace the Wide Field/Planetary Camera with a second generation instrument (WF/PC-II) having its own corrective elements. The image quality is expected to be improved substantially with these new instruments. What then is the role of image restoration for the HST in the long term? Through a series of numerical experiments using model point-spread functions for both aberrated and unaberrated optics, we find that substantial improvements in image resolution can be obtained for post-servicing mission data using the same or similar algorithms as being employed now to correct aberrated images. Included in our investigations are studies of the photometric integrity of the restoration algorithms and explicit models for HST pointing errors (spacecraft jitter).

Hanisch, R. J.↗

NASA Pathways: Intern Employment Program Work Report Summer 2014

This report documents the work experience and project involvement of Kyle Davidson during his tenure at Kennedy Space Center for the summer of 2014. Projects include the Nitrogen Oxygen Recharge System (NORS), Restore satellite servicing program, and mechanical handling operations for the SAGE III and Rapidscat payloads.

Pathways↗

Restore-L Intern Final Report

Every year, approximately 20 satellites are retired because their propellants are exhausted. Primarily limited by fuel, the satellites are usually fully functioning otherwise. The lifetimes of satellites can be extended with the capability of refueling. Not only would refueling extend satellite lifetime, it would also provide future satellites flexibility to prioritize other elements of their missions. Restore-L is a Goddard Space Flight Center Satellite Servicing Projects Division mission with the primary objectives of developing tools, technologies, and techniques to extend the lifetime of satellites - even if they were not designed to be serviced in or- bit. Equipped with five key servicing technology elements, the Restore-L Servicing Vehicle will demonstrate industry-changing satellite servicing technologies. The primary goal of the Restore-L mission is to rendezvous with, grasp, refuel, and relocate a government-owned satellite to extend its lifetime. The Propellant Transfer Subsystem (PTS) is required to deliver measured amounts of fuel to the client satellite in a safe manner.

Negi, Abhay↗

Towards a State Based Control Architecture for Large Telescopes: Laying a Foundation at the VLT

Large telescopes are characterized by a high level of distribution of control-related tasks and will feature diverse data flow patterns and large ranges of sampling frequencies; there will often be no single, fixed server-client relationship between the control tasks. the architecture is also challenged by the task of integrating heterogeneous subsystems which will be delivered by multiple different contractors. Due to the high number of distributed components, the control system needs to effectively detect errors and faults, impede their propagation, and accurately mitigate them in the shortest time possible, enabling the service to be restored. The presented Data-Driven Architecture is based on a decentralized approach with an end-to-end integration of disparate, independently developed software components. These components employ a high-performance standards-based communication middle-ware infrastructure, based on the Data Distribution Service. A set of rules and principles, based on JPL's State Analysis method and architecture, are use to constrain component-to component interactions, where the Control System and System Under Control are clearly separated. State Analysis provide a model-based process for capturing system and software requirements and design, greatly reducing the gap between the requirements on software specified by systems engineers and the implementation by software engineers. The method and architecture has been field tested at the Very Large Telescope, where it has been integrated into an operational system.

European Extremely Large Telescope (E-ELT)↗

Rehabilitation and the Veterans' Administration

The Veteran's Administration health care system provides prosthetic and sensory aids for the rehabilitation of neurologically handicapped veterans. Research and development centers include prosthetic clinic teams, orthopedic shops, restoration clinics, bioengineering services, orthotics, etc.

Meister, F.↗

CF6 jet engine performance deterioration results

The use of the performance baseline from the flight planning manual as a reference to measure changes in cruise fuel flow rates was discussed. For the CF6-6D engine, the introduction of design changes for performance and durability reasons was seen to introduce an average increment relative to this baseline of 3.2% WFM increase at Nl, 2.5% Fn increase at Nl, 0.8% specific fuel consumption (SFC) increase at Fn, and 7 C EGT increase at Nl, while maintaining sufficient SFC margin of the delivered airplane. The effect of revenue service deterioration and performance restoration relative to the reference was shown to be an adder on top of these design effects. A schematic of typical CF6-6D performance through revenue service and airline maintenance is presented in terms of percent cruise SFC relative to an airline datum point (average level upon entering revenue service). The typical changes in SFC margin are shown for airline revenue service through for installations and refurbishments.

Lewis, R. J.↗

Space Shuttle Mission STS-61: Hubble Space Telescope servicing mission-01

This press kit for the December 1993 flight of Endeavour on Space Shuttle Mission STS-61 includes a general release, cargo bay payloads and activities, in-cabin payloads, and STS-61 crew biographies. This flight will see the first in a series of planned visits to the orbiting Hubble Space Telescope (HST). The first HST servicing mission has three primary objectives: restoring the planned scientific capabilities, restoring reliability of HST systems and validating the HST on-orbit servicing concept. These objectives will be accomplished in a variety of tasks performed by the astronauts in Endeavour's cargo bay. The primary servicing task list is topped by the replacement of the spacecraft's solar arrays. The spherical aberration of the primary mirror will be compensated by the installation of the Wide Field/Planetary Camera-II and the Corrective Optics Space Telescope Axial Replacement. New gyroscopes will also be installed along with fuse plugs and electronic units.

Source record↗

Mission Use of the SpaceCube Hybrid Data Processing System

The award-winning SpaceCube v2.0 system is a high performance, reconfigurable, hybrid data processing system that can be used in a multitude of applications including those that require a radiation hardened and reliable solution. This presentation provides an overview of the design architecture, flexibility, and the advantages of the modular SpaceCube v2.0 high performance data processing system for space applications. The current state of the proven SpaceCube technology is based on 11 years of engineering and operations. Eight systems have been successfully operated in space starting in 2008 with eight more to be delivered for payload integration in 2018 in support of various missions. This presentation will highlight how this multipurpose system is currently being used to solve design challenges of a variety of independent applications. The SpaceCube hardware adapts to new system requirements by allowing for application-unique interface cards that are utilized by reconfiguring the underlying programmable elements on the core processor card. We will show how this system is being used to improve on a heritage NASA GPS technology, enable a cutting-edge LiDAR instrument, and serve as a typical command and data handling (CDH) computer for a space robotics technology demonstration.Finally, this presentation will highlight the use of the SpaceCube v2.0 system on the Restore-L robotic satellite servicing mission. SpaceCube v2.0 is the central avionics responsible for the real-time vision system and autonomous robotic control necessary to find, capture, and service a national asset weather satellite.

Petrick, Dave↗

NASA's Work in Exoplanet Hunting Satellites and Robotic Servicing of Satellites

An overview of three missions connected with NASA's Goddard Space Flight Center at the present time: (1) NASA's flagship mission, the James Webb Space Telescope, is nearing its 2021 launch date. The James Webb, which is considered the successor to the Hubble Space Telescope, will orbit at the Earth-Sun Lagrangian Point Two where it will peer back in time, using infrared detectors, to the beginnings of our Universe. (2) NASA is conducting pioneering work in the field of robotic satellite servicing in earth orbit. The RESTORE-L project, which is slated for a 2021 launch date, is expected to pave the way for the inception of robotic assembly for deep space exploration as well as the commercialization of satellite servicing. (3) The Transiting Exoplanet Survey Satellite (TESS) has been orbiting the Earth actively searching for new planets since April of 2018. The discoveries that TESS has made to-date have benefited from a careful characterization of the refractive lens assemblies on its science instruments. The presentation will provide a detailed description of how the index of refraction of the glasses used to fabricate the TESS lens assemblies were measured at Goddard to an accuracy that enables the ability to make exoplanet discoveries hundreds of light years from Earth.

Miller, Kevin H.↗