A study of first month space malfunctions

The study examines the first-month space performance of 57 Goddard Space Flight Center spacecraft. It is a sequel to a previous study of first-day space malfunctions of the same 57 spacecraft. A total of 154 malfunctions, of which 88 were classified as failures, have been summarized by year of occurrence, by major subsystem of a spacecraft, by type of defect, and by severity. Of the 57 spacecraft, 45 had one or more failures during the first month in space. However, the mission criticality data show that, of the 154 malfunctions, less than 10 percent would have resulted in major loss (50-100 percent) to the mission, and due to redundancy, only 5 percent did result in major loss to the mission. The data show that more than 50 percent of the first month's failures occurred in the first operational day in space. The data also show that, for the first month in space, the ratio of system-test failures to space failures for various devices ranged from 3 to 1 up to 10 to 1. For six spacecraft programs, the ratios of test to space failures ranged from 2 to 1 up to 8 to 1

A study of total space life performance of GSFC spacecraft

The space life performance of 57 Goddard Space Flight Center spacecraft is given. The time distribution of 449 malfunctions, of which 248 were classified as failures, is presented. Test data were available for 39 of the spacecraft and permitted a comparison of system test performance with the first-day, first-month, and total space life performance. The failures per spacecraft for the system environmental tests and the three time periods in space were 12, 0.9, 1.7, and 5.0, respectively. Relevance of the data to the pre-shuttle and shuttle eras is discussed. Classifications of failures by type of device and spacecraft subsystem are included. A continuation of the Goddard philosophy of requiring a system-level environmental test program is justified

Experience in Thermal-vacuum Testing Earth Satellites at Goddard Space Flight Center

Thermal-vacuum environmental testing of satellite

Failure rate analysis of Goddard Space Flight Center spacecraft performance during orbital life

Space life performance data on 57 Goddard Space Flight Center spacecraft are analyzed from the standpoint of determining an appropriate reliability model and the associated reliability parameters. Data from published NASA reports, which cover the space performance of GSFC spacecraft launched in the 1960-1970 decade, form the basis of the analyses. The results of the analyses show that the time distribution of 449 malfunctions, of which 248 were classified as failures (not necessarily catastrophic), follow a reliability growth pattern that can be described with either the Duane model or a Weibull distribution. The advantages of both mathematical models are used in order to: identify space failure rates, observe chronological trends, and compare failure rates with those experienced during the prelaunch environmental tests of the flight model spacecraft

A survey of particle contamination in electronic devices

The experiences are given of a number of National Aeronautics and Space Administration (NASA) and Space and Missile System Organization (SAMSO) contractors with particle contamination, and the methods used for its prevention and detection, evaluates the bases for the different schemes, assesses their effectiveness, and identifies the problems associated with each. It recommends specific short-range tests or approaches appropriate to individual part-type categories and recommends that specific tasks be initiated to refine techniques and to resolve technical and application facets of promising solutions

The effectiveness of systems tests in attaining reliable earth satellite performance

Effectiveness of testing complete satellite systems in attaining reliable performance - comparison of simulation and flight result

Changing the Ties That Bind? The Emerging Roles and Identities of General Practitioners and Managers in the New Clinical Commissioning Groups in the English NHS

The English National Health Service (NHS) is undergoing significant reorganization following the 2012 Health and Social Care Act. Key to these changes is the shift of responsibility for commissioning services from Primary Care Trusts (PCTs) to general practitioners (GPs) working together in Clinical Commissioning Groups (CCGs). This article is based on an empirical study that examined the development of emerging CCGs in eight case studies across England between September 2011 and June 2012. The findings are based on interviews with GPs and managers, observations of meetings, and reading of related documents. Scott’s notion that institutions are constituted by three pillars—the regulative, normative, and cognitive–cultural—is explored here. This approach helps to understand the changing roles and identities of doctors and managers implicated by the present reforms. This article notes the far reaching changes in the regulative pillar and questions how these changes will affect the normative and cultural–cognitive pillars

Strangeness production in jets from p+p \sqrt{s} = 200 GeV collisions

Measurements of strangeness production in jets help illuminate the QCD mechanisms in fragmentation. Furthermore, they provide a crucial baseline for heavy-ion studies where modifications in jet chemistry have recently been predicted. We present new results on strange particle production in jets from p+p \sqrt{s} = 200 GeV collisions measured by the STAR experiment. The momentum distributions of the \Lambda, \bar{\Lambda} and K0Short particles are obtained using various jet finding algorithms, and then compared to various models. Strange particle ratios in jets are obtained and compared to values obtained from the inclusive spectra. Finally, we show jets tagged with leading strange baryons and mesons, in order to investigate whether gluon or quark jets can be isolated in this way.Comment: 5 pages, 4 figures, Winter Workshop on Nuclear Dynamics 2010, Jamaic

Test of Chemical freeze-out at RHIC

We present the results of a systematic test applying statistical thermal model fits in a consistent way for different particle ratios, and different system sizes using the various particle yields measured in the STAR experiment. Comparison between central and peripheral Au+Au and Cu+Cu collisions with data from p+p collisions provides an interesting tool to verify the dependence with the system size. We also present a study of the rapidity dependence of the thermal fit parameters using available data from RHIC in the forward rapidity regions and also using different parameterization for the rapidity distribution of different particles.Comment: SQM2008 conference proceeding

Ten simple rules for socially responsible science

Guidelines concerning the potentially harmful effects of scientific studies have historically focused on ethical considerations for minimizing risk for participants. However, studies can also indirectly inflict harm on individuals and social groups through how they are designed, reported, and disseminated. As evidenced by recent criticisms and retractions of high-profile studies dealing with a wide variety of social issues, there is a scarcity of resources and guidance on how one can conduct research in a socially responsible manner. As such, even motivated researchers might publish work that has negative social impacts due to a lack of awareness. To address this, we propose 10 simple rules for researchers who wish to conduct socially responsible science. These rules, which cover major considerations throughout the life cycle of a study from inception to dissemination, are not aimed as a prescriptive list or a deterministic code of conduct. Rather, they are meant to help motivated scientists to reflect on their social responsibility as researchers and actively engage with the potential social impact of their research