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

Pain tolerance feedback and deliberate self-harm in men and women

There is a growing literature supporting the idea that those who engage in non-suicidal deliberate self-harm (DSH) have altered pain perception compared to individuals who do not. For example, individuals who report a history of non-suicidal DSH behavior have a decreased sensitivity to transient pain during laboratory-based pain induction (e.g., Glenn et al., 2014). Research suggests that brief manipulations targeting individual beliefs can affect performance on subsequent tasks, including measures of pain sensitivity. To date, however, no study has examined the effects of experimentally manipulated pain perception on DSH behavior. The Self-Aggression Paradigm (SAP: Berman & Walley, 2003; McCloskey & Berman, 2003) allows for the prospective observation of the effects of experimental manipulations on a laboratory analogue of DSH. Therefore, the aim of the current study was to determine if experimentally manipulated false feedback about pain tolerance affects DSH behavior during the SAP, thus potentially providing evidence for a causal linkage between pain perception and DSH. Eighty participants were randomly assigned to one of three feedback groups: High pain tolerance, low pain tolerance, and a control condition with neutral feedback provided after completing the SAP. Participants were provided false feedback regarding their pain tolerance after a pressure algometer task. It was predicted that participants in the high pain tolerance feedback groupwould have the highest DSH on the SAP, with DSH defined as the level of shock self-administered during a series of reaction-time trials. No significant group differences, however, emerged based on group assignment. Men engaged in more DSH than women during the study independent of feedback group assignment. A secondary aim of the current study was to provide further validation for the SAP using multiple pain induction modalities. Implications of the current findings and future research directions are discussed

Motivating students attending a teacher education programme in Hong Kong using quality learning teams

Purpose. In 1995, the Government of Hong Kong amalgamated six independent, Government sponsored Colleges of Education, which offered Certificate in Education courses, into the Hong Kong Institute of Education. The remit of the newly-formed, autonomous Institute was to attain university status and to upgrade courses to degree and post-degree level. Many of the existing staff remained with the newly-formed institute while a recruitment drive resulted in an increase in international lecturing staff. This study results from action research, undertaken by the author, to develop pedagogy suitable for both the international lecturing staff and the Chinese student teachers. The research set out to take advantage of the diverse backgrounds of the lecturing staff. Of the various pedagogic strategies employed by lecturing staff, the Total Quality Management (TQM) approach emerged as the most effective, promoting as it does a way for the students to plumb co-operatively the often difficult depths of what they are studying, as well as motivating them in their chosen career. The stringent examination system in Hong Kong, the lack of university places and the economic situation all play their part in determining the student population in the Institute of Education where students whose first choice is to enter the teaching profession could well be outnumbered by those who consider themselves without more attractive alternatives. In addition, the lecturing staff from overseas became aware of the Chinese culture of 'Shame’ among their students - the students who had failed were castigated and further marginalized by their family and friends. It was hoped that the employment of a TQM approach through the use of Quality Learning Teams would help to combat this 'shame' and, hopefully, increase the self-confidence of these 'shamed' students. The project's aim was to introduce and role-model a different pedagogic practice and to utilise constructivist-based pedagogy so that two major outcomes could be measured: (1) that student teachers would become active and confident learners who would themselves challenge their own pupils and (2) that colleagues outside the project could observe the usefulness of this alternative pedagogy and make use of the innovation in their own lecture rooms. This involved investigation of diverse aspects of teaching and learning. Research on individual areas has been quite extensive, but little research has been done in this particular area with regard to student teachers in Hong Kong and it is, therefore, the purpose of this study to add to existing knowledge, with specific emphasis on Quality Learning Teams. The rationale for the study was, on the one hand, the Hong Kong Special Administration (HKSAR) Government Educational Reforms, but also - and more importantly for the lecturers concerned - the search for a means to inculcate a culture of co-operative learning within the student-teacher body, as well as a means for international lecturing staff to create an effective pedagogy, utilizing both mother tongue and English as languages of instruction. Major Findings. The findings of the study indicated that student learning was enhanced by using Quality Learning Teams. This was demonstrated by the overall module results which showed higher module grades for the groups who were subjected to the innovative pedagogy than for those groups who were subjected to the normal 'traditional' pedagogy. Student self-esteem, self-confidence, trust in peers, and a work ethos of self-sufficiency developed amongst the majority of student teachers. Language skills were enhanced and strategies for learning were improved. It is hoped that the results of this study will assist in the future planning of courses in the education of student-teachers and in creating a more 'risk-taking' culture within the lecturing staff at the Institute

Authenticity in the Classroom: A Qualitative Study of Lesbian Health Educators

This paper discusses the findings of a qualitative study which implemented a narrative inquiry approach to explore how lesbian health educators navigate authenticity in a heteronormative higher education setting

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

Validation of spatial microsimulation models: a proposal to adopt the Bland-Altman method

Model validation is recognised as crucial to microsimulation modelling. However, modellers encounter difficulty in choosing the most meaningful methods to compare simulated and actual values. The aim of this paper is to introduce and demonstrate a method employed widely in healthcare calibration studies. The ‘Bland-Altman plot’ consists of a plot of the difference between two methods against the mean (x-y versus x+y/2). A case study is presented to illustrate the method in practice for spatial microsimulation validation. The study features a deterministic combinatorial model (SimObesity), which modelled a synthetic population for England at the ward level using survey (ELSA) and Census 2011 data. Bland-Altman plots were generated, plotting simulated and census ward-level totals for each category of all constraint (benchmark) variables. Other validation metrics, such as R2, SEI, TAE and RMSE, are also presented for comparison. The case study demonstrates how the Bland-Altman plots are interpreted. The simple visualisation of both individual- (ward-) level difference and total variation gives the method an advantage over existing tools used in model validation. There still remains the question of what constitutes a valid or well-fitting model. However, the Bland Altman method can usefully be added to the canon of calibration methods