Qualification Model Research Articles

New Satellite Testing Strategy for Commercial Programs

The commercial space industry is required by current and future programs to be always more competitive in terms of cost and schedule. In this context it is mandatory to establish suitable testing approaches that can be a reasonable compromise among the conflicting needs of cost/schedule reduction, technical risk and test effectiveness. The participation of Alenia Spazio in the Globalstar program, having the responsibility of integrating and testing one qualification model and 56 flight models satellites in less than 2 years, with a production rate of four satellites per month, gave the opportunity to investigate suitable test strategies that can achieve such a goal. This paper will describe the various aspects analyzed by Alenia Spazio to identify some aspects and areas related to testing strategy for medium/small size class satellites. The first part of the paper will examine the importance of the “Concurrent Engineering” approach—in place of traditional project environment—aiming to involve test engineers in the satellite project cycle, besides design engineers, from the early program phase. Then the model philosophy and derived test programs will be discussed, outlining the difference between the “design verification oriented” test approach, for satellite qualification purposes and the “workmanship check oriented” test sequence conceived only for recurring flight models. Further discussions will deal with the “island production” approach applicable when a high production rate of satellites is required to deploy in orbit a constellation of small/medium size spacecrafts in short time.

Competence in professional practice: some issues and concerns

Summary As a result of policy initiatives in the mid‐1980s, the Department for Education and Employment has been encouraging the development of national occupational standards and National and Scottish Vocational Qualifications (N/SVQs) in all occupational sectors within the UK. For the health and social care sector, these developments give rise to a number of issues and concerns. Using Health Promotion as an example of an area of professional practice within health and social care, this paper explores the relationship between academic assessment and the assessment of National and Scottish Vocational Qualifications; the relationship between the academic and the National and Scottish Vocational Qualification model of credit accumulation and transfer; and the relationship between qualification, licence to practice and competence in practice. Subsequently, it examines the development of the reflective professional practitioner and the relationship between ‘competence’ and notions of ‘excellence’ and ‘expertise’ in professional practice. Finally, it considers the role of knowledge and understanding in professional practice and the role of academic institutions in the development of a professional practitioner.

The TAUVEX space astronomy experiment

The TAUVEX space astronomy experiment will image wide sky areas in the 190–280 nm spectral region. The experiment is part of the SODART telescope complex on the Spectrum X-Gamma (SRG) spacecraft, and functions as a separate scientific instrument and service system for the spacecraft. TAUVEX consists of three bore-sighted telescopes with 20 cm diameter Ritchey-Chretien optics. Each telescope has a four-position filter wheel and can select one of six UV bands in the spectral region of operation. The photon-counting, imaging detectors cover a field of view of 0.9 degrees, with 80% of the energy from a point source within 10 arcsec, sampled at 3 arcsec intervals. The sensitivity allows the detection of 10–11 mag stars in 2 sec, and 20 mag stars in a typical SRG pointing of 5 hr. TAUVEX provides off-line aspect solutions for the SODART focal plane instruments and on-line fine pointing information to the SRG attitude and control system. The experiment is being constructed by El-Op Electro-Optical Industries Ltd, and is financially supported by the Government of Israel, through the Israel Space Agency, and the Ministry of Science and Arts. By mid-1994, four models of TAUVEX had been produced and supplied to the SRG integrators: size and mass models in 1992, a thermal model in early 1993, and an engineering model in spring 1994. A qualification model is being tested at El-Op and the flight model will be ready, after testing, burn-in and calibration, in the first quarter of 1997.

Professional development in transition: a Canadian provincial case study

Abstract There is no national information technology (IT) training policy in Canada as education is a provincial responsibility. IT training models vary considerably from province to province, but the Ontario Additional Qualification model for in‐service teacher training is perhaps one of the most extraordinary models found anywhere. This paper describes the Ontario model with particular reference to the component of it that deals with IT. The paper concludes with a discussion of the success of the model and future directions that in‐service training is likely to take in Ontario.

Star Mapper Using A Linear Charge-Coupled-Device Array

A star mapper using a Fairchild 2048-element linear CCD array (CCD 143) has been developed for the Indian Remote Sensing Satellite (IRS-1A), which is scheduled for launch in 1987. The star mapper is designed to scan stars up to 5th magnitude by using the orbital motion of the sun synchronous satellite, with a swath of 8° across the scan direction. Design details of the star mapper along with some test results of the qualification model are presented.

EXOSAT x-ray imaging optics

The European X-ray Observatory, EXOSAT, to be launched in 1981 will carry two Wolter I x-ray telescopes, each having a geometric area of ~100 cm(2). A qualification model of the Wolter I optics has been manufactured and extensively tested in optical and x-ray beams. The influence of manufacturing tolerances on the resolution of the optics is discussed, and mechanical and optical measurements of those deviations are presented. Finally, the x-ray imaging quality of the optics is presented, and the correlation with the achieved tolerances is shown.

Dielectric Charging-The Effects of Straggling and Soft X-Ray Irradiation

In this paper, we examine the charge distribution and electric field within a dielectric after it has been charged to saturation by an external kilovolt electron source and then irradiated by soft X-rays. We wish to know whether conditions exist for which soft X-ray irradiation can enhance the electric field in a precharged dielectric and thereby greatly enhance the likelihood of a discharge event. Van Lint et al. reported on discharge events observed on the Skynet satellite qualification model, one of which coincided with soft X-ray irradiation on the precharged satellite exterior. Mandell et al. have suggested a possible mechanism for such events involving surface flashover. We investigate a different mechanism which depends critically on the internal charge distribution and much less so on surface potential.

The Effect of Electron Precharging on SGEMP Response of Insulators

1. Surface potentials in excess of 15 kV can be sustained by kapton, teflon, paint, and fiberglass; with gradients of 106 V/m (at edges). Considerable fine-scale structure was noted. Observed potential decay rates are consistent with typical dielectric resistivities of 1016 to 1018 ohm cm. Spontaneous discharges and photo-induced charge transfers on the order of 2 ,iC were common, as compared to blow-off transfers of approximately 0.2 uCG. Numerous examples of radiation -induced charge redistribution were noted. 2. Enhanced prompt SGEMP response was noted for all samples. These emissions approximately followed the time history of the photon pulse, but with an amplitude 5 to 20 times larger than the uncharged sample. This observation is quantitatively explained and is attributed to the lateral transfer of low energy electrons under the influence of previously existing fields. 3. Contrary to the Skynet Qualification Model observation, no "triggered discharges" were observed in this series. However, on two occasions the paint sample exhibited a delayed component of current lasting 500 ns. This was noted in both the substrate to body current and between the sample and vacuum chamber implying net charge loss from the body rather than just charge transfer on the object. 4. Solar cells, regardless of size (2x2 or 4x4 cm) or thickness (0.006 or 0.012 in) spontaneously discharged at approximately 9±1 kV (e-gun voltages of 11 to 12 kV). These discharges showed considerable variation in nature and magnitude from less than 1 uC to much more than 10 μC. 5.