Thermal fatigue analysis of solar panel structure for micro-satellite applications

Thermal fatigue analysis based on 2D finite difference and 3D finite element methods is carried out to study the performance of solar panel structure during micro-satellite life time. Solar panel primary structure consists of honeycomb structure and composite laminates. The 2D finite difference (I-DEAS) model yields predictions of the temperature profile during one orbit. Then, 3D finite element analysis (ANSYS) is applied to predict thermal fatigue damage of solar panel structure. Meshing the whole structure with 2D multi-layer shell elements with sandwich option is not efficient, as it misses thermal response of the honeycomb structure. So we applied a mixed approach between 3D solid and 2D shell elements to model the solar panel structure without the sandwich option.

Micro-Satellite Structure Fracture Investigation techniques

Mounting accuracy of satellite payload and
ADCS (attitude determination and control subsystem) seats
is one of the requirements to achieve the satellite mission
with satisfactory performance. Deviation of the position of
the mounting seat for Multi-Band-Earth-Imager (MBEI) is
caused by cracks in the plate of the basis unit and bracket
for attachment of MBEI. These cracks were detected during
inspection of the satellite strength mock-up after vibration
testing for air transportation phase. Most probable reason of
the cracking is fatigue damage as strength mock-up
structure was subjected to prolonged vibration loading
during various loading cases. Total vibration duration
during testing is about 56 hours. In order to study the
cracking reasons, finite element modeling of the structural
parts of the basis unit including MBEI bracket and
instrument MBEI is subjected to harmonic response to
simulate vibration loading for the case of air transportation.
Numerical results are compared with the experimental ones,
and mechanical design of the basis-plate unit is modified

Thermal fatigue analysis of small-satellite structure

The small-satellite thermal subsystem main function is to control temperature ranges on equipments, and payload for the orbit specified. Structure subsystem has to ensure the satellite structure integrity. Structure integrity should meet two constraints; first constraint is accepted fatigue damage due to cyclic temperature, and second one is tolerable mounting accuracy at payload and Attitude Determination and Control Subsystem (ADCS) equipments’ seats. First, thermal analysis is executed by applying finitedifference method (IDEAS) and temperature profile for satellite components case is evaluated. Then, thermal fatigue analysis is performed applying finite-element analysis (ANSYS) to calculate the resultant damage due to on-orbit cyclic stresses, and structure deformations at the payload and ADCS equipments seats.

Thermal Deformation Analysis of Micro satellite Structure

Mounting accuracy of satellite payload and ADCS (attitude determination and control subsystem) seats is one of the requirements to achieve the satellite mission with acceptable performance. Components of mounting inaccuracy are technological inaccuracies, residual plastic deformations after loading (during transportation and orbital insertion), elastic deformations, and thermal deformations during orbital operation. This paper focuses on estimation of thermal deformations of satellite structure. Thermal analysis is executed by applying finite-difference method (IDEAS) and temperature profile for satellite components case is evaluated. Then, Perform thermal finite-element analysis applying the finite-difference model results as boundary conditions; and calculate the resultant thermal strain. Next, applying the resultant thermal strain, perform finite-element structure analysis to evaluate structure deformations at the payload and ADCS equipments seats.

Multicamera sport player tracking with Bayesian estimation of measurements

We propose a complete application capable of tracking multiple objects in an environment monitored by multiple cameras. The system has been specially developed to be applied to sport games, and it has been evaluated in a real association-football stadium. Each target is tracked using a local importance-sampling particle filter in each camera, but the final estimation is made by combining information from the other cameras using a modified unscented Kalman filter algorithm. Multicamera integration enables us to compensate for bad measurements or occlusions in some cameras thanks to the other views it offers. The final algorithm results in a more accurate system with a lower failure rate. (C) 2009 Society of Photo-Optical Instrumentation Engineers. [DOI: 10.1117/1.3114605]

Doping, sport and the law: time for repeal of prohibition?

This article concerns the legal issues that surround the prohibition of doping in sport. The current policy on the use of performance enhancing drugs (PEDs) in sport is underpinned by both a paternalistic desire to protect athletes’ health and the long-term integrity or ‘spirit’ of sport. The policy is put into administrative effect globally by the World Anti-Doping Agency (WADA), which provides the regulatory and legal framework through which the vast majority of international sports federations harmonise their anti-doping programmes. On outlining briefly both the broad administrative structures of international sport’s various anti-doping mechanisms, and specific legal issues that arise in disciplinary hearings involving athletes accused of doping, this article questions the sustainability of the current ‘zero tolerance’ approach, arguing, by way of analogy to the wider societal debate on the criminalisation of drugs, and as informed by Sunstein and Thaler’s theory of libertarian paternalism, that current policy on anti-doping has failed. Moreover, rather than the extant moral and punitive panic regarding doping in sport, this article, drawing respectively on Seddon’s and Simon’s work on the history of drugs and crime control mentality, contends that, as an alternative, harm reductionist measures should be promoted, including consideration of the medically supervised use of certain PEDs.