A brief analysis of US space employment

Space policy is an area of industrial economic policy. The space economy would vanish without the active role of the state. Although space may appear exotic to economist, it is not impossible to provide a quick economic insight into one of the most important aspects of all economic activities - the people employed. The space industry can attract employees from other industries in two ways. First, according to individual preferences and motivations. Second, on the basis of higher wages. Statistical evidence suggests the latter is more common. Moreover wages do not reflect productivity. NASA employees earn much more than employees in law or medicine. This does not match the social importance of these activities. Space employs many more people that stated by the OECD. Taking all activities together space employs almost half a million people in the USA. $1 billion given to NASA creates up to 24 000 vacancies in the space industry and also provides room for another 40 000 in the space economy in the long run. Current changes to the US national space programme suggest a decrease of $1.6 billion per year, implying a loss of up to 39 000 jobs.     

航空CAE品牌调查报告

计算机辅助工程(CAE)是用计算机对工程结构与产品的性能及其生产加工过程,进行分析、模拟、预测、评价、优化,是工业装备和产品创新设计的核心技术,也是国防和军工装备研制的战略技术.经过几十年的发展,CAE技术在航空、航天、机械、汽车、船舶等领域获得成功应用,已成为制造业信息化深化应用的关键技术.     

Long-term evolution of Galileo operational orbits by canonical perturbation theory

Galileo operational orbits are slightly affected by the 3 to 5 tesseral resonance, an effect that can be much more important in the case of disposal orbits. Proceeding by canonical perturbation theory we show that the part of the long-term Hamiltonian corresponding to the non-centralities of the Earth's gravitational potential can be replaced by an intermediary that shows the pendulum dynamics of the 3 to 5 tesseral resonance problem. Inclusion of lunisolar perturbations requires a semi-analytical integration, which is compared with the corresponding results from the well-established Draper Semi-analytical Satellite Theory.