卫星舱内两类剂量计测量结果的比较

本文利用1994年和1996年两次返回式卫星的搭载条件对舱内辐射剂量进行了对比测量．通过对比测量,研究不同掺杂、不同厚度LiF剂量计测量空间辐射剂量的特点;研究GM计数管计数和LiF剂量间的转换系数以及转换系数随屏蔽状况的变化;由剂量和GM计数研究粒子平均碰撞阻止本领的估计方法．结果表明,不同掺杂、不同厚度的LiF剂量计测量结果间无显著差异,而转换系数几乎不受舱内位置和屏蔽状态的影响．不同厚度LiF剂量计,不同屏蔽状态的GM计数管计数和剂量—计数转换系数的比较研究以及对粒子平均碰撞阻止本领的估计表明,舱内辐射剂量起决定作用的是高能粒子成分,其平均碰撞阻止本领估计约为5MeV／cm．     

Why space science and exploration benefit everyone

As well as providing practical information on Earth-besetting problems, space science and exploration are vital tools for capturing the public imagination and encouraging young people's interest in space. The relatively small scale of some scientific instruments also allows mission participation by developing countries. Citing the work of the UN and various NGOs in promoting study and distribution of space science data, the authors recommend that it be given a higher profile and suggest a number of projects -- the Mars drill study in Egypt, refurbishment of a telescope facility in Sri Lanka -- involving developing countries that should be followed up, as well as listing ongoing successful projects. The UN is urged to continue its annual workshops on space science (apparently under threat) and to ensure its inclusion in the forthcoming UNISPACE III Conference.     

International involvement in the US space station programme

This article considers the issues surrounding the nature and extent of involvement in the US space station initiative. The motives and objectives of US cooperation with its allies are analysed from the perspective of both the USA and its potential partners. Guidelines for the forthcoming negotiations between these parties are elaborated through a review of past experience in international space cooperation. Developing a framework for collaboration will require significant trade-offs and will have to accommodate a number of not always consistent interests.     

The United States, the only space superpower

The US space program has emerged from a difficult period of budget cuts and uncertainty about its goals leaner, fitter and much more focused. This contrasts with the world's other major spacefaring countries, which find themselves either the victim of severe economic circumstances (Russia), politically floundering (Europe) or no longer certain of their priorities (Japan). The author briefly appraises each major programme before analysing the current US success. He warns that leadership must not be squandered as it was in some fields after Apollo.     

US–Russian cooperation in human spaceflight: assessing the impacts

How far the broad security, political and economic goals behind the USA's invitation to Russia to participate in the International Space Station have been achieved is assessed in this synthesis of the views of a range of experts in Russian affairs and US foreign and national security policy. The article covers the impacts of cooperation on the Russian aerospace industrial base, on nonproliferation issues and on overall US–Russian relations. Various themes are identified—such as Russian ambivalence over embracing Western norms—and while the experts agreed on certain subjects, there was no overall unanimity.