中国液体火箭发动机如何进入21世纪

液体火箭发动机是宇航推进家族的重要成员,将会成为下一个历史时期使有效载荷达到第一宇宙速度的唯一推进手段,是制约航天发展速度的最关键因素。发展运载系统,动力必须先行。中国在21世纪初必须推出能与世界先进国家相当的大型运载火箭。这些火箭不能建立在用原有的发动机增加数量以加大推力的基础上,必须研制单台推力更大、更先进、无污染的新型发动机,同时还需开展火箭航天飞机及其发动机使用的气动塞式喷管的预先研究,以火箭航天飞机为突破口,赶上世界先进水平。     

The Strange Career of the American Spaceplane: The Long History of Wings and Wheels in Human Space Operations

What is it about the concept of a Space Shuttle that has been so inviting throughout the 20th century? A winged, reusable space vehicle for human flight beyond Earth dominated thinking about the task prior to the space age, but to compete with the Soviet Union in the human space spectaculars that began in the late 1950s the USA opted for easier to build and fly ballistic capsules. No sooner had that competition ebbed, however, than NASA returned to the pursuit of a spaceplane, resulting in the building of the winged, reusable Space Shuttle which flew for 30 years. This essay reviews the more than 40‐year history of the quest for a spaceplane that eventually found fruition with the operations of the Space Shuttle and continues with current attempts to create a replacement and ensure that spaceplane dreams are kept alive. Three major lessons concerning this quest come to the fore and are highlighted in this essay: (1) the power of an idea to push engineering reality, (2) the delta between technological knowledge and potential, and (3) the reality of how critical design elements are not only fostered by hard‐headed engineering analysis but also by other conventions and priorities.     

空天飞机的测控通信技术

详细描述了“黑障”产生的原因、对电波传播的影响、等离子体电特性参数;作为一次练习。估算了测控通信系统的工作频率、电波穿过“黑障”区的衰减常数;讨论了空天飞机测控通信体制、主要的系统功能和关键技术。