月球勘测者"月球勘测轨道器"

美国计划在未来十年内重返月球,向月球发射机器人月球登陆器,并再次实现载人登月.为了给这一宏伟计划做准备,NASA将在2008年十月发射"月球勘测轨道器"(LRO).     

Growth and development of plants flown on the STS-3 Space Shuttle mission

Pre-germinated pine seedlings and germinating oat and mung bean seeds were flown on the STS-3 Space Shuttle mission. Overall, the seedlings grew and developed well in space. Some oat and mung bean roots, however, grew upward. Lignin content was slightly lower in flight tissues and protein content was higher.     

实现机队的最大价值

KealizingtheGreatestValuefromYourFleet编者按：经营性租赁对于中国航空界来说已不是什么新概念，中国南方航空公司就曾在国内率先采用经营性租赁并收到了良好的效果。但是，与传统的购买飞机的航空公司运营方式相比，经营性租赁所占的比例仍较低。本文从经济学的角度详细论述了这种租赁方式的优点，它能令航空公司拥有一文灵活的机队，而无需占用过多的资金，应该说这对于那些新成立的航空公司，或急于占领市场的承运人来说无疑具有十分重要的意义。目前，在经历了1998年亚洲金融危机后，亚太地区，尤其是中国的航空公司普遍面临着效益…     

Seedling growth and development on space shuttle.

Young pine seedlings, and mung bean and oat seeds were flown on shuttle flights, STS-3 and STS-51F, in March, 1982 and July/August, 1985, respectively. The plant growth units built to support the two experiments functioned mechanically as anticipated and provided the necessary support data. Pine seedlings exposed to the microgravity environment of the space shuttle for 8 days continued to grow at a rate similar to ground controls. Pine stems in flight seedlings, however, averaged 10 to 12% less lignin than controls. Flight mung beans grew slower than control beans and their stems contained about 25% less lignin than control seedlings. Reduced mung bean growth in microgravity was partly due to slower germination rate. Lignin also was reduced in flight oats as compared to controls. Oats and mung beans exhibited upward growing roots which were not observed in control seedlings. Chlorophyll A/B ratios were lower in flight tissues than controls. The sealed PGCs exhibited large variations in atmospheric gas composition but the changes were similar between flight and ground controls. Ethylene was present in low concentrations in all chambers.