排序方式: 共有34条查询结果,搜索用时 0 毫秒
31.
Stefano Bertone Christophe Le Poncin-Lafitte Pascal Rosenblatt Valéry Lainey Jean-Charles Marty Marie-Christine Angonin 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》2018,61(1):89-96
Accurate tracking of probes is one of the key points of space exploration. Range and Doppler techniques are the most commonly used. In this paper we analyze the impact of the transponder delay, . the processing time between reception and re-emission of a two-way tracking link at the satellite, on tracking observables and on spacecraft orbits. We show that this term, only partially accounted for in the standard formulation of computed space observables, can actually be relevant for future missions with high nominal tracking accuracies or for the re-processing of old missions. We present several applications of our formulation to Earth flybys, the NASA GRAIL and the ESA BepiColombo missions. 相似文献
32.
复合材料在航空领域的大量使用带来了新的技术问题,由于这些材料的性能与"标准"金属不同,特别是要关注其损伤部位,因此重新考虑安装技术以获得有吸引力的机械性能、并使之相对易于操作是很有必要的。基于以上考虑,在阿基坦大区的支持下,Capaero与WCIE(西岸产业欧洲)和Bordeaux的LGM2B实验室一起针对机械工程和材料提出了这种EB2工艺方法。 相似文献
33.
为降低成本,人们正在研发像三维编织结构、三维编织物或纤维铺放等可以生产预型件后再浸胶的材料。该类技术的主要优势在于三维结构直接由一维原材料碳纤维纱线制成。这样就可以不受纤维束二维构型的约束,而是在设计预型件时考虑最终零件上的载荷,即可达到更高的性能。 相似文献
34.
Agnès Levy Bruno Christophe Gilles Métris Philippe Bério Jean-Michel Courty Serge Reynaud 《Space Science Reviews》2010,151(1-3):105-121
The Pioneer anomaly refers to the difference between the computed trajectories of the Pioneer 10 and 11 spacecrafts and their actual trajectories as observed through Doppler tracking. This difference has been described by the Jet Propulsion Laboratory (JPL) as a constant anomalous acceleration. In order to perform an independent analysis, specific trajectography software, named ODYSSEY, has been developed. The paper will focus on the models implemented in this software and on the results obtained. The existence of a constant anomalous acceleration is confirmed with properties similar to those reported by JPL. Time dependent components of the anomaly are also found and discussed. 相似文献