排序方式: 共有17条查询结果,搜索用时 31 毫秒
11.
K.G.H. Schuchardt W. Priester H.G. Peters P.W. Blum 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》1985,5(7):179-182
In order to obtain new insight into the detailed structure of the lower thermosphere the long-established method of drag analysis again proves to be a powerful tool. For near-circular satellite orbits, in addition to the semi-major axis, the eccentricity and the argument of perigee are strongly influenced by atmospheric drag. With the help of a new computational scheme, which is based on fundamental equations of satellite drag analysis, the amplitudes and phases of global density variations are derived. 相似文献
12.
Peters Lloyd S. Brackmann Elizabeth J. Park William T. 《Aerospace and Electronic Systems Magazine, IEEE》1987,2(2):12-16
The current emphasis on designing flexible manufacturing systems, particularly in the electronics manufacturing industry, is bringing automation and robotics technologies to the factory at increasing rates. The rate of advance in these technologies raises serious concerns among engineers and managers about how to proceed in building modern manufacturing systems. A large portion of this uncertainty results from the difficulty of fitting technological advances into the existing models of manufacturing. What is needed is a new framework within which to perceive automation and robotics which will permit the adoption of more encompassing design strategies and principles to be followed in the practice of modernizing and maintaining advanced electronics manufacturing systems. This paper provides a framework that might be adopted to structure new strategies for incorporating automation and robotics in manufacturing. The approach is one that we at SRI have found useful in considering automation and robotics issues for the NASA Space Station and other complex systems which need to incorporate new technologies throughout long lifetimes. These same issues are becoming increasingly important in electronics manufacturing system design and development. 相似文献
13.
The Lunar Orbiter Laser Altimeter Investigation on the Lunar Reconnaissance Orbiter Mission 总被引:3,自引:0,他引:3
David E. Smith Maria T. Zuber Glenn B. Jackson John F. Cavanaugh Gregory A. Neumann Haris Riris Xiaoli Sun Ronald S. Zellar Craig Coltharp Joseph Connelly Richard B. Katz Igor Kleyner Peter Liiva Adam Matuszeski Erwan M. Mazarico Jan F. McGarry Anne-Marie Novo-Gradac Melanie N. Ott Carlton Peters Luis A. Ramos-Izquierdo Lawrence Ramsey David D. Rowlands Stephen Schmidt V. Stanley Scott III George B. Shaw James C. Smith Joseph-Paul Swinski Mark H. Torrence Glenn Unger Anthony W. Yu Thomas W. Zagwodzki 《Space Science Reviews》2010,150(1-4):209-241
The Lunar Orbiter Laser Altimeter (LOLA) is an instrument on the payload of NASA’s Lunar Reconnaissance Orbiter spacecraft (LRO) (Chin et al., in Space Sci. Rev. 129:391–419, 2007). The instrument is designed to measure the shape of the Moon by measuring precisely the range from the spacecraft to the lunar surface, and incorporating precision orbit determination of LRO, referencing surface ranges to the Moon’s center of mass. LOLA has 5 beams and operates at 28 Hz, with a nominal accuracy of 10 cm. Its primary objective is to produce a global geodetic grid for the Moon to which all other observations can be precisely referenced. 相似文献
14.
A formal basis for the design of a checker used in validating safe schedules and in selecting error recovery schedules for satellite control systems is presented. This design includes a high-level specification of checker behavior and properties (called flight rules) of safe schedules. Specifications are written in timed linear logic (TLL). Validation of schedules is performed in terms of real-time telemetry and deduction system proof rules. Telemetry (state information for satellite subsystems) serves as input to the checker. Detection of violation of a flight rule by the checker results in the selection of a contingency plan (error recovery schedule). The checker is illustrated by an example involving the TOPEX/Poseidon Oceanographic Satellite System 相似文献
15.
Based on the results of studies carried out by ESA several possibilities are discussed to achieve mission cost reductions for large Spacelab instrument facilities as compared to their flight on several 7-day duration Spacelab missions. As an example three scientific telescope facilities are selected (LIRTS, EXSPOS, GRIST) which are defined to a Phase A level.Three new mission modes are considered:
- • —Shuttle attached Spacelab mission mode with extended flight duration (up to 30 days) for which the application of planned capability extensions and new elements of the STS/Spacelab (e.g. Short Spacelab Pallets, Power Extension Package) are investigated.
- • —Shuttle deployed mission mode, for which the telescope, accommodated on a Spacelab pallet, is docked to the Power Module, a new element of the Space Transportation System under study by NASA.
- • —Free-flying mission mode, for which Shuttle launched dedicated missions of the facilities are considered, assuming varying degrees of autonomy with respect to supporting services of the Shuttle.
16.
Rahardjo B. Peters J.F. McLeod R.D. 《Aerospace and Electronic Systems Magazine, IEEE》1995,10(7):8-11
Asynchronous circuits are circuits that operate without a common global clock. They are potentially suitable for low-power devices. This paper describes an approach to verify speed-independent asynchronous circuits by using a protocol validation tool 相似文献
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