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891.
A Retarding Potential Analyzer (RPA) is designed using a micro-channel plate in front of the collector as a flow amplifier, which makes it possible to detect ion species with very low concentration (<0,5 cm.?3). A technique is described for using the micro-channel plate at abnormally high pressure (>0.01 N/m2). This allows the precise determination of the mass composition of the low ionosphere. An adaptive retarding potential consisting of 2048 steps is used to increase the sensitivity. This retarding potential is applied in the range where dI/dU ≠ 0. The sensor is hermetically sealed and opens on command.  相似文献   
892.
Measurements of the precipitation of electrons and positive ions (in the keV to MeV range) detected aboard eight rockets launched from Northern Scandinavia are reported together with corresponding satellite data. The downgoing integral fluxes indicate the temporal fluctuations during each flight. Height profiles of the energy deposition into the atmosphere at different levels of geomagnetic disturbance are given.  相似文献   
893.
The environmental advantages of ovonic NiH2 batteries, due to the nontoxicity of ovonic alloys, are briefly discussed, and their general performance is described. Commercial progress in their development is summarized. Their use in electric vehicles is examined  相似文献   
894.
895.
Active nutation damping generally requires a unique element to provide the necessary damping torques, plus a nutation-sensing system to properly monitor and control the active element by closed-loop action. This paper describes and analyzes, by computer- assisted mathematical techniques, a nutation damper for a dual-spin spacecraft which does not require an active ?element?. Damping is achieved through the inherent cross-axis torques generated by the spacecraft products of inertia and the existing motor controlling the relative spin rates of the two dynamic components comprising the spacecraft.  相似文献   
896.
897.
Magnetic field experiment for Voyagers 1 and 2   总被引:1,自引:1,他引:0  
The magnetic field experiment to be carried on the Voyager 1 and 2 missions consists of dual low field (LFM) and high field magnetometer (HFM) systems. The dual systems provide greater reliability and, in the case of the LFM's, permit the separation of spacecraft magnetic fields from the ambient fields. Additional reliability is achieved through electronics redundancy. The wide dynamic ranges of ± 0.5 G for the LFM's and ± 20 G for the HFM's, low quantization uncertainty of ± 0.002 ( = 10–5 G) in the most sensitive (± 8 ) LFM range, low sensor RMS noise level of 0.006 , and use of data compaction schemes to optimize the experiment information rate all combine to permit the study of a broad spectrum of phenomena during the mission. Objectives include the study of planetary fields at Jupiter, Saturn, and possibly Uranus; satellites of these planets; solar wind and satellite interactions with the planetary fields; and the large-scale structure and microscale characteristics of the interplanetary magnetic, field. The interstellar field may also be measured.  相似文献   
898.
Calculations are made to obtain the raw electrical power that can be generated by using an ATS-6 type deployable parabolic dish as a surface for mounting solar cells without seriously interfering with its normal function as an antenna. A minimum of a few hundred watts to a maximum of a few kilowatts are generated during the apparent course of the Sun around the spacecraft. Academically, it seems that deployable solar cell panels along with their booms can be avoided.  相似文献   
899.
Dramatic reductions in size and weight have been achieved in the area of signal and information processing. Power conditioning circuits have not kept pace, primarily due to the relatively slow proggress ress in the passive energy storage and transformation devices. A novel converter topology is described that minimizes the task these components must perform and thereby achieve a significant improvement in power supply density.  相似文献   
900.
A satellite has been designed for application to radar calibration. Electromagnetic and mechanical characteristics of the satellite and their influence on the selection of shape and other parameters are discussed. Theoretical and experimental scattering data are included.  相似文献   
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