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21.
The Dawn Framing Camera 总被引:1,自引:0,他引:1
H. Sierks H. U. Keller R. Jaumann H. Michalik T. Behnke F. Bubenhagen I. B��ttner U. Carsenty U. Christensen R. Enge B. Fiethe P. Guti��rrez Marqu��s H. Hartwig H. Kr��ger W. K��hne T. Maue S. Mottola A. Nathues K.-U. Reiche M. L. Richards T. Roatsch S. E. Schr?der I. Szemerey M. Tschentscher 《Space Science Reviews》2011,163(1-4):263-327
The Framing Camera (FC) is the German contribution to the Dawn mission. The camera will map 4 Vesta and 1 Ceres through a clear filter and 7 band-pass filters covering the wavelengths from the visible to the near-IR. The camera will allow the determination of the physical parameters of the asteroids, the reconstruction of their global shape as well as local topography and surface geomorphology, and provide information on composition via surface reflectance characteristics. The camera will also serve for orbit navigation. The resolution of the Framing Camera will be up to 12 m per pixel in low altitude mapping orbit at Vesta (62 m per pixel at Ceres), at an angular resolution of 93.7 ??rad?px?1. The instrument uses a reclosable front door to protect the optical system and a filter-wheel mechanism to select the band-pass for observation. The detector data is read out and processed by a data processing unit. A power converter unit supplies all required power rails for operation and thermal maintenance. For redundancy reasons, two identical cameras were provided, both located side by side on the +Z-deck of the spacecraft. Each camera has a mass of 5.5 kg. 相似文献
22.
R. Herrmann P. Rudolph H. Krüger G. Schneider R. Röstel R. Kuhl A.S. Okhotin V.T. Khryapov E.V. Markov I.P. Kazakov 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》1981,1(5):163-166
Two sublimation experiments with PbTe were performed at 850°C and 750°C under microgravity conditions during the “Salyut-6”-“Soyuz-31” mission in 1978. The sublimation took place on the (100)-face of a PbTe crystal. The condensate grown at 850°C shows in the upper part the formation of a pyramidal habit. The bulk consists of parallel growth colums with [100]-boundary faces. The charge carrier concentration of the electrons (N=1,5·1019 cm?3) is higher than the homogeniety limit for 800°C should permit. This is in contrast to the result obtained on the PbTe crystal of the parallel experiment on the earth. At 750°C a laminated condensate is grown with a low growth rate. The microphotograph of the substrate shows the beginning whisker formation according to the VLS-mechanism. 相似文献