| Project/Area Number |
06650436
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| Research Category |
Grant-in-Aid for General Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Research Field |
情報通信工学
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| Research Institution | The Institute of Space and Astronautical Science |
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Principal Investigator |
YAMAMOTO Zenichi The Inst.of Space & Astronautical Sci., Assistent Prof., 衛星応用工学研究系, 助教授 (60183985)
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| Co-Investigator(Kenkyū-buntansha) |
KAWASHIMA Nobuki The Inst.of Space & Astronautical Sci., Prof., 惑星研究系, 教授 (60013702)
MIZUNO Ei-ichi The Inst.of Space & Astronautical Sci., Assistent, 惑星研究系, 助手 (20229701)
SASAKI Susumu The Inst.of Space & Astronautical Sci., Assistent Prof., 衛星応用工学研究系, 助教授 (00092221)
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| Project Period (FY) |
1994 – 1995
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| Project Status |
Completed (Fiscal Year 1995)
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| Budget Amount *help |
¥1,700,000 (Direct Cost: ¥1,700,000)
Fiscal Year 1995: ¥800,000 (Direct Cost: ¥800,000)
Fiscal Year 1994: ¥900,000 (Direct Cost: ¥900,000)
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| Keywords | Venus atmosphere / Radio occultation / Radar |
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| Research Abstract |
A new radio science technique to measure the Venus lower atmosphere (<35km) near the surface is proposed and analyzed. In order to overcome the difficulty of the ordinary radio accultation technique to measure the Venus atmosphere near its surface due to the high density of the atmosphere near the Venus surface, the reflection wave transmitted from an orbiting spacecraft towards the Venus surface is utilized. The light path difference of the reflected wave on the Venus surface and the one directly transmitted to the earth from the Venus orbiting spacecraft is measured. By changing the injection angle of the reflected wave, the altitude dependence of the refractive index can be obtained. The density profile can be obtained from the refractive index. In the course of the analysis, it is revealed that, though the atmospheric density is very high near the Venus surface, the deviation of the refractive index is still small so that the atmospheric structure can only be obtained when the injection angle to the atmosphere with respect to the horizontal plane should be small. The horizontal variation of the density profile can be obtained by the spacecraft motion.
Unfortunately, the NASA Venus spacecraft Megelan terminated its mission in the early phase of this research, and it was now impossible to test this idea using the spacecraft. The altitude information obtained by Magelan is very important for this new radio science technique. The participation in the next Venus exploration "Venus Multiprobe Mission " is also investigated.
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