宇宙用大型展開アンテナの熱変形解析
Abstract
宇宙機が抱える課題の一つに，太陽光に対する著しい温度変化への対応が挙げられる．２００６年打ち上げの技術試験衛星８型では，２００度近い温度変化により，大型展開アンテナからの照射ビーム先端が地上で約６０ｋｍ移動した．将来の通信衛星では，大容量ピンポイントの通信ビームが期待されることを踏まえ，本研究では，アンテナ内に配置されたバネに着目し，バネ力の制御によって熱変形を抑制する方法を数値的に検討した．
Space structures encounter various severe environments in space. One
of these environments is severe thermal condition where the difference of
temperature during day-time and night-time is about 200 degrees Celsius. Engineering
Test Satellite -VIII (ETS-VIII) was launched on December 2006. A signal level
of radio wave from the Large Deployable Reflector (LDR) mounted on the ETS-VIII
was observed to change during the Earth eclipse. This phenomenon was assumed to
be caused by thermal distortion of the LDR. The behaviors of a one-module
antenna model during several patterns of thermal transition are analyzed. From
the numerical results, it is confirmed that the displacements in the antenna do
not depend on the transition patterns of temperature. However, the increase
speed of temperature does seem to affect the internal forces observed in the structural
tubes.