Koryo Miura

Deployable antenna with 10-m maximum diameter for space use

This paper describes a large deployable antenna which is used at L-, C-, and Ka-bands on an artificial satellite in space. The main reflector with 10-m maximum diameter is formed using the tensioned truss concept which was proposed by one of the authors. The mechanical structure of the antenna is briefly explained and a more detailed description given of the electrical design of the antenna and the verification method of electrical characteristics. This antenna was successfully launched and deployed in space in 1997 and is used for a Space VLBI mission.

Preliminary evaluation of the spinning planar solar sail

A model o f sp inn ing p l a n a r s o l a r s a i l spacecraf ts i s proposed and evaluated f rom t h e view p o i n t s o f s t r u c t u r a l dynamics. Th is s tudy c l a r i f i e d t h a t t h e c e n t r i f u g a l f o r c e consequent on sp inn ing improves t h e p r o p u l s i v e e f f i c i e n c y o f a s o l a r s a i l and s t i f f e n s t h e whole spacecraf t . The miss ion f rom t h e geosynchronous o r b i t t o t h e moon i s taken as an example t o s tudy t h e c o n t r o l a b i l i t y o f a sp inn ing p lanar s o l a r s a i l spacecra f t , and t h e s u f f i c i e n t c o n t r o l to rque i s g iven by us ing c o n t r o l vanes. The s t a b i 1 i t y a n a l y s i s o f c o n t r o l vanes subjected t o t h e s o l a r r a d i a t i o n pressure i s c a r r i e d ou t by means o f v a r i a t i o n a l method, and t h e p r o b a b i l i t y o f f l u t t e r between t o r s i o n a l and i n p l a n e mot ion i s detected, b u t t h i s i n s t a b i l i t y can be avoided. I t i s shown t h a t t h e concept o f a sp inn ing p lanar s o l a r sa i 1 spacecra f t i s hopefu l candidate f o r f u t u r e s o l a r s a i l i n g .

Spacecraft antenna measurement eliminating gravity effect

The surface errors of a deployable mesh antenna are measured. A measurement method which eliminates the gravity effect is presented which is based on the near-field antenna measurement technique (D.M. Kerns, 1978) and Fourier series expansion in the polar coordinate fixed to measurement systems.<<ETX>>