In-orbit Deployment Characteristics Of Large Deployable Antenna Reflector Onboard Engineering Test Satellite VIII
- Paper number
IAC-07-C2.2.02
- Author
Dr. Akira Meguro, Japan Aerospace Exploration Agency (JAXA), Japan
- Coauthor
Dr. Kyoji Shintate, Japan
- Coauthor
Mr. Motofumi Usui, Japan Aerospace Exploration Agency (JAXA), Japan
- Coauthor
Mr. Akio Tsujihata, Japan Aerospace Exploration Agency (JAXA), Japan
- Year
2007
- Abstract
This paper describes design, ground testing, an in-orbit experiment and a novel in-orbit operation for large deployable antenna reflectors (LDRs). Two LDRs (TX-LDR for transmitting and RX-LDR for receiving) are installed on Engineering Test Satellite VIII (ETS-VIII). The objective of ETS-VIII is 1) to establish an advanced 3-ton-class satellite bus technology, 2) to develop large deployable antenna reflectors, 3) to demonstrate mobile satellite communication system technology that will enable audio/data communications with hand-held terminals, and 4) to study basic technology of geostationary satellite positioning system. Design philosophies of LDR are 1) the structure must have a perspicuous verification methodology for accuracy and reliability, 2) the structure must be designed to adapt the verification methodology, and 3) each structural element must have a perspicuous function to be verified. Consequently, the reflector design features that the antenna reflector whose aperture is 13 m in diameter (mechanical dimension is 19m x 17 m) consists of fourteen basic modules, and each basic module consist of gold-plated molybdenum mesh, a system of cables to form a mesh into a parabolic surface, and deployable frame structures to give a tension to the cables. Several ground tests had been performed using a modular nature to advantage. Single basic module, three combined modules, seven combined modules, and a fully-combined module were tested step by step. Analysis models were co-related in each step. We found that the accuracy of ground deployment testing would strongly rely on an analysis model when a test article becomes more than about 10 m in size. Therefore, we had to carefully evaluate deployment characteristics when a test article became more than seven modules Prior to the launch of ETS-VIII, we performed an in-orbit deployment experiment using LDREX-2 to confirm evaluation accuracy. The LDREX-2 consists of seven half-scale modules of LDR. Structural design is almost the same as LDR design, except for some detail of mechanical design. The LDREX-2 was launched by ARIANE 5 launch vehicle on 13 October 2006 (Universal Time) as a piggy-back payload. A deployment experiment was performed according to a predetermined program sequence, which started just after the separation of main satellites. Two of four payload attachment fittings (PAF) were used for LDREX-2 itself. Other PAF were used for a battery box and an electrical control box respectively. Two video motion cameras were installed to observe deployment behavior of LDREX-2. Deployment forces were measured to evaluate the accuracy of analytical prediction obtained by ground deployment testing. ETS-VIII was launched by H-IIA launch vehicle on 18 December 2006. After the successful injection into Geo Synchronous Orbit, the RX-LDR and the TX-LDR were successfully deployed on December 25th and 26th, respectively. Deployment behavior both in a close-up and distant view was observed by two onboard cameras for each LDR. Deployment forces and angles were also measured to evaluate the accuracy of analytical prediction obtained by ground deployment testing. In conclusion, we confirmed adequacy of the proposed design and ground verification methodology. We also found some issues to be considered in the future large deployable structures.
- Abstract document
- Manuscript document
IAC-07-C2.2.02.pdf (🔒 authorized access only).
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