Feasibility Study of Multi-bus Tethered-SPS
- Paper number
IAC-07-C3.1.02
- Author
Prof. Susumu Sasaki, Japan Aerospace Exploration Agency (JAXA)/ISAS, Japan
- Coauthor
Dr. Koji Tanaka, Japan Aerospace Exploration Agency (JAXA)/ISAS, Japan
- Coauthor
Dr. Ken Higuchi, Japan Aerospace Exploration Agency (JAXA)/ISAS, Japan
- Coauthor
Dr. N. Okuizumi, Japan Aerospace Exploration Agency (JAXA)/ISAS, Japan
- Coauthor
Dr. Hiroyuki Ogawa, Japan Aerospace Exploration Agency (JAXA)/ISAS, Japan
- Coauthor
Prof. Shigeo Kawasaki, Kyoto University, Japan
- Coauthor
Dr. Naoki Shinohara, Kyoto University, Japan
- Coauthor
Dr. Kei Senda, Jordan
- Coauthor
Dr. Kosei Ishimura, Hokkaido University, Japan
- Coauthor
Dr. Yoshiyuki Fujino, National Institute of Information and Communications Technology, Japan
- Year
2007
- Abstract
The structure, dynamics, thermal properties, and electrical performance of the Tethered-Solar Power Satellite (Tethered-SPS) have been studied. The most important feature of the Tethered-SPS is that it is constructed by perfectly equivalent power generation/transmission units. Each unit panel, 100 m x 95 m, is suspended by four 5 km-tether wires deployed from a bus unit. The weight and output power of the unit SPS are about 45 MT and 2.2 MW, respectively. They are integrated to the commercial SPS of 1 GW class, by connecting the unit panels and by grouping the bus units. In the concept of the multi-bus system, any scale of SPS can be constructed, depending on the power demand. The unit of Tethered-SPS consists of 3,800 structural unit panels of 5 m x 0.5 m x 0.02 m. The weight of the structural panel is 10.6 kg. The structural panel has 10 power modules of 0.5 m x 0.5 m. In each power module, the electric power generated by the solar cells is converted to the microwave power and no power line interface exists between the modules. The frequency and phase of the local oscillator in each module are synchronized by the bus unit using wireless LAN system. Each module can transmit a 55 W microwave power constantly. The thermal analysis shows the temperature inside the panel keeps the operational temperature from -40˚C to +50˚C if a heater is activated during the low sun angle phase. The structural unit panels are folded in a package of 10 m x 5 m x 3.8 m which is a unit cargo transported from the ground to the low earth orbit by Reusable Launch Vehicles (RLV). The cargo is transferred to the Orbit Transfer Vehicle (OTV) in the low earth orbit around 500 km and is transported to the geo-stationary orbit. The unit of Tethered-SPS is deployed automatically to a 100 m x 95 m panel and is integrated to the SPS main body, which can manipulated by commands from the ground. A series of studies have shown that the multi-bus Tethered-SPS is highly robust and potentially low cost.
- Abstract document