Design of Onboard Communication Systems for Formation Flight SCOPE Mission
- Paper number
IAC-05-B3.6.06
- Author
Dr. Tomoaki Toda, Japan Aerospace Exploration Agency (JAXA)/ISAS, Japan
- Coauthor
Dr. Yoshifumi Saito, Japan Aerospace Exploration Agency (JAXA), Japan
- Coauthor
Dr. Yuichi Tsuda, Japan Aerospace Exploration Agency (JAXA), Japan
- Year
2005
- Abstract
SCOPE (Scale COupling in Plasma universE) is the mission exploring the magnetospheric tail of the Earth following the successful work with GEOTAIL launched in 1992. GEOTAIL played a big role to impress the importance of ions behavior for understanding physics in the geomagnetic tail. It triggered to pay attention to further microscopic scale phenomena, i.e. electrons role and its interaction with ions and waves in the plasma known as the dynamics in the cross scale coupling mechanism. One of the most effective ways studying these interacted particles and waves is to probe them directly with formation flying satellites, which tell us their time-and-space resolved important facts from multiple viewpoints. SCOPE is JAXA's first formation flying mission proposed for this purpose. In the SCOPE mission, 5 satellites are to work cooperatively in their long elliptical orbit. They are composed of a mother satellite and 4 daughter satellites, all of which are spin-stabilized. One of the daughters is placed close to the mother with its spin axis normal to the mother one and the rests are respectively placed in the orthogonal axes with their spin axis parallel to the mother one. The inter-satellite link between the mother and daughters are used for both command/telemetry and ranging operation. In this configuration, the communication systems for the SCOPE mission must be designed. Because their launch vehicle will be M-V of JAXA, the resources permitted for the communication systems are strictly restricted. The operation of satellites has 2 stages. In the first stage succeeding the launch operation, the satellites are controlled through the mother satellite with the daughters flying its proximity and all the acquired scientific data of the 5 satellites are transmitted through the fast X-band link of the mother. In the second stage where the daughter satellites move away from the mother satellites by more than 100km, all the satellites are directly linked to our ground station, via X-band for the mother and S-band for the daughters. The inter-satellite links are established with S-band to save the communication resources of the daughters. Based on the above outline, the system requirements are as below are demanded in the first stage. 1.Clock synchronization error among satellites less than 1us. 2.Ranging capability between any 2s of satellites and the accuracy between the mother and daughters less than 1m. 3.Assurance of continuous 40kbps data link from the daughters to the mother. A possible model for the mother and daughter satellites communication system satisfying above requests will be discussed. The trade-offs between securing the communication link establishment among the satellites and assuring a higher data rate within limited resources of daughter satellites are important design factors.
- Abstract document
- Manuscript document
IAC-05-B3.6.06.pdf (🔒 authorized access only).
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