We introduced a parallel computer made by HPC Systems.
Research
This research is conducted on the basis of the results obtained by past research project by KAKENHI. The objectives of this researchis to formulate a theory for a fast and highly precise dynamic analysis of large gossamer multi-body space structure, and to understand the essense of the motion of such a structure by using the theory . Here large gossamer multi-body structure means a structure that consists of gossamer structure such as large membrane and cable, and support structures such as extensible booms and spacecraft main body. We pursure the following three theme:
To develop a large scale parallel analysis code NEDA3.0 that can calculate 10 milion time steps of the motion of large gossamer multi-body structure such as so-called "IKAROS2" (DOF is around 200 thousands), ans to show the condition for stable spin deployment and for maintainance of deployed shape of IKAROS2 (for example, appropriate initial spin rate, the amount of solar pressure torque to be cancelled by actuators, and so on),
To show appropriate experimental method of small scale model of large gossamer structure on the flat table (1G, 1atom), in large vacuum chamber (1G, 0 atom), and under micro-gravity environment (0G, 1 atom) using the spin deployment of membrane and self-deployment of membrane truss as examples, to establish a similarity rule to predict the motion of large gossamer structure on orbit from the ground experiment of its small scale model, and to verify the proposed similarity rule by comparing with the numerical results and flight data of IKAROS,
To establish the prediction method of dynamics of large gossamer structure on orbit from small scale ground experiment and numerical analysis results, to show the method to evaluate the effect of each design parameter on the whole motion of the structure quickly by applying the model reduction procedure and error estimation method of model reduction, and to clarify the feature, essense of the motion of large gossamer structure by the examples of spin deployment of membrane and self-deployment of membrane truss.
So-called "IKAROS2"is the spacecraft to explore the Troijan asteroid that is now under study by solar power sail WG of JAXA. It deploy membrane of about 50m square that is covered with thin membrane solar cells. IKAROS2 employs ion thrusters usin ght electric power generated by the solar cells, and explore to the asteroid by way of Jupiter. The area of the membrane is more than ten times of that of IKAROS that has 14m square membrane. The spacecraft main body looks like a tiny object put on large membrane. That's surely "large gossamer muti-body space structure". As you can see at the web site of ISAS
This middle sail (it becomes large spacecraft if it deploys the membrane. But the dimension and the mass of the spacecraft at the launch is middle, so that it is called &middle% sail) uses the membrane as the solar array to supply large electric power to the ion thrusters rather than solar sail propulsion.
"Self-deployment of membrane truss" mentioned above means the self-deployable truss consisting of bi-convex booms that is researched in the project "Realization of large space structure by ultra-light high stiffness convex boom" supported by KAKENHI until FY2014. If membrane is attached to this truss, it becomes a typical gossamer multi-body structure that consists of membrane, flexible booms, and nodes of rigid body. We are also interested in the way to attach the membrane to the truss structure, how to stretch the membrane (how to minimize the effect of the crease of the membrane, how to stretch with wrinkle-free).
Go ONO, Kengo SHINTAKU, Yoji SHIRASAWA, Osamu MORI, Yasuyuki MIYAZAKI, Saburo MATUNAGA, "Study of Asynchronous Solar Sail Deployment Using Finite Element Method", TRANSACTIONS OF THE JAPAN SOCIETY FOR AERONAUTICAL AND SPACE SCIENCES, AEROSPACE TECHNOLOGY JAPAN, Vol. 12 (2014) No. ists29 p. Pc_63-Pc_67, August 2014, DOI: http://dx.doi.org/10.2322/tastj.12.Pc_63.
Space Structure Systems Laboratory
College of Science and Technology, Nihon University
7-24-1 Narashinodai, Funabashi, Chiba 274-8501, Japan
e-mail: asel (at) forth.aero.cst.nihon-u.ac.jp
