Saburo Matsunaga

Analysis of Membrane Dynamics using Multi-Particle Model for Solar Sail Demonstrator "IKAROS"

1 Post-doctoral Researcher, JAXA Space Exploration Center, 3-1-1 Yoshinodai, Chuo-ku, Sagamihara, Kanagawa, Japan. 2 Assistant Professor, JAXA Space Exploration Center, 3-1-1 Yoshinodai, Chuo-ku, Sagamihara, Kanagawa, Japan. 3 Professor, Department of Aerospace Engineering, 7-24-1 Narashinodai, Funabashi, Chiba, Japan. 4 Assistant Professor, Department of Mechanical and Aerospace Engineering, 2-12-1 Ookayama, Meguro-ku, Tokyo, Japan. 5 Graduate Student, Department of Aeronautics and Astronautics, 4-1-1 Kitakaname, Hiratsuka, Kanagawa, Japan. 6 Assistant Professor, Institute of Space and Astronautical Science, 3-1-1 Yoshinodai, Chuo-ku, Sagamihara, Kanagawa, Japan. 7 Post-doctoral Fellow, JAXA Space Exploration Center, 3-1-1 Yoshinodai, Chuo-ku, Sagamihara, Kanagawa, Japan. 8 Associate Professor, Department of Built Environment, 4259-G3-6, Nagatsuta, Midori-ku, Yokohama, Japan. 9 Associate Professor, Department of Mechanical and Aerospace Engineering, 2-12-1 Ookayama, Meguro-ku, Tokyo, Japan. 10 Visiting Professor, Faculty of Science and Engineering, 55S-608, 3-4-1 Okubo, Shinjyuku, Tokyo, Japan. 11 Professor, JAXA Space Exploration Center, 3-1-1 Yoshinodai, Chuo-ku, Sagamihara, Kanagawa, Japan. 52nd AIAA/ASME/ASCE/AHS/ASC Structures, Structural Dynamics and Materials Conference 19th 4 7 April 2011, Denver, Colorado AIAA 2011-1890

Small-scale Experiments and Simulations of Centrifugal Membrane Deployment of Solar Sail Craft "IKAROS"

ecently, a variety of solar sail spacecrafts using thin large membranes have been developed in US, Europe and Japan. In Japan, centrifugally deployed solar sails have been mainly investigated 1 . A solar power sail demonstration spacecraft “IKAROS” was developed by Japan Aerospace Exploration Agency and was launched on May 21th, 2010 by H-IIA launch vehicle. 2,3 Figure 1 shows an overview of “IKAROS” in space. The square solar sail with 20 meters in diagonal and 7.5 micrometers in thickness was successfully deployed by centrifugal force using no extendable booms. The sail consists of four trapezoidal petals which were folded up into strips and rolled up around the spacecraft in stowed configuration. The deployment of the membrane consists of two stages. In the first stage, the strips are quasistatically reeled out. In the second stage, the strips are dynamically unfurled. Since on-ground dynamic deployment experiments of the large membrane are impossible, small-scale experiments and numerical simulations are necessary to predict the deployment dynamics. In this paper, a deployment experiment of a smallscale square membrane similar to “IKAROS” is conducted in a vacuum chamber and corresponding numerical simulations are performed by employing a spring-mass system model. The deployment behavior is discussed and the results of the experiment and simulations are compared to examine the validity of the simulations.

In-orbit performance of avalanche photodiode as radiation detector onboard a pico-satellite Cute-1.7+APD II

Cute-1.7+APD II is the third pico-satellite developed by students at the Tokyo Institute of Technology. One of the primary goals of the mission is to validate the use of avalanche photodiodes (APDs) as a radiation detector for the first time in a space experiment. The satellite was successfully launched by an ISRO PSLV-C9 rocket in Apr 2008 and has since been in operation for more than 20 months. Cute-1.7+APD II carries two reversetype APDs to monitor the distribution of low energy particles down to 9.2 keV trapped in a Low Earth Orbit (LEO), including South Atlantic Anomaly (SAA) as well as aurora bands. We present the design parameters and various preflight tests of the APDs prior to launch, particularly, the high counting response and active gain control system for the Cute-1.7+APD II mission. Examples of electron/proton distribution, obtained in continuous 12-hour observations, will be presented to demonstrate the initial flight performance of the APDs in orbit.

Development of the X-ray polarimetry small satellite "TSUBAME"

TSUBAME is a university‐built small satellite mission to measure polarization of hard X‐ray photons (30–100 keV) from gamma‐ray bursts using azimuthal angle anisotropy of Compton‐scattered photons. Polarimetry in the hard X‐ray and soft gamma‐ray band should play a crucial role in the understanding of high energy emission mechanisms and the distribution of magnetic fields and radiation fields. TSUBAME has two instruments: the Wide‐field Bust Monitor (WBM) and the Hard X‐ray Compton Polarimeter (HXCP). The WBM detects a burst and determines on board the direction of the burst occurrence with an accuracy of 10 degrees. The spacecraft is then slewed to the GRB in 15 seconds from the trigger using CMG, a high speed attitude control device. HXCP will measure the polarized X‐ray photons from the GRB while the spacecraft is slowly spinning around the bore sight. In this paper, we present an overview of the TSUBAME mission, its expected performance of X‐ray polarization measurement based on Monte Carlo simulation...