Takumi ABE

Sound measurements were carried out using rocket-based propagation diagnostics in the middle and upper atmosphere via infrasonic/acoustic waves to investigate their frequency dependence. The S-310-41 sounding rocket was used, equipped with one main microphone, two sub-microphones, and a loudspeaker, to examine the sound propagation in the payload section of the rocket as a function of the ambient atmospheric pressure. The output from the loudspeaker showed a clear trend of gradual attenuation with decreasing atmospheric pressure at almost all frequencies. Acoustic wave propagation was measured, and was in good agreement with the predictions of attenuation of the sound strength of the mass spectrometer incoherent scatter model (NRLMSISE-00).

The project to verify the performance of space tether technology was successfully demonstrated by the launch of the sounding rocket S520 the 25th. The project is the space demonstration of science and engineering technologies of a bare tape electrodynamic tether (EDT) in the international campaign between Japan, USA, Europe and Australia. Method of "Inverse ORIGAMI (Tape tether folding)" was employed in order to deploy the bare tape EDT in a short period time of the suborbital flight. The deployment of tape tether was tested in a various experimental schemes on ground to show high reliability of tape tether deployment. The rocket was launched on the summer of 2010 and deployed a bare electro-dynamic tape tether with length 132.6 m, which is the world record of the length deployment of tape tether. The verification of tether technology has found a variety kind of science and technology results as the first in the humankind and will lead a large number of applications of space tether technologies.

The experiment of charged particle collection experiment by bare electrodynamic tape tether was performed by using JAXA's sounding rocket S-520-25 on August 31, 2010. This was the first experiment of bare tether in space in the world. This paper shows the outline of the experimental apparatus and the initial experimental results of the verification of bare electrodynamic tether operation and the charged particle collection theory. As experimental results, Valuable data of electron collection by the induced electromotive force and ion collection by a space potential probe in space were obtained, although charged particle collection data by tether and boom were not obtained by a trouble of high voltage power source.