Abstract: A method for estimating a right-under point position of an on-orbit object includes an imaging step of capturing an observation image of an on-orbit object, together with a known object of which an orbit is known, a first right-under point position calculation step of calculating a right-under point position with respect to a center point of the observation image, and a second right-under point position calculation step of calculating a right-under point position of the on-orbit object based on the right-under point position with respect to the center point of the observation image.

Abstract: An artificial-satellite antenna mounted in an artificial-satellite including a satellite body, the artificial-satellite antenna includes solar cell panels, radiators, and conductors that are mechanically and electrically connected to the solar cell panels, in which the solar cell panels and conductors are used as reflectors.

Abstract: A process for producing a terbium alloy or terbium metal in which terbium(III) oxide substantially free from terbium(IV) oxide as the starting substance is subjected to electrolytic reduction in a molten salt electrolysis bath is described. According to the process of the present invention, a terbium alloy or terbium metal can be easily produced at a high yield.