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The model of artificial satellite Ajisai: the diagram of the mirrors' positions on its surface. The longitude is plotted on the X-axis, the latitude of the reflector is plotted on the Y-axis. The corner reflectors are marked as blank squares.
Source publication
Photometry is used to make remote diagnostics of an artificial
satellite's motion around its centre of mass. Experimental satellite
Ajisai was designed to explore the effects of the space factors, such as
gravitation and magnetic fields, solar radiation and others, on its
orbital motion and rotation. In the present study we consider the use of
pecu...
Context in source publication
Citations
... The study of the Ajisai light curves has shown that the mirrors in each ring should be considered as triplets (Korobeynikova et al., 2012) as all the mirrors in a triplet are inclined at the same angle (which varies for different triplets) to the mid-latitude of the ring in which they are mounted and toward the satellite's spin axis, which coincides with its symmetry axis within the accuracy of our model. Thus, as envisaged by the EGS manufacturers, certain three mirrors with the same inclination will always be able to reflect light towards an observer during one revolution of the satellite around its axis of symmetry. ...
... That enabled to considerably improve the accuracy in the determination of the current sidereal rotation period during a single satellite's pass. Subsequently, we used those data to determine the satellite's spin-axis spatial orientation and study the non-uniformity of its rotation (Korobeynikova et al., 2012;Kucharski et al., 2010b). ...
... The middle latitude of each ring of the corner cube reflector (CCR) panels, as well as the number of CCR panels in each ring is known (Kucharski et al., 2009(Kucharski et al., , 2010aKirchner et al., 2007). The number of mirrors in each ring and their angular sizes were calculated when developing the geometric model of Ajisai having taken the proportions and symmetry of the CCRs arrangement into account (Korobeynikova et al., 2012). Later on, the arrangement of the set of mirrors has been confirmed many times by the comparison of the model positions of individual mirrors to the observation data. ...
This paper investigates the evolution of the spin parameters of Japanese Geodetic Satellite Ajisai. The satellite is spherical and equipped with 318 solar reflecting mirrors on its outer surface, which enables to use photometry for our purpose. In the present study, we have improved the method of the determination of all spin parameters of the satellite by fast photometry discussed in our earlier papers. Using a tracking telescope at the Astronomical Observatory of Odessa National University and a dedicated high-speed recording system, 279 Ajisai light curves were obtained over seven years (2009-2015). The temporal resolution is 20. msec and time measurement error no greater than 0.1. μsec. The analysis of a sequence of multiple specular glints enabled us to update the model of the arrangement and orientation of the mirrors and to apply this model to determine the inertial rotation period and spin-axis orientation for each pass of the satellite. The secular decrease and periodic variation in the spinning rate, as well as the spin-axis precession pattern known from the SLR-observations (Kucharski et al., 2010a, 2013) have been obtained independently. New spin-axis nutation-precession parameters obtained in this study adequately confirm the empirical model by Kucharski et al. (2016). The method for photometric determination of the Ajisai spin parameters discussed here has the same level of accuracy as the SLR method, and thus, it can be widely used by observatories not fitted out with sophisticated laser ranging equipment.
