[J09-P] Poster

[J09-P-10] Simulation of Hayabusa2 crossover orbit analysis using laser altimeter data

^○Keiko Yamamoto¹, Koji Matsumoto¹, Toshimichi Otsubo², Noriyuki Namiki¹, Hayabusa2 Astrodynamics Team³ (1.National Astronomical Observatory of Japan, Tokyo, Japan, 2.Hitotsubashi University, Tokyo, Japan, 3.-)

The asteroid explorer “Hayabusa2" was launched in 2014, and will arrive the target C-type asteroid, Ryugu in the middle of 2018. Hayabusa2 will stay there for one and a half years, and perform exploration with small rover and lander, sample acquisition from Ryugu's surface, and various remote-sensing observations. In the mission, in order to estimate Hayabusa2 orbit and Ryugu's geodetic parameters as precise as possible, crossover orbit analysis using laser altimeter (LIDAR) between Hayabusa2 and Ryugu is planned, in addition to conventional radiometric tracking data analysis.
In this study, as a preparation for actual data analysis, we simulated Hayabusa2 orbit analysis in offline. We developed a simulation program for Hayabusa2 orbit analysis, including crossover orbit analysis. Test data of Hayabusa2 orbit, Ryugu ephemeris, and Ryugu shape model were also created for the simulation. The orbit analysis was simulated in the following order: 1) Hayabusa2 orbit determination with range and range rate observations from ground tracking stations to Hayabusa2, 2) Determination of Hayabusa2 orbit with respect to Ryugu center by crossover orbit analysis using LIDAR-observed ranges between Hayabusa2 and Ryugu, 3) improvement of Ryugu ephemeris using 1) and 2) results, 4) improvement of Hayabusa2 orbit by performing 1) again with updated Ryugu ephemeris, and 5) iteration of 1) to 4). We discuss how much the precision of determined Hayabusa2 orbit changes by changing error magnitudes of each observations and Ryugu ephemeris.