TOPICSThe orbit of Hayabusa2 from launch to just
before returning to Earth (TCM-3)

The orbit of Hayabusa2 from launch to just before returning to Earth (TCM-3) has been released:

Hayabusa2 orbit information : hayabusa2_orbit_20201021e

The period covered by the data is from the launch of Hayabusa2 on December 3, 2014, through to just prior to the spacecraft’s return to Earth (before TCM-3) on November 25, 2020. The released data has an orbit accuracy of 1000 km. Please use this when creating figures and CG, as well as for teaching materials concerning the trajectory of Hayabusa2 to Ryugu. This data should be sufficiently accurate to create a bird’s eye view of the Solar System and to plot the position of the spacecraft on a star chart. Do note that this data cannot be used for more accurate discussions.

The data is explained below.

Each row of data begins with the date and time given in UTC, where UTC is the “Coordinated Universal Time”. To convert to Japan time, add nine hours to the UTC time. In addition, the following column labelled “L+” gives the total date counted from the launch date. Here, “L” stands for “launch”.

The next nine columns give coordinate values (x, y, z) of Hayabusa2, Earth and Ryugu. The values are written in kilometers. This is the coordinate value based on the ecliptic coordinate system. Since the x-y plane of the coordinate system almost coincides with the orbital plane of the Earth (the ecliptic plane), when drawing the orbit of a celestial body that is not far from the Earth’s orbital plane (i.e. the value of z remains small), you can understand the orbit by plotting only on the x-y plane. (For a detailed explanation of the ecliptic coordinate system, please refer to a book on celestial orbits.)

The following values are also listed:

Rs: Distance between Hayabusa2 and the Sun
Re: Distance between Hayabusa2 and the Earth
Ra: Distance between Hayabusa2 and Ryugu
Vs: Cruising speed of Hayabusa2 (relative to the velocity of the Sun)
Ve: Relative speed of Hayabusa2 to the Earth
alpha: Right ascension of Hayabusa2 as seen from the Earth
delta: Declination of Hayabusa2 as seen from the Earth
Dflt: Total flight distance of Hayabusa2

We hope this orbital data will allow you to enjoy Hayabusa2’s journey even more!

Hayabusa2 Project