This is the orbit data of Sakigake re-processed in 2016 to recover historical data at ISAS/JAXA.

Sakigake orbit data files

• orb8587_eclp.txt Orbits of Sakigake and the earth (Ecliptic coordinates) 1985-1987 (1 data point per day)
• orb9194_eclp.txt Orbits of Sakigake and the earth (Ecliptic coordinates) 1991-1994 (1 data point per 12 hours)
• orb9194_eqtr.txt Orbits of Sakigake and the earth (Equator coordinates) 1991-1994 (1 data point per 12 hours)
• orb9194_GSE.txt Orbit of Sakigake in the earth-based coordinates (GSE coordinates) 1991-1994 (1 data point per 12 hours)
• orb92ja_eclp.txt Orbits of Sakigake and the earth (Ecliptic coordinates) 1992-01-06 – 1992-01-09 (during the passage of the Earth’s magnetosphere; 1 data point per hour)
• orb92ja_GSE.txt Orbit of Sakigake in the earth-based coordinates (GSE coordinates) 1992-01-06 – 1992-01-09 (during the passage of the Earth’s magnetosphere; 1 data point per hour)
• orb92ja_GSM.txt Orbit of Sakigake in the earth-based coordinates (GSM coordinates) 1992-01-06 – 1992-01-09 (during the passage of the Earth’s magnetosphere; 1 data point per hour)
• orb92sp_eclp.txt Orbits of Sakigake and the earth (Ecliptic coordinates) 1992-09-09 – 1992-10-17 (during the passage of the tail of the Earth’s magnetosphere; 1 data point per hour)
• orb92sp_GSE.txt Orbit of Sakigake in the earth-based coordinates (GSE coordinates) 1992-09-09 – 1992-10-17 (during the passage of the tail of the Earth’s magnetosphere; 1 data point per hour)
• orb92sp_GSM.txt Orbit of Sakigake in the earth-based coordinates (GSM coordinates) 1992-09-09 – 1992-10-17 (during the passage of the tail of the Earth’s magnetosphere; 1 data point per hour)

Description of Files orb8587_eclp.txt, orb9194_eclp.txt, orb92ja_eclp.txt, orb92sp_eclp.txt

These list the orbits of Sakigake and the earth (Ecliptic coordinates).

Example of the data file

1985 3 18 0 0 -0.1285849100D+09 -0.8054390000D+07 -0.3114340000D+07
-0.1487426400D+09 0.6898921000D+07 0.3422209500D+03
1985 3 19 0 0 -0.1281220000D+09 -0.1086963800D+08 -0.3123910000D+07
-0.1488822200D+09 0.4316731000D+07 0.3355095200D+03

Format

• Year(4-digit integer) Space(1x)
• Month(2-digit integer) Space(1x)
• Day(2-digit integer) Space(1x)
• Hour(2-digit integer) Space(1x)
• Minute(2-digit integer) Spaces(2x)
• Sakigake orbital position: X (D17.10 (Float number in 17 characters of double exponential format including 10 digits after the decimal point) in [km])
• Sakigake orbital position: Y (The same as for X)
• Sakigake orbital position: Z (The same as for X)
• New-line, Spaces(19x)
• Earth position: X (D17.10 (Float number in 17 characters of double exponential format including 10 digits after the decimal point) in [km])
• Earth position: Y (The same as for X)
• Earth position: Z (The same as for X)

The coordinates are EME50 (i.e., the right-handed ecliptic coordinates in which the origin of the coordinates is at the sun with the X-axis defined as the vector from the earth on the spring equinox toward the sun and Z-axis defined as perpendicular to the ecliptic plane toward the north).

Description of File orb9194_eqtr.txt

The format is the same as above, but in the equatorial coordinates.

Description of Files orb9194_GSE.txt, orb92ja_GSE.txt, orb92sp_GSE.txt

These list the orbit of Sakigake in the earth-based coordinates (GSE coordinates) in units of [km].

Example of the data file

1991 9 1 0 0 0.1455233377D+08 -0.1107301902D+08 0.2750523857D+07
1991 9 1 12 0 0.1440548931D+08 -0.1126439082D+08 0.2772088867D+07
1991 9 2 0 0 0.1425871162D+08 -0.1145297199D+08 0.2793382823D+07

Format

• Year(4-digit integer) Space(1x)
• Month(2-digit integer) Space(1x)
• Day(2-digit integer) Space(1x)
• Hour(2-digit integer) Space(1x)
• Minute(2-digit integer) Spaces(2x)
• Sakigake orbital position: X (D17.10 (Float number in 17 characters of double exponential format including 10 digits after the decimal point) in [km])
• Sakigake orbital position: Y (The same as for X)
• Sakigake orbital position: Z (The same as for X)

The coordinates are the GSE coordinates, which are the right-handed system with the origin at the earth, (positive) X-axis pointing towards the sun, and Z-axis perpendicular to the ecliptic plane toward the north.

Description of Files orb92ja_GSM.txt, orb92sp_GSM.txt

These are similar to the above (the GSE ones), but in the GSM coordinates in units of [km]. The format is the same as for the GSE ones, except described in the GSM coordinates.

The GSM coordinates are right-handed. Their origin is at the earth. The X-axis is defined as pointing towards the sun (the same as for the GSE coordinates), but the Y-Z plane is rotated around the X-axis so that the magnetic poles of the earth are sitting on the X-Z plane.