Card 6t - ORBDEF5 Spacecraft Orientation Parameters
This optional card defines the spacecraft orientation parameters.
Parameter | Value | Description |
---|---|---|
ORBDEF5 |
ORBDEF5 or 45 | mnemonic |
ID |
Integer | ID number |
V1X |
real | X component of vector1 in the global coordinate system |
V1Y |
real | Y component of vector1 in the global coordinate system |
V1Z |
real | Z component of vector1 in the global coordinate system |
V2X |
real | X component of vector2 in the global coordinate system |
V2Y |
real | Y component of vector2 in the global coordinate system |
V2Z |
real | Z component of vector2 in the global coordinate system |
SATDIR |
1 | For ORBDEF4 ANOPT = LONGSAT , S/C is ascending at the
LONGSAT position |
2 | For ORBDEF4 ANOPT = LONGSAT , S/C is descending at
the LONGSAT position |
|
SATLAT |
real | S/C latitude (active for ORBDEF4 ANOPT =
LONGSAT ) |
RASUN |
real | Right ascension angle of the sun in degrees |
V1X
V1X
is the X coordinate of vector1 on ORBDEF1
in the global coordinate system.
V1Y
V1Y
is the Y coordinate of vector1 on ORBDEF1
in the global coordinate system.
V1Z
V1Z
is the Z coordinate of vector1 on ORBDEF1
in the global coordinate system.
V2X
V2X
is the X coordinate of vector2 on ORBDEF1
in the global coordinate system.
V2Y
V2Y
is the Y coordinate of vector2 on ORBDEF1
in the global coordinate system.
V2Z
V2Z
is the Z coordinate of vector2 on ORBDEF1
in the global coordinate system.
SATDIR
SATDIR
is the flag specifying whether the spacecraft is ascending or descending when ORBDEF4 ANOPT = LONGSAT
. Otherwise, it should be 0.
SATLAT
SATLAT
is the spacecraft latitude in degrees if ORBDEF4 ANOPT = LONGSAT
. Otherwise, it should be 0.
RASUN
RASUN
is the sun right ascension angle value in degrees if ORBDEF3 SOLOPT = SUNDECL
for planets other than Earth (ORBDEF1 PNAME = EARTH
). Otherwise, it should be 0.
The sun right ascension angle is the angle measured eastward from the Vernal equinox axis in the planet’s equatorial plane to the projection of the sun vector onto the equatorial plane.
The vernal equinox is the time when the apparent position of the sun crosses the equator moving from south to north. The vernal equinox axis is a line from the Earth's center to the point where the sun crosses the equator moving from South to North.