Pioneer Venus Orbiter Magnetometer data are taken from the PDS (Planetary Data System)
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Available parameters :
b_sc (orbits 1 to 3601) : Magnetic field in the PVO Inertial Spacecraft Coordinate System : X is the component that lies in the sunward direction in the plane that contains the Sun-spacecraft vector and the spacecraft spin axis, Y is formed by the right-handed vector cross product of the X and Z unit vectors where the Z axis is anti-parallel to the spacecraft spin axis and the X-Z plane contains the Sun, Z is defined to be anti-parallel to the spacecraft spin axis during orbital operations.
b_mag (all orbits) : Magnitude of the magnetic field.
bz_sc (orbits 3602 to 5055) : Z-component of the magnetic field in the PVO Inertial Spacecraft Coordinate System. The Z axis is defined to be anti-parallel to the spacecraft spin axis during orbital operations.
The dataset for orbits 3602 to 5055 differs from the previous orbits due to an anomaly in the multiplexor that controlled the sampling of the magnetometer sensors. During orbit 3602, and for the remainder of the mission, the spacecraft downlink contained magnetometer data from only the P sensor. The P sensor is the sensor which is aligned with the spacecraft spin axis, nominally in the direction of the ecliptic normal.After the anomaly was first detected, the magnetometer team made a substantial effort to recover the average magnetic field vector using the single sensor data. Since the sensor is not perfectly aligned with the spacecraft spin axis, a small amount of spin modulation is present in the sensor data.In theory, the amplitude of the spin plane field can be determined from the amplitude of the spin modulation and knowledge of the true sensor mounting geometry. In practice, this turned out to be a very difficult task because the spin axis of the spacecraft is not sufficiently constant in body-fixed coordinates.