Data Set Overview : This data set consists of magnetic field vector data recorded by the Fluxgate Magnetometer on board the Pioneer 11 spacecraft, during the Saturn encounter period. Data include 5 minute averages of the magnetic field in RK spherical coordinates and spacecraft trajectory in Kronographic (L1) coordinates. Data Sampling : At Saturn, instantaneous vector measurements were obtained every 146.3 second, in synchronism with the spacecraft spin period of 7.7 second. The NSSDC documentation does not contain information about what data resolution this data set (5 minute) is averaged from. The time resolution for this data set is described as 5 minute in the NSSDC documentation. However, data point spacing in the file is variable and found mostly about 7 minute. Data Processing : No detailed information of data processing is found in the NSSDC documentation pertinent to this data set. Pioneer 11 spacecraft was operating under a spin-stablized condition and had a spin period of 7.7 second. Data Format : The Pioneer 11 magnetometer data for Saturn encounter were originally written on an ASCII magnetic tape created on the MODCOMP IV computer from card images. The original file was re-formatted into a new ASCII file named P11_FGM_SAT_ENC_5MIN.TAB which contains the following data columns: -------------------------------------------------------------------- Column Column Column Name Format Description -------------------------------------------------------------------- TIME A24 Time in yyyy-mm-ddThh:mm:ss.sssZ R F6.3 Distance of Pioneer 11 from Saturn in Rs LAT F7.2 Latitude of Pioneer 11 in L1 coordinates LON F8.3 Longitude of Pioneer 11 in L1 coordinates BR F9.5 Radial component of the magnetic field in RK coordinates BTHETA F9.5 Polar component of the magnetic field in RK coordinates BPHI F9.5 Azimuthal component of the magnetic field in RK coordinates -------------------------------------------------------------------- Coordinate System for Data : Kronographic (L1) coordinates is a Saturn centered spherical system, based on the Saturn Longitude System (Voyager Measurements of the Rotation Period of Saturn's Magnetic Field, Desch and Kaiser, JGR, 8, 253, 1981). RK coordinates is based on two principle directions, Saturn to Pioneer 11, R, and Saturn spin axis, J. X:R points away from Saturn. Y is a vector in the direction of J cross R. Z is X cross Y. Radial direction R, points away from Saturn, polar direction THETA, positive northward, and azimuthal direction, PSI, parallel to the X-Y plane, positive eastward. Ancillary Data : There is no ancillary data associated with this data set. Instrument Calibration : The fluxgate magnetometer was calibrated at the GSFC Magnetic Test Facility by means of a 2 meter diameter, single axis Helmholtz coil system. Typically hysteresis observed after exposure to 2.5 mT fields was less than 1 part in 10**3 (one count). Temperature stability is better than +- 0.5% over the temperature range of -20 to +40 degree Celsius in spite of the open loop design of the instrument. This is due to the fact that the characteristics of the magnetic material used in the sensor cores are fairly independent of temperature over the indicated range. The stability figure includes the A/D converter drift and a large portion of it is due to the single ramp design of the latter. Nevertheless, minimum power consumption requirements and flight qualified component availability precluded the used of more stable A/D converter designs (ACUNA&NESS1974).

Confidence Level Overview : No data confidence information is found in the NSSDC documentation pertinent to this data set. There is no flagged values in this data set.