While only a small number of science observations did not use standard AOT modes (e.g. polarisation and coronographic observations), a large number of calibration and engineering test measurements were performed using the Calibration Uplink System (CUS), or other specialised commanding systems.
In IDA the special measurements are found under `non-standard' data (CAM99) and `engineering' data (CAM60, CAM61, CAM62 and CAM63). No science data were taken in these measurements.
After leaving the Van Allen radiation belts (see the ISO Handbook Volume I, [40]), the CAM instrument was activated and put in standby.
Next step in the activation sequence of CAM, was flashing the detectors (both LW and SW) with the Internal Calibration Devices (ICDs).
Before entering the radiation belts, the instrument was switched off. In the so-called `de-activation' sequence, a set of calibration measurements was performed which were used to monitor the camera's behaviour during the mission. The sequence consisted of LW dark measurements of 2 seconds on-chip integration time, LW dark measurements of 5 seconds on-chip integration time (only until revolution 125), SW dark measurements of 2 and 6 seconds (from revolution 270) and ICD illumination of the detectors through the LW2, LW3, SW1 and SW3 filters (the so-called `internal flat-fields'; see Gallais & Boulade 1998, [35]).
During the handover of the satellite control from the VILSPA station to the station in Goldstone, another set of CAM calibration measurements was performed. These started only after revolution 150 and included LW dark measurements of 5 and 2 seconds on-chip integration time. The dark current measurements obtained this way were used to model the dark current trends throughout the mission (see Section 4.2.2; Gallais & Boulade 1998, [35]; Biviano et al. 1998a, [5]; 2000, [9]). Later in the mission the sequence of measurements was modified. The 2 and 5 seconds integration darks were measured on revolutions with odd numbers. A new set of measurements of 0.28 and 10 secs were performed on the even numbered revolutions. This alternating sequence started at revolution 764.
The results of the trend analysis based on the CAM62 and CAM63 measurements is described in Gallais & Boulade 1998, [35].
CAM99 data were obtained from so-called CUS (Calibration Uplink System) observations which were used in general for calibration measurements. Specific scientific observations like the coronographic mode or polarisation measurements needed special commanding and so also used the CUS that allowed more freedom and flexibility than the more conservative AOTs.