Overall Status

Martin Kessler

Since ISO 's successful launch by Ariane during the night of 16-17 November, the spacecraft has been commissioned and the detailed performance checks and core calibrations of the instruments are proceeding well. Work is on track to start routine operations on 4th February as planned pre-launch.

The first 21 days after launch were devoted to the so-called ``Satellite Commissioning Phase''. During this time, the operational orbit was attained, the spacecraft was shown to be in excellent condition with performances exceeding the specifications, first light for all instruments was achieved (e.g. see the CAM image of M51 on the back cover), engineering checks were successfully made of all the four scientific instruments and the integrated ground segment was validated.

The following 56 days (``Performance Verification Phase'') are dedicated to a detailed verification of the instruments' performances and establishment of their core calibrations. At just past the half-way point, the following general statements can be made:

• With the exception of an anomaly in the scanning of the LWS long-wavelength Fabry-Pérot interferometer, the instruments appear to operate functionally as expected from ground-based testing.

• High energy particle impacts (glitches), and their solutions, adversely affect the sensitivity of the two spectrometers. Preliminary analyses have showed sensitivity losses of up to around X4, depending on detector type; however, recent indications are that this loss may be reduced by optimised operating conditions and improved data processing.

• The sensitivities of CAM and PHT appear to be close to their pre-launch expectations, although, an additional set of procedures may be needed for some detectors once per day to remove effects induced by high energy particle impacts.