Next: Pointing Improvements Up: ISO Info no. 10 Previous: Introduction
Project Status
A special issue --November (II) 1996-- of the journal Astronomy and Astrophysics dedicated to the initial results of ISO has been published. This contains 91 letters with results from all instruments, mainly from the early parts of the mission. As with all topics in this status summary, the ISO WWW pages (URL: http://www.iso.vilspa.esa.es/) can be consulted for more detailed information.
The ISO spacecraft continues to operate extremely well. A direct measurement of the remaining liquid helium in September gave a result of 203 kg. Combining this with a mass flow rate derived from thermal models confirms the previous lifetime estimate of about 24 months, meaning that ISO should be operational until December 1997. A series of investigations, some using engineering time, and fine tunings of the pointing system have been made. These have resulted in improvements to the absolute pointing accuracy; currently, this is around the 2 arc sec level and further improvements are expected. On two occasions, once in August and once in September, ISO automatically re-configured itself into an ``autonomy'' mode; a redundant ``remote terminal unit'' on the service module is now being used. An orbit maintenance manoeuvre was successfully carried out without incident.
In late November, investigations showed that the LWS change wheel --carrying the two Fabry-Pèrot interferometers and an aperture for the grating mode -- did not always reach its commanded position. Thus, as of 28 November, all LWS observations were suspended pending reaching an understanding of the problem. At the time of writing, the goal is to resume LWS operations in early February.
Work continues with ISOPHOT on improving its calibration and establishing its faint source detection limits in the presence of various levels of astronomical backgrounds. These points were addressed in a review of ISOPHOT's status held in early November; one of the purposes of this review was to brief the Observing Time Allocations Committee Chairs prior to their review of the Supplemental Call proposals.
Plans for releasing the remaining observing modes have proceeded more slowly than foreseen in the previous ISO INFO. Commissioning cases for the ISOPHOT absolute photometry modes (PHT05/25) are being carried out and a general release is expected in January. The LWS ``Fabry-Pérot Wavelength Range Spectrum'' AOT (LWS03) is likely to be given a limited release in the New Year with caveats on its ability to measure the continuum. Good results have been obtained on instrument polarisation with ISOCAM and ISOPHOT's polarisation modes; observers are being contacted directly regarding the next steps. On the data product side, reprocessing capability is being added to the Science Operations Centre. Currently, per day, two days worth of ``old'' data can be re-processed in parallel to handling the new data.
A workshop entitled ``Taking ISO to the Limits: Exploring the Faintest Sources in the Infrared'' will be held on 3-4 February 1997 in the ISO Science Operations Centre, Villafranca, Spain -- contact `faintsrc@iso.vilspa.esa.es' for more details.
Next: Pointing Improvements Up: ISO Info no. 10 Previous: Introduction
Tue Jan 7 17:47:45 MET 1997