Herschel Status Report - April 2010
26 April 2010 11:00
Report for period 21 March to 21 April 2010
Mission operations of the Herschel space observatory continued nominally during the reporting period, with the spacecraft and subsystems all performing as expected.
The spacecraft is operating nominally.
Star tracker warm pixels
The tentatively detected spatial clustering of "warm" pixels may have a natural explanation: according to analyses performed on full CCD dumps which are taken every other week, these clusters correlate very well with stars of mv ≥ 8 in the Tycho catalogue.
Herschel still meets its pointing requirements (Absolute Pointing Error (APE) requirement is 3.7 arcseconds, predicted and hoped for was 2.05 arcseconds, the actual APE is ~2 arcseconds with a probability of p ≥ 0.68, corresponding to a 1σ value for a Gaussian distribution). If the absence of "speed bumps" in scan maps after the CCD temperature reduction were confirmed, this would allow reconstruction of scan maps to a similar spatial accuracy.
All three instruments, HIFI, PACS and SPIRE, continue to operate nominally. In April, Herschel was declared to be in Routine Science Phase Mode and all preceding phases (Commissioning Phase, Performance Verification Phase, and Science Demonstration Phase) were formally declared "completed". The last Science Demonstration Phase (SDP) observations which had not yet been performed, were restored to the list of normal (non-SDP) observations, and will be executed as part of the routine phase. Very occasionally, for example when a new instrument observing mode needs to be commissioned, a few hours of commissioning/performance-verification type activities will be inserted. This however will be handled within the allocation of "calibration observations" which are performed regularly for each instrument.