25 Jan 2011 15:34

Spacecraft

The spacecraft continues to be in good health and has operated nominally during the reporting period, except for a few star tracker anomalies encountered on two successive days just before Christmas. On the first day it was found that the satellite had declared the standard star tracker (STR-1) unhealthy and autonomously reconfigured operations to STR-2. The standard configuration was restored during the ground station pass. On the following pass it was found that both STR-1 and STR-2 had been declared unhealthy, albeit for different reasons. The star tracker configurations were returned to nominal again, and have remained nominal ever since.

Payload

The three instruments have operated nominally for nearly the whole of the reporting period. At the expense of some observing time a SPIRE single event upset (SEU) had to be recovered from. Two other SEUs occurred with HIFI, but because the instrument was inactive during both events they could be recovered from without any loss of observing time.

Ground Segment

The first observations from the approved Open Time (OT1) programmes have been carried out. These programmes were selected from the proposals received in response to the first in-flight call for observing proposals (see the status report from November 2010). Completion of the Key Programmes (KPGT and KPOT) and the first in-flight Guaranteed Time (GT1) observations continues to take precedence, but OT1 observations are now also being inserted into the schedule. These help to maintain the highest possible scheduling efficiency for Herschel when no KP or GT1 observation of appropriate duration and compatible with the attitude constraints is available.

As of 13 January 2011, the completion of the different programme parts was:

For more details of these different programme parts, see the "overview of Herschel observing" linked from the right-hand menu.
 
Over the past 6 months, on average, 18.96 hours have been spent per day collecting science data. For the latest completed observing cycle (#31) this average was more than 20 hours per day. The remaining time can either not be used (because, for example, the PACS and/or SPIRE coolers are being recycled, or no observation of appropriate duration is available, or spacecraft activities are incompatible with the taking of science data), or this time is spent performing calibration/engineering observations (nominally these activities account for about 15% of the time, or about 3.6 hours per day).

Mission Operations
During the reporting period, mission operations have been conducted with the support of the ESA New Norcia ground station. Observational data stored on-board Herschel was received on ground during communication passes lasting approximately three hours.

Archiving
The ground segment is operating nominally. Data products are generated routinely and ingested into the Herschel Science Archive (HSA).

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Legal disclaimer
This report is based on the Herschel mission manager's report dated 20 January 2011. Please see the copyright section of the legal disclaimer (linked from the home page http://sci.esa.int) for terms of use.