10 Apr 2012 15:36

Spacecraft

The spacecraft continues to be in good health and is operating nominally. The current best estimates of the remaining amount of liquid helium for the spacecraft's active cooling system, which directly determines Herschel's lifetime for scientific observations, place the exhaustion of the cryogen in the first quarter of 2013 (with an uncertainty of some months).
Planning activities are being pursued for beyond that point; into the Herschel Post-operations Phase. A working group has been established to study possible post-science, in-orbit, demonstration activities using the Herschel spacecraft (but not the science instruments, which depend on lilquid helium to work). These demonstration activities would be of potential benefit for the design of future missions.

Payload

Operations for all three instruments, PACS, SPIRE and HIFI, have been largely nominal during the reporting period.

Occasional single event upsets (SEUs) were handled via standard procedures. Only one had any impact on Herschel's observations: an SEU in the HIFI Instrument Control Unit (ICU) caused HIFI to switch off. The instrument autonomous processes and operational recovery procedures that are available ensured an unproblematic and full recovery, only with some observing time lost. Even allowing for the occasional SEU, Herschel's time average of executing observations in recent months still exceeds the pre-launch expectations, by more than one hour per day.

Ground Segment

Ground segment operations have been nominal and 100% of the data continues to be recovered. As of 30 March 2012, the approximate completion of the different programme parts was:

For more details of the different programme parts, see the "overview of Herschel observing" linked from the right-hand menu.

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

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

The HSA currently has over 2000 registered users, and the number continues to grow. The data processing software has been downloaded over 3800 times.

The iPhone/Android app for interrogating archived quick-look products has been downloaded almost 1400 times already since its release in December 2011. The number of available quick-look products in the HSA will increase substantially with an upcoming bulk reprocessing of all data.

Future Milestones

• 14 May 2012: Third launch anniversary of Herschel

---
Legal disclaimer
This report is based on the Herschel mission manager's report dated 4 April 2012. Please see the copyright section of the legal disclaimer (linked from the home page http://sci.esa.int) for terms of use.