XMM-Newton-NEWS  #85,    10-Dec-2008

XMM-Newton Science Operations Centre at
ESA's European Space Astronomy Centre,
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XMM-Newton Has Resumed Nominal Science Operations with Full Efficiency

A new operational concept has been successfully defined and implemented for the XMM-Newton Observatory. This followed the loss of contact on the 18th of October 2008 and subsequent recovery on the 22nd. In November, astronomical observations were performed using only one of the two on-board antennas to communicate with the Earth and taking advantage of the favourable celestial geometry (see Newsletter #83).

With the new strategy, XMM-Newton is once again able to fully utilise the available science windows and operate with the efficiency achieved before the anomaly. The definition of the new operational concept has been the result of several experts from ESA and industry working together on the evaluation of the advantages and disadvantages of different possible scenarios. A number of tests have been performed during which XMM-Newton was always safe and fully under the control of the mission control team at ESOC, while the instrument health was being monitored by the science operations team at ESAC. When the best strategy was identified, the mission planning team at ESAC made a very fast and efficient update of the planning software to include the new constraints and the team at ESOC modified their validation routines accordingly. This has made it possible to run a test revolution which started on the 1st of December and after its success, to declare this new mode as operational and start using it on December 5.

The net impact of the non-standard November operations on observing time has been of the order of 370 ks lost in slightly more than one month. This is 20% of the observing time that would have been available in that month with the nominal efficiency. If we add the seven revolutions lost earlier due to the loss of contact, the final time lost is about 6% of the total time available in one year. No further impact is expected in the future other than mission planning being slightly more complex, but this in the end is expected to have little, or no impact on XMM-Newton users.

We are therefore glad to inform you that XMM-Newton has gone through her 9th anniversary perfectly in shape.

Happy Birthday, XMM-Newton!

We take the opportunity to remind you that today marks another anniversary of XMM-Newton: on December 10th at 14:32 GMT it is exactly nine years ago that the European Space Agency's XMM-Newton observatory was placed into its orbit and started exploring the wonders of the X-ray universe.

Yours sincerely,
XMM-Newton SOC