XMM-Newton geared up to serve its users even better
1 February 2001With a spacecraft behaving admirably, a greatly improved efficiency in managing observations, and the extremely high-quality science data being returned, members of the XMM-Newton Science Working Team (SWT), who met in Spain on 23-24 January, were justifiably happy. Attendance was exceptional for this last SWT in its present form.
Mission operations during the first year have largely been devoted to instrument calibration and to guaranteed-time observations for the Principal Investigator teams, as planned. But since 1 January 2001, a sizeable fraction of the observing time is being used by guest observers. In order to better serve this wider community the XMM-Newton Project Scientist, Fred Jansen, is recommending to ESAs Director of Science that the SWT henceforth becomes a users group.
Fred Jansen is already preparing the second call for proposals for the next round of observations. The Science Working Team, including all those who have made XMM possible, has done a remarkable job, he explains. We must now be guided by people outside, by the majority of the astronomers we aim to serve. They must be able to tell me what they think the Science Operations Centre (SOC) should be doing.
ESAs X-ray observatory was accomplishing its 205th orbit as the SWT met at XMM-Newtons SOC at VILPSA near Madrid. It is there that observations are scheduled and where the science data arrives. After a slow start, the operating efficiency has practically reached its theoretical limit.
We have entered a more stable and mature phase of the project, said Jean Clavel, Science Operations Manager. We are now planning observations 9-10 revolutions in advance. Certain manual adjustments to the observation timelines are still required but our overall efficiency is around 60%, much like NASAs Chandra.
The observatory will soon be able to continue observations whilst at its furthest distance from Earth. A new tracking station at Santiago in Chile is joining those at Perth and Kourou. This will allow uninterrupted reception of science data during the apogee passage. Santiago will be brought on line early February.
The ground segment controlling the spacecraft and receiving the science data is functioning very well, reported Dietmar Heger, Spacecraft Operations Manager. Everything aboard XMM is nominal, none of the spacecrafts backup systems is being used and energy-wise we have comfortable margins: we are using less than 600 grams of hydrazine a month, and our solar-panels are holding good. There were no problems during the eclipse period last year and we are confident for the next one in March said Heger. In fact things are going so smoothly that more than 99% of the science data is being recovered.
The meeting heard reports on the status of all the science instruments. Although the two of the CCD detector chains of the Reflection Gratings Spectrometer (RGS) are inoperative, and no satisfactory explanation has yet been given for sudden occurrence of hot pixels on the European Photon Imaging Camera (EPIC), overall degradation is in line with expectations, as had been reported at last Novembers Radiation Workshop. However some participants warned against all sense of complacency. Natural decay of our instruments is occurring and we should not assume that everything will be fine for the next five years said EPIC PI Martin Turner.
In the final presentations, all the missions Principal Investigators agreed that the missions scientific results todate were truly living up to expectations. With each observation, XMM-Newton is identifying dozens of new X-ray sources and the new spectral and image data obtained on many known targets is providing a greater understanding of the cosmic processes at work. Many past interpretations are having to be reviewed.
XMM-Newton observations will inevitably raise questions which require other instruments, and or wavelength ranges, to solve the issues which are arising as a result of the XMM-Newton observation, and Project Scientist Fred Jansen announced at the SWT that joint observations are now under consideration with the European Southern Observatory (ESO), with NASAs Chandra mission, and with ESAs forth-coming gamma-ray space telescope, INTEGRAL.