An unexpected spin-off from the XMM-Newton
commissioning phase, the spacecraft has snapped a picture of
mother Earth. The image was taken with one of the two Small Visual
Monitoring Cameras (VMC).
The IRIS and Fuga cameras
fixed on the outside of the
satellite pointing towards the
service module had already
sent back pictures of the
observatory itself during the
early orbit phase just before
Christmas. Views then also showed the black spacecraft during and
just after a thruster firing.
The cameras were on test on 16 February when, for independent
reasons, the spacecraft, at an altitude of between 45000 and 50000
km was slewing and pointed towards the Earth. The IRIS colour
camera was undergoing a long exposure duration test and
unfortunately its image is overexposed and our planet is completely
white.
However the Fuga camera with its logarithmic response obtained a
nice image of both XMM-Newton and the Earth in the background.
The Earth reveals a cloud pattern which matches a picture taken at
the same time by Meteosat, in its geostationary position over the
Indian Ocean.
The VMC cameras are being activated on a regular basis to check
their state of health. The images obtained, and particularly this Earth
view confirm that the camera CCDs and electronics are standing up
well to the space environment and particularly to the repeated
passages through the radiation belts. XMM-Newton was then on its
35th revolution. This verification of the VMC micro cameras is useful
in the event of similar ones flying again on other ESA missions.
