ISO star tracker response to radiation
The following information concerning the ISO star tracker (STR)
response to the radiation environment has been provided by J.
Faelker at Vilspa:
Indirectly, the STR may experience the impact of impinging
trapped particles or cosmic rays, which will disturb the search/tracking
function when tracking a star, or during the acquisition process
of a star. However, the STR does not provide a means to measure
the background count rate, like a radiation counter of type
Cerenkov. A single event upset (SEU) may or may not be detected
autonomously as FALSE EVENT by the STR, because the tracking
window is very small (8 x 8 pixels) wrt to the 3° x 4° STR FOV
(284 x 372 pixels). We do maintain FALSE EVENT statistics, but
due to the before hand mentioned realities, the contents are
For questions, comments, and further information,
please contact P.
Nieminen at ESA/ESTEC.