Resurs 1-4 rocket and Envisat

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On this spring, the precession of this satellite had been –23mn/year, function of its altitude, inclination and excentricity. Its RA of ascending node (RAAN) had been the same that of Envisat so we saw these two major satellites transiting together. See photo hereafter, on 21 April 2007/23H18 (TU+2) Resurs 1_4 roc alone.

Like every year, we release the summing up of all observations; frequency versus inclination of orbit.

We see on the board, the new major one, METOP-A and observe that Abrixas roc although being a small one, is seen frequently. The reason is that its inclination 47.6° is almost the same that of the latitude of observation Auffargis 47.7° so the satellite is frequently on the zenith.