THE ORBIT OF ARIEL 3 (1967-42A)

The definitive orbit for Ariel 3 has been computed, from Minitrack observations, for a period of 27 12 months from the launch of the satellite. The orbit was represented by a model with seven independent orbital parameters and the values of these parameters were determined, and are listed, at three-day intervals. Typical accuracies are 0.00001 in eccentricity and 4 seconds in angular parameters, that is, about 12 km in position. A curious feature of the secular variation of orbital inclination, viz. that the expected decrease of about 0.02 deg appeared to occur over a three-month period instead of the full 27 12-month period, is discussed but has not been explained.