Errors in long-term orbital prediction for satellite 1961o₁

The results of orbital prediction over periods of 2 to 6 months are presented. The orbits used in the predictions were based on Doppler data obtained within not more than 24 hours. After removal of the drag contribution, the remaining prediction error is found to grow linearly with time, contrary to the theory of Moe. An alternative expression for the growth of error is given. It is shown that the contribution from measurement error is an order of magnitude below the contribution from geodetic errors.