Halley's spin state determined

Since VEGA and GIOTTO flybys of comet Halley, there was a rising controversy about the nature of the spin state of its nucleus. The problem was resolved by M. J. S. Belton et al., who found a spin state that simultaneously satisfies the VEGA and GIOTTO imaging data and a wide range of ground-based data. The total spin is not fixed in the nucleus but is inclined to the total angular momentum vector at an average angle of 21.4 deg and precesses around it with an average period of 3.69 days.