Attitude Motion of Unbalanced Partial-Spin Spacecraft

Both the paper and the model use the same Floquet decomposition with P(τ) the 2π-periodic rotation and a constant 2×2 off-diagonal R. Both reduce stability to the sign of u1 u2, which equals the sign of σ, and reach the same classification: σ<0 bounded oscillations, σ=0 linear growth, σ>0 exponential growth. The model adds two clarifications: (i) generic solutions are quasi-periodic for σ<0 unless frequencies are commensurate; (ii) at σ=0 the homogeneous Floquet factor is generally nilpotent (e^{τR}=I+τR) unless u1=u2=0, whereas the paper writes Φ(τ,0)=P(τ) in that case. These are minor issues of precision; the core argument and result coincide.