资源环境科技发展态势分析平台

For the first time for any planetary body other than the Earth, the free wobble of the pole called the Chandler wobble has been detected for Mars with a period of 206.9 ± 0.5 days and amplitude of 10‐cm from radio tracking observations of Mars Odyssey, Mars Reconnaissance Orbiter (MRO), and Mars Global Surveyor (MGS), in order of decreasing sensitivity. The motion of the rotation pole location on the surface of Mars, or polar motion, is observed using two different approaches: (1) joint global estimates of Mars’ orientation and its gravity field, and (2) time‐series solutions of C₂₁ and S₂₁. For Mars interior models, the Chandler wobble period is combined with other measurements including the moments of inertia from our estimated precession rate ψ ̇ = −7603.9 ± 1.3 mas/yr and tidal Love number k₂ = 0.169 ± 0.006. The Chandler wobble period constrains the rheology of the Martian mantle and in particular its long‐term frequency dependence.