2σ constraints that can be placed by a prospective ice giant mission on Yukawa-like extensions to the inverse square law. The grey area above the green and red linen corresponds to the parameter space that is currently ruled out by local observations of the Earth’s (green) and Mars’ (red) orbital precession. The solid blue and cyan lines denote the constrains that can be placed by a future mission to Neptune and Urnaus respectively, without any improvement from Cassini-era Allan deviations. The dashed lines denote the constraints that would be achievable with a target Allan deviation of σ_A = 10⁻¹⁷. Any improvement in Allan deviation is likely to rule out regions of the parameter space that correspond to length scales of the order 30 AU.