High-precision radar ranging to planets and spacecraft reveals small but persistent timing and distance residuals relative to best-fit ephemerides built under standard GR plus a smooth ΛCDM cosmology, even after accounting for known tidal, relativistic, and nongravitational effects (Fienga 2024; Iorio 2012). ΛCDM assumes that any influence of cosmic expansion or dark energy on Solar System scales is utterly negligible and that gravity is perfectly described by GR with constant parameters, so unexplained residuals either demand ever more intricate local modeling or hint at subtle mismatches between the assumed large-scale background and the actual spacetime in which the inner planets move (Williams et al. 2014; Pitjeva & Pitjev 2013).