Local Constraints on the Dark Sector by Future Missions to Uranus and Neptune

Future ice giant missions could be used to constrain the dark sector. Modifications to the third Kepler-law and deviations from the inverse square law of gravity can be tested by observing the extra perihelion precession of Uranus and Neptune, which allows probing the local dark matter density, modified gravity scenarios and Yukawa-like interactions. As of now, the extraprecession measurements of ice giants are done via ephemerides measurements, which have large uncertainties and provide looser constraints with respect to constraints by other planets. Current upper bound on the local dark matter density lies around ρ_DM ~ 10^-20 g/cm³. However, Doppler tracking missions to Uranus and Neptune with radio ranging accuracy of a few meters can improve this upper bound by 2 to 3 orders of magnitude via the extraprecession technique. Moreover, estimates coming from the spacecraft cruise time energy budget could yield an even better estimate than the Doppler ephemerides measurements, potentially providing evidence for dark matter or shedding light on modified gravity scenarios. Therefore, in addition to planetary science, in situ exploration of Uranus and Neptune also carries significance for exploring the local dark sector and probing fundamental physics.