Prospects for a local detection of dark matter with future missions to Uranus and Neptune

Past years have seen numerous papers underlining the importance of a space mission to the ice giants in the upcoming decade. Proposed missions to Uranus and Neptune usually involve a ~10 year cruise time to the ice giants. In this phase, the spacecraft trajectories will mainly be determined by the configuration of massive bodies in the solar system. Interplanetary trajectories are monitored by recording Doppler shifts in the time series of the radio link between Earth and the spacecraft. The presence of dark matter (DM) affects the trajectory by introducing a small radial acceleration, which in turn reduces the velocity of the spacecraft over years of interplanetary travel. Additionally, bounds on the precession rate of ice giants could help constrain the local DM density and potentially rule out modified gravity scenarios.

We investigate the possibility of detecting the gravitational influence of DM in the solar system on the trajectory of prospective Doppler ranging missions to Uranus and Neptune, and also estimate the constraints such a mission can provide on modified and massive gravity theories via extra-precession measurements using orbiters around the ice giants.

The precision of these measurements is limited by the noise on the the two-way frequency fluctuation of the Doppler link. For the trajectory deviations, we developed a numerical procedure for reconstructing the influence of DM in the Doppler signal of thousands of simulated ice giant missions.

The noise improvements required to guarantee a local detection of dark matter in the early 2040s are realistic, provided they become one of the priorities during mission development.