We report the results of a study aimed at inferring direct information on the repulsive three-nucleon potential $V^R_{ijk}$textemdash driving the stiffness of the nuclear matter equation of state at supranuclear densitiestextemdash from astrophysical observations. Using a Bayesian approach, we exploit the measurements of masses, radii and tidal deformabalities performed by the NICER satellite and the LIGO/Virgo collaboration, as well as the mass of the heaviest observed pulsar, to constrain the strength of $V^R_{ijk}$. The baseline of our analysis is the widely employed nuclear Hamiltonian comprising the Argonne $v_{18}$ nucleon-nucleon potential andthe Urbana IX model of three-nucleon potential. The numerical results, largely determined by the bound on the maximum mass, suggest that existing and future facilities have the potential to provide valuable new insight into microscopic nuclear dynamics at supranuclear densities.