I spoke too soon again on Celestial Mechanics and Dynamical Astronomy for Feb (vol.138 #1). They’re still still going:
Fereoli, G. McMahon, J. W. Interior gravity characterization of small celestial bodies using cylindrical harmonics 12 s10569-026-10281-7
As I’ve said before, asteroids have low gravity- very low. Yet, asteroid orbiting and landing (more like docking) is still nontrivial, because asteroid gravity fields, low as they are, are low and irregular. If a body had high gravity, that body would pull itself into a sphere (like our Large Achondrite). Asteroids cannot overcome mechanical forces, and are not spheres but ‘potatos’. And potato mass results in a potato gravity field… lumpy and non-spherical.
Okay, granted that some asteroid and its gravity is multi-dimensional, how do we go about characterizing, then navigating that body and its field? The straightforward plan is to model the asteroid shape, make some assumptions about density and homogeneity, then plot out the expected gravity field, given that mass distribution. But this is an unsatisfying process, with guesses and (likely) miscalculations. Fereoli et al. propose a new method. Can’t be much worse than the status quo.