There’s a mid-month Advances In Space Research– 15 February (vol. 77, #4):
Zhu, X. Liu, Y. Peng, F. Three-stage homotopy approach for asteroid landing desensitized trajectory optimization initialized via quadratic programming Pgs 5009 .2025.11.117
Yuan, W. Deng, H. Gao, S. et al. Integrated attitude-orbit control and control allocation of solar sails hovering an asteroid Pgs 5076 .2025.12.054
Landing on an asteroid is easy. But a specific site on that specific asteroid, that’s the challenge. Because of true microgravity, lander missions can gently approach and settle upon most asteroids; it’s more like docking than landing. But because almost all asteroids are non-spherical and irregular (“potatos”), their gravity is irregular too, and in turn the descent trajectory is not well-known in advance. Hence early, pioneering missions (NEAR Shoemaker, Philae) were satisfied to land wherever they did, no specific spot planned. It was Hayabusa2 and OSIRIS-REx that attempted precision landings.
Zhu et al. attempt to remedy this. Using new algorithms, they attempt to make the question of landing deterministic, and not random, or even “left as an exercise for the human”. Humans can’t actively ‘joystick’ it for most asteroids, since the round-trip light-time won’t allow realtime commands.
Separate from actual landing is hovering, or even deterministic orbiting. Again, the gravity field about a potato is another potato, often not well-known in advance. Using solar sails is a new complication. Just like a regular sailboat, one attempts to use limited available command authority, to maneuver. It’s not always direct and obvious what control input will lead to what force, and in turn what change in velocity/position. Yuan et al. then try to rationalize ‘sailing’ about a space potato.