In the Acta Astronautica issue for Nov (vol. 236):
Acciarini, G. Izzo, D. Biscani, F. EclipseNETs: Learning irregular small celestial body silhouettes p. 514 .2025.06.002
Chen, Z. Shen, S. Cui, H. et al. Robust adaptive guidance for autonomous asteroid landing via search-based meta-reinforcement learning p. 723 .2025.07.001
Zhu, W. Wu, Y. Zhang, C. et al. Distributed control for spacecraft formation near irregular asteroids via quantized information exchange p. 1012 .2025.07.036
Lee, J. Park, C. Analysis of rigid-body potential models for spacecraft orbiting small celestial bodies p. 1167 .2025.07.065
As typical for Acta Astronautica, papers are more about engineering of instruments and missions, less about pure science and underlying physics/chemistry. Here, we have four papers on flight dynamics:
Acciarini et al. exploit the fact that almost all small Solar System bodies (asteroids, comets, and transition objects) are nonspherical- basically, “potatos”. If a body is a potato, then its sihouette is irregular and changing. This is an issue for navigation, if one still assumes (like Earth orbiters) that one is orbiting a sphere. But if one uses the irregularities, then eclipses (navigation stars passing behind the body) can be a feature, not a bug- knowing the potato shape, together with time, gives orientation.
Landing on an asteroid, per se, is not hard. Hayabusa did it accidentally, and NEAR Shoemaker did it despite not even being a lander. But those were untargeted, or only loosely targeted landings. If one is trying to land on a specific point on the asteroid, well, that’s different- the irregular and low gravity of a ‘potato’ means the descent will be long and curvy, in ways that may be hard to predict. Unless you’re Chen et al.- they claim to have cracked that nut.
Now, what if one is not flying a monolithic mission, but a constellation or swarm? Same issue, multiplied- and typically, with fewer resources available per spacecraft platform. Zhu et al. extend the status quo approach, by having the units of the constellation communicate with each other- what, how, how much?
Lee et al. take it to a higher degree- not only does a ‘potato’ have an irregular gravity field compared to a sphere, but for close orbits, the irregularities become significant for attitude control. The force gradient- in effect, a tide- of the asteroid on the spacecraft can (gently) turn it in unplanned ways.