The first January issue of Acta Astronautica (vol. 226 part 1) is a good one. Here’s some light reading for your holiday:
Iwry, J. Collective action problems in planetary defense p. 25 .05.029
Wang, Y. Guan, W. Hu, J. High-fidelity landing modeling of small-body probes: Considering solar panel deformation and soil properties p. 125 .10.017
Bianchi, C. Niccolai, L. Mengali, G. Robust solar sail trajectories using proximal policy optimization p. 702 .10.065
Huang, Y-L. Hsieh, J. H. Wang, W-C. et al. Investigation of discharge voltage characteristics of a lanthanum hexaboride heaterless hollow cathode p. 760 .11.018
Li, J. Shen, Y. Experimental study on beam focusing of ionic liquid electrospray thruster with focus structure p. 827 .10.051
Planetary defense is, well… planetary. An inbound impactor doesn’t care which area or nation will be under it on the big day. Unfortunately, this sets up problems of agency and ethics, when areas or nations conclude (or default to) a position of ‘not my problem.’ Iwry tackles the dilemma, and possible answers.
Landing on a small body, as I’ve mentioned, is just not that risky overall, due to low gravity, low accelerations, and low touchdown speed. Still, we can’t just dismiss this, and neither does Wang et al.
When I say “act fast”, I mean eventually. Solar sails and electric thrusters do not make for jackrabbit starts and dramatic missions, but they will eventually drive a probe to high speed- higher than with chemical thrusters. But chemical rocket technology has, oh… forty years or so of a head start on electric rocket technology, and even moreso on solar sailing. The next three papers deal with refining the technology for such high-speed, low-propellant, low-mass missions. This high final speed and low initial mass represents enabling tech for us to reach some asteroids, and most comets, without needing an enormous launch vehicle and its associated program constraints.