In Acta Astronautica for October (vol. 235):
Broslav, T. Dreyer, C. Sercel, J. Optical mining of carbonaceous chondrite simulants: Testing and lessons learned in asteroid mining research p. 1 .2025.04.033
Wang, Y. Zhu, Y. Ding, Y. Research on the ignition characteristics and discharge performance of LaB6/W composite cathode arcjet thruster p. 69 .2025.05.060
Saiki, T. Tsuda, Y. Mori, O. et al. Mission concept of Japanese comet sample return exploration in the 2030s p. 120 .2025.05.048
Hernandez Megia, H. Ho, T-M. Grundmann, J. T. et al. Modeling and control techniques for landing on (99942) Apophis: An analysis of a mission scenario p. 185 .2025.04.031
Academics T. Broslav and C. Dreyer join J. Sercel of TransAstra, a commercial (NewSpace) company. Optical mining refers to using directed sunlight to warm materials, releasing their volatiles for collection and use. In this case, the authors report their water, organics, and other light molecules (e. g., sulfur compounds, noble gases) from “carbonaceous chondrite” meteorite material.
Arcjets are interesting engines- more efficient than chemical propulsion, but scaling to higher thrusts than “real” electric rockets. That is, if you can keep the arc electrodes from destroying themselves at high power. Tungsten and borides are durable, and thus typical electrode candidates; here, the authors give their tungsten/boride arc behavior and use experience.
The Japanese had achieve a “first”- first asteroid sample return, from (25143) Itokawa. They do not intend for that to be a lone laurel. We have seen talk of a sample return from the Jupiter Trojans; here is nontrivial discussion of a comet sample return, as the US abandoned CAESAR (Comet Astrobiology Exploration Sample Return). Apparently, the US intends OSIRIS-REx to be lone.
In the case of the Hayabusas, OSIRIS-REx, and yes, CAESAR, the space probe would only briefly contact the body, with a sampling arm. MMX and an optical miner would need to “land” on its target (more like docking, at these actually low gravities). Though this is no showstopper (see: NEAR at Eros), one does not get approved and funded by making assumptions and wishes. Hernandez Megia et al. put some numbers on a notional Apophis lander.