One in-scope paper in Planetary and Space Science, vol. 256 (Feb), and none in March:
De Keyser, J. Edberg, N. J. T. Henri, P. H. et al. Optimal choice of closest approach distance for a comet flyby: Application to the Comet Interceptor mission Art. 106032 .2024.106032
Flying by a comet is no cakewalk. Too close, and you’re riven with hypervelocity dust particles. Too far, and you’ve wasted how many millions on a mission that didn’t see all that much. For the Comet Interceptor mission in particular, the target ‘comet’ isn’t even known yet, so we can’t say if it’s particularly active or inactive. Ideally, a new interstellar object appears in time for the mission; this is not so farfetched, since the Vera Rubin Observatory will be operating later this year. Our ability to spot new objects- and at a distance that gives us schedule slack- will rise dramatically like the new aperture available. But one of the two interstellar objects seen so far- 1/I ‘Oumuamua- was a “transition object”- its activity was so low, no coma was visible. Its cometary nature was only betrayed by nongravitational force: the thrust from lopsided emissions.
As a matter of due prudence, the main Comet Interceptor craft will have dust shields. It is the two daughtercraft that will pass the target nucleus at dangerous distance. But that doesn’t form some nice, thick rug under which we can just sweep the problem. The plasma/fields people want data on the exosphere, heliospheric influence(s), their variabilities, and possible exotic phenomena not seen around planets. That’s part of the argument for having three spacecraft. For this, foreknowledge of the target’s activity will shape the decision on the flyby distances. A more active comet pushes the interplanetary medium back into a ‘bow shock’ further out than a less active comet. An inactive body has, pretty much, a tail only. Again, we’ll just have to await the choice of target to set the final distance decision.
Comet Interceptor: potentially groundbreaking science, or potentially a bust (the backup comets, already identified, are rather weak ones). Let’s go see!