And now we sharpen the pencils. In this issue (Jul) of Advances in Space Research:
Kikuchi, S. Shirai, K. Ishibashi, K. et al. Simultaneous geometric calibration and orbit-attitude det… p. 899 .04.057
Peña-Asensio, E. Sánchez-Lozano, J. M. Statistical equivalence of metrics for meteor dynamical a… p. 1073 .05.005
Hayabusa2 deployed a remote, short-lived camera, to observe its SCI cratering experiment without risk to the main craft. The ejected camera system, “DCAM3,” worked. Kikuchi et al. have not only back-calculated the wobbling of the camera system from the returned images; they solved for the trajectory of the DCAM3 about asteroid Ryugu. In turn, the trajectory of the test mass tells us of the gravity field about Ryugu. In other words, there were two probes at the asteroid.
Peña-Asensio et al. write of the association of individual meteors, into meteor showers, and hopefully into a parent body of that meteor shower. This is nontrivial: if you happen to see a meteor in the sky, who’s to say that particle trajectory is related- explicitly and causatively related- to another meteor, and ten others, and a thousand others? We have the similarity criterion, but that’s a statistical parameter. The cutoff between ‘similar’ and ‘not that similar’ values is somewhat arbitrary. And let’s not forget the visibility bias: what do the meteors we see indicate about all the meteors we didn’t see?