THE LINKAGE PROBLEM
State of the Art
The current surveys, like Pan-STARRS, produce an always increasing number of asteroid observations. Several of them are not yet used in the current Orbit Determination (OD) procedures, but they are stored in a database: the isolated tracklet file (ITF), available at the Minor Planet Center website. To the present date the ITF file contains more than 12 million of observations. In view of the next generation asteroid surveys, like LSST or the European Fly-Eye telescope, if more efficient algorithms for OD are not developed, the new observation technologies will surpass the capability of processing the collected data, and this can make questionable the construction of new powerful telescopes. The identification and correlation problem is very relevant in the context of space debris. New algorithms have been recently introduced but they have not been tested yet on large data sets. Another problem is how to patch different dynamics. Patched dynamics is used as a first approximation of more complex models: the solutions of the simpler problem can be used as a starting guess to compute the solutions of the more difficult one, or sometimes they can be used to obtain the qualitative behaviour of the more complex system. Some examples can be found in the field of astrodynamics, and in celestial mechanics, to study close approaches of asteroids with the Earth or the passage through shadow for an Earth satellite.
WP4 covers all activities related to Initial Orbit Determination (IOD) and the use of observational data and measurements both optical and radar for both asteroids and space debris. It will introduce techniques to process large databases and link spatially and temporally distant data sets.
Cavallari, I., Gronchi, G.F., Baù, G. On the Sun-shadow dynamics. Preprint, November 2020, https://arxiv.org/abs/2011.10784.