The scientific objective of this proposal is the set up of the
physico-chemical models of the Rosetta mission possible target asteroids
based on the observations from ISO and ground-based telescopes relevant
to both the optimization of the mission scenario and the refinement design
of the payload instruments.
In particular the proposer intends i) to determine the compositional type
of possible target asteroids to contribute to the best choice of the targets
to be included in the actual mission, ii) to study the texture and the
composition of the asteroid surface layers to infer some of their bulk
physical and chemical properties; iii) to model the thermal behaviour
of the target asteroids; iv) to use all the data concerning the studied
asteroids to constrain the reference model of the selected target asteroids.
The mid- to far-infrared region contains a wealth of diagnostic spectral
features but is basically unexploited in the study of asteroid surface
composition. We propose to study the three most probable Rosetta target
asteroids (not yet defined at the time of the first call for ISO proposal)
by obtaining low resolution spectra in the range 2-45 microns.