heavily on results from the recently completed Rosetta mission to comet 67P/
Churyumov-Gerasimenko (hereafter 67P—it is the only object which I abbreviate
purely to this type of designation). Rosetta was a mission designed to study the
nucleus and its immediate environment. The data are available from the Planetary
Science Archive (PSA) of ESA, and only Rosetta data available through this source
have been used herein. The spacecraft, even when driven away from the nucleus by
the activity as the comet approached perihelion, was never more than 2000 km from
the nucleus during its prime mission. This is in stark contrast to earlier missions to
comets which were fly-bys. Unlike Rosetta, these missions were also equipped with
more extensive instrumentation for investigating the plasma produced by the ionization of cometary gases and the subsequent interaction of that plasma with the solar
wind. While this plasma interaction is an interesting physical problem and its
historical importance (e.g. the deduction of the existence of the solar wind through
studies of cometary plasma tails by Biermann in 1951) cannot be underestimated, I
have decided to tip the balance of this work towards the source of this material
because, for the reasons discussed above, it is the wish to access this “unprocessed”
nucleus that forms the driving goal in cometary physics today.
Bern, Switzerland
Nicolas Thomas
xiv
Preface (Motivation and Scope)
Churyumov-Gerasimenko (hereafter 67P—it is the only object which I abbreviate
purely to this type of designation). Rosetta was a mission designed to study the
nucleus and its immediate environment. The data are available from the Planetary
Science Archive (PSA) of ESA, and only Rosetta data available through this source
have been used herein. The spacecraft, even when driven away from the nucleus by
the activity as the comet approached perihelion, was never more than 2000 km from
the nucleus during its prime mission. This is in stark contrast to earlier missions to
comets which were fly-bys. Unlike Rosetta, these missions were also equipped with
more extensive instrumentation for investigating the plasma produced by the ionization of cometary gases and the subsequent interaction of that plasma with the solar
wind. While this plasma interaction is an interesting physical problem and its
historical importance (e.g. the deduction of the existence of the solar wind through
studies of cometary plasma tails by Biermann in 1951) cannot be underestimated, I
have decided to tip the balance of this work towards the source of this material
because, for the reasons discussed above, it is the wish to access this “unprocessed”
nucleus that forms the driving goal in cometary physics today.
Bern, Switzerland
Nicolas Thomas
xiv
Preface (Motivation and Scope)