Geoscience Reference
In-Depth Information
•
From direct and comparative imaging of the surface morphologies, the
determination of the cratering of the surfaces and an assessment of their
overall geologic histories.
•
The determination of the likely thermal history of the two bodies, includ-
ing a reliable estimate of the size of the core.
•
A new understanding of the role of water in controlling asteroid
evolution.
•
A reliable test of the current paradigm of Vesta as the HED parent body
and the determination of which, if any, meteorites come from Ceres.
•
The determination of a quantitative geologic context for HED origin.
4. Current Status of the Mission and Conclusions
From the above mentioned list of scientific results that we expect from
Dawn, including but not limited to a definitive solution of the Ceres-Vesta
paradox, it is evident that, if successful, this mission will mark an important
milestone in the history of planetary science. In particular, we will obtain
information on two bodies whose properties are directly reminiscent of the
very early phases of planetary growth in our Solar System. Moreover, these
two large asteroids are located in a region which marks a transition between
the rocky terrestrial planets and the icy bodies of the outer Solar System.
In this way, we have excellent reasons to hope that Dawn will provide a
new wealth of quantitative information, to build our overall understanding
of the origin of our planetary system on a much more solid background of
observational evidence.
With the caveat that the launch and subsequent operation of a system
as complex as a spacecraft entails much risk, it appears that the Dawn
operations are going smoothly. Dawn is currently in the Assembly, Test,
Launch, and Orientation (ATLO) phase and no real show-stoppers have
been identified so far. The instruments have been delivered, and nearly all
the hardware has been integrated to the spacecraft. However, the activities
are currently (December 2005) in a state of stand down. This action was
taken in response to concerns about the availability of funding in FY2006 to
cover any problems that might arise during environmental and performance
testing, particularly with regard to several pieces of subsystem hardware
perceived to have experienced significant problems. As a consequence, the
Dawn launch date, originally planned in mid-2006, moves now toward 2007.
As for ourselves, we will obviously keep our fingers crossed not just until
then but for many years to come!
