Geoscience Reference
In-Depth Information
In this mission an atmospheric probe to Saturn with scientific payload
similar to those on the Galileo and Huygens Probe is a must. A microwave
sounder on the SAPPORO Orbiter is essential for the study of the deep
interior of the Saturnian atmosphere. Depending on the power system, a
ring hopper is not out of the question. Another novel scientific platform
that will be the delight of the Kuiper belt community has to do with the
lander on Phoebe which is the largest irregular satellite in retrograde orbit
at the outskirt of the Saturnian system. The close-up observations by the
remote sensing instruments on the Cassini spacecraft have shown Phoebe
to be a primitive body captured from the planetesimal population feeding
the accretion zone of the outer planets — which in turn might be akin to
the KBOs. Chemical analysis of the sample materials on Phoebe's surface
has therefore, the potential of serving as a time machine leading us back to
the epoch when the solar system was originally formed.
This ensemble of mission ingredients might seem extravagant at first
sight. But we must remember that most of them can be ready-made even
at present days on the basis of previous and current ESA, JAXA, and NASA
missions. Following the trend like a weathercock, we have very good reason
to believe that the combined momentum of space technological development
and the cooperative efforts of several major advancing nations in Asia will
help pave the road to return to Saturn by 2025 as envisaged here. With
this spirit, we hope that a preliminary assessment study could be given to
this mission concept so that some preparatory inter-agency dialogs might
be initiated. In Sec. 2, we will describe the scientific objectives of the SAP-
PORO mission. In Sec. 3, we will compare the SAPPORO mission concept
to projects in planning for the exploration of outer planets. In Sec. 4, we will
discuss how the concept of SAPPORO could be extended to the rendezvous
missions to Uranus and Neptune of truly international in scope.
2. Scientific Objectives
From the discussions among a team of scientists, a preliminary list of sci-
entific objectives covering a wide spectrum of important research fields in
planetary science have been identified. Four of those that would answer
fundamental questions are outlined here. As described below, these inves-
tigations would also require different instrumentations and platforms.
2.1.
Saturn atmospheric probe
Figure 2 compares the scenario of the NASA Galileo probe mission to
Jupiter to that of the ESA Huygens probe mission to Titan. Both successful
