**IN SITU SURVEYING OF SATURN'S RINGS.** P.E. Clark^1^, M.L. Rilee^1^ ,
S.A. Curtis^2^, and C. Cheung^2^ ^1^Affiliation: L3 Communications,
Government Services, Inc., 3750 Centerview Drive, Chantilly, VA 20151,
Correspondence: Code 695, NASA/GSFC, Greenbelt, MD 20771, Email:
Pamela.clark@ gsfc.nasa.gov.^2^Affiliation: Code 695, NASA/GSFC,
Greenbelt, MD 20771.

**Introduction:** The Saturn Autonomous Ring Array (SARA) mission
concept \[1\] is a new application for the Autonomous Nano-Technology
Swarm (ANTS) architecture \[2,3\], a paradigm being developed for
exploration of high surface area and/or multi-body targets to minimize
costs and maximize effectiveness of survey operations
\[4,5,6,7,8,9,10\]. Systems designed with ANTS architecture are built
from potentially very large numbers of highly autonomous, yet socially
interactive, specialists, in approximately ten specialist classes. Here,
we analyze requirements for such a mission as well as specialized
autonomous operations which would support this application \[11,12,13\].

SARA \[1\] would perform in situ observations of Saturn's rings, both
from the individual particle and collective plasma standpoints. This
population is of great interest from the standpoint of solar system
origin However, such in situ observations of spacecraft-scale targets
with high density distribution in a large gravity well represents a
challenge unachievable by conventional (direct control of single
spacecraft from Earth) or even evolutionary (direct control of multiple
spacecraft from Earth surrogate) mission designs (Figure).

Each nanocraft would be on the order of kilograms in mass, and thus
require gossamer structures for all subsystems. Onboard power
requirements, met by small nuclear batteries, would be constrained to
milliwatts. The hundreds or even thousands of individual specialists
include Workers, the vast majority, that acquire scientific
measurements, as well as Messenger/Rulers that provide communication and
coordination.

**Methodology:** The patented model of bilevel intelligence which
supports this architecture is described in detail elsewhere \[1,2,3\].
Detailed formulation of requirements and operational scenarios for SARA
is underway \[1\] and the aspects of this application which drive
requirements in a different direction than other applications and their
implications are examined here.

**Discussion:** Potential science goals for SARA (Table).provide the
context for this discussion. The high density distribution of particles
on the scale of particles size, combines with the high intensity gravity
and magnetic field environment to produce dynamic plasmas. Although
composition is essentially cometary with high volatile abundances, great
variations remain in the dust/gas ratio and the composition of dust
component for individual particles. Thus, a broad spectrum of in situ
instruments, with very different requirements, are required, with
specialists developing strategies to obtain in situ measurements as
individuals, teams, in a highly dynamic environment, as appropriate.
Plasma, particle, wave, and field detectors will probably fly just above
or below the ring plane to observe the result of particle interactions.
Imagers and spectrometers will need to develop a strategy for serial
rendezvous with individual particles through the ring. The high density
of particles, some nanocraft-scale, makes collision avoidance a problem
that must also be solved autonomously in situ. The numbers and distances
of these particles, as well as anticipated high attrition rate, require
large numbers of each specialist class,

What would the structure and size of a swarm of specialists need to be?
According to our design for the neural basis function, a minimum of five
specialists are needed for collective decision making \[1,2,3\], and we
allow for ten instrument specialist teams (Table). That means a minimum
size of 50 in a subswarm. Allowing for a high attrition over the couple
of years required for a survey, numbers of specialists should initially
be 100 in a subswarm. The use of ten to twenty of such subswarms should
allow for the characterization of thousands of particles and ring
features over the course of the traverse of the rings.

The SARA concept includes assembly of self-packaging, self-deploying,
self-similar components at facilities built on ANTS architecture
\[1,2,3\] as described for the ANTS Prospecting Asteroid Mission (PAM).
Transportation requirements and capabilities are being considered as
part of a propulsion system trade-off study for SARA, which combines
navigating in low gravity with maneuvering in the high gravity regime of
Saturn's rings, demanding hybrid propulsion.

**Conclusions:** ANTS mission architecture is ideally suited for in situ
surveys such as SARA. The ANTS approach allows simultaneous survey of
many interesting targets by teams of flexible instrument specialists,
which can be configured for optimal operation. Redundancy allows for
planned high attrition of individual workers without compromising
ongoing survey work.

**References:** \[1\] Curtis et al (2003) Saturn Autonomous Ring Array,
NASA RASC Proposal; \[2\] Curtis et al (2004) The Autonomous
NanoTechnology Swarm, NASA RASC Final Report (in preparation); \[3\]
Clark et al (2004) 35^th^ LPSC; \[4\]Curtis et al (2000) Abstracts of
IAF, 51st Congress; \[5\] Clark et al (2001) AAS/DPS, BAAS, vol. 33, no.
3; \[6\] Clark et al (2001) EOS Trans. AGU, 82 (47), 2001; \[7\] Clark
et al (2002) LPSC XXXIII, 1394; \[8\] Clark et al (2002) EOS Trans AGU,
P521-01, \[9\] Curtis et al (2003)Abstracts of Third International
Workshop on Satellite Constellations and Formation Flying, Pisa, Italy;
\[10\] Clark et al (2003) 34^th^ LPSC; \[11\] Rilee et al \[2002\] IEEE
Aerospace Conference, Big Sky, MT, 209; \[12\] Curtis et al (2003) IEEE
Aerospace Conference, Big Sky, MT; \[13\] Curtis et al (2003), Large
Autonomously Reconfigurable Antennas for Space-based Radio Astronomy,
NASA MSMT Proposal;

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height="8.818897637795275e-2in"}![](media/image1.jpeg){width="8.385826771653543e-2in"
height="0.11456692913385827in"}![](media/image1.jpeg){width="8.385826771653543e-2in"
height="0.11456692913385827in"}![](media/image1.jpeg){width="8.385826771653543e-2in"
height="0.11456692913385827in"}![](media/image1.jpeg){width="8.385826771653543e-2in"
height="0.11456692913385827in"}![](media/image1.jpeg){width="8.385826771653543e-2in"
height="0.11456692913385827in"}![](media/image1.jpeg){width="8.385826771653543e-2in"
height="0.11456692913385827in"}![](media/image1.jpeg){width="8.385826771653543e-2in"
height="0.11456692913385827in"}![](media/image1.jpeg){width="8.385826771653543e-2in"
height="0.11456692913385827in"}![](media/image2.jpeg){width="0.7047244094488189in"
height="0.5208661417322835in"}**Acknowledgment**: Support for this work
has been provided through NASA contract NAS5-99189, subcontract
0299189EER, with ITMI.

Return to or visit ANTS home or SARA web page:

<http://ants.gsfc.nasa.gov/pamtest/website.html>

<http://ants.gsfc.nasa.gov/pamtest/sara.html>

<table style="width:100%;">
<colgroup>
<col style="width: 9%" />
<col style="width: 9%" />
<col style="width: 9%" />
<col style="width: 9%" />
<col style="width: 10%" />
<col style="width: 10%" />
<col style="width: 10%" />
<col style="width: 10%" />
<col style="width: 10%" />
<col style="width: 10%" />
</colgroup>
<tbody>
<tr class="odd">
<td colspan="10"><strong>Science Context Table for SARA</strong></td>
</tr>
<tr class="even">
<td><blockquote>
<p><strong>Modes of Study</strong></p>
</blockquote></td>
<td colspan="6"><blockquote>
<p>Particle populations, view from above or below ring planes</p>
</blockquote></td>
<td colspan="3"><blockquote>
<p>individual particles, collect thru ring</p>
</blockquote></td>
</tr>
<tr class="odd">
<td><blockquote>
<p><strong>Measurements</strong></p>
</blockquote></td>
<td colspan="2"><blockquote>
<p>Electrodynamics: plasma, particles waves</p>
</blockquote></td>
<td><blockquote>
<p>Electrodynamics: fields</p>
</blockquote></td>
<td><blockquote>
<p>Ring thickness, density</p>
</blockquote></td>
<td colspan="2"><blockquote>
<p>Emissivity, reflectivity, size, and</p>
<p>volatility distribution</p>
</blockquote></td>
<td><blockquote>
<p>Refractory element abundances</p>
</blockquote></td>
<td><blockquote>
<p>mineral assemblages</p>
</blockquote></td>
<td><blockquote>
<p>volatiles, organics</p>
</blockquote></td>
</tr>
<tr class="even">
<td><blockquote>
<p><strong>Specialists</strong></p>
</blockquote></td>
<td><blockquote>
<p>Particle/Plasma</p>
</blockquote></td>
<td><blockquote>
<p>Search Coil</p>
</blockquote></td>
<td><blockquote>
<p>Magnetometer/E Field</p>
</blockquote></td>
<td><blockquote>
<p>UV/Visible imaging</p>
</blockquote></td>
<td><blockquote>
<p>Mid to Thermal IR</p>
</blockquote></td>
<td><blockquote>
<p>Radio Sounder</p>
</blockquote></td>
<td><blockquote>
<p>APX,laser ablation MS</p>
</blockquote></td>
<td><blockquote>
<p>UV/Vis/IR reflectance</p>
</blockquote></td>
<td><blockquote>
<p>Mass Spectrometer</p>
</blockquote></td>
</tr>
</tbody>
</table>