**IAC-04-IAA.3.8.1.08**

**LARA: Near Term Reconfigurable concepts and components for lunar
exploration and exploitation**

**P.E. Clark**

**Location: Code 695, NASA/GSFC, Greenbelt, MD 20771 USA**

**Affiliation: L3 Communications, GSI., 3750 Centerview Drive,
Chantilly, VA 20151 USA**

**Pamela.Clark@gsfc.nasa.gov**

**M.L. Rilee**

**L3 Communications, GSI, 3750 Centerview Drive, Chantilly, VA 20151
USA**

**Michael.L.Rilee.1@gsfc.nasa.gov**

**S.A. Curtis**^1^**, C.Y. Cheung**^1^**, G. Marr**^2^**, W.
Truszkowski**^3^**,**

^1^**Code 695,** ^2^**Code 588,** ^3^**Code 595, NASA/GSFC, Greenbelt,
MD 20771 USA**

**u5sac@lepvax.gsfc.nasa.gov**

**M. Rudisill**

**MS 328, NASA/LARC, Hampton, VA 23681 USA**

**m.rudisill@pop.larc.nasa.gov**

**[ABSTRACT]{.underline}**

NASA's Exploration Initiative requires tools to support of near term
human activities on the Moon or Mars. ANTS Architecture is well suited
to such applications using current ElectroMechanical Systems (EMS) for
Addressable Reconfigurable Technology (ART). We have analyzed the nature
and behaviors required of ANTS components for such an application
designated LARA (Lander Amorphous Rover Antenna). Basic structures are
highly modular, addressable arrays of robust nodes, from which highly
reconfigurable struts, tethers, and fabric are autonomously and
reversibly deployed for all functions. An ANTS craft is an appendageless
multi-tetrahedral structure, harnessing the effective skeletal/ muscular
system of the frame itself to enable more 'natural' movement,
effectively allowing 'flow' across a surface or into a particular
morphological form. Individual craft would be deployed, with or without
a human crew, land, using a miniaturized version of high impulse
thruster technology, transform into rovers, bowl-shaped antennas,
hut-like human shelters, or more specialized service providers, as
needed, and ultimately return to the point of deployment. We have
developed conceptual and physical models of ANTS systems to determine
design requirements and are currently working on an EMS-based prototype.
ANTS structures could be thus used for exploration, reconnaissance,
communication, transportation, and construction, , protecting human
crews and facilitating their work.

**[Context of the ANTS Approach]{.underline}**

The ANTS approach to exploration \[1,2,3,4,5\] discussed here is
directly relevant to the NASA's Exploration Initiative goals of
sustainable and affordable robotic exploration of the solar system
\[6,7\]. The mission application, Lander Amorphous Rover Antenna (LARA),
is particularly in line with the new Initiative goals for the Moon and
Mars, where the focus is on establishing human crews with robotic
assistance in bases on the Moon and Mars and exploring to search for
evidence of resources, biological precursors, or life itself \[6,7\].

The LARA concept would result in further development of enabling
technologies identified in the Initiative \[6,7\] as well: a)
sustainable autonomous systems and robotics, b) advanced, reusable,
transportation in space and on the ground, and c) reliable, durable,
modular systems and structures.

In this paper, we will describe the conceptual framework, design, and
models, for LARA, based on ongoing work. We will identify requirements
and essential features, and assess capabilities the ANTS architecture to
provide reconnaissance, transportation (lander and rover),
communication, and shelter, and other functions to support the
establishment of a human presence on the Moon and Mars (**Tables 1 and
2**).

What is the nature of the contribution to exploration of the Moon and
Mars that the ANTS architecture can provide through the use of the LARA
concept \[8a,8b\] **(Tables 3 and 4**)? The LARA concept could be
implemented within the next decade using current technology, and be
available to assist the human return to the Moon in 2015-2020, to
prepare for human exploration of Mars. By using the structures
themselves as a skeletal muscular frameworks, LARA craft use a
dramatically new strategy of transforming themselves for the required
activity enroute to or on the surface, providing far higher flexibility
for visits to multiple targets and cost effectiveness than the currently
utilized approaches, where the major systems, landing, surface
transportation, and communication, require separate structures. Stowed
LARA craft could be launched from Crew Exploration Vehicles.
Reconfigurable, reshapable LARA craft could also be used to provide
temporary shelters or to enclose natural formations, such as lava tubes,
providing permanent shelters, as tools to search for and acquire natural
resources, or, collectively, as antenna arrays for communication on the
ground or in space. On the Moon, starting in about a decade, the use of
the LARA concept would thus enable the goal of performing a global
reconnaissance of resource potential, as roving robotic explorers with
or without humans, and of providing a testbed for the human return to
Mars. LARA systems would allow the human/robotic interface to be fully
optimized with less risk of failure.

On Mars, starting in about two decades, the LARA craft could be used for
a robotic mission capable of returning samples from the most desirable
locations from the standpoint of the search for life and water: cracks,
crevices, and caves. Mars terrain, particularly the volcanic terrain of
interest, is highly fractal and thus so extremely hazardous as to be
inaccessible to permanently appendaged (wheeled or legged) vehicles.

**[The ANTS Concept]{.underline}**

ANTS SMART (Super Miniaturized Addressable Reconfigurable Technology)
architecture was initiated at Goddard Space Flight Center (GSFC) to
develop a revolutionary approach to space vehicles and systems
epitomizing the 'form follows function' approach. Such craft are capable
changing form to optimize function or to adapt to environmental demands
(4,5). The basic unit of the structure is a tetrahedron consisting of
nodes interconnected with struts that can be reversibly and/or partially
deployed or stowed to allow motion, forward on a surface, at a
controllable scale or gait. 3D networks are formed from interconnecting
reconfigurable tetrahedra, making structures which are scalable,
massively parallel systems. As more tetrahedra are interconnected, the
degrees of freedom are increased and motions evolve from simple to
complex, and from stepped to continuous. ANTS Addressable Reconfigurable
Technology (ART) can be constructed from the available electromechanical
systems available. The prototype is being constructed from macroscopic
electromechanical systems (EMS)-***ART,*** and LARA could be developed
at this level of technology. As Micro-EMS (MEMS ART, Miniaturized ART or
***MART)*** or nano-EMS (Super Miniaturized ART or ***SMART)*** become
available, within the next decade or two, such components could be
incorporated to minimize mass and power requirements. The 3D network of
actuators and structural elements is composed of nodes that are
addressable as are pixels in an LCD screen. The full functionality of
such a system requires fully autonomous operation, and will ultimately
be realized through a neural basis function (NBF) possessing the
capability for actuator-level autonomic response and heuristic-level
decision-making, which will be discussed elsewhere (9a,9b,9c,9d). The
ANTS architecture for LARA will be discussed here.

**[LARA: Application of ANTS to EXPLORATION of Terrestrial planetary
surfaces]{.underline}**

What have we learned from our attempts to explore the surface of the
Moon **(Table 4**)? The campaign for human exploration of the solar
system was inaugurated with the Apollo Program. The challenge of
launching a human crew along with a large payload to support them into
deep space, delivering them into orbit around another body, landing them
on that body, returning them alive from another its surface, and having
them gather a scientifically useful payload from that surface was a
remarkable achievement, one that was accomplished in ten years and then
repeated successfully 6 times. As a result of the samples gathered from
the surface and data gathered from orbit, major advances were made in
our understanding of planetary formation and conditions for the origin
of life \[10,11\].

Although only limited portions of the lunar surface were sampled, the
Apollo Program was cancelled early. Some mission operations were
automated, but not autonomous, with control resident on the ground,
resulting in high demand for resources, time and expense despite the
limited duration (days) of the missions. Many questions, which demand
the gathering of samples from the still largely unexplored lunar
surface, remain unanswered. Clearly, the development of autonomous
systems and robotics was required to cut down on the use of resources.
But, well trained and curious human explorers are extremely valuable in
guiding the discovery process, as witnessed by the extraordinary job
done by the astronauts in selecting and documenting the sites they
visited. The lesson here apparently is that, in order to make
exploration sustainable, additional support required for human
activities should be utilized as an important enhancement to truly
autonomous robotic exploration, when the human presence is critical for
leading the exploration.

What have we learned from our attempts to explore Mars **(Table 4**)?
The exploration of Mars, largely driven by interest in the possibility
of finding life on Mars, has been entirely remote, and, more recently,
robotic. Mariner 9 was the first spacecraft to orbit Mars, but revealed
nothing until the global dust storms cleared. Viking orbiters, Mars
Global, Surveyor, and Mars Odyssey have revealed progressively more
details of Mars complex terrane as instrument resolutions have improved:
evidence for the largest mountains (volcanoes) and canyons observed in
the solar system, and a past global magnetic field \[12\]. These
missions most striking revelation is that water has played a major role
in creating Mars landscape: cyclical climate changes have caused
periodic ice ages \[13\] which have resulted in massive outflow
channels, and loss of an earlier ocean \[14\]. Speculation and now
substantial evidence for the existence of liquid water on Mars surface
has resulted in renewed interest in the search for life on Mars \[15\].
Rovers have been deployed to look for this evidence in samples. Viking
Landers had indicated Mars was covered with weathered iron-rich clay
derived from basalt in a rugged terrain, a result confirmed by Mars
Pathfinder \[16,17\]. Viking biological experiments had given
unexpected, but not convincing results, for the presence of life \[16\].
Mars Exploration Rovers Spirit and Opportunity have collected many
samples on their traverses within a small area, and, with the finding of
hematite deposits, given even more evidence for the presence of liquid
water during formation of these samples, but have not found water in the
present \[18\].

Of course, the limitations of robotic rovers prevent them from going to
the more rugged landscapes. Their permanent appendages, wheels in this
case or even the 'leg's that are planned, make them relatively
inflexible, optimize them permanently for operation over a limited range
of landscape scales. But it will be highly fractal landscape, with
constantly varying scales of relief and roughness where the deep
fissures buried in chaotic outwash channels, where life would continue
to exist on Mars. Because the risk of injury to appendages is great even
in the typical desert pavement being traversed, extensive decision
making must go into every step, placing tremendous demands for autonomy
that are difficult to meet. As a result, the cautious, slow (due to the
roundtrip light time to Mars) telepresence approach to navigation will
continue to be limit autonomy and coverage. The lesson here may be that
we need a dramatic breakthrough in our approach to robotic rover design
in order to locate and reach areas most likely to contain evidence for
life with any degree of autonomy.

The LARA application of ANTS architecture, summarized in **Table 5**,
uses application of EMS (ART) level systems which are currently
available, or MEMS (MART) level system which will become available over
the next two decades, to address the two the greatest challenges in
longer duration missions far more effectively than existing vehicle
designs. These challenges are a) the need for far greater flexibility
and autonomy in robotic operations, and b) the need for far more
sustainable and efficient use of expendables for autonomous operation
and for crew support and protection.

The ANTS architecture creates a space filling material from addressable,
reconfigurable, self-similar components which provides a skeletal
muscular framework. The structural components themselves are flexible,
allowing adaptation, through their reversible rapid reconfiguration over
seconds, for functions required at each phase of a mission. ANTS
reconfigurable structure thus reduce mass, power, and expendable
requirements by eliminating the need for specialized systems for key
functions such as space and ground transportation, communication, and
shelter.

We first considered the Autonomous Nano-Technology Swarm (ANTS)
architecture for a future application, the PAM concept, which is
discussed in detail elsewhere \[19,20,21\] (See ANTS: The Movie at the
official ANTS website \[1\]).. Here we consider the LARA application in
detail **(Figure 1).** (See LARA: The Movie at the official ANTS website
\[1\]). The LARA craft is transformed from lander to rover over rugged
terrain, to various functions, all described in **Table 6**. These
include antenna for transmitting or receiving information, carrier for a
payload such as a sample collector/analyzer, to provider of crew
shelter. These functions could be performed autonomously, or through
interface with crew either in situ or remote.

**[ANTS/LARA Design Features]{.underline}**

LARA **frame** components are electromechanical structures forming a
continuous network of struts which are network of struts which are
reversibly deployable/stowable from EMS or MEMS nodes equipped for
wireless operation. Payload and subsystem components are attached
'inside' the tetrahedral network, between layers of nodes, and thus
protected. After manufacture, the frame could be reduced to a **minimum
strut extension size for shipping** to a launch or deployment size.

**Nodes and Struts** would be used for all functions The greatest number
would be structural nodes which deploy/stow flexible struts based on one
of several design schemes, ranging from a) telescoping struts extended
or contracted by various mechanisms, including cables or springs, and b)
double 'tape measure' device which links or unlinks the oppositely wound
flexible rolled sheets. Rolls with opposite orientations develop great
tensile strength when combined. Similar nodes could be used as
attachment points for payloads, such as instruments. These structures
are discussed in more detail elsewhere \[19,20,21\].

![](media/image1.jpeg){width="3.194488188976378in"
height="3.141732283464567in"} An **outer covering** for the LARA craft,
also discussed in more detail elsewhere \[19,20,21\], could be provided
by specially designed nodes which would deploy carbon fiber composite
'memory' sheets with relatively low aerial density using Polymer/Carbon
Nanotube Composite (PNC) springs and structural elements \[22,23\]. A
stack of 'sheet' roll devices could deploy multi-layered sheets for
external covering of the desired thickness and reflectivity.

The LARA **Lander** (**Figures 1 and 2 )** is formed by flattening the
tetrahedral network so that mini chemical propulsion thrusters are
effectively attached around the periphery.

The LARA **Amorphous Rover** **(**on right in **Figure 2** ) is created
by continuous![](media/image2.jpeg){width="1.6437007874015748in"
height="5.375196850393701in"}![](media/image3.jpeg){width="1.645275590551181in"
height="5.375196850393701in"}![](media/image4.jpeg){width="1.6216535433070867in"
height="5.375196850393701in"}contraction and extension of struts in a
way that optimizes the efficiency of movement across a terrain, and thus
depends on the variability and scale of the relief and roughness in a
given terrain. The ability to control the timing and extent of strut
deployment allows control of the scale and gait of the rover.

A single tetrahedron **(Figure 2**), like the prototype we are currently
building, rocks from side to side as it moves forward. Put an additional
strut at each node and divide that tetrahedron into 4 tetrahedron (like
the 4Tet we are proposing to field test), and an inner space is created
for attachment of a payload. In a 12Tet model **(Figure 2**), motion is
far more continuous \[19\]. Ultimately, with interconnecting, space
filling tetrahedral material, very high degree of freedom movement
emerges, more 'natural' than wheels, effectively allowing 'flow' across
a surface and into a particular morphological form.

Examples of morphological forms for the continuous tetrahedral motion
can be observed in **Figure 2**. Clear amoeboid-like movement can be
observed for very rough surface, more 'natural' than wheels, effectively
allowing 'flow' across a surface or into a particular morphological
form. For a very smooth surface, or for 'storage' the minimum surface
area spheroid, rolling across the ground, could be effective. Uphill
climb or slipping through narrow openings could require a slithering
snakelike morphology. When surmounting obstacles, the rover could either
change its scale, growing in size, or use a climbing motion, pulling
itself over using facets on the obstacle itself as 'toe holds'.

LARA craft is transformed into an **Antenna** **(Figure 2**) whenever
significant bandwidth communication is required. The tetrahedral network
itself, bowl-shaped above with a broader base below, is equipped to
receive and transmit data.

The **Payload** could be placed within active or passive nodes on the
'inside' of the tetrahedral structure. (A continuous network could have
an 'inside' and 'outside'.

**[LARA Mission Scenarios]{.underline}**

A wide variety of mission scenarios could be employed in using LARA
systems. Deployment and use could be either entirely robotic and
autonomous, or through a human interface. The human interface could be
remote in near real time, through telepresence, or in situ, acting as
extensions for a human crew active on the surface.

LARA craft could first land payloads autonomously, then form roving
'advance reconnaissance teams', mapping, gathering and analyzing samples
and images of the terrain for use in site selection. Such analysis of
samples, to determine elemental, mineral, water, biogenic material, or
rock abundances, or terrains, to determine stratigraphy, morphology,
age, would inevitable lead to the identification of sites with important
clues on the origin of planets, the solar system, or life itself.
Whenever necessary, rovers could form antenna to transmit findings and
receive instructions. Such systems could also be used to provide
shelter, by creating, seeking, and enclosing natural semi-enclosed
formations. LARA craft could also find, collect, or mine materials of
use in exploration or construction. A network of LARA craft could be
used to form a temporary or permanent communication, navigation, or
observatory facilities.

**[Realizing the ANTS Concept: Requirements and Enabling
Technologies]{.underline}**

As part of the ANTS/LARA study, we are determining the major
requirements for such mission **(Table 7**). We should be able to meet
all of these requirements with anticipated, incremental technology
developments over the next two decades. Anticipated incremental
improvements in MEMS technology subsystems will be useful, but are not
essential. Improvements in the efficiency of nuclear batteries and solar
cells, communication and tracking devices, would also be useful in
reducing weight and power requirements.

The development of **autonomous navigation without appendages** is an
area we are now actively engaged in developing. We have already
developed simulations of the movement of single, 4, 12, and continuous
tetrahedral structures (See still and movies at the official ANTS
website \[1\]). The first demonstration model of an EMS-level (ART)
single ANTS tetrahedron, designed to be a walker (TET), will be
completed in October 2004 (TRL 3). Plans are underway to test the TET in
January 2005 in Antarctica with remote operation via the Internet using
a 3-D graphical user interface. We have completed a preliminary
conceptual design of a 4-tetrahedron system (4-TET) capable of carrying
a scientific payload in a central node, and have proposed to build and
test that system on a field campaign in Iceland ('Mars on Earth') (TRL
6). The next milestone will be to build the 12TET model. At this level,
the ability for 'continuous' movement clearly emerges.

LARA utilizes a totally new type of space architecture based on an
autonomous, addressable, reconfigurable components. The potential
flexibility and adaptability of such a system demands a level of
**artificial intelligence** we are in the process of developing through
our role in ST-8 COTS High Performance Computing and Multi-agent
Simulations using Beowulf clusters here at GSFC \[1,9c\].

Another key technology driver is the availability of **carbon-based
materials** to form surface structures in order to minimize deployment,
mass, and power requirements. Ultimately, to minimize the mass and power
requirements, ANTS structures will be built entirely on carbon-based
materials. Currently available carbon fiber composites \[23\] are the
most lightweight, durable, and rigid materials that are currently
available. Specially manufactured thin sheets of this carbon film on
fiber material with shape memory have already been manufactured \[22\].
A particular area of concern for our application would be the ability to
'retain' memory over potentially millions of deployments, and the power
expenditure requirement to hold the material at partial deployment.

**[Acknowledgements]{.underline}**

We would like to acknowledge the important contributions to this work
made by our students Jason Leggett, Richard Watson, Noah Desch, Tom
Comberiate, and Jeff Lee. We thank NASA/GSFC IR&D, GSFC Codes 695 and
588, and the RASC program for their support.

**[References]{.underline}**

\[1\] The Official ANTS website: http://ants.gsfc.nasa.gov

\[2\] Curtis, S.A. et al., 2000.: Autonomous Nano-Technology Swarm.
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\[3\] Clark, P.E., Iyengar, J., Rilee, M.L., Truszkowski, W., Curtis,
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\[4\] Rilee, M.L., Clark, P.E., and Curtis, S.A., 2002. IAU Proceedings,
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\[5\] Curtis, S.A., Truszkowski,W.F., Rilee, M.L., and Clark, P.E.,
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\[6\] The President's Vision for Space Exploration, February 2004.

\[7\] Report of the President's Commission on Implementation of United
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\[8a\] Clark, P.E., Curtis, S.A., Rilee, M.L., Truszkowski, W.F., Marr,
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\[8b\] Clark, P.E., Curtis, S.A., Rilee. M.L., Cheung, C.Y., 2003, From
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\[9a\] Rilee, M.L., Curtis, S.A., Clark, P.E., Cheung, C.Y.,
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\[9b\] Rilee, M.L., Curtis, S.A., Clark, P.E., Cheung, C.Y.,
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\[9c\] Cheung, C.Y., Curtis, S.A., Rilee, M.L., Clark, P.E., Shaya, E.,
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\[10\] http://www.hq.nasa.gov/office/

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\[16\] Mars Viking 1 and 2 website:
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\[19\] Clark, P.E., Rilee, M.L., Curtis, S.A., Cheung, C.Y., Marr, G.,
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\[20\] Clark, P.E., Curtis, S.A., Rilee, M.L., Truszkowski, W., Marr,
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\[21\] Curtis, S., Clark, P.E., Cheung, C.Y., Rilee, M.L., Truszkowski,
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\[22\] http://www.esli.com

\[23\]http://www.meetingsmanagement.com/pdf/PF_2004.pdf