M. Meyyappan

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Nanotechnology for Space Exploration
M. Meyyappan Chief Scientist for Exploration
Technology
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What is Nanotechnology?
Nanotechnology is the creation of
USEFUL/FUNCTIONAL materials, devices and systems
(of any size) through control/manipulation of
matter on the nanometer length scale and
exploitation of novel phenomena and properties
which arise because of the nanometer length scale
Physical Chemical Electrical Mechanical
Optical Magnetic
Source K.J. Klabunde, 2001
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Why Nanotechnology at NASA?
Advanced miniaturization, a key thrust area to
enable new science and exploration
missions - Ultrasmall sensors, power sources,
communication, navigation, and propulsion
systems with very low mass, volume and
power consumption Revolutions in
electronics and computing will allow
reconfigurable, autonomous, thinking
spacecraft Nanotechnology presents a whole
new spectrum of opportunities to build device
components and systems for entirely new space
architectures - Networks of ultrasmall
probes on planetary surfaces - Micro-rover
s that drive, hop, fly, and
burrow - Collection of microspacecraft
making a variety of measurements Nanomater
ials and composites for civilian aeronautics.
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• National Nanotechnology Initiative (NNI)
• Grand Challenge Report
• Nanotechnology in Space Exploration
• addressing
• Nanomaterials
• Microspacecraft
• Micro-Nanorobotics
• Nano Sensors and Instrumentation
• Nano-Micro-Macro Integration
• Astronaut Health Management

To download report, visit http//www.nano.gov,
follow links to report
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Some examples of nanotechnology for mission
insertion at NASA Ames
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What Do We Expect from a Well-Designed Sensor
System?
First, a single device has no value. We need a
system consisting of - Sensor or sensor
array - Preconcentrator (almost always
needed) - Micropump? Microfan? - Sample
handling, delivery, fluidics - Signal
processing unit - Readout unit (data
acquisition, processing, storage) - Interface
control I/O - Integration of the
above Criteria for Selection/Performance
- Sensitivity (ppm to ppb) - Absolute
discrimination - Small package (size,
mass) - Low power consumption - Rugged,
reliable - Preferably, a technology that is
adaptable to different platforms - Amenable
for sensor network or sensor web when needed
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Why Nanomaterials/Nanosensors?
Compared to existing systems, potential exists
to improve sensitivity limits, and certainly
size and power needs Why? Nanomaterials have
a large surface area. Example SWCNTs have a
surface area 1600 m2/gm which translates to
the size of a football field for only 4
gm. Large surface area large
adsorption rates for gases and vapors
changes some measurable properties of the
nanomaterial basis for
sensing - Dielectric - Capacitance - Condu
ctance - Deflection of a cantilever - -
4 grams
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Various Carbon Nanostructures
Single-walled carbon nanotubes
(SWCNTs) - Either a single tube or a film used
in the device - Vapor or gas adsorption on
the material leading to a measurable property
change - Multiwalled carbon nanotubes (MWCNTs)
may not be as good Vertically Oriented Carbon
Nanofibers (CNFs) - Multiwalled carbon
nanofibers - Walls are not parallel, instead
bamboo-like - Individual, free-standing,
vertical - Function as nanoelectrode, support a
probe molecule at the tip amenable for
interaction with target - Nanoelectrode array
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Conductivity Change of CNTs Upon Gas/Vapor
Adsorption
Early chemical sensors were of the CHEMFET type
with SnO2 and other oxide conducting
channels Similar CNT-FETs have been tested in
the literature, exposing to NH3, NO2, etc.
change in conductivity has been
observed Limitations of CNT-FET - Single
SWCNT is hard to transfer or grow in
situ - Even a film of SWCNTs by controlled
deposition in the channel is
complex - 3-terminal device is complex to
fabricate - Commercial sensor market is very
cost sensitive
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NASA Ames Alternative to CNT-FET Interdigitated
Chemiresistor
Conventional thin film transistor approach is
complex and expensive Two terminal
chemiresistor is cheaper, easier to
fabricate 1. Interdigitated electrode device
using simple microfabrication 2. Disperse
purified SWCNTs in DMF 3. Solution casting of
SWCNTs across the electrodes
Jing Li et al., Nano Lett., 3, 929 (2003) Y. Lu
et al., Chem. Phys. Lett., Vol. 391, p. 344
(2004).
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Nanosensing Technology
A relative resistance or current is measured from
each sensor

• Operation
• The relative change of current or resistance is
  correlated to the concentration of analyte.
• Array device learns the response pattern in the
  training mode.
• Unknowns are then classified in the
  identification mode.

Using pattern matching algorithms, the data is
converted into a unique response pattern
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Scalable Array Approach (Multi-channel Sensing
Chip)
12 to 36 sensing elements are on a chip (1cm x
1cm) now with heaters and thermistors. Number
of sensing elements can be increased on a
chip. Number of chips can be increased on a 4
wafer. Wafer size can be increased to 6, 8,
or 12. SWCNT solution-casting by ink jetting
or using microarrays
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Sensitivity is the slope of the calibration
curves. The average slope is 0.0340.002 (6).
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Sensing Mechanisms
Nitrotoluene
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Analytes Tested and Selectivity Issues

• Ensuring Selectivity
• Functionalization of CNTs
• CNT polymer composites
• Doping catalytic metal clusters
• Field effect gate bias for selective detection
  
• Programmed temperature control
• Sensor array with pattern recognition
• electronic nose
• Combination of the above

Analytes Tested NO2 NH3 CH4 SO2 Cl2 H
Cl Acetone Benzene Toulene Nitrotoulene
Hydrogen Peroxide Formaldehyde
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Flight Demo Unit for Satellite U.S. Navy Flight
in 2007
Ceramic chip carrier

• Sensing module
• Collection/integration of multiple sensor input
• Sampling system
• Data storage and transmission
• RS-422 connection

32-channel sensor chip
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Nano Biosensors for NASA Missions
Biosensor for in situ life detection, CEV water
quality monitoring, biomedical applications
Carbon nanotube based sensor combined with
microelectronics and microfluidics for a complete
system to meet mission needs.
PI Jun Li
Team members Alan Cassell, Hua Chen, Barbara
Nguyen, and Jessica Koehne
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Nanoelectrode Array for Biosensors
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Nanoelectrode Array (NEA)

• Break a solid micro- or macro electrode into an
  array of 100 to 109 nanoelectrodes
• Each electrode is well separated with the
  neighbors (gt 6R) so that the NEA behaves similar
  to a single NE.
• Can further create an individually addressed
  multiplex array in an array-in-array format

Challenges Reliable fabrication techniques with
affordable cost, particularly for low-density
NEAs.
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Commonly Used Carbon Electrodes
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Macroelectrode vs. Nanoelectrode
I total Iplanar Iradial
glassy carbon
Semi-infinite planar linear diffusion
Semi-infinite hemispherical diffusion
When reducing the size (r), orders of magnitude
improvements are found in (1) Spatial
resolution defined by r (3) Temporal
resolution Cell time constant t RuCd r
Cd0/4k (2) Sensitivity signal-to-noise ratio
is/in µ nFC0D0/r
Nanoelectrode Array
High sensitivity Easily measurable signal
Fast detection
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Nanoelectrode Array Fabrication
Embedded CNT Array after planarization
30 dies on a 4 Si wafer
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Carbon Nanotube Electrodes at Different Densities
CNT coverage 20 (3.0x109
CNTs/cm2) Average nearest-neighbor
distance 300 nm
CNT coverage lt 1 (1x108 CNTs/cm2) Average
nearest-neighbor distance gt 1500 nm
CV in 1mM K4Fe(CN)6 in 1M KCl at 20 mV/s
J. Li, H. T. Ng, A. Cassell, W. Fan, H. Chen, Q.
Ye, J. Koehne, J. Han, M. Meyyappan, Nano.
Lett., 2003, 3 (5), 597.
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Electrochemical Detection by AC Voltametry
J. Li, H. T. Ng, A. Cassell, W. Fan, H. Chen, J.
Koehne, J. Han, M. Meyyappan, Nano. Lett., 2003,
3, 597.
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Nanotube Materials for Hubble Space Telescope
(HST)
Current Problem Hubble Space Telescope Imaging
Spectrograph overheats, causing data
degration Solution Carbon Nanotube (CNT) as
thermal interface greatly improves HSTs ability
to dissipate excess heat This technology has
been licensed to industry for computer chip
cooling.
PI Alan Cassell Team Members Jun Li, Brett
Cruden, and Quoc Ngo
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Nanotechnology in CEV Development
Metal catalyst Particles (Rhodium)
Environmental management of contaminants during
long duration space flight Carbon nanotubes
have large surface area
Jun Li, Alan Cassell, Metin Setti (CMU)
PI Jing Li
Jim Arnold, Deepak Srivastava, Mairead Stackpoole
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Thermoelectric Refrigeration
Advances in thermoelectric cooling and power
generation rely on the ability to increase the
thermoelectric figure-of-merit ZT to 3 and
above. Inorganic nanowire arrays of bismuth
telluride, indium antimonide offer potential
to meet this goal. Applications - Power
supplies for robots, rovers, CEV, human
habitats - Efficient coolers for electronics,
lasers and detectors - Waste heat recovery
PI Laura Ye Modeling Natalio Mingo
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Radiation-hard Nanodevices

• Novel nanomaterials
• Such as inorganic nanowires (Si, Ge, oxides,
  nitrides
• Next-generation rad-hard devices
• - Logic, memory devices
• - Optoelectronics UV and IR detectors,
  nanolasers for astronomy
• - General requirements low power, high
  performance, ultrasmall, rad-hard
• Highly integrated smart nanosystems
• - Integration of computing technology with
  on-chip embedded functionalities
• Sensing, photonics,

Novel Vertical Transistor
Novel architecture
Information processing
Information storage
Sensing
Integrated Logic-Memory-Sensing Brain-like
system
PI Bin Yu, Cun Zheng Ning
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Carbon Nanotube Field Emitters For Spacecraft
Instruments
X-ray diffraction/fluorescence (XRD/XRF)
instrument, for quantitative mineralogy analysis
of planetary surfaces (1 liter, 1 kg, 5 watts).
Miniature carbon nanotube field emission X-ray
tube
David Blake, Cattien Nguyen, Bob Espinosa
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Structure of CNT Field Emitters
Nature of nanotubes (SWNTs, MWNTs,
CNFs) Clean emitting sites vs. adsorbates
(water vapor, oxygen) Microstructure Screen
ing effect Diode vs. triode
Current is controlled by gate voltage,
independent of acceleration voltage
High voltage required and/or gap needs to be
adjusted
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Carbon Nanotube Field Emission
Various types of emitters were studied
Integration in miniature X-ray tube (Oxford XTG
Inc.)
CNT emitter fabrication NASA Ames
Field emission characterization NASA Ames

• SWCNT - MWCNT - CNF
• Silicon and metal substrates
• Film, arrays

• Optimum type of CNT?
• Optimum CNT/substrate attachment?
• Optimum site density?

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Nanotechnology in Civilian Aeronautics
High strength/low weight nanocomposites,
coatings and other nanomaterials
for - Load-bearing structures - Lightning
protection - EMI protection - Adhesives,
quick repair kits - Quick cleaning of
wings - Sensors - Light weight, high
efficiency power sources Intelligent
computational materials design
Computational material science will play the
critical role in early 21st Century just as what
Computational Fluid Dynamics did for aircraft
industry in late 20th century.