G O D D A R D S P A C E F L I G H T C E N T E R

Multiwalled carbon nanotubes (MWCNT) for stray light suppression in space flight instruments

John G. Hagopian

Optical Physicist NASA GSFC

Stephanie Getty, Manuel Quijada,

Patrick Roman, James Butler,

Georgi Georgiev, Cleophus Hunt,

Alejandro Maldonado;

NASA Goddard Space Flight Center

(GSFC)
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 Motivation for improved stray light control

• Stray light impacts many scientific observations

– High contrast regions such as coastal areas during Earth observations

• Loss of data can be as high as 40%

– Faint objects such as dark companions near bright stars

– Other experiments requiring stringent isolation of stray light

– 10x improvement in surface treatments could result in 10,000x less stray

light in focal plane
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Background of studies

• Current stray light treatments

– NASA Z306 paints are most widely used

– Black anodize turns reflective at longer wavelengths

– Other treatments such as Martin Black and Ultrapol are blacker than

Z306 but too fragile for space flight use

• Due to multiple bounces in instruments improvement in surface treatment

can result in exponential improvement in system stray light

• NASA Goddard Space Flight Center work on Multiwalled Carbon

Nanotubes initiated in October 2007 in support of IRAD continuing to

present with additional funding coming from Projects

– Initial measurements on AMES randomly oriented samples

– Measurements on GSFC oriented Multiwalled Carbon Nanotube

(MWCNT) samples in Dec 2007 showed much lower reflectance

– Optimization of process at GSFC on a variety of substrates

– Optimization of adhesion on substrates by use of an underlayer
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Hemispherical Reflectance Data
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BRDF of MWCNT on various

substrates vs Z306 at 0 degree incidence

Viewing Angle, Deg

B

R

D

F,

-

sr
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Technology

• Oriented Carbon Nanotubes are black because of their high absorption, morphology, high surface area and low density.

• They are much more efficient absorbers when oriented like a

carpet instead of randomly oriented like spaghetti
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• ORCA looks for faint spectral

signal and requires stray light

suppression to avoid

contamination of signal by

scattered light

• Isolation is accomplished by

entrance aperture slit

• Silicon slit is first NASA

component to be treated with

carbon nanotubes for stray

light suppression

• Slit is treated on both sides

Technology Applications; Ocean Radiometer for

 Carbon Assessment (ORCA)
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• LISA Stray Light Challenge

- Telescope used in duplex

- Tx beam is 109x intensity of Rx Beam

- Tx beam reflected/scattered off of center of

telescope secondary mirror (SM) must be

suppressed by 109

- Suppression in central obscuration on

secondary mirror

- Z306 paint

- Carbon nanotube patch

- Hole in secondary mirror

Constellation of 3 Sciencecraft with linked Telescopes 

Secondary 

Mirror (SM)

Primary 

Mirror (PM) Aft Optics

Focal Surface

Technology Applications; Laser Interferometer

Space Array (LISA) Gravity Wave Experiment
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Z306 Paint Carbon Nanotubes on Si Hole in SM

Carbon Nanotubes Provide 10x Better

Suppression than Z306
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Commercial Applications

• Nearly any precision Optical or IR device would benefit from

using this technology to reduce noise

– Binoculars

– Night vision goggles

– Cameras

– Projection devices

– Scientific instrumentation

– Calibration references

• Possible use as absorber in IR detectors

– Much more robust than gold black
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Collaboration Opportunities

• NASA Goddard is installing a 6” nanotube furnace to

accommodate larger components

• Desire would be to partner in the scale up of this technology

and transfer the production to industry partner to deliver

flight and GSE parts

• We are also pursuing development of carbon nanotube sheets

for use on larger non-conformal surfaces using alternate

approach, looking for partners in this effort as well
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Contact Information

• For further information contact:

John.G.Hagopian@NASA.gov

(240)678-9475
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Backup Slides
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Initial specular reflectance measurements of

Multiwalled Carbon Nanotubes (MWCNT)

performed 12/07 demonstrated potential
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II. Hemispherical reflectance characterization

allows for measurement of all reflected light

Hemispherical Reflectance

is also known as Total

Integrated Scatter (TIS)
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Low specular reflectance not necessarily

predictive of low hemispherical reflectance
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III. Full modeling requires measurement of

Bidirectional Reflectance Distribution Function

BRDF; reflectance as a function of angle

GSFC Scatterometer (Butler/Georgiev)