Development of a new test bench dedicated to adhesion ...€¦ · Development of a new test bench dedicated to adhesion characterization of lunar dust simulants in space environment

Development of a new test bench dedicated to adhesion characterization of lunar dust simulants

in space environment

ISMSE 14th – ICPMSE 12th

Pauline Oudayer – ONERA/DPHY/CSECo-authors: Jean-Charles Matéo-Vélez(1), Célia Puybras(2), Jean-François

Roussel(1), Sébastien Hess(1), Pierre Sarrailh(1) and Gaël Murat(1)

(1) ONERA, the French Aerospace Lab(2) La prépa des INP, Institut National Polytechnique

Context – Dust contamination on Mars

2Development of a new test bench dedicated to adhesion characterization of lunar dust simulants in space environment

Photo of before and after dust contamination of Opportunity roverCredit: NASA/JPL-Caltech/Cornell Univ./Arizona State Univ.

• Dust cleaning improved the rover lifetime• Wind can be simultaneously decontaminant and contaminant factor

January 2014 March 2014

• Opportunity and Curiosity missions feedback: dust contamination happened• Mars has its own atmosphere and dust• Wind → « cleaning event »

Context - Origins of dust contamination on the Moon


Credit: NASAApollo archives

Before After

• Human activity - Dust contamination occured due to astronauts work

Surface obscurations

Space suit anomalies Lunar module contamination

Context - Surface properties of the Moon


• Moon surface is covered in dust layer called regolith (< 1cm)• Lunar dust is the < 20 µm portion of the regolith• Results from differents processes:

• Impact of large and small meteoroids• Steady bombardment of particles from the Sun

• Thickness between 5 m (mare areas) and up to 15 m (highlands)• Dust adheres a lot and lead to heavy dust contamination

Moon surface (Apollo 11)Credit: NASA


Context - Origins of dust contamination on the Moon

• Bombardment of meteroids• Charging environment around the Moon

• Electron recollection from solar wind → negatively charged surface• Day-side: photoemission phenomena → positively charged surface• At the night/day frontier: electrostatically lofted dust (Horizon Glow)

Photo of the Horizon Glowtaken by the Clementine probe

Context – Origins of dust contamination on Earth


• To a smaller extent, dust contamination may still appear in clean rooms

• « Pre-flight » contamination

Objectives

• Understand complex adhesion physical phenomena

• Develop and validate a new experimental setup dedicatedto adhesion force quantification

• Use it under conditions representative of the lunar chargingenvironment


Table of contents

• Reminder on adhesion force

• Development of a new setup at ONERA in the DROP facility

• Preliminary results

• Conclusions and perspectives


Van der Waals adhesion force

• Van der Waals force resulting of dipolar interactions: London, Debye, Keesom

• For an interaction between a smooth sphere and substrate in vacuum:

• A = Hamaker constant [J]. Typical values: 10-20; 10-19 J • Rp = particle radius [m]• d = minimum separation distance [m]. Typical value: a few angstroms

→ Estimation of all three parameters is challenging


��

��²∝Rp

Particle

Substrate

Shape of lunar samples


Credit: Liu, 2011 (and references hereby)

SEM photos of lunar dust samples

• Irregular shape

• Rugged forms

• « somewhatelongated »

• Asperities

• Porous

Effect of roughness on adhesion force


��

6��

1

1 �58��

λ²

�1

1 �1,82��

��

�

• Previous equation only supposed an interaction with a smooth surface

• (Rabinovich, 2000) proposed a more precise expression for Fadwhere the substrate has a roughness rms

→ As substrate roughness increases, adhesion force decreases

Rp


• Surface treatments (ion bombardment, coatings… ) have been used in order to increase a surface rougness


Credit: Devaud, 2014

Images of virgin (left) and treated (right) black Kapton sample

AFM

Photos after dustdeposition and removal


• Dust adhesion force quantification done using AFM methodbetween a smooth tungsten sphere and varying roughnesssubstrates


Courtesy of S. Peillon (paper submitted)

Development of a new setup

14 Development of a new test bench dedicated to adhesion characterization of lunar dust simulants in space environment

Credit: Mittal, 2015

Credit: http://research.iitgn.ac.in/

Existing setups providing adhesion force measurement:

Credit: Mizes, 2008

AFM (atomic force microscope)

Shear strengh

Centrifugal force

Experimental facility


• Quantifying adhesion force → use of centrifugal force• Vacuum chamber called DROP (Dust Regolith or Particles)• Vacuum: < 10-6 mbar• External motor goes from 100 rpm to 1500 rpm• Measurement ex-situ: binocular magnifier

Vacuum chamber

External motor Rotor

Sample preparation


• Simulant used: DNA-1• > 140 µm• [50 µm, 140 µm]• [25 µm, 50 µm]• < 25 µm

• Density: 2,9.103 kg/m3

• Substrates: aluminum and graphite samples (size: 20x20 mm, 2 mm thick)

Dust

Substrate

• In order to improve the contrast, a black dot is printed on the substrate(scale: 200µm)

Rotor

SEM photos of DNA-1 simulant

Adhesion forces measurements


• Assumption: dust particles are spherical

• Centrifugal force:

�( �ω²� ∝ ��*

m: particle mass [kg]ω: angular speed of rotation [rad/s]R: rotor radius [m]

• Adhesion force (just before particle detachment) :

�� − �(,,�- � �. ~− �(,,�- as01

02,3456 108�

Individual grains (aluminum substrate), scale=100µm:

Particle mean size: 22 µmFad ~ 20-30 nN

Adhesion forces measurments – Preliminary results


Before

Before After 1500 rpm

After 1500 rpm

Particle mean size: 35 µm

Comparison with literature


Interaction between a W sphereand a rough tokamak surface

Interaction between a W sphere and a smooth W surface (rms = 15 nm)

Interaction between a W sphereand a rough W surface (rms = 750 nm)

Present work

Interaction between dust simulant and a virgin and a treated surface

• Use of centrifugal force as a method of determining adhesion force is reachable under vacuum and for lunar dust simulant down to at least 20 microns in diameter

• Limitation of the system: only data of none and fully-spun sample → overestimation of the adhesion force

• Needs improvement to reach in-situ optical measurements in real-time and high resolution optical measurements

• Obtained results are in agreement with literature• Substrate roughness has a big importance in the adhesion force

Observations of dust clusters on the graphite substrate, scale=100µm:

Conclusions


Before BeforeAfter 1500 rpm After 1500 rpm

Perspectives


• Test bench validation using clearly identified situations: • Use of spherical samples• Use of substrates of varying roughnesses

• Take into account electrostatic forces in space environment and quantifytheir contribution to dust adhesion and contamination using electron gun and VUV source

SEM photos of glass particlesSize: 30±20 µm

Acknowledgments

“The major issue the Apollo astronauts pointed out was dust,dust, dust.”


Professor Larry Taylor, University of Tennessee

Authors would like to thank CEA Cadarache and IRSN forproviding data and discussions

Some references


• Sandra A. Wagner, “The Apollo Experience Lessons Learned for Constellation Lunar Dust Management.” 17-Jan-2008.

• M. Horanyi et al., “A permanent, asymmetric dust cloud around the Moon,” Nature, vol. 522, no. 7556, pp. 324–326, Jun. 2015.

• J. N. Israelachvili, Intermolecular and surface forces, 3. ed. Amsterdam: Elsevier, Acad. Press, 2011.• Y. I. Rabinovich, J. J. Adler, A. Ata, R. K. Singh, and B. M. Moudgil, “Adhesion between Nanoscale

Rough Surfaces,” J. Colloid Interface Sci., vol. 232, no. 1, pp. 10–16, Dec. 2000.• A. Autricque et al., “Simulation of W dust transport in the KSTAR tokamak, comparison with fast camera

data,” Nucl. Mater. Energy, vol. 12, pp. 599–604, Aug. 2017.• M. Soltani and G. Ahmadi, “Detachment of rough particles with electrostatic attraction from surfaces in

turbulent flows,” J. Adhes. Sci. Technol., vol. 13, no. 3, pp. 325–355, Jan. 1999.• A. Dove, G. Devaud, X. Wang, M. Crowder, A. Lawitzke, and C. Haley, “Mitigation of lunar dust adhesion

by surface modification,” Planet. Space Sci., vol. 59, no. 14, pp. 1784–1790, Nov. 2011.• S. Peillon, A. Autricque, F. Gensdarmes, C. Grisolia, “Adhesion of tungsten microspheres on rough

tungsten surfaces using Atomic Force Microscopy.” Submitted to Journal of Colloid and Interface Science.

• K. L. Mittal and R. Jaiswal, Eds., Particle Adhesion and Removal: Mittal/Particle. Hoboken, NJ, USA: John Wiley & Sons, Inc., 2015.

• G. Devaud, C. Haley, C. Rockwell, and A. Fischer, “Surfaces that shed dust: unraveling the mechanisms,” presented at the SPIE Optical Engineering + Applications, San Diego, California, United States, 2014, p. 919603.

• J. Gaier, D. Waters, B. Banks, R. Misconin, and M. Crowder, “Evaluation of Surface Modification as a Lunar Dust Mitigation Strategy for Thermal Control Surfaces,” in 41st International Conference on Environmental Systems, Portland, Oregon, 2011.

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Development of a new test bench dedicated to adhesion ...€¦ · Development of a new test bench dedicated to adhesion characterization of lunar dust simulants in space environment