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Sampling of Regolith Particles from Asteroids Utilizing Alternative

Electrostatic Field

Hiroyuki KawamotoWaseda University, Tokyo

June 19, 2013; Low-Cost Planetary Missions Conference (LCPM-10) @Caltec

©JAXA

total 16 slides

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Outline

• After the success of the HAYABUSA (JAXA), additional projects on sample returning from asteroids are being planned in Japan and the US. Because HAYABUSA hardly succeeded in obtaining a sufficient sample by the bullet firing technique, a more reliable technology is required

• We are developing a new sampling system that employs electrostatic force

• This system is simple, virtually zero-power, has no mechanical moving parts, and suitable for autonomous operation in space

NASA

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©JAXA

Electrostatic Capture

Electrostatic Transport

traveling-wave

Principle of Electrostatic Sampling System

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Electrostatic Sampling System

++++

−−−−

CH1

CH2

CH3

CH4

CHA

CHB

Switching of ±±±±DC power supplies

are controlled by a µµµµ-comp

regolith

µµµµ-comp.

++++

−−−−

parallel screen electrodes

particle conveyer

time

time

µµµµ-comp.µµµµ-comp

++++

−−−−

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5

Lunar Soil Simulant Used for Experiments

FJS-1 (similar to JSC-1A)

50 µµµµm

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capturing

20 mm

transporting

Demonstration of Particle Capture

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0

100

200

300

400

0 50 100 150

Time Required for Capturing

• applied voltage: 8 kVp-p，，，，30Hz• gap: 0 mm• inclination: 30 deg

operation time s

Substantial amount of regolith can be captured even at one-

second operation

captured regolith m

g

1 second

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Sampling on Earth

10 kVp-p, 10 Hz

1.5 mm

observed calculated (DEM)

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9

Experiment in Zero-G Environment

parabolic flights by JAXA

150 mm

capture

conveyer

capsule

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1 G zero-G

Effect of Gravity

In zero-G: Regolith can be captured at high altitudeLarge particles can be captured

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• 900 mg regolith was captured only in one-second operation

• Large particles was captured

Captured Particle Size

1000

volume

%

0.5

0.4

0.3

0

0.2

0.1

100101

particle diameter mm

captured in 0-G

captured in 1-G

initial

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Performance on Small Asteroid

observed in

• zero-G• w/ air drug

calculated in

• zero-G• w/ air drug

calculated in

• zero-G• w/o air drug

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iron

ice ice mixed with lunar regolith

glass

Sampling for Varied Particles

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Power Consumption

0

0.2

0.4

0.6

0.8

0 2 4 6 8 10

applied voltage kVp-p

power m

W

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Merits of This System

■■■■ Operation in Space

The performance of this system will be much better in space than on the Earth because of low gravity and higher threshold voltage against insulation breakdown in vacuum

■■■■ Adaptability for Autonomous Operation

Because the system consumes less power, it can begin the operation before the spacecraft lands on the asteroid, and end the operation after the collection of the regolith is confirmed. Precise timing adjustment is not necessary; therefore, it is suitable for autonomous operation

■■■■ Reliability

The system is highly reliable because it is very simple and because moving parts or firing systems are not necessary

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Wanted !

For more information

Hiroyuki Kawamoto, Prof.

Waseda University, Tokyo, Japan

Phone/FAX: +81-3-5286-3914

E-mail: kawa@waseda.jp

http://www.kawamoto.mech.waseda.ac.jp/kawa/

We hope to conduct a joint-research with laboratories who are interested in this technology and who have a high activity in space technology.