Automated

Hybrid Microwave Heating

for Lunar Surface Solidification

Shawn M. Allan Dr. Jeffrey Braunstein - Rensselaer Polytechnic Institute

Inessa Baranova, Nicholas Vandervoort, Morgana Fall, Dr. Holly Shulman - Ceralink

Ceralink Inc.

Rensselaer Technology Park

Troy, New York

ASCE Earth and Space 2012

Symposium 1:

5th NASA/ASCE Workshop on Granular Materials in Space Exploration

Pasadena, California

April 17, 2012, 10:20 AM

Acknowledgement

Information presented from:

Ceralink independent investigations

Sponsored in part by New York State Energy Research and Development Authority

With Dr. Paul Hintze, Kennedy Space Center

and

NASA Phase I SBIR, NNX10RA69P

Automated Hybrid Microwave Heating for Lunar Surface Solidification

Outline

Technical Accomplishments

Microwave Solidification Experiments

Modeling Work

Summary

Information presented from: From Contract Number: NNX10RA69P, Report Number: NNX10RA69P-03

July 15, 2010

NASA Applications

The primary application targeted by this Phase I project was:

Lunar surface dust passivation and surface stabilization

Technology also applicable to Mars and asteroid regoliths

Hybrid microwave heating method also applicable to:

processing of regolith for bricks

making glass

refining metals

heat intensive applications

generation of oxygen and other valuable gases

Technical Accomplishments Phase I SBIR

First microwave surface heating demo

Largest scale lunar simulant densification via

microwave heating

Advanced modeling with prediction capabilities

Test Apparatus Deep-bed Microwave Surface Heating Module

Microwave penetration from the surface only

Simulate heating above a deep regolith layer

Test Apparatus Microwave experiments

Heated 8-9 kg (5-6 liters) of JSC-1A

Approach 1

MW only

Approach 2

MW + susceptors

Approach 3

MW + suscepting bed

Solidification: Solidification: Solidification:

Deep, localized Shallow, localized Thick, uniform

Solidified Sections Mechanical Testing

Test bar machined from solidified JSC-1A

Flexural Strength Data

Material

Modulus of Rupture

(MPa)

Testing

Method

Buechel Stone Corp. Indiana

Limestone 4.8 ASTM C99

Buechel Stone Corp. Silverdale

Stone 8.1 ASTM C99

NRMCA Concrete In Practice 5.3

ASTM

C78/C239

Solidified JSC-1A Lunar Simulant

Bars 9 to 20 ASTM C1161

Modeling

An advanced model was developed:

Electromagnetic solver

Thermal solver

Option for thermal heat source

Flexibility to build in additional effects

Used measured dielectric properties of JSC-1A

Results generated were verified experimentally

Breakthrough for predicting microwave heating!

Model Base

Autowave- microwave chamber

Insulation box with

metal box inside

Dielectric Properties Testing At Microwave Frequencies for JSC-1A

Loss tangent indicates good heating from 25 °C

Data used in the modeling work

0

2

4

6

8

10

12

0 200 400 600 800 1000 1200Temperature (°C)

Re

al

Pe

rmit

tiv

ity

, e'

0.1

1

10

Die

lec

tric

Lo

ss

, e"

Real Permittivity

Dielectric Loss on Heating

Dielectric Loss on Cooling

0

50

100

150

200

250

300

0 200 400 600 800 1000 1200

Temperature (°C)

Ha

lf P

ow

er

De

pth

(m

m)

0.01

0.1

1

Lo

ss

Ta

ng

en

t, t

an

d

Half Power Depth

Loss Tangent

Modeling Work Comparison to Experimental Microwave Self Heating

Modeling Work Comparison to Experimental Susceptor Heating

Solid Model of

insulation box with

metal box and

susceptor-lid

1

5

9

13

17

21

25

29

33

37

41

45

49

S1

S4

S7

S1

0

S1

3

S1

6

S1

9

S2

2

S2

5

S2

8

S3

1

S3

4

S3

7

S4

0

S4

3

S4

6

S4

91300-1

400

1200-1

300

1100-1

200

1000-1

100

900-1

000

800-9

00

700-8

00

600-7

00

500-6

00

400-5

00

300-4

00

200-3

00

100-2

00

0-1

00

60 minutes

Computational Model

of insulation box with

metal box and

susceptor-lid

Experimental Result of

insulation box with

metal box and susceptor-lid

Susceptor-lid

Sintering Rate Comparison

Ceralink method faster vs. Taylor single mode*

Ceralink 1 hr (2.2 Kg) – Taylor > 49 hours (equivalent mass)

Estimate 4 rovers with 6 kW microwaves could pave 10k m2 JSC-1A 3 years

Taylor showed lunar regolith microwave heated in 1/3 time at ½ power compared to JSC-1A

Estimate 4 rovers could pave 10k m2 Lunar Regolith 0.5 years * L. Taylor et. al. LEAG Conference on Lunar Exploration 2005.

1746

12

2.48

0.045

2.2

25

0.01

0.1

1

10

100

1000

10000

Single Mode - Taylor Ceralink Phase I Theoretical Limit Sintering

Rate

[kg/hr]

Time for

10,000 m2

[years]

Sintering Rate [kg/hr]

Time for 10,000 m2 [years]

1746

12

2.48

0.045

2.2

25

0.01

0.1

1

10

100

1000

10000

Single Mode - Taylor Ceralink Phase I Theoretical Limit Sintering

Rate

[kg/hr]

Time for

10,000 m2

[years]

Sintering Rate [kg/hr]

Time for 10,000 m2 [years]

Conceptual Paving Rover

Rover fitted with microwave equipment and portable power supply

Concept developed with Rensselaer Polytechnic Institute and Gerling Applied Engineering

Thermionic/fission power

source (modeled after

TOPAZ-II – roughly to scale)

6 kW

Magnetron

Waveguide

Regolith

preheat

Closed-loop

vertical position

control

Summary

JSC-1A Solidification

Complete surface solidification w/ microwave energy

Largest scale surface only microwave heating

Inert atmosphere

60 min to solidify a 7” x 7” x 1.5” volume of JSC-1A

Suscepting materials improved heating efficiency and uniformity

Best result with distributed particulate susceptor (<400 g/m2)

Solidification sufficiently load bearing (9-20 MPa flex strength)

Far Exceeded (100-300x) NASA’s load bearing requirements of 70 kPa (0.07 MPa).

Modeling

Models showed excellent approximations of the experimental microwave heating

Model developed to use thermal and electromagnetic effects

First measurement and input of lunar simulant dielectric properties as a function of temperature

Anticipated Lunar Regolith Solidification

Surface solidification of 10,000 m2 in 0.5 yrs with 4 rovers

each with 6 kW magnetron

Future Work

Measure dielectric properties of Apollo 17 75001 regolith

Have thruster tests performed on solidified sample

Develop continuous process (lab-scale demo)

Explore complimentary technologies