Shields-1, a CubeSat with a radiation

shielding research payload

D. Laurence Thomsen III1, Wousik Kim2, Nathanael A. Miller3, Amanda M. Cutright3, and James W. Cutler4

(1) NASA Langley Research Center, Advanced Materials and Processing Branch, 6A West Taylor Street, MS 226, Hampton, VA 23681.

(2) Jet Propulsion Laboratory, Mission Environments Group, 4800 Oak Grove Drive, MS 122-107, Pasadena, CA 91109-8099.

(3) NASA Langley Research Center, Mechanical Systems Branch, 1 North Dryden Street, MS 432, Hampton, Virginia 23681

(4) University of Michigan, Department of Aerospace Engineering 1320 Beal Avenue, 3013 FXB Building, Ann Arbor, MI 48109-2140.

Agenda

I. Materials

Advanced Materials and Processing Branch, NASA Langley Research Center

II. Shields-1:

1. Mission Overview

2. Experiment Overview

3. Space Environment

4. Dosimetry

5. Radiation Shielding Experiment

III. Conclusion

IV. Collaborators

V. Acknowledgements

VI. Questions

Materials

Advanced Materials and Processing Branch

• Extreme-Use Temperature Composites • Radiation Shielding • Refractory Ceramics • Materials on The International Space Station Experiment (MISSE)

Materials for Extreme Environments

MISSE deployment on ISS, containing NASA LaRC Materials

Advanced Materials, Polyimide Resins and

Composites

Maturation of PETI-5: Requirements Driven High Performance Adhesive and Composite Matrix Resin

PETI-5/IM7 Skin Stringer Panel (6 ft x 10 ft)

•About 20,000 pounds of IM7/PETI-5

unidirectional tape prepared in the

HSR program

• Performance at 350°F for 60,000 hrs

(previously unattainable)

• Technology patented and

licensed to 4 companies

NASA LARC Advanced Materials R&D

Polyimide Based R&D 100 Winners

2005 PETI-330 High Temperature Resin

2001 TEEK Polyimide Foam

2000 Macro Fiber Composite Actuators

2000 Atomic Oxygen Resistant Polymers

1996 LaRC -SI

Methods of Making Atomic Number Z-grade

Radiation Shielding

Titanium 6-4 Tantalum Copper

Schematic of Z-grade Lay-up with Fiber Metal Laminate

Ta on IM-7 Carbon Fiber (CF) Fabric SEM cross-sectional image

Thickness ~196 - 210mm

Ta

CF

U.S. Patent 8,661,653, 4 March 2014, “Methods of Making Z-Shielding.” D.L. Thomsen III, R.J. Cano, B.J. Jensen, S.J. Hales, and J.A. Alexa.

2 mil Ta coating on Al 6061

5 cm

Radio Frequency (RF) Plasma Spray Ta on Aluminum (Al)

Ta RF Plasma Spray Coated Al Radiation Shielding

2 mil Ta coating on Al 6061

Ta Ta

Al

Al

• Disappearance of pores, when coated on Al sheet. • RF Plasma Spray process is variable

2 mil Ta coating on Al 6061

5 cm

RF Plasma Spray Ta on Aluminum (Al)

Rf Plasma Spray Ta Foil Properties

1. Maissel and Glang, Handbook of Thin Film Technology, McGraw Hill Publishing, 1970.

Tantalum Material Properties Density (g/cm3) Volume Resistivity (mohms-cm)

Crystal Structure

Reference

Rf Plasma Spray Ta (Z=73) 16.02 +/- 0.02 49 +/- 6 bcc

Bulk Ta 16.6 13 bcc 1.

Thin Film Ta 15.6 25-50 bcc 1.

Radio Frequency Plasma Spray Facility

NASA-LaRC RF Plasma Spray Facility 1 Rotary water

cooling coupler Sting Rotat ional/

Translat ional Shaft

2"/ sec.

Plasma Spray

Chamber

Powder

Injector

Probe

RF Torch

Mandrel

120 RPM

Melted Part icles

2

Chamber Interior

RF Torch

Mandrel

3

Plasma

Plume

4 Metal Deposition on Rotating Substrate

Equipment Schematic

Metal

Deposit

Shields-1

Shields-1 CubeSat Mission Overview

Proton Belt Electron Belt

Shields-1 focuses on enabling future research and commercial space technology mission by reducing the harmful effects of harsh radiation environments to spacecraft. This is accomplished by raising the TRL of Atomic Number (Z) grade radiation shielding technologies.

Mission features: - Radiation Shielding

Experiment - Secondary small

satellite payload mission planned for Geostationary Transfer Orbit (GTO)

- Charge Dissipation Film - Vault enables use of

COTS components

Total ionizing dose (TID) environment: Shielddose-2 Calc: 2.70 krad/yr , 3 g/cm2 Al

Shields-1 Experiment Overview

Shields-1 3U CubeSat Schematic

Graphical Concept of the Dose Depth Curve (DDC)

demonstrating Shields-1 ability to provide data to validate atomic

number (Z) grade radiation shielding solutions Charge Dissipation Film

Luna Innovations , NASA STTR Program

Shields-1 provides performance data of multiple radiation shielding materials that ultimately enable the success of future missions

Areal density

TID

2 mil Ta coating on Al 6061

5 cm

RF Plasma Spray Ta on Al

RF Plasma Spray Ta Carbon Fiber Laminate

Space Environment Comparison: GTO and P-LEO

Proton Fluence, 1 year

1.E+06

1.E+07

1.E+08

1.E+09

1.E+10

1.E+11

1.E+12

1.E+13

1.E+14

1.E+15

1.E+16

0.01 0.1 1 10

Log

Inte

gral

Ele

ctro

n F

lue

nce

(cm

-2)

Log Energy (MeV)

GTO

P-LEO

1.E+06

1.E+07

1.E+08

1.E+09

1.E+10

1.E+11

1.E+12

1.E+13

1.E+14

1.E+15

1.E+16

0.1 1 10 100 1000

Log

Inte

gral

Pro

ton

Flu

en

ce (

cm-2

)

Log Energy (MeV)

GTO

P-LEO

Electron Fluence, 1 year

1.E+08

1.E+09

1.E+10

0.1 1 10 100 1000

Log

Inte

gral

Pro

ton

Flu

en

ce (

cm-2

)

Log Energy (MeV)

Shielded GTO,Al 3 g/cm2

Shielded P-LEO,Al 0.5 g/cm2

SPENVIS: AP8min-AE8 Max Model for GTO and Polar LEO, ELaNa III Satellite Environment

1.E+05

1.E+06

1.E+07

1.E+08

1.E+09

1.E+10

1.E+11

0.01 0.1 1 10

Log

Inte

gral

Ele

ctro

n F

lue

nce

(cm

-2)

Log Energy (MeV)

Shielded GTO,Al 3 g/cm2

Shielded P-LEO,Al 0.5 g/cm2

Total Ionizing Dose (TID) Environment

GTO:

• GTO Orbit: 23o inclination, 37,500 km apogee, 240 km perigee

• Shields-1 Initial Planning Environment

• Total ionizing dose (TID) environment: Shieldose-2 calculation2:

2.7 kRad/yr , 3 g/cm2 Al

Polar- LEO:

• Orbit: 102o inclination, 775 km apogee, 458 km perigee

• ELaNa III1 CubeSat environment: AUBIESAT-1, RAX-2, DICE, Explorer,

M-Cubed/COVE.

• TID environment Shieldose-2 calculation2: 5.0 kRad/yr total dose,

0.5 g/cm2 Al

1. http://www.nasa.gov/pdf/627975main_65121-2011-CA000-NPP_CubeSat_Factsheet_FINAL.pdf 2. SPENVIS, https://www.spenvis.oma.be/, Shieldose-2 calculation, AP8min-AE8 Max Model Environment.

GTO Trapped Proton Challenges: SEUs

• CRRES1 experimentally determined single event upset (SEU) rate for most sensitive electronic devices: 10-3 bit-1 / day in Proton Belt (L<2.5) and 10-5-6 10-3 bit-1 / day in regions outside of proton belt (L>2.5).

• 10-3 bit-1 / day in Proton Belt (L<2.5) is two orders of magnitude higher SEU rate than recommended2-3 for COTS.

1. E.G. Mullen and K.P. Ray, “Microelectronics Effects as Seen on CRRES”, Adv. Space Res. Vol. 14, No. 10, pp. 797- 807, 1994.

2. J.R. Wertz and W.J. Larson, Space Mission Analysis and Design, 3rd Edition. 2007, Microcosm Press, p. 976.

3. NASA Preferred Reliability Practices, PD-ED-1258. “Space Radiation Effects on Electronic Components in Low-Earth Orbit”, April 1996. p. 7.

0

Dosimetry and Data Collection Plan

Radiation shielding sample RADFET, dosimeter backing

(Side-view)

FOV deg

radius

Dosimetry sample geometry options with larger areal density backing than sample.

Past Space Dosimeter Experiments: GOES-7 (1978): CRRES (1990) LDEF (1991) METEOSAT-3(1991) Van Allen Belt Storm Probe (2013)

To capture Trapped Proton and Electron belt Doses, greater and less than L shell ~2.5

FOV = field of view

1. Approximate half-spherical shell

(Side-view)

2. Approximate Infinite Slab

Proton Belt region

Electron Belt region

L shell ~ 2.5

1

10

100

1000

10000

100000

1000000

0 1 2 3

Log

Do

se in

Si (

Rad

/ye

ar)

Areal Density (g/cm2)

TrappedProtons

TrappedElectrons

Bremsstrahlung

Shieldose-2 model center of Al Spheres dose divided by 2 for half-sphere sample geometry.

Radiation Shielding Experiment

2 mil Ta coating on Al 6061

Ta 5 cm

1. RF Plasma Spray Ta on Al

2. RF Plasma Spray Ta Carbon Fiber Laminate

Experimental Samples Baseline Samples

1. RF Plasma Spray Tantalum Foil

2. Tantalum Sheet

3. Carbon Fiber Laminate

4. Aluminum

4 samples: 0.5, 1.3, 2, and 3 g/cm2

• 4 to 5 Samples planned for each material (0.5 g/cm2 – 3 g/cm2) • Build experimental dose depth curves for proton belt and electron belt regions • Compare to trapped belt models

Al half-sphere geometry baseline dose depth curve

Conclusion

• RF plasma spray coatings enable new forms of Z-grading.

• The GTO trapped proton and electron belt environments offer

the opportunity to test radiation shielding materials in more

than one environment.

• Z-grading is not limited to electron dominant environments. Z-

grading will be increasingly important with benchmarking the

state of the art in passive radiation shielding.

Collaborators

• Shields-1: Mr. Victor Stewart (LaRC), Mr. Mark Jones (LaRC),

Dr. Bill Seufzer (LaRC), Mr. Stephen Casey (LaRC), Mr. Kevin

Vipavetz, (LaRC), Mr. Salvatore Scola (LaRC), Mr. David Way

(LaRC).

• Materials Research and Development: Mr. Roberto Cano

(LaRC), Dr. Brian Jensen (LaRC), Dr. Steven Hales (LaRC), and

Mr. Joel Alexa (AMA).

• Radiation Physics: Dr. Sheila Thibeault (LaRC).

• Modeling: Ms. Suzanne Maddock (Science Systems and

Applications, Inc.), Dr. Francis Badavi (Christopher Newport

University), and Dr. Martha Clowdsley (LaRC).

• Scanning Electron Microscopy: Mr. James Baughman (AMA).

• Density Measurements: Ms. Helen Herring (AMA).

Acknowledgements

• Dr. Henry Garrett, JPL

• Dr. Insoo Jun, JPL

• Dr. Cheryl Marshall, GSFC

• Dr. Robert Bryant, LaRC

• Dr. Steven Walker, Old Dominion University

• Mr. Adam Goff, Luna Innovations