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.
2.
3.
4.
5.
III.
IV.
V.
VI.
Mission Overview
Experiment Overview
Space Environment
Dosimetry
Radiation Shielding Experiment
Conclusion
Collaborators
Acknowledgements
Questions
Materials
Advanced Materials and Processing Branch
Materials for Extreme Environments
• Extreme-Use Temperature Composites
• Radiation Shielding
• Refractory Ceramics
• Materials on The International Space
Station Experiment (MISSE)
MISSE
deployment
on ISS,
containing
NASA LaRC
Materials
Advanced Materials, Polyimide Resins and
Composites
NASA LARC Advanced Materials R&D
Maturation of PETI-5:
Requirements Driven High Performance Adhesive and
Composite Matrix Resin
•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
Polyimide Based R&D 100 Winners
2005
PETI-330 High
Temperature Resin
2001
TEEK
Polyimide Foam
PETI-5/IM7 Skin Stringer Panel (6 ft x 10 ft)
2000
2000
Macro Fiber
Atomic Oxygen
Composite Actuators Resistant Polymers
1996
LaRC -SI
Methods of Making Atomic Number Z-grade
Radiation Shielding
Ta
CF
Titanium 6-4
Tantalum
Copper
Ta on IM-7 Carbon Fiber (CF) Fabric
SEM cross-sectional image
Thickness ~196 - 210mm
5 cm
Schematic of Z-grade Lay-up with Fiber Metal Laminate
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
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
5 cm
2 mil Ta coating on Al 6061
RF Plasma Spray Ta on Aluminum (Al)
• Disappearance of pores,
when coated on Al sheet.
• RF Plasma Spray process is
variable
Rf Plasma Spray Ta Foil Properties
Tantalum Material Properties
Density (g/cm3)
Volume
Resistivity
(mohms-cm)
Crystal
Structure
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.
Reference
1. Maissel and Glang, Handbook of Thin Film Technology, McGraw Hill Publishing, 1970.
Radio Frequency Plasma Spray Facility
1
NASA-LaRC RF Plasma Spray Facility
2
Equipment Schematic
Powder
Inject or
Probe
Plasma Spray
Chamber
RF Torch
St ing Rot at ional/
Translat ional Shaft
Rot ary wat er
cooling coupler
Melt ed Part icles
1 2 0 RPM
2 "/ sec.
Mandrel
3
Chamber Interior
4
Metal Deposition on Rotating Substrate
RF Torch
Plasma
Plume
Mandrel
Metal
Deposit
Shields-1
Shields-1 CubeSat Mission Overview
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.
Total ionizing dose (TID) environment:
Shielddose-2 Calc: 2.70 krad/yr , 3 g/cm2 Al
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
Electron Belt
Proton Belt
Shields-1 Experiment Overview
5 cm
Shields-1 provides performance data of multiple radiation shielding
materials that ultimately enable the success of future missions
2 mil Ta coating on
Al 6061
TID
RF Plasma Spray Ta on Al
Areal density
RF Plasma Spray Ta Carbon
Fiber Laminate
Shields-1 3U CubeSat
Schematic
Charge Dissipation Film
Luna Innovations , NASA STTR Program
Graphical Concept of the Dose
Depth Curve (DDC)
demonstrating Shields-1 ability to
provide data to validate atomic
number (Z) grade radiation
shielding solutions
Space Environment Comparison: GTO and P-LEO
Electron Fluence, 1 year
1.E+16
1.E+15
1.E+14
1.E+13
1.E+12
1.E+11
1.E+10
1.E+09
1.E+08
1.E+07
1.E+06
GTO
P-LEO
0.1
1
10
100
1000
Log Integral Electron Fluence (cm-2)
Log Integral Proton Fluence (cm-2)
Proton Fluence, 1 year
1.E+16
1.E+15
1.E+14
1.E+13
1.E+12
1.E+11
1.E+10
1.E+09
1.E+08
1.E+07
1.E+06
GTO
P-LEO
0.01
1.E+10
1.E+09
Shielded GTO,
Al 3 g/cm2
Shielded P-LEO,
Al 0.5 g/cm2
1.E+08
0.1
1
10
Log Energy (MeV)
0.1
1
10
Log Energy (MeV)
Log Integral Electron Fluence (cm-2)
Log Integral Proton Fluence (cm-2)
Log Energy (MeV)
100
1000
1.E+11
1.E+10
1.E+09
1.E+08
Shielded GTO,
Al 3 g/cm2
1.E+07
1.E+06
Shielded P-LEO,
Al 0.5 g/cm2
1.E+05
0.01
0.1
1
10
Log Energy (MeV)
SPENVIS: AP8min-AE8 Max Model for GTO and Polar LEO, ELaNa III Satellite Environment
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.
Dosimetry and Data Collection Plan
Past Space Dosimeter Experiments:
Dosimetry sample geometry options with larger
areal density backing than sample.
GOES-7 (1978):
1. Approximate half-spherical shell
CRRES (1990)
LDEF (1991)
0
METEOSAT-3(1991)
(Side-view)
Van Allen Belt Storm Probe (2013)
To capture Trapped Proton and Electron belt
Doses, greater and less than L shell ~2.5
Radiation shielding sample
RADFET, dosimeter
backing
2. Approximate Infinite Slab
FOV deg
L shell ~ 2.5
Electron Belt region
radius
Proton
Belt region
(Side-view)
FOV = field of view
Radiation Shielding Experiment
Experimental Samples
5 cm
Baseline Samples
1.
2.
3.
4.
Ta
2 mil Ta coating on
Al 6061
1. RF Plasma Spray Ta on Al
RF Plasma Spray Tantalum Foil
Tantalum Sheet
Carbon Fiber Laminate
Aluminum
Al half-sphere geometry baseline dose depth curve
2. RF Plasma Spray Ta
Carbon Fiber Laminate
Log Dose in Si (Rad/year)
1000000
Shieldose-2 model center of Al
Spheres dose divided by 2
for half-sphere sample geometry.
100000
10000
Trapped
Protons
Trapped
Electrons
Bremsstrahlung
1000
100
10
1
0
1
2
4 samples: 0.5, 1.3,
3 2, and 3 g/cm2
Areal Density (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
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. Zgrading 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