Grace T. Yi

Hathaway Brown School, Shaker Heights, Ohio

Kim K. de Groh

Glenn Research Center, Cleveland, Ohio

Bruce A. Banks

Alphaport, Inc., Cleveland, Ohio

Athena Haloua, Emily C. Imka, and Gianna G. Mitchell

Hathaway Brown School, Shaker Heights, Ohio

Overview of the MISSE 7 Polymers and 

Zenith Polymers Experiments After 1.5 Years

of Space Exposure

NASA/TM—2013-217848

March 2013
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Grace T. Yi

Hathaway Brown School, Shaker Heights, Ohio

Kim K. de Groh

Glenn Research Center, Cleveland, Ohio

Bruce A. Banks

Alphaport, Inc., Cleveland, Ohio

Athena Haloua, Emily C. Imka, and Gianna G. Mitchell

Hathaway Brown School, Shaker Heights, Ohio

Overview of the MISSE 7 Polymers and 

Zenith Polymers Experiments After 1.5 Years

of Space Exposure

NASA/TM—2013-217848

March 2013

National Aeronautics and

Space Administration

Glenn Research Center

Cleveland, Ohio 44135

Prepared for the

12th International Symposium on Materials in the Space Environment (ISMSE-12)

cosponsored by the European Space Agency and ESTEC

Noordwijk, The Netherlands, September 24–28, 2012
Acknowledgments

We would like to thank Patty Hunt for her continual support of the NASA Glenn Research Center (GRC) and Hathaway Brown 

School collaboration. We acknowledge and thank prior PEACE students for their help preparing and pre-fl ight characterizing the 

MISSE 7 samples. We extend our thanks to Ed Sechkar for his help with acquiring surface areas with the AutoCAD Trace Design 

software. We would like to thank Don Jaworske of NASA GRC for coordinating all the GRC MISSE experiments and for his help 

and dedication to the MISSE Program. We greatly appreciate the support provided of Carl Walz (retired) and Fran Chiaramonte of 

NASA Headquarters, Fred Kohl and Tom St. Onge of NASA GRC, and Stu Cooke and Melissa Ashe of NASA Langley Research 

Center (LaRC) for their support of MISSE post-fl ight analyses. Finally, we would express our sincere appreciation to Phil Jenkins 

of the Naval Research Laboratory and Gary Pippin (retired) of Boeing for providing the unique opportunity to fl y the Zenith 

Polymers and the Polymers Experiment, respectively, as part of MISSE 7. This research was supported by the International Space 

Station (ISS) Research Program and the MISSE-X Project.

Available from

NASA Center for Aerospace Information

7115 Standard Drive

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National Technical Information Service

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Available electronically at http://www.sti.nasa.gov

Trade names and trademarks are used in this report for identifi cation 

only. Their usage does not constitute an offi cial endorsement, 

either expressed or implied, by the National Aeronautics and 

Space Administration.

Level of Review: This material has been technically reviewed by technical management. 
NASA/TM—2013-217848 1

Overview of the MISSE 7 Polymers and Zenith Polymers 

Experiments After 1.5 Years of Space Exposure

Grace T. Yi

Hathaway Brown School

Shaker Heights, Ohio 44122

Kim K. de Groh

National Aeronautics and Space Administration

Glenn Research Center

Cleveland, Ohio 44135

Bruce A. Banks

Alphaport, Inc.

Cleveland, Ohio 44135

Athena Haloua, Emily C. Imka, and Gianna G. Mitchell

Hathaway Brown School

Shaker Heights, Ohio 44122

Abstract

As part of the Materials International Space Station Experiment 7 (MISSE 7), two 

experiments called the Polymers Experiment and the Zenith Polymers Experiment were flown on 

the exterior of the International Space Station (ISS) and exposed to the low Earth orbit (LEO) 

space environment for 1.5 years. The Polymers Experiment contained 47 samples, which were 

flown in a ram or wake flight orientation. The objectives of the Polymers Experiment were to 

determine the LEO atomic oxygen erosion yield (Ey, volume loss per incident oxygen atoms, 

given in cm3

/atom) of the polymers, and to determine if atomic oxygen erosion of high and low 

ash containing polymers is dependent on fluence. The Zenith Polymers Experiment was flown in 

a zenith flight orientation. The primary objective of the Zenith Polymers Experiment was to 

determine the effect of solar exposure on the erosion of fluoropolymers. Kapton H® was flown in 

each experiment for atomic oxygen fluence determination. This paper provides an introduction to 

both the MISSE 7 Polymers Experiment and the MISSE 7 Zenith Polymers Experiment, and 

provides initial erosion yield results. 

Introduction

Materials used in spacecraft design are often exposed to threats in LEO space environment, 

such as atomic oxygen (AO) interaction, ultraviolet radiation (UV), micrometeoroid and debris 

impacts, charged particle radiation, temperature effects and thermal cycling. These threats can 

result in embrittlement and degradation of exposed materials, threatening their performance and 

durability. 

Of these threats, arguably the most prominent is AO erosion. Atomic oxygen is formed 

through photodissociation of molecular oxygen by short-wavelength UV radiation (>5.12 eV, 

<243 nm) from the sun (Ref. 1). At spacecraft velocities (~7.7 km/s), a number of chemical 
NASA/TM—2013-217848 2

reactions with surface molecules can occur, including elastic scattering, scattering with partial or 

full thermal accommodations, recombination, or excitation of ram species (Ref. 2). These 

reactions are vigorous enough to cause bond breakage, oxidation, and consequent material 

erosion. Exposure to LEO AO atmosphere causes structural degradation and problems with 

functionality. Therefore, it is essential to quantify the erosion yield (Ey) which is the volume lost 

per incident oxygen atom (cm3/atom) of space-exposed polymers. Even materials protected from 

atomic oxygen can be susceptible to AO erosion. Imperfections in the substrate surfaces of 

atomic oxygen protected materials, such as microscopic scratches or dust particles, can cause 

defects in the respective protective coatings (Ref. 3). These defects provide a pathway for AO 

degradation and undercutting erosion of the substrate. 

Another LEO threat to spacecraft materials is solar UV radiation, which has a typical 

wavelength of 0.1 to 0.4 micrometers (Ref. 4). UV radiation is energetic enough to cause the 

breaking of organic bonds such as C = C, C = O, and C-H as well as other functional groups 

(Ref. 5). A molecule is raised to an excited state when an organic molecule absorbs a photon of 

UV radiation; bond dissociation can occur if the molecule acquires enough energy at the excited 

state. Depending on the temperature and physical properties of the materials, the dissociated 

radical species are reactive intermediates, with the capability of diffusing several atomic 

distances from their point of origin and can participate in further reactions (Ref. 5). Solar 

radiation often results in bond breakage in materials as well as threats to functionality and 

stability of the materials. Of interest to this study is whether solar radiation can have an impact 

on the erosion of materials.

As part of the Materials International Space Station Experiment 7 (MISSE 7), two 

experiments called the Polymers Experiment and the Zenith Polymers Experiment were flown on 

the exterior of the International Space Station (ISS) and exposed to the low Earth orbit (LEO) 

space environment for 1.5 years. The primary objective of the Polymers Experiment was to 

determine the LEO atomic oxygen erosion yield (Ey, volume loss per incident oxygen atoms, 

given in cm3

/atom) of the polymers and the primary objective of the Zenith Polymers 

Experiment was to determine the effect of solar exposure on the erosion of fluoropolymers. This 

paper provides an introduction to both the MISSE 7 Polymers Experiment and the MISSE 7 

Zenith Polymers Experiment, and provides initial erosion yield results.

Materials International Space Station Experiment (MISSE) Overview

MISSE is a series of experiments that have flown on the exterior of the International Space 

Station (ISS). The overall objective of the MISSE flight experiments is to analyze the durability 

and stability of materials in the space environment in order to both determine the best-suited 

materials for space applications and to gain knowledge about material characteristics in order to 

predict the longevity of new materials and components that could potentially be used in the 

future. Individual flight experiments are flown in containers called Passive Experiment

Containers (PECs) that allow for exposure to the space environment. The PECs are closed during 

launch to protect the samples. Once on orbit, the PECs are opened back-to-back and exposed to 

the space environment for the duration of the mission (Ref. 3). The PECs are placed in a 

ram/wake or a zenith/nadir orientation. The orientation highly affects environmental exposure. 

The ram facing PEC will receive a high flux of directed AO and sweeping solar exposure. A 

zenith facing experiment will receive a low flux of grazing arrival AO and the highest solar 

exposure. Wake surfaces receive very low AO fluxes and solar radiation similar to ram 

experiments. 
NASA/TM—2013-217848 3

The MISSE 7 Polymers Experiment and Zenith Polymers Experiment were flown and placed 

on the exterior of the International Space Station (ISS) during the STS-129 Shuttle mission on 

November 23, 2009. The experiments were placed in two MISSE PECs, one of which was flown 

in a zenith/nadir orientation (designated as MISSE 7A Zenith Experiment) while the other was 

flown in a ram/wake orientation (designated as MISSE 7B Polymers Experiment). Once 

positioned, the experiments remained in low Earth orbit (LEO) for approximately 1.5 years, until 

they were retrieved during the STS-134 Shuttle mission on May 20, 2011. Figure 1 shows 

MISSE 7A and 7B as imaged during the STS-130 mission in February 2010.

Figure 1. On-orbit photo of MISSE 7A (left, zenith surface shown) and 7B (right, ram surface 

shown) as imaged during the STS-130 shuttle mission in February 2010.

MISSE 7B Polymers Experiment 

The MISSE 7B Polymers Experiment was a passive experiment that contained 44 samples, 

which were flown in both the ram and wake flight orientations in the MISSE 7B PEC. The two 

objectives of the Polymers Experiment were: 1) to determine the LEO atomic oxygen erosion 

yield (Ey, volume loss per incident oxygen atoms, given in cm3

/atom), of the polymers and 2) to 

determine if atomic oxygen erosion of high and low ash containing polymers is dependent on 

fluence. Thirty-seven of the samples were flown in the ram orientation, exposing them to high 

AO and solar radiation. Seven samples were flown in the wake orientation, exposing them to 

solar radiation with minimal AO. The high and low ash containing samples were exposed to 

varying levels of AO fluence by the inclusion of very thin sacrificial Kapton film covers.

Tables 1, 2, and 3 below provide a list of 20 MISSE 7B Polymers Experiment samples

analyzed for mass loss based Ey, along with sample ID, sample size, film thickness, number of 

layers flown (to allow mass measurements to be made in the event that erosion of more than one 

layer would occur) and flight orientation (ram or wake exposure). The majority of samples were 

flown in two trays: Tray B7-R which held 15 – 1” (2.54 cm) square samples, shown in Figure 2, 

and Tray N5-R which held 16 – 0.75” (1.905 cm) square samples, shown in Figure 3. Samples

B7-12 - B7-15 in Figure 2, and N5-9 – N5-11 in Figure 3 were part of other MISSE 7 

experiments.

Kapton H® was flown as part of the Polymers Experiment for atomic oxygen fluence 

determination in the ram direction. In addition, numerous samples were flown in Al foil holders 

which were taped directly to the baseplate using thermal control tape to maximize sample 
NASA/TM—2013-217848 4

exposure on-orbit. Some of the taped sample holders contained tensile samples. PVC (B7-10)

was flown on the top of a small Atomic Oxygen Scattering Chamber and hence was flown with a 

0.127” (0.323 cm) diameter hole in the center. The results of the taped and tensile samples, and 

samples that are not characterized for mass-loss based on Ey are not discussed in this paper.

Comparison of Ey values from other MISSE flight experiments will be discussed in future work.

Table 1. MISSE 7 Polymers Experiment Ram “B7-R” Tray Samples.

MISSE 

Sample 

ID

Material Trade Name 

(Abbreviation) Size Thickness (mils)

Number 

of 

Layers

B7-1 Crystalline polyvinyl fluoride w/ white 

pigment White Tedlar (PVF) 1" x 1" 2 1

B7-2 Crystalline polyvinyl fluoride w/ white 

pigment (w/ 0.5 mil Kapton H cover) White Tedlar (PVF) 1" x 1" 2 1

B7-3 Crystalline polyvinyl fluoride w/ white 

pigment (w/ 1.0 mil Kapton cover) White Tedlar (PVF) 1" x 1" 2 1

B7-8 Polyimide (PMDA) Kapton H (PI) 1" x 1" 5 4

B7-9 Polyimide Vespel 1" x 1" 19.7 1

B7-10 Polyvinyl chloride (small dia. hole) on top 

of AO Scattering chamber ClearLay (PVC) 1" x 1" 5 1

B7-11 TiO2/Al2O3/fluorinated ethylene propylene TiO2/Al2O3/FEP 1" x 1" 2 1

Table 2. MISSE 7 Polymers Experiment Ram “N5-R” Tray Samples.

MISSE 

Sample 

ID

Material Trade Name (Abbreviation) Size 

(inches)

Thickness 

(mils)

Number 

of 

Layers 

N5-1 Polyethylene (PE) 0.75 x 0.75 2 18

N5-2 Polymethylpentene TPX (PMP) 0.75 x 0.75 2 9

N5-3 Polyethersulfone (PES) 0.75 x 0.75 3 6

N5-4 Aluminized-fluorinated 

ethylene propylene* Aluminized-Teflon (Al-FEP) 0.75 x 0.75 5 1

N5-5 Polyimide (PMDA) Kapton H (PI) 0.75 x 0.75 5 4

N5-6 Polyimide (PMDA) Kapton H (PI) 0.75 x 0.75 5 4

N5-7 Polyimide (PMDA) with a 

0.5 mil Kapton H cover Kapton HN (PI) 0.75 x 0.75 5/0.5 4

N5-8 Polyimide (PMDA) with a 

1.0 mil Kapton H cover Kapton HN (PI) 0.75 x 0.75 5/0.5 4

N5-12 Polyamide-imide Torlon 4203 (PAI) 0.75 x 0.75 70 1

N5-13 Polyvinyl alcohol 

(in Al holder) MonoSol M1000 (PVOH) 0.75 x 0.75 1.5 24

N5-14 Cellulose nitrate Celluloid (CN) 0.75 x 0.75 5 7

N5-15 Polyimide (AO resistant) CORIN 0.75 x 0.75 6 7

N5-16 Urethane/liquid crystal 

polymer (LCP)

Urethane/Vectran mesh

(Urethane/LCP mesh) 0.75 x 0.75 10 1

*Teflon layer is space facing
NASA/TM—2013-217848 5

Figure 2. Pre-flight photo of the MISSE 7 B7-R Tray with sample IDs.

Figure 3. Pre-flight photo of the MISSE 7 N5-R Tray with sample IDs.

The MISSE 7B Polymers Experiment included samples from the Japan Aerospace 

Exploration Agency (JAXA), Towson University, Montana State University, NeXolve 

Corporation, ATK Space, NASA Langley Research Center (LaRC) and the National Institute of 

Aerospace.

MISSE 7A Zenith Polymers Experiment

The objective of the Zenith Polymers Experiment was to determine the effect of solar 

exposure on the Ey of fluoropolymers in the zenith orientation under high solar/low AO exposure. 

This was accomplished by comparing atomic oxygen fluence ratios to solar exposure, including 

samples flown as part of other MISSE polymer experiments, such as the MISSE 7B Polymers 

Experiment. Whether or not there is a synergistic effect of solar radiation on AO erosion is a 

concept that is a highly debated subject in the Space Environmental Durability community

(Ref. 6).

The experiment consisted of 15 square polymer samples, 1”x1” (2.54 cm2), flown in the 

MISSE 7A “Z” tray. The specific polymers flown are listed in Table 3 along with sample ID, 

sample size, film thickness and number of layers flown. Kapton H® was flown for atomic oxygen 

fluence determination in the zenith direction. Samples of Al-FEP and silvered-Teflon FEP (AgFEP) were included in order to determine the effects of metallization on AO Ey. Four program 

specific samples were also included: JWST sunshield material (Si/2 mil Kapton E/VDA), Orion 

LIDS Seal O-ring samples and two atomic oxygen and vacuum ultraviolet (VUV) radiation 
NASA/TM—2013-217848 6

barrier coated FEP samples from Montana State University. A pre-flight photo of the Zenith 

Polymers Experiment sample tray is shown in Figure 4.

The Zenith Polymers Experiment also included 10 “taped” samples, flown in Al holders 

which were taped directly to the baseplate. Five of the taped samples were for mass loss based 

Ey and 2 holders contained five tensile samples. Analyses of the Orion LIDS Seal O-ring 

samples and the taped samples will be discussed in future work. 

Table 3. MISSE 7 Zenith Experiment Samples.

MISSE 

Sample 

ID

Material Trade Name 

(Abbreviation) Size Thickness (mils)

Number 

of 

Layers 

Z-1 Polytetrafluoroethylene Chemfilm DF-100 

(PTFE) 1" x 1" 5 1

Z-2 Fluorinated ethylene propylene Teflon (FEP) 1" x 1" 5 1

Z-3 Chlorotrifluoroethylene Kel-F (CTFE) 1" x 1" 5 2

Z-4 Ethylene-tetrafluoroethylene 

copolymer Tefzel ZM (ETFE) 1" x 1" 5 2

Z-5 Polyvinylidene fluoride Kynar 740 (PVDF) 1" x 1" 3 2

Z-6 Ethylene-chlorotrifluoroethylene Halar 300 (ECTFE) 1" x 1" 3 3

Z-7 Polyvinyl fluoride Clear Tedlar (PVF) 1" x 1" 3 12

Z-8 Polyimide (PMDA) Kapton H(PI) 1" x 1" 1 3

Z-9 Aluminized-fluorinated ethylene 

propylene* Al-Teflon (Al-FEP) 1" x 1" 2 1

Z-10 Silvered-fluorinated ethylene 

propylene* Ag-Teflon (Ag-FEP) 1" x 1" 5 1

Z-11 Polyethylene (low oxygen) PE 5 8

Z-12 Si/2 mil Kapton E/vapor

deposited aluminum

Si/2 mil Kapton E/

VDA 1" x 1" 2 1

Z-14 Al2O3/FEP Al2O3/FEP 1" x 1" 2 1

Z-15 TiO2/Al2O3/FEP 1" x 1" 2 1

*Teflon layer is space facing
NASA/TM—2013-217848 7

Figure 4. Pre-flight photo of the MISSE 7A Zenith Tray with sample IDs.

Erosion Yield and Atomic Oxygen Fluence Determination 

The erosion yield (Ey) of the MISSE 7 flight samples was determined using mass loss 

measurements. The equation to find the Ey of a flat (non-stressed) sample calculates the volume 

lost per incident atomic oxygen atom:

Ey = ∆M

ρAF

where

ΔM = dehydrated mass loss (g)

ρ = polymer density (g/cm3)

A = exposed surface area (cm2)

F = atomic oxygen fluence (atoms/cm2

) 

The AO fluence (F) is can be determined by measuring the mass loss of a Kapton H witness 

sample because Kapton H has a well characterized erosion yield (3.0 x 10-24

cm3/atom) in the 

LEO environment (Refs. 7 to 10). The atomic oxygen fluence for the samples can be calculated 

by solving Equation 1 for F and using the Kapton H mass loss value and density.

Experimental Procedures

Mass Loss Determination

When using mass loss data to obtain accurate erosion yield measurements, it is critical to 

recognize the hydroscopic (absorbing up to 2% of their weight in moisture) properties of many 

polymer samples, including Kapton. This causes fluctuations in mass with corresponding 

humidity and temperature. It is therefore imperative that samples be fully dehydrated (i.e., in a 

vacuum desiccator) before measuring mass for both pre-flight and post-flight measurements.

(1)
NASA/TM—2013-217848 8

All MISSE 7 flight samples were dehydrated in a vacuum desiccator with a mechanical 

roughing pump. The samples were placed under vacuum in the desiccators at a constant pressure 

of 0-100 mtorr (0-0.013kPa) for at least 72 hours prior to weighing. In order to keep all the 

samples under vacuum during the weighing process, the desiccator would be put back under 

vacuum immediately when an individual sample was removed for weighing.

Duration of time under vacuum, relative humidity and temperature in the room were recorded 

prior to each set of weighing. For each sample, time at which the sample was removed from the 

desiccator, times at which samples were weighed, and sample mass were also recorded. Previous 

tests determined that the mass of a dehydrated sample was not affected by quickly opening a 

desiccator to retrieve another sample and putting it under vacuum again, which allowed multiple 

samples to be dehydrated and weighed together in sets. 

The average of three mass readings was used to calculate mass loss, which was determined 

by subtracting the average post-flight mass from the average pre-flight mass. Pre-flight mass 

measurements were obtained using a Mettler Balance 3M. Post-flight mass measurements were 

taken using a Sartorius ME 5 Microbalance. 

Density Determination 

The densities of the samples were based on density gradient column measurements of 

polymers for the MISSE 2 PEACE Polymers experiment (Refs. 6, 11, and 12). The density 

gradient columns for the PEACE experiment were created in 50-mL burets with solvents of 

either cesium chloride (CsCl) and water (H2O), for less dense polymers, or carbon tetrachloride 

(CCl4) and bromoform (CHBr3), for more dense polymers. Glass standards of known densities 

were placed in the column and allowed to settle, and then small pieces of various polymers were 

placed in the columns. A curve was fit to the positions and known densities of the glass 

standards. A plot of the positions of the test polymers on the curve yielded density values for 

each material. 

Where possible, the same batch of material was used for MISSE 7 as was used for MISSE 2. 

Manufacturers’ densities were used for Vespel, PVC, PMP, PES, Torlon, PVOH, CN, CORIN, 

Vectran Mesh, and Kapton E, as they were not flown as part of the PEACE experiment.

Surface Area Determination

The exposed surface area of the samples was generally determined by taking three different 

width measurements and three different length measurements of each sample tray opening with 

Max-Cal electronic digital calipers. The average width was multiplied by the average length to 

calculate the square opening. However, the trays have rounded corners with a 0.062 inch 

(0.15748 cm) radius. Therefore, 0.02129 cm2 (the area of the four rounded corners) was 

subtracted from each square area to get the actual exposed sample area.

For two irregularly shaped samples on the N5-R tray, PVOH (N5-13) and urethane coated 

Vectran Mesh (N5-16), AutoCAD computer design software was used to trace the surface area 

from a photograph of the sample taken with a Sony digital camera. An example of the photo 

trace on the Vectran mesh sample is shown in Figure 5 below. 
NASA/TM—2013-217848 9

Figure 5. Example of AutoCAD phototrace (Vectran mesh (N5-16)).

Sample Stacking

For weighing, the samples were divided into 2 different parts. Part A consisted of the single 

top layer and Part B was made up of all additional layers. Part A and Part B were weighed 

separately post-flight. This way, only Part A needed to be weighed post-flight for samples with 

less than one layer of erosion.

Optical Microscopy 

Optical microscopy was used to document select samples. The pictures were taken at 

magnifications of 7.5x to 20x with an Olympus SMZ stereo-zoom optical microscope equipped 

with a Canon digital camera. 

Results and Discussion

Mass Loss Verification

The mass of the MISSE 7 control samples were obtained with the Sartorius ME 5 

Microbalance used for post-flight massing and were found to be consistent with the pre-flight 

masses of the same samples taken with the Mettler Balance 3M.

Post-flight Inspection 

B7-R Tray

Upon initial inspection post-flight, the B7-R tray showed discoloration and some sample 

degradation. This can be seen by comparing the post-flight photo of the B7-R tray, shown in 

Figure 6, to the pre-flight photo, shown in Figure 2. The Kapton films covering PVF (B7-2 and 

B7-3) were shown to have been completely eroded away. Samples exhibiting discoloration postflight included FEP/PTFE/POM/PEO (B7-4), Kapton H/Mylar/PE/PG (B7-5), AO Pinhole 

Camera (B7-7), Kapton H (B7-8), Vespel (B7-9), and TiO2/Al2O3/FEP (B7-11). Discoloration of 

samples can be attributed to erosion or radiation darkening. The FEP/PTFE/POM/PEO (B7-4)

and Kapton H/Mylar/PE/PG (B7-5) samples, made for recession depth measurements, are not 

reported in this paper. Metal samples B7-12 - B7-15 are part of another experiment. 
NASA/TM—2013-217848 10

Figure 6. Post-flight photo of the MISSE 7 B7-R Tray.

The PVC sample (B7-10) also was found to have changed from a clear film to a very dark 

color, as shown in Figure 7. It was also eroded though at one edge and was curled up; hence, the 

Ey will be greater than the value determined. An impact site, formed by collision with 

micrometeorite or space debris, was discovered on the PVC sample and is shown in Figure 8.

 a. b.

Figure 7. The PVC flight sample (B7-10): a). Pre-flight photo, and b). Post-flight photo.

Figure 8. Micrometeoroid or debris impact site on the PVC (B7-10) flight sample.

0.3 mm
NASA/TM—2013-217848 11

N5-R Tray

During initial post-flight inspection, several samples in the N5-R tray showed significant 

discoloration and some sample degradation. This can be seen by comparing the post-flight photo 

of the N5-R tray, shown in Figure 9, to the pre-flight photo, shown in Figure 3. Samples showing 

discoloration included PE (N5-1), PES (N5-3), Kapton HN (N5-6), and Torlon (N5-12). An 

example of sample discoloration is shown in Figure 10 below for sample PES (N5-3). 

Figure 9. Post-flight photo of N5-R Tray.

Figure 10. Post-flight photo of the PES (N5-3) flight sample (all layers stacked together)

along with a control sample, showing sample discoloration.

Several samples showed substantial degradation, such as PE (N5-1), PMP (N5-2), Kapton H

(N5-5), PVOH (N5-13), and CN (N5-14). The CN sample eroded completely through all seven 

layers flown, leaving a small amount of material in the exposed area, as can be seen in Figure 11. 

The erosion yield of this sample will be greater than the value determined. Figure 12 below 

shows a close up optical microscope picture taken of the fringe on the left side of the CN sample. 
NASA/TM—2013-217848 12

Figure 11. Post-flight photo of the CN (N5-14) flight sample (top layer (Part A) separated from 

bottom 6 layers (Part B)) along with a control sample, showing erosion through all layers. 

Figure 12. Close up photo of left border fringe on CN (N5-14) flight sample. 

Zenith Tray

The Zenith tray exhibited significant sample discoloration and changes in texture. This can 

be seen by comparing the post-flight photo of the tray, shown in Figure 13, to the pre-flight 

photo, shown in Figure 4. Samples with discoloration included ETFE (Z-4), PVDF (Z-5), 

ECTFE (Z-6), PVF (Z-7), and Kapton H (Z-8). Samples with changes in texture included

Kapton H (Z-8) and PE (Z-11), as shown in Figures 14 and 16 respectively. Figure 15 shows a 

close up image of the eroded border of the ETFE (Z-4) sample. For example, Kapton H (Z-8)

developed a more matte appearance. 

0.3 mm
NASA/TM—2013-217848 13

Figure 13. Post-flight photo of MISSE 7 Zenith Tray.

Figure 14. Post-flight photo of the ETFE (Z-4) flight sample (all layers stacked together) along 

with a control sample, showing sample degradation and discoloration. 

Figure 15. Close up of eroded border of ETFE (Z-4) flight sample. 
NASA/TM—2013-217848 14

Figure 16. Post-flight photo of the Kapton H (Z-8) flight sample (all layers stacked together) 

along with a control sample, showing changes in sample texture. 

Atomic Oxygen Fluence and Solar Exposure

The mass loss, surface area, density, erosion yield values, and computed fluence values are 

shown in Table 5 for the ram Kapton H fluence sample (B7-8) and the zenith Kapton H fluence 

sample (Z-8). The atomic oxygen fluence for the MISSE 7B ram tray was determined to be

4.22 x 1021 atoms/cm2

, and the atomic oxygen fluence for the MISSE 7A zenith tray was 

determined to be 1.58 x 1021 atoms/cm2. Similar ram fluence values (4.2±0.1 x 1021 atoms/cm2)

have been reported based on mass loss and thickness loss of Kapton HN (Ref. 13).

Table 5. Atomic Oxygen Fluence Determination.

MISSE 7 

Tray

Sample 

ID Material Mass Loss (g)

Surface 

Area 

(cm2)

Density 

(g/cm3

)

Kapton Ey 

(cm3/atom)

MISSE 7 

Fluence 

(atom/cm2)

Ram Tray 

B7-R B7-8 Kapton H 0.077547 4.291 1.4273 3.00E-24 4.22E+21

Zenith Tray Z-8 Kapton H 0.002897 4.278 1.4273 3.00E-24 1.58E+20

Estimates of solar exposure in equivalent sun hours (ESH) have been determined for the 

MISSE 7 ram, wake and zenith surfaces. The ram surface received an estimated 2,400 ESH and 

the wake surface received an estimated 2,000 ESH based on UV diode measurements on 

readings from ram and wake trays, respectively, monitored by the Lead-Free Technology 

Experiment in Space Environment (LTESE) (Ref. 13). Computations of the of zenith solar 

exposure have been conducted by Naval Research Laboratory (NRL) and were determine to be 

approximately 4,300 ESH (Ref. 14).

Erosion Yield Values

Ram Samples

Tables 6 and 7 provide sample ID, material, total mass loss, surface area, density, AO fluence, and 

erosion yield for the ram B7-R and ram N5-R trays, respectively. In the B7-R tray, samples with the 

highest Ey values and therefore the least durable included Kapton H (B7-8), Vespel (B7-9), and PVC

(B7-10). Because the PVC sample was eroded through at one edge and curled up, as shown in Figure 7, 

the reported erosion yield is a lower bound. The polymer sample with the lowest erosion yield was the 

TiO2/Al2O3 coated FEP sample (B7-11). 
NASA/TM—2013-217848 15

Table 6. Erosion Yield Values for B7-R Tray.

MISSE 

Sample 

ID

Material Mass 

Loss (g)

Surface 

Area 

(cm2)

Density 

(g/cm3

)

MISSE AO 

Fluence in 

atoms/cm2

MISSE 7 

Ey

(cm3/atom)

B7-1 White Tedlar 0.004343 4.289 1.624 4.22E+21 1.48E-25

B7-2 White Tedlar (with 0.5 

mil Kapton H cover) 0.004063 4.290 1.624 3.79E+21 1.54E-25

B7-3 White Tedlar (with 1.0 

mil Kapton cover) 0.003907 4.281 1.624 3.37E+21 1.67E-25

B7-8 Kapton H 0.077547 4.294 1.427 4.22E-24 3.00E-24*

B7-9 Vespel 0.076224 4.292 1.430 4.22E+21 2.94E-24

B7-10 PVC (small dia. hole) 0.041485 4.209 1.340 4.22E+21 >1.74E-24

B7-11 TiO2/Al2O3/FEP 0.000031 4.291 2.144 4.22E+21 7.99E-28

*Kapton Ey from previous flight experiments (Refs. 7 to 10)

Table 7. Erosion Yield Values for N5-R Tray.

MISSE 

Sample ID Material Mass Loss (g)

Surface 

Area 

(cm2)

Density 

(g/cm3

)

MISSE AO 

Fluence 

(atoms/cm2)

MISSE 7 

Ey 

(cm3/atom)

N5-1 Polyethylene (PE) 0.033375 2.097 0.918 4.22E+21 4.11E-24

N5-2 Polymethylpentene

(PMP) 0.032763 2.096 0.833 4.22E+21 4.45E-24

N5-3 Polyethersulfone (PES) 0.033721 2.093 1.37 4.22E+21 2.79E-24

N5-4 Al-FEP 0.003428 2.094 2.144 4.22E+21 1.81E-25

N5-5 Kapton H 0.038461 2.095 1.427 4.22E+21 3.05E-24

N5-6 Kapton HN 0.038111 2.095 1.435 4.22E+21 3.01E-24

N5-7 Kapton HN (with 0.5 mil 

Kapton H cover) 0.03257 2.097 1.435 3.79E+21 2.85E-24

N5-8 Kapton HN (with 1.0 

mil/Kapton H) 0.022312 2.094 1.435 3.37E+21 2.20E-24

N5-12 Polyamide-imide (Torlon) 0.021855 2.099 1.42 4.22E+21 1.74E-24

N5-13 Polyvinyl alcohol

(PVOH) 0.025248 1.490 1.28 4.22E+21 3.14E-24

N5-14 Cellulose nitrate (CN) 0.091079 2.099 1.4 4.22E+21 >7.34E-24

N5-15 CORIN 0.000368 2.099 1.36 4.22E+21 3.05E-26

N5-16 Urethane/Vectran Mesh 0.001827 0.671 1.4 4.22E+21 4.61E-25

The Ey of the white Tedlar samples (B7-1, B7-2, B7-3) were analyzed. While B7-1 was 

flown as the sample uncovered, B7-2 and B7-3 were flown with Kapton H covers 0.5 mil and

1.0 mil thick respectively, which altered the fluence each white Tedlar sample received. 

Factoring in the fluence to erode each Kapton H film, fluence vs. Ey were plotted along with the 

Ey of a MISSE 2 sample (Ref. 6) and a line of best fit was graphed, as shown in Figure 17. As 

can be seen, the Ey decreases with increasing AO fluence. This is attributed to a buildup of AO 

durable TiO2 particles on the surface of the samples with increasing AO exposure. The TiO2 can 

protect the underlying material from erosion, thus decreasing the Ey with increasing AO fluence.

White Tedlar results are further discussed in Banks 2012 (Ref. 15).
NASA/TM—2013-217848 16

Figure 17. AO Fluence vs. Ey of White Tedlar from MISSE 2 and MISSE 6.

In the N5-R tray, the polymer sample with the highest erosion yield (most erosion) was CN

(N5-14). Because the sample eroded all the way through during flight, the true Ey of the CN 

sample will be higher than the calculated Ey in this experiment. Other samples with notably high 

erosion yields included Kapton HN (N5-6), PE (N5-1), PMP (N5-2), and PVOH (N5-13). 

The polymer sample with the lowest erosion yield was CORIN (N5-15), an AO resistant 

polymer. Other samples with low erosion yields included Al-FEP and the urethane coated 

Vectran mesh, samples that are commonly used in spacecraft applications.

Erosion yield values for Kapton HN covered with a 0.5 mil Kapton H cover (N5-7) and 

Kapton HN with a 1.0 mil Kapton H cover (N5-8) were found to have significantly lower erosion 

yields than expected. Even more surprising was that the three Kapton HN samples (N5-6 

included) showed a trend of increasing Ey with increasing fluence. The reason for this is 

currently unknown.

Zenith Samples

Tables 8 provides the sample ID, material, total mass loss, surface area, density, AO fluence, 

and erosion yield for the zenith “Z” samples. The polymer sample in the zenith tray with the 

greatest Ey was PE (Z-11). Other samples exhibiting high erosion yields included ECTFE (Z-6) 

and CTFE (Z-3). Samples with the lowest Ey include the three coated samples: Al2O3/FEP (Z-14)

and TiO2/Al2O3/FEP (Z-15) and Si/2 mil Kapton E/VDA (Z-12).

1.48E-25

1.54E-25

1.91E-25

1.01E-25

y = 5E-13x-0.578

R2 = 0.9872

0

0 5E+21 1E+22

Eroson Yield (cm3/atom)

AO Fluence (atoms/cm2)

MISSE 2
NASA/TM—2013-217848 17

Table 8. Erosion Yield Values for Zenith Tray.

MISSE 

Sample 

ID

Material Mass 

Loss (g)

Surface 

Area (cm2

)

Density 

(g/cm3)

MISSE AO 

Fluence 

(atoms/cm2)

MISSE 7 

Ey 

(cm3/atom)

Z-1 Polytetrafluoroethylene (PTFE) 0.001330 4.256 2.150 1.58E+20 9.19E-25

Z-2 Fluorinated ethylene propylene (FEP) 0.001407 4.263 2.144 1.58E+20 9.74E-25

Z-3 Chlorotrifluoroethylene (CTFE) 0.002893 4.265 2.133 1.58E+20 2.01E-24

Z-4 Ethylene-tetrafluoroethylene 

copolymer (ETFE) 0.001752 4.269 1.740 1.58E+20 1.49E-24

Z-5 Polyvinylidene fluoride (PVDF) 0.002069 4.267 1.762 1.58E+20 1.74E-24

Z-6 Ethylene-chlorotrifluoroethylene 

(ECTFE) 0.004038 4.281 1.676 1.58E+20 3.56E-24

Z-7 Polyvinyl fluoride (PVF) 0.001347 4.280 1.379 1.58E+20 1.44E-24

Z-8 Polyimide (Kapton H) 0.002897 4.279 1.427 1.58E+20 3.00E-24*

Z-9 Aluminized-fluorinated ethylene 

propylene (Al-FEP) 0.003219 4.285 2.144 1.58E+20 2.22E-24

Z-10 Silvered-fluorinated ethylene 

propylene (Ag-FEP) 0.001689 4.276 2.144 1.58E+20 1.17E-24

Z-11 Polyethylene (low oxygen) 0.005077 4.303 0.918 1.58E+20 8.13E-24

Z-12 Si/2 mil Kapton E/Al 0.000116 4.279 1.420 1.58E+20 1.21E-25

Z-14 Al2O3/FEP 0.000091 4.300 2.144 1.58E+20 6.22E-26

Z-15 TiO2/Al2O3/FEP 0.000020 4.289 2.144 1.58E+20 1.40E-26

*Kapton Ey from previous flight experiments (Refs. 7 to 10).

Determination of the effect of UV radiation, and corresponding temperature effects, on the 

Ey of polymers flown in both ram and zenith directions can be made for PE, FEP and 

TiO2/Al2O3/FEP. The Ey of the PE on the zenith tray, which received approximately 1.8X the 

ESH as the ram tray, was twice as high as the Ey of PE on the ram tray. The Ey of Teflon FEP on 

the zenith tray was an order of magnitude higher (12X) than the Ey on the ram tray. And, 

although the values were very small, the Ey of TiO2/Al2O3/FEP on the zenith surface was 

approximately 18X greater in the zenith direction. These results indicate that solar radiation and 

corresponding temperature effects can play a significant role in polymer functionality and 

exacerbates degradation and therefore erosion of polymers in the space environment. It is desired 

to compare the Ey of these samples to similar polymers flown on previous MISSE missions, and 

other space exposure flight experiments.

Summary and Conclusions

MISSE 7, which contains the Polymers Experiment and the Zenith Polymers Experiment, 

flew on the ISS for 1.49 years. Mass loss, density, surface area, and fluence were determined to 

calculate the erosion yield of 34 samples flown as part of these two spaceflight experiments.

Samples with the highest erosion yields included CN (N5-14), PMP (N5-2), PE (Z-11, N5-1), 

Kapton H (Z-8, B7-8, N5-5). Samples with the lowest erosion yields included TiO2/Al2O3/FEP

(B7-11, Z-15), Al2O3/FEP (Z-14), Si/2 mil Kapton E/VDA (Z-12) and urethane coated Vectran

Mesh (N5-16). 

Samples that flew on both N5-R (ram) and zenith trays exhibit much higher Ey values on the 

zenith tray (with more solar exposure and resulting higher average temperatures), indicating that 

solar exposure and therefore solar radiation play a vital role in polymer durability and intensify 

polymer degradation in space. 
NASA/TM—2013-217848 18

Desired future work includes: error analyses of fluence and Ey values, Ey determination of 

MISSE 7 wake and taped samples, erosion morphology studies, comparing MISSE 7 data to 

previous mission data for fluence effects, analysis of optical properties of samples, and more 

imagery and discussion on individual samples. 

References

1. M. Nicolet and P. Mange, “The Dissociation of Oxygen in the High Atmosphere,”

J. Geophys Res (1954) Vol. 59, Issue 1, pp. 15-45.

2. Gregory: Gregory, J. C. “Proceedings of the NASA Workshop on Atomic Oxygen 

Effects,” Nov. 10-11, 1986, JPL 87-14, 1987, pp. 29-30.

3. de Groh, K. K., Banks, B. A., Dever, J. A., Jaworske, K. J., Miller, S. K., Sechkar, E. A. 

and Panko, S. R., “NASA Glenn Research Center’s Materials International Space Station 

Experiments (MISSE 1-7),” Proceedings of the International Symposium on 

“SM/MPAC&SEED Experiment,” Tsukuba, Japan, March 10-11, 2008, JAXA-SP-08-

015E, March 2009, pp. 91 – 119; also NASA TM-2008-215482, December 2008. 

4. 2000 ASTM Standard Extraterrestrial Spectrum Reference E-490-00 2000, Available at 

http://rrede.nrel.gov/solar/sectra/AMO.

5. Dever, J. A., “Low Earth Orbital Atomic Oxygen and Ultraviolet Radiation Effects on 

Polymers,” NASA TM 103711, February 1991.

6. de Groh, K. K. Banks, B. A. McCarthy, C. E. Rucker, R. N. Roberts L. M. and Berger, L. 

A., “MISSE 2 PEACE Polymers Atomic Oxygen Erosion Experiment on the International 

Space Station,” High Performance Polymers 20 (2008) 388-409.

7. Banks, B. A., Mirtich, M. J., Rutledge, S. K. and Swec, D. M., “Sputtered Coatings for 

Protection of Spacecraft Polymers,” Thin Solid Films, 127, pp. 107-114, 1985.

8. J. T. Visentine, L. J. Leger, J. F. Kuminecz and I. K. Spiker, “STS-8 Atomic Oxygen 

Effects Experiment,” AIAA-85-0415, 1985.

9. Koontz, S. L., Leger, L. J., Visentine, J. T., Hunton, D. E., Cross, J. B. and Hakes, C. L., 

“EOIM-III Mass Spectrometry and Polymer Chemistry: STS 46, July-August 1992,” 

Journal of Spacecraft and Rockets, Vol. 32, No. 3, May-June 1995, pp. 483-495.

10. Silverman, E., M., “Space Environmental Effects on Spacecraft: LEO Materials Selection 

Guide,” NASA CR 4661, Part 1, August 1995.

11. de Groh, K. K., Banks, B. A., McCarthy, C. E., Berger, L. A., and Roberts, L. M., 

“Analysis of the MISSE PEACE Polymers International Space Station Environmental 

Exposure Experiment,” ESA SP-616, September 2006.

12. de Groh, K. K., Banks, B. A., McCarthy, C. E., Rucker, R. N., Roberts, L. M., and Berger, 

L. A., “MISSE PEACE Polymers Atomic Oxygen Erosion Results,” Proceedings of the 

2006 National Space & Missile Materials Symposium (NSMMS); also NASA TM-2006-

214482, November 2006. 

13. M. M. Finckenor, C. Moore, J. K. Norwood, B. Henrie, K.de Groh, “Estimated 

Environmental Exposures for MISSE-7B” Proceedings of the National Space and Missile 

Materials Symposium, Tampa, FL, June 2012.

14. Jenkins, P. P., personal communication, November 2012

15. Banks, B. A., Simmons, J. C., de Groh, K. K., Miller, S. K., “The Effect of Ash and 

Inorganic Pigment Fill on the Atomic Oxygen Erosion of Polymers and Paints,”

Proceedings of the 12th International Symposium on Materials in the Space Environment

(ISMSE 12),” Noordwijk, The Netherlands (ESA SP-705, March 2013).

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Overview of the MISSE 7 Polymers and Zenith Polymers Experiments After 1.5 Years of 

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Yi, Grace, T.; de Groh, Kim, K.; Banks, Bruce, A.; Haloua, Athena; Imka, Emily, C.; 

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14. ABSTRACT

As part of the Materials International Space Station Experiment 7 (MISSE 7), two experiments called the Polymers Experiment and the 

Zenith Polymers Experiment were flown on the exterior of the International Space Station (ISS) and exposed to the low Earth orbit (LEO) 

space environment for 1.5 years. The Polymers Experiment contained 47 samples, which were flown in a ram or wake flight orientation. 

The objectives of the Polymers Experiment were to determine the LEO atomic oxygen erosion yield (Ey, volume loss per incident oxygen 

atoms, given in cm3/atom) of the polymers, and to determine if atomic oxygen erosion of high and low ash containing polymers is 

dependent on fluence. The Zenith Polymers Experiment was flown in a zenith flight orientation. The primary objective of the Zenith 

Polymers Experiment was to determine the effect of solar exposure on the erosion of fluoropolymers. Kapton H (DuPont, Wilmington, DE) 

was flown in each experiment for atomic oxygen fluence determination. This paper provides an introduction to both the MISSE 7 Polymers 

Experiment and the MISSE 7 Zenith Polymers Experiment, and provides initial erosion yield results.

15. SUBJECT TERMS

Earth orbital environments; Polymers; Atomic oxygen (AO); Erosion; International Space Station (ISS); Flight experiment 

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