1. The Effect of Microgravity on the Oxidation of Iron Exposed to a Saltwater Solution
Griffin Eslinger and Alexander Puckhaber
Co-Principal Investigators
Palmetto Scholars Academy
North Charleston, SC

2. Description of Experiment
Our experiment compared the structural integrity of an iron bar oxidized in the presence of saltwater in microgravity to an iron bar oxidized in the presence of saltwater on Earth.

3. Hypothesis 
We predicted that the iron bar oxidized in microgravity would be weaker than the iron bar oxidized on Earth. Without gravity, the surface tension of the salt water will be relatively
stronger. Stronger surface
tension in microgravity might
make the oxidation process
happen at a faster pace.

4. Why this is Important 
If we find that the iron bar oxidized in microgravity is significantly weaker than the iron bar oxidized on Earth, our findings could impact how engineers design space missions.
Many pressurized spacecraft are built with iron alloys. There would most likely be oxygen and water on the inside. If rust in microgravity causes iron to become weaker than expected, there might be a high potential for catastrophic failures.

5. Materials Experiment Materials Type Two FME (Fluid Mixture Enclosure)
3.5% salt water solution
Iron tensile testing bar (9.5mm by 75mm by 2mm)
Testing Materials
Tensile testing machine
Scanning electron microscope

6. Methods 5 identical FMEs prepared and numbered (+2 old FMEs)
One (Sample #2) randomly selected to go to ISS
Sent up for 9 weeks in space as part of SSEP Mission 4
Upon return, tested at University of South Carolina Mechanical Engineering Department on a Tensile Testing Machine.
After tensile testing, surface examined under scanning electron microscope at NOAA lab.

7. Tensile Testing Five properties measured
Modulus of Elasticity (Young’s Modulus)
Yielding Strength
Maximum Strength
Elongation
Ductility

8. Tensile Results

9. Scanning Electron Microscope
Space sample had small circular rust spots. Controls had larger plate-like rust patches.
Space
Earth Control

10. Scanning Electron Microscope
The controls had a rougher surface (more rusting) and a thicker breaking cross section
Space
Earth Control

11. Summary The Iron bar that went to space:
Yielding Strength: Average
Elongation: Average
Maximum Strength: 2nd highest
Modulus of Elasticity: Average
Ductility: Highest
But none statistically significant
SEM showed less rust and in a different pattern.
Hypothesis: false, bar not weaker

12. Acknowledgments
Thank you to the Partners and Sponsors who made this experiment possible:
Partners
Space and Naval Warfare Systems Command (SPAWAR)
Center for the Advancement of Science in Space (CASIS)
National Center for Earth and Space Science Education
College of Charleston
Medical University of South Carolina (MUSC)
National Oceanic and Atmospheric Administration (NOAA)
Sponsors
ISHPI
Google
CASIS
Palmetto Scholars Academy Board Members
Palmetto Scholars Academy Families

13. Questions?

15. Closeup of Stress vs Strain Curves