Materials for the Thermal and Micrometeoride Protection of the Space Suits

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Materials for the Thermal and Micrometeoride
Protection of the Space Suits

• By Vitaliy Vatkovskiy

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Contents

• Goals of this research.
• Overview of space suit functionality.
• Background on current outer layer of the suit.
• Proposed tests.

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Problems of current design

• Expensive
• Heavy unsuitable for Martian surface

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2 Goals

• Minimizing cost
• Minimizing weight
• While maintaining other important parameters

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Functions of Space Suits

• Atmospheric Preassure
• Breathable Atmosphere
• Maintaining Temperature
• Physical Protection
• Radiation Protection

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Oxygen and Other Life-Support Funcions

• These functions are provided by the PLSS. It
• Maintains breathable atmosphere
• Has systems for cooling down the astronaut
• Contains communications equipment

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Cooling the Astronaut

• Cooling water is circulated through the LCVG
  (Liquid Cooling and Ventilation Garment).

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Pressure - Inner Layers

• Pressure Bladder (Urethane Coated Nylon)
• Restraint Layer (Dacron)

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Physical, Thermal and Radiation Protection
Outer Layers

• Thermal Micremeteoroid Garment Liner
• Neoprene Coated Nylon Ripstop
• Multi-Layered Insulation 6 layers of
  Aluminized Mylar
• Thermal Micrometeoroid Garment Cover
• Ortho-Fabric

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Functions of Outer Layers

• Thermal Protection
• Physical Protection
• Radiation Protection

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Radiation Protection?Not Really

• Need large mass.
• Little research in this area.

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Study of Radiation Transmission of Space Suit
Fabrics
Test involved hitting space suit materials with
beam of high energy protons.
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Results of Study

• Material of suit itself has little effect.
• Average energy of the beam went from 23.68 to
  19.92MeV.
• LCVG had much higher effect.
• Average energy of parts of beam that went through
  LCVG was around 7MeV.
• So structure of LCVG has much higher impact than
  design of outer layers.

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Radiation Conclusions

• Fabrics of the suit itself provide virtually no
  protection from radiation.
• So radiation can be ignored when looking at the
  materials for outer layer of the suit
• LCVG provides significant radiation protection,
  so radiation should be a consideration in its
  design.

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Micrometeorite Protection

• Main function of outer layers
• Micrometeorites/space debris are increasingly
  common

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Current Materials are Effective in Stopping
Micrometeorites

• One study tested different combinations of layers
  of Maylar, duct-tape, rubber and wire-mesh.
• All materials performed reasonably well.
• The best performance was from plastic covered by
  rubber, similar to HUT.

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Age of Design

• Layout of the layers of the suit remained the
  same since Gemini.
• Materials used today are almost same as Apollo.
• Maylar was invented 50 years ago.

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Obtaining Materials

• Seek advice from chemical companies.
• Try to get free samples.
• If companies dont help, look through advertising
  literature for strong and heat-insulating
  materials.
• Compare advertised parameters, then retest
  ourselves.
• Possibly select different materials for strength
  and heat resistance.

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2 Areas, 4.5 Tests

• Thermal Protection
• Heat Conductivity
• Possible Thermal Expansion
• Physical Protection
• Puncture Resistance
• Tensile Strength
• Abrasion Resistance

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Heat Conductivity

• Shine bright light on material to simulate sun.
• Either calculate specific heat capacity (hard) or
  simply compare rates of heating (easy).
• Main test in vacuum with possible pre-testing in
  air.

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Thermal Expantion

• Very low 1.710(-5) in/in/C for Mylar. So
  about 2.55mm for a 1.5m astronaut for 100C
  temperature difference.
• Some materials could have much higher
  coefficient.
• Could be critical for some other parts, such as
  joints.
• Will have to find a lab to do this.

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Puncture Resistance

• Only necessary equipment is projectile launcher.
• Simplest test no precise measurements, just
  depth of penetration.
• Could be performed by ourselves.

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Tensile Strength

• Not as important, because pressure is contained
  in inner layers.
• Still important indicator of durability.
• Requires very precise measurements.

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Abrasion Resistance

• Simulate astronaut falling on a rock, getting hit
  by a robotic arm, etc.
• Hit material with a knife or another sharp
  object.
• Visual inspection of damage.
• Repeat of tensile strength and thermal
  conductivity tests.

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Conclusion

• Current design is over 30 years old.
• It works, but is too expensive and too heavy.
• Need to
• Minimize cost for space.
• Minimize weight for Mars.
• Maintain current physical and thermal
  characteristics.