Atmosphere: Meteoroid, Orbital Debris, and Radiation Protection

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Atmosphere Meteoroid, Orbital Debris, and
Radiation Protection
Camron Gorguinpour Bioengineering
155 Spring 2005
Picture Courtesy of NASA
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Overview

• EM Radiation
• Meteoroids
• Space Junk

Picture Courtesy of NASA
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Electromagnetic Radiation
Picture Courtesy http//rredc.nrel.gov
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Electromagnetic Radiation

• Primary effects of UV radiation are on skin and
  eyes
• UV effects on human health
• Sunburn
• Tanning
• Vitamin D Production
• Photo-Aging
• Non-Melanoma Skin Cancer
• Malignant Skin Cancer
• Cataract

Picture Courtesy http//medlib.med.utah.edu
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Electromagnetic Radiation

• Other important types of EM Radiation
• X-Rays
• Gamma Rays
• These are considered Ionizing Radiation and
  will be considered in subsequent lectures
• Primary source of these types of radiation is the
  Sun

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Meteoroid, Meteor, Meteorite

• Meteoroids are the rocks and dust that orbit the
  Sun, but are too small to be considered asteroids
  or comets
• Meteors are meteoroids that enter the Earth's
  atmosphere and burn up (aka shooting stars)
• Meteorites are meteors that reach Earth's surface

Picture Courtesy of NASA
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Meteoroid, Meteor, Meteorite

• 40,000 100,000 tons of material are swept up by
  earth each year
• Average speeds for meteoroids reaching Earth
  orbit 20km/s (44,000 mph)
• In LEO, Orbital Debris is a much greater threat

Picture Courtesy of http//www.nhm.ac.uk
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Orbital Debris

• Over 40 years of space exploration, more than
  2,000,000 kg of junk has accumulated
• Average Speed 10 km/s
• Range of sizes

NASA Reference Publication 1408
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Where Does Orbital Debris Come From?

• Fragmentation Material 40
• Nonfunctional Spacecraft 25.3
• Rocket Bodies 19.4
• Mission-Related Items 13.3
• Unknown Sources 2

Picture Courtesy of NASA
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MMOD Tracking

• Three Primary MMOD Detection Methods
• Radar Measurements (gt 1 mm)
• Optical Measurements (gt 1 mm)
• Surface Examination (lt 1 mm)

Picture Courtesy of NASA
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MMOD Probability of Non Penetration (PNP)

• International Space Station .999989/m2-year
• Zarya Module (length 12.6 m, width 4.1 m)
• Space Suit .99875 non-fatality/year
• Assuming Peak 624 hours/year

Picture Courtesy of NASA
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Things to Know...

• Atmospheric Protection from EM Radiation
• UV Radiation Risk
• Origin and Relative Abundances of Meteoroids and
  Orbital Debris
• Meteor, Meteoroid, Meteorite Definitions
• Relative Penetration Probabilities for MMOD

Picture Courtesy of NASA