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The Space Environment

The Space Environment. The Space Environment. The Cosmic Perspective Where Is Space? The Solar System The Cosmos The Space Environment and Spacecraft Challenges of the Space Environment Gravity Atmosphere Vacuum Micrometeoroids and Space Junk The Radiation Environment

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The Space Environment

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  1. The Space Environment

  2. The Space Environment • The Cosmic Perspective • Where Is Space? • The Solar System • The Cosmos • The Space Environment and Spacecraft • Challenges of the Space Environment • Gravity • Atmosphere • Vacuum • Micrometeoroids and Space Junk • The Radiation Environment • Charged Particles • Living and Working in Space • Hazards to Humans in Space • Free Fall • Radiation and Charged Particles • Mental and Emotional Effects Unit 1, Chapter 3, Lesson 3: The Space Environment

  3. Packing for a Trip • Where’d you go on Spring Break? • Would you have packed differently if you were going to Alaska? • It is vital to know something about the environment you visit in order to know what you’re up against

  4. The Cosmic Perspective “Cosmos” = orderly arrangement (Greek) • Where is space? • The solar system • The cosmos Unit 1, Chapter 3, Lesson 3: The Space Environment SECTION 3.1

  5. Where Is Space? • No clear definition of where space begins • US Air Force’s Astronaut Wings awarded for those who achieve 92.6 kilometers (57.6 miles) • For astronautics, space begins when an object can maintain an orbit for a short time about 130 kilometers (81 miles) altitude • Perspective for low-Earth orbit: if the Earth were a peach, most satellites would be just above the “fuzz” • Spaceship One: 328,000’ WHERE EARTH’S ATMOSPHERE ENDS Unit 1, Chapter 3, Lesson 3: The Space Environment

  6. The Solar System: The Sun • The Sun generates every second enough energy to supply the U.S. for 624 million years • 600 million tons of hydrogen burned per second in nuclear fusion Unit 1, Chapter 3, Lesson 3: The Space Environment

  7. The Sun: Radiation • Sun sends energy in the form of electromagnetic (EM) radiation • Radiation travels in waves • Sun’s EM radiation has many wavelengths: radio waves, infrared (heat), visible light, ultra-violet, x-rays and gamma rays Unit 1, Chapter 3, Lesson 3: The Space Environment

  8. Electromagnetic (EM) Radiation • We classify Electromagnetic radiation in terms of the wavelength (or frequency) of the energy Electromagnetic (EM) Radiation Unit 1, Chapter 3, Lesson 3: The Space Environment

  9. The Sun: Charged Particles • The intense heat from nuclear fusion breaks atoms into basic building blocks: • Protons • Electrons • Neutrons (quickly decay into an electron and a proton) • The Sun’s magnetic field propels these particles toward us at high speed: solar wind The Atom Unit 1, Chapter 3, Lesson 3: The Space Environment

  10. The Sun: Solar Flares • Areas of the Sun’s surface sometimes erupt in solar flares • Flares can extend as far as the Earth’s orbit • Generate more energy than many nuclear weapons 11 year cycles: next peak in 2011 Unit 1, Chapter 3, Lesson 3: The Space Environment

  11. The Planets • Aside from the Sun, other players in the solar system are • Planets • Moons • Asteroids • For most space missions, Earth is the primary player • Gravitation • Atmosphere • Magnetic field Unit 1, Chapter 3, Lesson 3: The Space Environment

  12. The Cosmos • Solar system is part of the Milky Way Galaxy—about half way from the center • Galaxy rotates once every 240 million years • Next closest star in the galaxy—Proxima Centauri—is 4.22 light years away Galactic Distances = One Cosmic Year Unit 1, Chapter 3, Lesson 3: The Space Environment

  13. The Cosmos • What is a light year? • Distance light can travel in one year • An interplanetary probe traveling at 35,000 m.p.h. would take 80,000 years to get to Proxima Centauri Unit 1, Chapter 3, Lesson 3: The Space Environment

  14. Stellar Distances • Sun is marble 1 inch in diameter: in Denver, Colorado • Nearest star Proxima Centauri is 932 miles away: in Chicago, Illinois • Milky Way Galaxy is 21 million miles across Stellar Distances Unit 1, Chapter 3, Lesson 3: The Space Environment

  15. Challenges of the Space Environment • Gravity / Free fall • Atmosphere • Vacuum • Micrometeoroids and Space Junk • Electromagnetic Radiation • Charged Particles Unit 1, Chapter 3, Lesson 3: The Space Environment SECTION 3.2

  16. Gravity and Free-fall • Not “zero gravity” • Low-Earth orbit is about 91% of gravity at sea level • Physical impacts on equipment • Methods to measure quantities on Earth not effective • Plumbing must be pressurized—no “gravity feed” • Advantages • Opportunity to develop super alloys and pharmaceuticals • Heavier ingredients in materials won’t settle to the bottom Unit 1, Chapter 3, Lesson 3: The Space Environment

  17. Drag • Spacecraft slow down when they run into particles in the upper atmosphere • Slower speeds mean less energy and smaller orbit • If uncorrected, will eventually re-enter The Atmosphere: Drag • Shuttle depends on drag to slow down from orbital speed to landing speed • Few particles above 600 kilometers altitude (375 miles) Unit 1, Chapter 3, Lesson 3: The Space Environment

  18. RUST OXIDATION Unit 1, Chapter 3, Lesson 3: The Space Environment

  19. The Atmosphere: Oxygen Most oxygen near Earth’s surface in the form of “O2” (two oxygen atoms bound together) Oxygen in upper atmosphere has trouble finding a “partner,” so it exists as “O” (monatomic oxygen) Weakens structures Changes thermal properties of coatings Degrades sensors LDEF Refer to P. 91 in book Unit 1, Chapter 3, Lesson 3: The Space Environment 20

  20. Pressure 14.696 psi How do aircraft account for decreased pressures with altitude? Unit 1, Chapter 3, Lesson 3: The Space Environment 21

  21. Impact of a Near-Vacuum • Outgassing • Gasses kept inside materials by atmosphere’s pressure may be “coaxed” out by near-zero pressure • Escaping gasses can cloud sensors • Spacecraft are “baked” in hot vacuum chambers before being launched into space Thermal vacuum chamber Unit 1, Chapter 3, Lesson 3: The Space Environment

  22. Impact of a Near-Vacuum (cont’d) • Cold Welding • No air layer between contacting parts • Moving parts tend to bind • Limited Heat Transfer • Convection and conduction are options to transfer heat only within the spacecraft • Radiation is the only means to transfer heat into and out of the satellite Unit 1, Chapter 3, Lesson 3: The Space Environment

  23. Conduction • Heat flows by conduction through an object from the hot end to the cool end. • Spacecraft use conduction to remove heat from hot components. Unit 1, Chapter 3, Lesson 3: The Space Environment

  24. Convection • Boiling water on a stove shows how convection moves heat through a fluid from the fluid near a hot surface to the cooler fluid on top. • Special devices on spacecraft use convection to remove heat from hot components Unit 1, Chapter 3, Lesson 3: The Space Environment

  25. Radiation • Radiation is the only way to transfer heat out of the spacecraft because there is no liquid (air) to tranfer it via conduction. Unit 1, Chapter 3, Lesson 3: The Space Environment 26

  26. Micrometeoroids and Space Junk • Natural Sources • 20,000 tons of debris bombard Earth annually • Vary in size from dust-like particles to large asteroids • Artificial Sources • Old satellites, parts of launch vehicles • Tools, paint chips • Small Objects at High Speed (lots of momentum) Unit 1, Chapter 3, Lesson 3: The Space Environment

  27. NEWS LAST NIGHT What was the boom and flash in the skies last night? Unit 1, Chapter 3, Lesson 3: The Space Environment 28

  28. Micrometeoroids and Space Junk Cerise spacecraft lost a 6-foot boom from a collision with a piece of space junk Crater in Space Shuttle Challenger’s window from collision with a paint chip Unit 1, Chapter 3, Lesson 3: The Space Environment

  29. http://orbitaldebris.jsc.nasa.gov/photogallery/beehives.html#leohttp://orbitaldebris.jsc.nasa.gov/photogallery/beehives.html#leo Unit 1, Chapter 3, Lesson 3: The Space Environment 30

  30. The Radiation Environment • Primarily from the Sun • Mainly visible light and infrared (heat) • X-rays and gamma radiation also present • Impact: • Photons good for generating electrical power (solar panels) • Heat radiation (infrared) heats spacecraft • Ultra-violet radiation can damage electronic equipment, disrupt communications • Photons striking surfaces can impart a force: solar pressure Unit 1, Chapter 3, Lesson 3: The Space Environment

  31. Solar Max Spacecraft • Spacecraft with large surface areas, such as solar panels, must correct for the pressure from solar radiation that may change their altitude Unit 1, Chapter 3, Lesson 3: The Space Environment

  32. Charged Particles • Sources: • Solar wind and flares • Galactic cosmic rays (solar wind from distant stars, remnants of Big Bang) • Van Allen Radiation Belts—regions of the Earth’s magnetic field Van Allen Radiation Belts Unit 1, Chapter 3, Lesson 3: The Space Environment

  33. Charged Particles (cont’d) • Effects on Spacecraft • Charging • Similar: cross a carpeted room and touch a door knob • Rapid and unpredicted discharges can “fry” equipment • Sputtering • Wearing down of spacecraft surfaces by continual bombardment of particles • Similar to sandblasting • Single Event Phenomenon (SEP) • Electronic disruptions caused by deeply penetrating charged particles • “Bit-flip”: changing of a zero to a one or vice-versa Unit 1, Chapter 3, Lesson 3: The Space Environment

  34. Living and Working in Space • Free Fall • Radiation and Charged Particles • Mental and Emotional Effects Unit 1, Chapter 3, Lesson 3: The Space Environment SECTION 3.3

  35. Living and Working in Space • Free Fall • Fluid shift • Fluids equalize (no longer concentrated in lower body) • Edema • Dehydration • Increased heart rate Unit 1, Chapter 3, Lesson 3: The Space Environment

  36. Space Environment Effects on Humans • Free fall (cont’d) • Motion sickness • Reduced load on weight-bearing tissues • Decalcifies bones • Reduces production of blood cells • Weakens bones and muscles Unit 1, Chapter 3, Lesson 3: The Space Environment

  37. Space Environment Effects on Humans (cont’d) • Radiation and Charged Particles • Measurement of exposure • Dosages of radiation add up over time • Cumulative effects over time • Prolonged exposure to radiation means higher dosages • Total effect depends on biological impact of the dosages Unit 1, Chapter 3, Lesson 3: The Space Environment

  38. Space Environment Effects on Humans (cont’d) • Mental and Emotional Effects • Excessive workload • Isolation, loneliness, depression • Careful screening and busy schedules help prevent problems. Unit 1, Chapter 3, Lesson 3: The Space Environment

  39. Summary • The Cosmic Perspective • Where is Space? • The Solar System • The Cosmos • The Space Environment and Spacecraft • Challenges of the Space Environment • Gravity • Atmosphere • Vacuum • Micrometeoroids and Space Junk • The Radiation Environment • Charged Particles • Living and Working in Space • Hazards to Humans in Space • Free Fall • Radiation and Charged Particles • Mental and Emotional Effects Unit 1, Chapter 3, Lesson 3: The Space Environment

  40. Next • Now that you know about the conditions you and your spacecraft can encounter in space, we’re ready to start discussing the basics of orbital motion. Unit 1, Chapter 3, Lesson 3: The Space Environment

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