Space Radiation. Philip T. Metzger. Florida Space Institute, UCF

Transcription

1 Space Radiation Philip T. Metzger Florida Space Institute, UCF

2 What is Normal? Radiation is a normal characteristics of the universe We grew up in a very abnormal corner of the universe If we want to go to normal places, we need to deal with radiation

3 We Live in a Universe The Big Bang resulted hydrogen, helium and some deuterium, but life cannot exist with only this: we need other elements

4 We Live in a Galaxy The matter in the universe clumped into galaxies, which formed spiral shock waves that help stars to form. Stars explode and seed the galaxy with the other elements! But exploding stars also make Galactic Cosmic Radiation (GCR)

5 Image Credit: NASA and Space Telescope Science Institute)

6 Image Credit: NASA/ESA & Valentin Bujarrabal (Observatorio Astronomico Nacional, Spain)

7 Image Credit: NASA/JPL/Hubble Heritage Team (STScI/AURA)

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9 We Live in a Solar System Life depends on liquid water Water needs heat to be liquid Thus, we need to be on a planet near a star!

10 SOHO (ESA/NASA)

11 How Oceans Stay Warm Sunlight Tidal Forces Radioactive decay

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13 Stars Make Particle Radiation Solar Particle Events Solar Flares Impulsive Occur over several hours Coronal Mass Ejections More gradual Occur over several days

14 Solar Flares SOHO (ESA/NASA)

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16 Coronal Mass Ejections SOHO (ESA/NASA)

17 SOHO (ESA/NASA)

18 Space Radiation Spectrum Sporadic but extremely high flux when SPE occurs Solar Particle Events Cosmic Rays MeV Continuous, lowlevel flux unacceptable mission dose 100 MeV 1000 MeV

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20 Measured by Cassini spacecraft Image courtesy JPL Planetary Radiation Belts Earth Jupiter and other giant gas planets Significant radiation belts Especially bad at Europa

21 Our Protection on Planet Earth Global Magnetic Field Thick Atmosphere NASA/MSFC Space Plasma Physics (Adapted)

22 NASA / STS39 Crew

23 Image Credit: Wikimedia

24 So we have to live In the universe In a galaxy In a solar system On a planet in an ocean

25 Emerging from Special Locations When complex life emerged from the ocean, it carried bags of ocean water with it Their bodies were their space ships to leave the protected ocean Lungs, limbs, Warm blooded adaptation permitted them to move to colder climates

26 Human Expansion Biology has limited ability to adapt, but technology takes us beyond that limit Clothes & stone tools extended hunter/gatherer range Agricultural Revolution: concentrated energy for cities writing, math, tech Industrial revolution: machine energy to extend our bodily abilities Computer revolution: extend mental abilities Now we are on the verge of going to space

27 Outside the Protected Environment Vacuum Gravity Thermal extremes Lack of liquid water Lack of a food chain Lack of a supply chain for our machines Radiation

28 Effects in Spaceflight Biological Effects Delayed: cumulative effects of total dose Acute: immediate effects of intense exposure A single SPE may be lethal Electronic Effects

29 Strategies Faster spacecraft to have shorter missions Fly closer to the sun and/or during solar maximum Develop biological countermeasures Reengineer ourselves biologically Become androids Spacecraft shielding

30 Passive (Material) Shielding The most successful method, to date Foams or other materials on outside of spacecraft The spacecraft structure, itself Consumables placed strategically food drinking water

31 Passive Shielding, continued Problems Spacecraft Mass may become excessive Secondary radiation Some radiation gets through, which is not acceptable during the high flux of SPEs StormShelter approach

32 Problems with Storm Shelters Excessive time in cramped quarters Gradual SPE may last 4 or 5 days Psychologically and physically distressing Crew unable to attend to the spacecraft During the precise time when it needs the most attention (due to radiation effects) May need quick response to manage spacecraft Provides no protection for spacecraft electronics May suffer irreparable damage resulting in eventual loss of mission and crew

33 Magnetostatic Shield Attempt to mimic the shielding due to Earth s magnetic field Requires heavy, superconducting coils to produce sufficient magnetic field Hazard that coil could explode under the energy of the fields Better to use the mass of the coil as foam on the outside of the spacecraft

34 e e e e e e H + e e e e H + Electrostatic Shield e + e e e e e e e e

35 Plasma Shield

36 Multipole Expansions Monopole Dipole Quadrupole etcetera An arbitrarilycomplex electric field can be described as an infinite sum of these terms

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38 Φ( x = ξ, y = ξ, z = ξ ) Positive barrier deflects protons Negative barrier deflects electrons H e Damaging highenergy protons kept out of this region Vast quantities of lowenergy electrons kept out of this region

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40 Image credit: Deep Space Industries

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49 Image credit: The Planetary Society

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51 Why We Go Into Space

52 The Kardashev Scale of Civilizations Type 1 Uses the energy of an entire planet. Type 2 of an entire star. Type 3 of an entire galaxy.

53 The Kardashev Scale of Civilizations Type 1 Uses the energy of an entire planet. Type 2 of an entire star. Type 3 of an entire galaxy.

54 The Kardashev Scale of Civilizations Type 1 Uses the energy of an entire planet. Type 2 of an entire star. Type 3 of an entire galaxy.

55 The Kardashev Scale of Civilizations Type 1 Uses the energy of an entire planet. Type 2 of an entire star. Type 3 of an entire galaxy.

56 How About some Earlier Categories? Type 3 an entire galaxy Type 2 an entire star Type 1 an entire planet

57 How About some Earlier Categories? Type 3 an entire galaxy Type 2 an entire star Type 1 an entire planet Type 0 an entire continent

58 How About some Earlier Categories? Type 3 an entire galaxy Type 2 an entire star Type 1 an entire planet Type 0 an entire continent Type 1 an entire river valley Image credit: Eric Desrentes, Panoramio

59 How About some Earlier Categories? Type 3 an entire galaxy Type 2 an entire star Type 1 an entire planet Type 0 an entire continent Type 1 an entire river valley Type 2 an isolated enclave Image credit: Eric Desrentes, Panoramio Image credit: Eric Desrentes, Panoramio

60 Crossing the Barriers: A New Level of Civilization

61 Global Challenges Image credit: Wikipedia Image credit: Image credit: Wikipedia Image credit: Howard Rees

62 We do not have a resource problem. What we have is an imagination problem. Philip.T.Metzger@nasa.gov

63 Think Outside the Sphere

64 Thank you!