Radiation Belt Fun Facts

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Radiation Belts -- Fun Facts

  • º Two radiation belts filled with electrons and charged particles surround Earth. The inner one is fairly stable, but the outer one swells and shrinks over time.
  • º When the inner belt swells, this region of dangerous radiation expands to include the orbits of the International Space Station and many other satellites.
  • º The first evidence for the radiation belts was reported in 1958 by James Van Allen using data from a cosmic ray detector on the very first NASA mission: Explorer 1 spacecraft.
  • º When the Radiation Belts were first discovered, the radiation was so intense that at first scientists thought they might be recording a Soviet nuclear test.
  • º RBSP will be placed into a highly elliptical orbit, also known as a "geostationary transfer orbit".
  • º RBSP's orbit is known as a "geostationary transfer orbit" since it is the same orbit that is also used to boost spacecraft into geosynchronous orbit.
  • º Particles that fall out of the radiation belts can affect the chemistry and composition of Earth's atmosphere.
  • º The material in the radiation belts is made of charged particles – a material called "plasma." Plasma surrounds the sun and pervades much of the universe.
  • º Magnetic fields are invisible to the eye, but they provide a structure throughout space that guides how charged particles move.
  • º The Van Allen Radiation Belts are one part of Earth's dynamic magnetic environment, known as the magnetosphere.
  • º The radiation belts look like two giant donuts. Earth sits at the center of the "donut hole."
  • º The inner radiation belt was discovered with data from the very first American satellite, Explorer 1. Explorer 1 launched into Earth's orbit on a Jupiter C missile from Cape Canaveral, Florida, on January 31, 1958.
  • º The outer radiation belt was discovered a few months after the inner belt using data from Explorer IV and Pioneer 3, both launched in 1958.
  • º During periods of intense space weather, the density and energy of radiation belt particles can increase and pose a danger to astronauts, spacecraft, and even technologies on the ground.
  • º Some particles in the radiation belts move at nearly the speed of light, which is about 186,000 miles per second.
  • º Our society relies on more than 800 satellites operating in the radiation belts for communication and navigation.
  • º The outer radiation belt is typically about 8,400 to 36,000 miles above Earth's surface.
  • º The most intense area of radiation within the outer belt is between about 9,000-12,000 miles above Earth’s surface.
  • º The more we understand about what happens in the radiation belts, the better we can protect our satellites.
  • º Earth’s magnetic field shields us from solar storms and the constantly streaming solar wind.
  • º The largest, single hazard for astronauts traveling to Mars will be overcoming exposure to solar storms and radiation.
  • º One sensor on the RBSP spacecraft measures their lifetime radiation exposure giving engineers accurate information to build radiation tolerant spacecraft and instrumentation in the future.


Page Last Updated: September 30th, 2013
Page Editor: Holly Zell