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Radiation and the International Space Station Recommendations to Reduce Risk (2000) / Chapter Skim
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3 Relativistic Electrons and the International Space Station
Pages 32-38

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From page 32...
... The other is relativistic electrons electrons with energies above 500 keV, which penetrate space suits in the outer radiation belt. To assess the electron radiation hazard to ISS, CSSP/CSTR first clarified the extent to which the ISS orbit penetrates the volume of space where relativistic electrons occur and then considered how fluxes of relativistic electrons vary over time and on what they depend.
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From page 33...
... 3.2 MONITORING OUTER BELT ELECTRONS The flux of relativistic electrons in the outer radiation belt varies over time by many orders of magnitude. The variation is marked by events, called highly relativistic electron (HRE)
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From page 34...
... These two categories also pertain to HRE events recorded by other satellites, such as OGO 5,2 DMSP,3 PoLAR,4 and SAMPEX.5 Decay rates of several days agree with theoretical calculations using diffusion and atmospheric loss processes. Longer decay rates have been attributed to an additional acceleration of ambient plasma around L = 6.6 The rapid rise and exponential decay events recorded by NOAA-12, a POES, permit developing and testing a prediction model that can be applied to such events.
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From page 35...
... Others have reported a similar decay rate from analyses of similar data recorded on several different satellites.7 With the decay time set at 5.18 days, this procedure was applied to nine other rapid rise and exponential decay events captured in the NOAA-12 data for 1997. The results are shown in Table 3.1, with event A being the event taken here as the standard, the January event of Figure 3.2.
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From page 36...
... 3.5 OPERATIONAL STRATEGY A strategy for developing an operational capability to predict high-energy electron events of concern to astronauts on the ISS should include the following elements: · Real-Time Event Identification from GOES Data. An operational system to predict the flux of energetic electrons in the outer radiation belt using the scheme described above must monitor particle fluxes in a timely manner.
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From page 37...
... constructing a reasonable dynamic model of the radiation belts with physics included. This chapter has cited evidence for a good correlation between changes in solar wind conditions and the onset of HRE events.
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From page 38...
... Mewaldt, and R.D. Zwickl, "Relativistic electron acceleration and decay time scales in the inner and outer radiation belts: SAMPEX," Geophys.
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Key Terms

  • radiation belt
  • outer belt
  • relativistic electrons
  • relativistic electron
  • solar wind

  • hre events
  • energetic electrons
  • iss orbit
  • belt electrons
  • electron fluxes

  • wind conditions
  • iss spends
  • decay time
  • electron belt
  • rapid rise

  • return data
  • electron flux
  • exponential decay
  • electron annulus
  • kev electron

  • radiation belts
  • space environment
  • fluxes recorded
  • hre event
  • upstream solar

  • electron events
  • spe zones
  • outer electron
  • electron acceleration
  • orbit exposed


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