The interaction of high-energy space radiation with spacecraft materials ge
nerates a host of secondary particles, some, such as neutrons, are more bio
logically damaging and penetrating than the original primary particles. Bef
ore committing astronauts to long term exposure in such high radiation envi
ronments, a quantitative understanding of the exposure and estimates of the
associated risks are required. Energetic neutrons are traditionally diffic
ult to measure due to their neutral charge. Measurement methods have been l
imited by mass and weight requirements in space to nuclear emulsion, activa
tion foils, a limited number of Bonner spheres, and TEPCs. Such measurement
s have had limited success in quantifying the neutron component relative to
the charged components. We will show that a combination of computational m
odels and experimental measurements can be used as a quantitative tool to e
valuate the radiation environment within the Shuttle, including neutrons. C
omparisons with space measurements are made with special emphasis on neutro
n sensitive and insensitive devices. (C) 2001 Elsevier Science Ltd. All rig
hts reserved.