NASA NTRS1997
Timely data on low altitude energetic protons is very important for predicting the effect on humans and satellites. Because of the high bioeffectivity of protons in tissue, determination of the geographical location of the south Atlantic anomally (SAA) would be especially useful for reducing the risk associated with extravehicular activities. Because the AP8 model was developed with an epoch several decades old, the location of the south Atlantic anomally is incorrectly positioned in the model. The lack of extensive present-epoch energetic proton data at low altitude has prevented the update of the AP8 proton model. While there are studies in progress which are attempting to update the model at low altitude by using the path-integrated column density of the residual atmosphere as an organizing parameter, success in those studies will be defined by consistency in organization of old data. New data will still be required to provide a good present epoch model. As an alternative to using instrumental measurements of proton fluxes, background effects, proxy data sets such as SEUs, anomalies in instruments, enhanced background in shielded sensors believed to be induced by high energy protons, and dosimeter data in which key parameters (energy, efficiency, geometric factor, shielding, etc.) are poorly known can also be used. This in situ data is not as precise as direct measurement of the proton flux as geometric factor and shielding etc. are not calibrated, but these factors do not affect determination of the location of the SAA.