re made using the methods and procedures indicated above have shown good agreement in some instances; others were off by as much as an order-of-magnitude. In general, proton induced SEU rates have been understated by the analysis, probably due to the known propensity for AP8 to under-predict trapped proton population at lower altitudes. The general characteristic of heavy ion induced SEU has been to over-estimate the frequency of occurrence. New models of trapped proton flux, and/or the application of factors or ratios by the analyst to AP8 modeled predictions, revised CREME96 models for heavy ion flux, and improved ground based characterization of device susceptibility should enable acceptably accurate prediction of device level effects. 5.3.4 Effects and Consequence on System Operations [LaBel962] The ability to examine the effects and consequences which single event effects present to the operation of systems is a difficult undertaking. It is usually informative to classify system level effects into those consequences which influence the data within a payload or spacecraft and those which affect the control operations. The effect of a single event upset in the storage of user data in an ASIC register, processor memory, or solid state recorder may be easily understood; a bit error in the data which is delivered by the satellite. The consequence of the bit error may be near zero if the error contribution is less than the bit-error-rate specified for the system. The consequence may be degraded quality of service, possibly requiring detection and correction mitigation, but the consequence is unlikely to result in outage and degradation in the availability of the system to users. Corruption in the control process can result in fairly benign consequences, such as limited loss of user data, to a crash of the system resulting in total loss of user access and compromised availability of the system to users. The ability to examine the propagation of individual single event upset occurrences to achieve an understanding o