for upset production. The basic formalism for proton-induced SEEs from nuclear reaction recoil products has not changed appreciably since its introduction in the mid-1980s. In 1989, a paper emphasizing application of the 2-parameter Bendel approach showed improved agreement with test data for modern devices with small feature size [Shim-89]. This was followed the next year by another paper advocating the 2-parameter approach and pointing out the importance of proton testing at higher energies to increase rate prediction accuracy [Stap-90]. In addition to the 1995 Short Course notes, the interested reader should refer to the 1997 NSREC Short Course segment on "Single Event Analysis and Prediction" by Ed Petersen [Pete-97]. This course offers an excellent discussion of proton upset mechanisms, models, and rate prediction tools, as well as practical consideration for proton upset cross section measurement. These course notes also provide detailed descriptions of the expanded range of component types for which proton SEEs are important. This includes not only memories, but also processors, ASICs, linears, and most modern circuit families. Additional related materials are found in Ed Petersen's review article on, "Approaches to Proton Single Event Rate Calculations," [Pete-96]. Given the level of discussion on the general topics of proton upset measurement and rate predictions in these two previous Short Courses (and references therein), the following material will be devoted to other proton-related special topics important to spacecraft developers. In the three sections to follow, we first treat two special topics related to the "classic" phenomenology of proton-induced recoil initiated SEEs. Next we treat a relatively recent phenomenon affecting several types of very sensitive devices in which protons can initiate upsets by direct ionization. Finally, the last portion of this section will examine various classes of proton-initiated hard errors. 4.1 Test Issues and Special Cases The "classic" approach to proton SEE t