tn PP Jericho Test Program, and test operation support. Under the test planning section, it is noted that detailed plans are being developed for extended series of underground tests at NIS, and an opensea Pacific series not requiring the use of EPG as either a firing site or a staging area. Livermore "believes that the underground testing technique can be developed to the point where diagnostic information sauxka comparable with that from above ground tests can be obtained. Investigations are under way into new instrumentation and methods for obtaining high quality data from underground shots." This had led the laboratory to develop a program of tunnel excavation for shots up to 30 to 40 kt with studies under way for sites to contain up to 200 kt. "LRL has assumed that, if Continental ‘testing is resumed, it will be underground and that even if atmospheric testing is permitted, LRL would plan to test underground for operational flexibility and with the anticipation that at some future date atmospheric testing would be prohibited." Also noted is that studies are under way to develop ways of testing in outerspace since this will be the only practical way to test megaton range devices in the anticipation of an atmospheric test ban. test diagnostics A number of problems in are being addressed and the Jericho program is aiming toward tests possibly in the spring of 1960. Further, in the area of test operations support, a portion of L Division is supporting proposed Plowshare experiments as well as preparations for possible test resumption. © The rest of the program letter addresses Plowshare, Sherwood, and Pluto programs.