¢ January, 19599: The TX-53 has entered Phase III and is to be a weapon with a full fuzing option (FUFO). February, 1959: The XW-54 is added to the specific devices in Phase III and it is stated, "This program, formerly the XW-51 ‘| f _ a _ _——- oneemer _ a _fAlso, the nat tte" XW-52 and 53 are both shown as being in Phase II rather than preliminary. Sandia engineers, draftsmen, and administrative personnel moved into new facilities for Sandia at Livermore this month. Note that in April of 1959, Sandia changed their reporting system so that the monthly report was greatly abbreviated to include only specific device details and specific testing summaries and the bulk of the former monthly reports wes now to be included in a quarterly report, the first of which covered April through June of 1959. April - June, 1959: The addition to the specific device activities is the XW-55 for Subroc applications which has been authorized for Phase III. One of the appendices is entitled, "Using Nuclear Explosives in the Construction of Geothermal Power Plants." Tae proposal at this time was to use nuclear ex- plosives detonated far underground in geothermal steam regions to greatly increase the size of a cavity and provide extensive boundary surfaces. Another appendix is entitled, "High Altitude Measuring and Sampling" and notes the recent high altitude events and the probability that future testing will include such events. Sandia, therefore, is developing a rocket and sampling system