To summarize with respect to future capabilities, our main objective is to achieve a sampling capability at altitudes significantly above 100,000 feet. feet. Presently available balloons can lift substantial loads to 140, 000 This will eventually be increased through use of 14-million-cubic-foot balloons designed to lift 200-pound loads to 150,000 feet. Although suitable vehicles are available, sampling techniques tailored to low density operation must be developed, These may utilize alternating current blower system and high speed air turbines. The liquid nitrogen cooled adsorption pump also appears to be a promising approachto the collection of particles and gases of interest. References 1. General Mills Report No. 1903 to Division of Biology and Medicine, USAEC, Contract No, AT(11-1)-401, 2. General Mills Report No. 1907 (as above), 1 July 1959. 3, E, A. Martell, Letter Report Dated 29 May 1961, to Mr. J. Z. Holland, USAEC. 158 1 May 1959.