roswell

altitude as it has no further buoyancy. This altitucie stability exists only as long as the balloon is in the fully inflated or "taut" state. Once the balloon sta.rtE descending (due to loss of hydrot;en by diffusion or by other loss) ii:i becomes flabby and is no longer ~table. It will continue descerrling until corrective action is taken or until it reaches the earth. The altitude control is to be used is the ballast valve. When correctly set it will determine the lower limit of .the be.lloon' s oscill~tion as it would release a free flowing liquid ballast from a reservoir whenever the balloon descends a short distance below a preset altitude. To test this tentative solution to the basic problem, inter- mediate sizes of balloon made of suitable fabric or films c.re needed in addition to the altitude controls. Balloons Balloon manufacturers and fabricators of plastic films were contacted to locate a suitable balloon material. The following materials were suggested: Material Plastic Film Polyethylene Saran Advantages Good low temperature properties (Gen.l{ills desires to fabricate Picard's balloons from this). Transparent, low permeability, high tensile strength. Disadvantages Low tensile strength, Milky-translucent, Medium permeability. Tears easily, fair low temperature pro- perties (?),weak at seams if heat sealed. - 20 - Disposition 10 ea. 15 ft. balloons being fabricated from it. 5 large ~lloons being fabricated.