gas in the bag mixed with the oxygen in the atmosphere. Preparation Despite the concerns, in 1935 the NGS and Army Air Corps decided to make another attempt. To eliminate the hazard of the hydrogen lifting gas, it was decided instead to use helium—to which the United States had a monopoly. The lower lifting efficiency of helium gas meant that a larger balloon would be needed, so Goodyear-Zeppelin increased the volume to . Dow Chemical Company assembled a larger, lighter gondola made of "Dowmetal"—a magnesium-aluminium alloy— that would carry a two-man crew with a reduced amount of scientific instrumentation. The cabin was in diameter with a mass of and could transport a payload. It was manufactured from a single, large plate that was cut up into form that could be reshaped and welded into a sphere. In order to make crew escape easier, the portholes were made wider than on the Explorer I. The atmosphere in the interior of the capsule was supplied from liquid air instead of liquid oxygen in order to reduce the fire hazard. The modified balloon was ready by the spring of 1935 and the first launch occurred July 10, 1935. Unfortunately, this too proved a failure with the balloon rupturing at liftoff. Following a review by the NBS, the balloon was prepared for another attempt after Goodyear strengthened the material. Examination of climatological data for the Stratobowl collected over the previous fifteen years was examined, and it was determined that the month of October typically had periods of good weather that would last sufficiently long for a flight attempt. A team of meteorologists was assembled at the Stratobowl in early September and they proceeded to put together a weather station. The meteorological requirements for the launch was for clear skies—with no precipitation—lasting for the duration of the flight, as well as surface wind speeds that were not to exceed . With a cold front approaching, on the night of November 10, 1935, the balloon was prepared for launch. The temperature dropped to overnight, so the of fabric was kept warm and pliable through the use of stoves. The task of inflating the balloon with helium from the 1,685 steel cylinders took eight hours, during which the team needed to repair a long tear that formed in the fabric. Once inflated, the balloon stood tall. The gondola was kept anchored to the earth by a team