Editing Explorer II (section)

==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<ref name="AmExp"/>—to which the United States had a monopoly. The lower lifting efficiency of helium gas meant that a larger balloon would be needed,<ref name="DeVorkin1991"/> so [[Goodyear Tire and Rubber Company|Goodyear-Zeppelin]]<ref name="Ryan2003"/> increased the volume to {{Convert|3,700,000|cuft|m3|abbr=on|disp=flip}}. [[Dow Chemical Company]] assembled a larger, lighter gondola<ref name="Maurer1987"/> made of "Dowmetal"<ref name="Ryan2003"/>—a magnesium-aluminium alloy<ref name="SI"/>— that would carry a two-man crew with a reduced amount of scientific instrumentation. The cabin was {{Convert|9|ft|m|abbr=on|disp=flip}} in diameter with a mass of {{Convert|640|lb|kg|abbr=on|disp=flip}} and could transport a {{Convert|1500|lb|kg|abbr=on|disp=flip}} payload.<ref name="SI"/> It was manufactured from a single, large plate that was cut up into form that could be reshaped and welded into a sphere.<ref name="Froes2006"/> In order to make crew escape easier, the portholes were made wider than on the ''Explorer I''.<ref name="SI"/> The atmosphere in the interior of the capsule was supplied from liquid air instead of liquid oxygen in order to reduce the fire hazard.<ref name="Davis2008"/> 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.<ref name="DeVorkin1991"/>

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 {{Convert|14|mph|kph|abbr=on|disp=flip}}.<ref name="Potter2010"/>

With a [[cold front]] approaching, on the night of November 10, 1935, the balloon was prepared for launch. The temperature dropped to {{Convert|6|°F|°C|disp=flip}} overnight, so the {{Convert|115,845|sqft|m2|abbr=on|disp=flip}} 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<ref name="Ryan2003"/> took eight hours,<ref name="Potter2010"/> during which the team needed to repair a {{Convert|17|ft|m|abbr=on|disp=flip}} long tear that formed in the fabric.<ref name="Maurer1987"/> Once inflated, the balloon stood {{Convert|316|ft|m|abbr=on|disp=flip}} tall.<ref name="FWP2008"/> The gondola was kept anchored to the earth by a team of more than 100 soldiers holding cables.<ref name="Ryan2003"/> Preparations were complete by 7:01&nbsp;am the following morning<ref name="Potter2010"/> and the conditions were deemed suitable for a launch.<ref name="DeVorkin1991"/>