Editing Explorer II (section)

==Flight==
[[File:Historic weather balloon "Explorer II." Lake Andes NWR, South Dakota. - NARA - 283835.jpg|right|thumb|''Explorer II'' gondola at the landing site]]

The crew of the ''Explorer II'' consisted of Captain Albert W. Stevens, in command of the mission, and Captain [[Orvil A. Anderson]].<ref name="Davis2008"/> A crowd of around 20,000 viewers gathered to watch the event. (The local residents had raised and contributed $13,000 for the mission.<ref name="Ryan2003"/>) Lift-off occurred at precisely 8:00 am with the release of {{Convert|75|lb|kg|abbr=on|disp=flip}} of ballast made of fine lead shot. A few moments after liftoff, wind shear propelled the balloon into a side canyon, but thereafter it ascended normally.<ref name="Ryan2003"/>

The ''Explorer II'' reached a peak altitude of {{Convert|22,066|m|ft|abbr=on|lk=off}}<ref name="Bilstein2001"/> at 12:30 pm and remained there for 80 minutes.<ref name="Ryan2003"/> This set a new world altitude record, and one that would last for nearly two decades.<ref name="Bilstein2001"/> The crew became the first humans to document the [[curvature]] of the Earth. Unfortunately, the fan that was to be used to rotate the gondola proved ineffective at that altitude, so they were unable to avoid the Sun's glare. This made viewing from one side of the capsule nearly useless. Despite this, Captain Stevens reported seeing details of the Earth's surface for hundreds of miles. They were too high up to be able to view any movement on the ground,<ref name="Ryan2003"/> but their photography showed the potential of high-altitude [[reconnaissance balloon]]s.<ref name="SI"/>

''Explorer II'' included communications equipment, and constant radio contact was maintained throughout the flight with the signal being broadcast across the U.S. and in Europe.<ref name="Ryan2003"/> The onboard instruments collected data on [[cosmic rays]], the ozone distribution and electrical conductivity of the atmosphere at different altitudes, the atmospheric composition of the stratosphere, and the luminosity of the Sun, Moon and Earth. In addition, microorganisms were collected from the stratosphere.<ref name="Maurer1987"/> Mold samples were carried along to determine the effects of cosmic ray exposure. Stevens took along a camera to take pictures, including the first ever motion pictures shot from the stratosphere.<ref name="Ryan2003"/> The collected data showed that the ozone in the upper atmosphere was effective at blocking most of the ultraviolet radiation from the Sun. It was also found that the percentage of oxygen at the peak altitude was about the same as that at sea level.<ref name="Davis2008"/>

Finally, the descent was begun and it proceeded normally. At an altitude of {{Convert|1000|ft|m|abbr=on|disp=flip}}, the crew began releasing scientific instruments that would descend by their own parachutes. This was done to protect the data in case the gondola had a rough landing. The precautions proved unnecessary as the balloon landed gently in an open field near the town of [[White Lake, South Dakota]] at 4:13 pm.<ref name="Ryan2003"/>