The first to touch the edge of space

In 1931, Auguste Picard and Paul Kipfer’s pioneering flight aboard the hydrogen-filled FNRS-1 balloon set a monumental milestone in human exploration. Reaching approximately 15,800 meters, they entered the stratosphere — a layer of the atmosphere above the troposphere known for its thin air and unique characteristics. This altitude was higher than any human had previously ventured, resulting in several extraordinary observations. One of the most significant experiences was seeing the Earth's horizon visibly curve, with the sky turning nearly black due to the thinning atmosphere. This direct visual confirmation provided compelling evidence for scientific theories of Earth’s shape and atmosphere structure, long understood mathematically but never witnessed by human eyes before. Picard, a physicist fascinated by cosmic rays, leveraged this expedition not only to expand human presence into the stratosphere but also to study these high-energy particles originating from outer space. His work helped deepen knowledge about cosmic radiation’s interaction with Earth's atmosphere. The FNRS-1 balloon used hydrogen gas, chosen for its lightness, enabling the balloon to climb to such a rarefied altitude. Such early balloon ascents paved the way for further advancements in atmospheric science and aviation technology. This historic flight marked the first time humans touched the edge of space, expanding our understanding of the atmosphere’s layers and laying groundwork for future space exploration. The legacy of Picard and Kipfer’s ascent remains a testament to human curiosity and the quest to explore beyond our everyday experience.