Red Bull Stratos was a high-altitude diving project involving Felix Baumgartner. In 2012, Felix Baumgartner flew 39 km (24 mi) into the stratosphere in a helium balloon before free falling in a pressure suit and then parachuting to Earth. Flat-Earthers invented various excuses to dismiss the resulting footage from the project.
Auguste Piccard was a Swiss-Belgian physicist, inventor, and explorer, known for his record-breaking balloon flights to the stratosphere, as well as the invention for bathyscaphe to allow for deep ocean exploration.
Unfortunately for him, flat-Earthers are claiming him as their own these days. It started from a Popular Science article from 1931, saying:
Through portholes, the observers saw the earth through copper-colored then bluish, haze. It seemed a flat disk with upturned edge.
But, no. In reality, Auguste Piccard was not even close to being a flat-Earther.
High-altitude balloon footage is often abused by flat-Earthers to show us that the Earth is flat when seen from a high altitude.
We analyzed more than two dozens of footage taken from high-altitude balloons on YouTube, and we can easily conclude the curvature is there and usually easy to spot, including in the cases where flat-Earthers use the video as ‘proof’ of a flat Earth.