GoPro sticked to a Rocket => Round Earth

" class="bbc_link" target="_blank" rel="noopener noreferrer">

You can admire the beauty of the curved horizon 

" class="bbc_link" target="_blank" rel="noopener noreferrer">

You can admire the beauty of the curved horizon 

I certainly know that we live on a globe, but like most goPros that uses quite a wide angle lens with considerable barrel distortion (loosely, but incorrectly labelled a "fish-eye").

Note at 1:47s it shows "wonderful curvature",
  but at 1:51s there is a slight curve on the horizon
then at 1:56s the curvature is distinctly "concave", not "convex".

So, while I would agree that it shows slight curvature, you would gets lots of arguments against.

Ya, definitely "fish-eye".

At :10, the horizon is concave and everything isn't "normal".
At :17, the fences are very distorted. I assume they should be linear.

BTW, even IF the camera had a "normal" (~50-55 mm lens), depending on where in the frame the horizon is also determines "curvature". Probably the "fish-eye" exaggerates this even more.