I don't even understand this claim. Is it backed up by anything? I don't put it beyond the government to lie, but something for me to "do my own research" before I set off my expedition to find the great icewall at the end of the flat earth would help.

Why lie? Because NASA gets 70 million USD of tax payer money per day. https://www.youtube.com/watch?v=0kRTzMsPUUU

aside from NASA's reasons, they all made bank on it https://m.primal.net/PBeF.png