Its not radio emissions necessarily, but general EMI, which isn’t illegal. But we’re talking about such sensitive instruments looking for incredibly faint signals. While the noise from 1 satellite might be insignificant, the combined effects of 100,000+ of all the planned constellations is going to be brutal to the noise floor. It’s the same deal with optical astronomy. Bright spots are an issue, but they are also going to increase the general diffuse brightness (noise) of the night sky, which is already reaching ‘problem’ threshold with the current number of satellites.

https://www.aanda.org/10.1051/0004-6361/202346374 https://www.nature.com/articles/s41550-023-01904-2#Sec2

Sure, professionals can work around it, but for amateurs it fucking sucks.

Its also not just optical astronomy either, they shit out RF on the reserved radio astronomy frequencies too.

It’s wrecking astronomy already and we aren’t even at the peak of satellite constellations.