I think regulators would be much more hesitant to allow thousands of 45 meter diameter antennae in low orbit.
That's a significantly increased collision risk, as well as increasing interference with astronomy and potentially increased brightness mitigation challenges.
Practicality wise, such a large antenna would add a lot of drag, such as to meaningfully shorten how long a satellite can stay in operation (which would cause an entire bunch of tradeoffs in terms of mass budget to need to be reevaluated).
That's true - although the antenna can be oriented to be perfectly parallel to the direction of travel - therefore only experiencing drag from the edge cross sectional area.
> increasing interference with astronomy
The antenna could be painted matt black. It can also consist of ~95% holes without much loss in functionality.
> increased collision risk,
I don't think it will matter while the number of uncontrollable satellites remains low. If I were a regulator, I would put a cap on the number of uncontrollable satellites that may be in orbit at any given time, and if that cap is exceeded prevent all new launches and require active de-orbiting of existing ones.
That's a significantly increased collision risk, as well as increasing interference with astronomy and potentially increased brightness mitigation challenges.
Practicality wise, such a large antenna would add a lot of drag, such as to meaningfully shorten how long a satellite can stay in operation (which would cause an entire bunch of tradeoffs in terms of mass budget to need to be reevaluated).