> prohibitively expensive to just boost them into the sun or elsewhere, while in low orbit?
It’s easier to exit the Solar System than it is to boost mass into the Sun from any Earth orbit [1][2]. The atmosphere providing braking for “free” is a huge propellant saver.
It’s easier to exit the Solar System than it is to boost mass into the Sun from any Earth orbit [1][2]. The atmosphere providing braking for “free” is a huge propellant saver.
[1] https://en.m.wikipedia.org/wiki/File:Solar_system_delta_v_ma...
[2] https://space.stackexchange.com/questions/3612/calculating-s...