What's your take on the idea of on-orbit propellant gathering?[0] That is, the concept of a solar-electric propulsion sat in low orbit 80-120km, scooping up atm

What's your take on the idea of on-orbit propellant gathering?[0] That is, the concept of a solar-electric propulsion sat in low orbit 80-120km, scooping up atmosphere, ejecting the nitrogen to compensate drag while storing the oxygen for a propellant depo. I tried to run some numbers on it and it seems like it might work, but maybe doesn't pay for itself fast enough to be worthwhile. [0] http://hpepl.ae.gatech.edu/papers/ProgAerospace_Singh_V75_2015_pp15-25.pdf http://hpepl.ae.gatech.edu/papers/ProgAerospace_Singh_V75_20...