I was just thinking, as its possible to get a balloon to over 40 kilometres above the earth, then would it be possible to harness the earth’s electromagnetic field to push the balloon further into space by releasing the balloon above the North Pole. Maybe it would be possible to use ionised gas, or maybe the thinner atmosphere would allow a plasma to be used, confined by magnets. One reason I was thinking this might be possible is because some black holes eject plasma above their north and south poles, despite their massive gravity.

One other thing, since hydrogen balloons are rarely used because the hydrogen escapes through the lining of the balloon. Would it be possible to replace the lining with a fuel cell membrane to conduct electricity? I’m sure that some configuration of a hydrogen balloon with a fuel cell could produce plenty of electricity, so would it be possible to attach an ion engine already used by some satellites to push a balloon into space?