Kind of a follow-up question to Could a helium balloon on Mars and on Triton float at air pressures lower than it could on Earth due to the bodies' low gravities?. As stated in the linked question, the highest a helium balloon has gone above Earth is about 53 km (actually higher: 176,200 ft). For a balloon to reach the mesosphere, it needs to have very much volume, a tiny enough payload and must be of a certain material. Is it possible from a realistic point of view to reach 65 km or 214,000 feet from the Earth, and what requirements would such a balloon have to meet?
This question is about pushing the limits of balloon flight closer to the Kármán line and the threshold of space. Questions about balloons and balloon flight are on-topic here since they are routinely used as platforms for space exploration:
- near space vacuum balloon
- What cosmic ray sensor is attached to this Balloon?
- High pressure Helium tanks for the Vega balloon experiments
- Scientifically useful measurements from low-budget high-altitude balloon flights
- Around Venus in 8 days by Balloon?
- Maximum height for a Mars Balloon?
and sometimes discussed as launch platforms:
and for science education:
and for space suit development: