On: GAGA-1

[Raphael]

But we need to conserve helium!

[russss → Raphael]

There's some talk in the high-altitude ballooning community about using hydrogen - it's much cheaper - but as yet I don't know of anyone doing it.

[wwortiz → russss]

There a plenty of people who use hydrogen in the gas balloons, even in places where helium is cheaper

Here's some info: http://www.balloonfiesta.com/gas-balloons/gas-ballooning-faq...

but there is more to be found.

[edge17 → russss]

This guy used hydrogen - https://medschool.vanderbilt.edu/vusm-blogs/really-crazy-ide...