| Can a micro satellite be launched from a hydrogen filled balloon? NASA has calculations of hydrogen balloons up to 90km, carrying a 10kg object. [0] Wind at that altitude can be as much as ~50 m/s, and occasionally even travel from west to east (important for orbital launching). [1] http://www.ccpo.odu.edu/SEES/ozone/class/Chap_2/2_4.htm Low Earth orbit requires at minimum ~6.5km/s, so launching from the equator into the right stratospheric wind could allow a 10kg launch into orbit from a balloon if it can accelerate from Earth's natural rotation plus the wind speed, totaling around 500m/s, to 6500m/s. [2] Traditional small rockets seem to have a lower limit in the 100s of kg total mass.
Using a solid microrocket(s) [3], you might be able to get a payload into orbit between 10-500 grams. I know MIT was working on this as well as micro-jet engines... [4] [0] https://www.grc.nasa.gov/WWW/K-12/Numbers/Math/Mathematical_... [1] http://www.ccpo.odu.edu/SEES/ozone/class/Chap_2/2_4.htm [2] https://en.wikipedia.org/wiki/Orbital_speed [3] https://www-bsac.eecs.berkeley.edu/projects/microrockets/mas... [4] https://www.semanticscholar.org/paper/Performance-of-a-High-... |
https://en.m.wikipedia.org/wiki/Rockoon
If you mainly care about altitude as with a sounding rocket, it can help quite a bit.
Also some launche loop designs have parts of the structure supported by inflatable members.
And there are even plans for a rather exotic airship design that could be flown to orbit with the help of solar powered electric engines:
https://en.m.wikipedia.org/wiki/JP_Aerospace