Have there been advancements in materials or safety procedures since the Hindenburg that would allow us to safely use hydrogen as a lifting gas? It seems a waste to use helium for anything other than cooling big magnets.
The “S0S” makes me more uncomfortable than it should…
Edit: My discomfort does not stem from the mere concept of an SOS button; It’s more subtle than that. If “SOS” stands for “save our souls”, does “S0S” stand for “save zero souls”?
It’s been gradually ramping up with things like the Inspiration4 and Axiom missions, but still relatively slow. Yuri Gagarin’s historic flight is further from today than the Wright Brothers’ flight is from Yuri Gagarin’s flight.
Orbital fatalities so far are just Soyuz 1, Soyuz 11, STS-51-L, and STS-107. We are still a bit early, but Space exploration has been surprisingly safe so far.
Major natural sources of potassium nitrate were the deposits crystallizing from cave walls and the accumulations of bat guano in caves. Extraction is accomplished by immersing the guano in water for a day, filtering, and harvesting the crystals in the filtered water.