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h0l0cube

This article popped up on HN a few months ago advocating 100% hydrogen airships for 'crew-less' cargo shipping

https://www.thecgo.org/benchmark/bring-back-hydrogen-lifting...

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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-...

Rocket launches from high altitude baloons have been done:

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

So like, a rocket the size of a lamppost launching from a balloon the size of a tractor-trailer to deliver a payload the size of a softball?

Neat!

This is the winning strategy. There is no need for crew on cargo craft.

But they are still flying bombs, even without crew.

Except, they are not flying bombs. Notably, the only people killed when the Hindenberg blew were on board. And, fewer than half of them. The flames in the film were the (very flammable!) gas bag itself and the kerosene fuel. The escaping gas went up and away.

A modern craft would not be made of readily flammable material.

Your comments are filled with misinformation:

The gas-bag and paint theory is debunked: https://www.airships.net/hindenburg-paint/

The "nobody died from the hydrogen" line is debunked: https://www.airships.net/hindenburg/disaster/myths/#advocate...

That the craft is made out of flammable material is debunked: https://www.airships.net/hindenburg/disaster/myths/#flammabl...

> The "nobody died from the hydrogen" line is debunked

I don't see that claim in the comments you're replying to.

So are airplanes? And other things, like literal bombs and missiles?

Yes, 9/11 proved that.

Flying bombs that are being controlled remotely. And we know there’s no possible way that a hacking or ransomware group could exploit that channel and fly it into a couple of towers, right? Inconceivable!!

Fly-by-wire control of passenger airplanes hitting the World Trade Center was the plot of the 2001 series The Lone Gunmen[1]. Yes, that was 6 months before 9/11.

[1] https://en.wikipedia.org/wiki/The_Lone_Gunmen_(TV_series)#Si...

A gas bag that bumped into a building would bounce off. Or rip and the hydrogen shoot up to the sky.

So, no, not especially conceivable. Or plausible.

What's to stop the hackers from running the halt and catch fire instruction?

+1 for obscure references

Lest we forget drone strikes.

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