I recently analyzed the High Frontier book by Gerard K. O'Neill for an academic project.

While he did not realize his dream of housing millions of people in rotating space colonies, his ideas have had a profound impact 50 years later.

Three highlights: 1) Star Wars:
O'Neill's supporters like the L5 Society and Pournelle's Citizens Advisory Council on National Space Policy pushed the Reagan administration to start the SDI, in the hopes that space colonization could ride on space-based national defense. Now we have the USSF.

Rocket engineers have long had to choose between performance and toxicity.

The TOXMAX rocket concept resolves the problem decisively.

Lithium kept molten by radioactive Cesium-137, reacting with fluorine, provides superlative performance with maximum environmental impact.



This is for @That_Chemist and it is an overdue update to the @anderssandberg question that prompted my first attempt at this:


Here are some more details:

https://twitter.com/ToughSf/status/1290049294808965120

In Avatar 2, the ISV spaceships ride antimatter rockets down to the surface.
(No spoilers, shown in trailers)

In case you were wondering: it's doable, but it's worse than you think for everyone involved.
Let's start with the radiation:
Avatar's ISV is based on Charles Pellegrino's Valkyrie. Antimatter annihilation engines are used to brake into Pandora's orbit. Their exhaust is a shower of gamma rays and a beam of pi-mesons at near lightspeed.
The ship needs a 20cm tungsten shield to survive its own radiation.

The latest @lasers_llnl fusion ignition record blasted a DT target with 2.05 MJ of laser energy and gained 3.15 MJ in return.
llnl.gov/news/national-…
How far does this put us from a self-sustaining fusion reactor?
And update to last year's thread:

https://twitter.com/ToughSf/status/1428403511822258179

/7 In the previous record, the target absorbed 150 kJ of energy from a 1.8 MJ pulse. We don't know yet how much was absorbed in this attempt, but it could be 170 kJ.
That means:
2050 kJ in
170 kJ absorbed
->1880 kJ waste heat
->3150 kJ fusion output
-->5030 kJ out

Could Sholz's Star have triggered an extinction event that will hit us (literally) in 2 million years? It passed within 52,000 AU of the Sun, which would be enough to disturb the orbits of large number of comets in the Oort cloud.
These would strike the Earth at ~42 km/s.
1/6: Sholz's Star was a red dwarf star with 15% the mass of our Sun, accompanied by a small brown dwarf star. About 70,000 years ago, it came very close to our Solar System. I did a bit of maths to understand the consequences of this event.
2/6:

Human industrial civilization only exists thanks to a short-lived anomaly in Earth's evolutionary history that gave us coal.
The access to 25 MJ/kg in a dense, storable and easy to burn package allowed even early steam machines to bootstrap our progress into the modern era. But think about how unlikely this is. In a short gap between 360 and 300 million years ago, plants evolved to harden themselves with lignin but fungi and bacteria had not yet learnt to digest it. Even then it was interrupted for 15 million years by the Permian extinction.

One of the most down-to-earth and factual description of encryption and how it should actually be depicted in #scifi, #cyberpunk and media in general is found in this short piece by @ian_mallett: plus.google.com/u/0/+IanMallet…
I'll attach the statements for when G+ shuts down (thread): Art by Joakim Englander : artstation.com/artwork/g1AwZ
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Lunar Dust will be a major problem for future missions and settlements on the Moon! It is microscopic, infiltrates every crack, accumulates in the smallest corners and sticks to all surfaces.
Lungs, skin, mechanical joints, bearings, lenses and reflective coatings all suffer. Most of lunar dust's danger is caused by the fact that it is extremely sharp and as hard as steel. It can cut into most materials, especially the lightweight ones optimized for spaceflight.
What is the solution to lunar dust? Here is a few: