Recent comments in /f/space

BWright79 t1_j5wr38l wrote

Reply to comment by atwegotsidetrekked in Hey, can someone explain to me why we are not stending nuclear waste into space having a reliable rocket that can carry a decent amounts of cargo? I'm thinking about Falcon Heavy. One start a year would mean that US doesn't need to store anymore waste underground. by William0fBaskerville

Thanks, that's good news. Before I responded earlier I was seeing articles as recent as 2022 saying we did this. Granted this article is also from 2022... in my head though I can't help but think how we still use soviet era munitions and even though production as stopped... we are probably still using them.

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Shrike99 t1_j5wqvjj wrote

Reply to comment by FrostyAcanthocephala in NASA to test nuclear thermal rocket engine for the first time in 50 years | CNN by dem676

I mean nuclear fuel is typically comprised of uranium-235 and uranium-238, both of which occur naturally and can be found in low levels within all rock, soil, and water. Soil for example contains about 12 milligrams of uranium per kilogram on average.

A typical space-based fission reactor contains abut 30 kg of uranium. If a rocket blew up halfway through the launch and scattered that perfectly over a radius of say 50km, and it was all absorbed by just the top 1cm of soil, that would amount to an additional 0.3 milligrams of uranium per kilogram of soil.

Of course, if it spread over a smaller area the concentration would be higher, but it would have to be a pretty small area for there to be enough to matter, so it's not likely to be a major hazard in the grand scheme of things.

 

In practice it's more likely that the fuel rods would remain largely or entirely intact and end up at the bottom of the ocean somewhere. The ocean contains approximately 4 billion tonnes of uranium, so even if the fuel rods were gradually eroded, they'd quickly be diluted into irrelevance.

Now, there are some ways that it might be possible for someone to be exposed to a dangerous quantity - for example, say something like a gram of uranium being chipped off and somehow ingested by someone, my point is more that it's not going to be a widespread ecological disaster.

Whereas in the case of a disaster like Chernobyl, there were a lot of nasty isotopes present in the partially spent fuel rods, most notably iodine-131, caesium-134, caesium-137 and strontium-90. These isotopes are tens of millions of times radioactive than uranium-235 or uranium-238, so even the most miniscule quantities are dangerous.

I'd also point out that we already regularly launch other dangerous substances on rockets. Hydrazine for example has comparable toxicity per milligram to uranium, and large satellites are regularly launched with literal tonnes of that onboard.

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michaelklr t1_j5wqpep wrote

Reply to If you were in space facing Antartica and you flew towards it, gravity-wise would you be going up or down? by lifesyndrome

Hmmmm, I wonder if time dilation works on a "Being" that gravity has no effect on.

Now that is food for your thoughts.

Wait.... now how about those "Tic Tacs" that supposedly use earths gravity with anti-gravity technology to move about effortlessly. Zero time dilation? Or are they on another level of understanding?

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farticustheelder t1_j5wq6s0 wrote

Reply to Mycotecture — the use of mushrooms and other fungal substances for architectural purposes — could be key to building affordable, fire-resistant, insulated habitats on the Moon and Mars. NASA aims to experiment with the technique on the Moon in 2025. by clayt6

Not to be overly critical but this thing just bent the needle on my BS meter!

Folks, take a good look at 3D printing. We can 3D print metals, ceramics, and stone!

Yes! 3D print Lunar habitats out of Lunar materials! Martian habitats out of Martian materials!

Growing mushrooms is neat. Growing them in space is neat. So why all the BS about them being anything more than a pizza topping?

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DrHugh t1_j5wpvx1 wrote

Reply to If you were in space facing Antartica and you flew towards it, gravity-wise would you be going up or down? by lifesyndrome

Gravity is towards the center of the Earth. If you are in space, in freefall you wouldn't have a sensation of "down." If you are accelerating in a direction, you'd have a sense of down from "behind" you (think of how the Apollo astronauts were on their backs on liftoff, even though the spacecraft arced out and changed angle).

In space, there is no up and down. You could identify a convention, that the "top" of the solar system is where the planets all seem to go in this direction around the sun, so if they seem to go the other way, you are "below," but that's just for consistent terminology.

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nukeemrico2001 t1_j5womdw wrote

Reply to comment by Original-Aerie8 in Mycotecture — the use of mushrooms and other fungal substances for architectural purposes — could be key to building affordable, fire-resistant, insulated habitats on the Moon and Mars. NASA aims to experiment with the technique on the Moon in 2025. by clayt6

I don't think it's that. The world is literally talking more about mushrooms. The collective conscious is fascinated with mushrooms atm.

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sordidcandles t1_j5woj5y wrote

Reply to comment by Pro_phet in Mycotecture — the use of mushrooms and other fungal substances for architectural purposes — could be key to building affordable, fire-resistant, insulated habitats on the Moon and Mars. NASA aims to experiment with the technique on the Moon in 2025. by clayt6

I had my first ever shroom trip last year, followed by two more trips spaced out by a couple months, and they were all superb. Had some freaky moments but it was mostly all amazing and changed how I see the world a bit.

I hope as weed becomes legal and accepted in more parts of America, shrooms do too. I think the potential benefits for some folks are great. Massachusetts is working on it!

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