this post was submitted on 27 Oct 2024
-33 points (18.9% liked)

Technology

59148 readers
1986 users here now

This is a most excellent place for technology news and articles.


Our Rules


  1. Follow the lemmy.world rules.
  2. Only tech related content.
  3. Be excellent to each another!
  4. Mod approved content bots can post up to 10 articles per day.
  5. Threads asking for personal tech support may be deleted.
  6. Politics threads may be removed.
  7. No memes allowed as posts, OK to post as comments.
  8. Only approved bots from the list below, to ask if your bot can be added please contact us.
  9. Check for duplicates before posting, duplicates may be removed

Approved Bots


founded 1 year ago
MODERATORS
 

Notice the continuous mention of bones.

top 32 comments
sorted by: hot top controversial new old
[–] [email protected] 16 points 1 week ago (2 children)

What a dumbass. If we send people in the quickest possible way (or any way at all, really) and they all die in the attempt, that will set the whole project back decades.

The answer to the radiation problem is better shielding, not a fundamentally unsafe mission.

btw it is not the nuclear propulsion that I'm calling unsafe. It is the idea that we could do without redundancy. That's just a monumentally stupid idea.

[–] [email protected] 7 points 1 week ago (4 children)

Since the astronauts need water to survive, why not line the spaceship with reservoirs of it to provide the shielding? Or does water not block space radiation well enough?

[–] [email protected] 8 points 1 week ago

They did that in the novel "Seveneves", used a massive chunk of ice as the bow of their ship on a one-way, twenty year plus trip. It didn't stop all the radiation, though. Just enough to keep a minimum number of crew alive to complete their mission. They all developed different types of cancers, anyways,but the kinds that could be treated along the way and extend their chances.

[–] [email protected] 5 points 1 week ago (6 children)

But then they’re drinking irradiated water, no?

Unless it’s really easy to remove the radiation safely, this doesn’t seem like the right solution.

[–] [email protected] 6 points 1 week ago

You wouldn't want to drink reactor coolant water (mostly because of the chemistry additives) but water in a tank that just stays between the people and the hot stuff would mostly just get warm.

Most of what you'd get at that kind of distance is neutrons, and they are more likely to bounce off the hydrogen than to do something like activate the oxygen into N16 which dies off pretty fast anyway.

[–] [email protected] 6 points 1 week ago (1 children)

Irradiated water is fine.

You're thinking of radioactive water, which is water with radioactive stuff in it.

Subjecting regular water to regular amounts of radiation is fine, even if it's high-energy gamma rays. If there's enough radiation to make water itself radioactive then you have bigger problems than radioactive water.

[–] [email protected] 2 points 1 week ago

Ah yes, that’s the difference. Thanks!

[–] [email protected] 5 points 1 week ago (1 children)

"remove" what exactly? water is not alive so it's okay to irradiate it https://en.wikipedia.org/wiki/Food_irradiation

[–] [email protected] -2 points 1 week ago (1 children)

Dude...wut.

Can't tell if you're joking or not.

[–] [email protected] 5 points 1 week ago (1 children)

i don't get what you fail to understand, water doesn't became radioactive or harmful in any other way after irradiation, and irradiation of food is routinely used for extending its shelf life

[–] [email protected] 4 points 1 week ago* (last edited 1 week ago)

I don't think it works that way. The water slows down the neutrons so that when and if they get to you they don't have enough energy to hurt you. The radiation doesn't contaminate the water any more than a microwave oven does.

[–] [email protected] 2 points 1 week ago (1 children)

They used the ice for everything, including cooling and heating the ship as needed. They got the bad effects from the cosmic radiation pinging in from all other directions, not from using the water. The volume of ice was larger than that of the ship, I think it also absorbed physical damage from micrometeorites. Let's hope someone in the Big Green Machine reads the novel.

[–] [email protected] 1 points 1 week ago

I mean, they put nuclear waste at the bottom of miles deep water wells, because it absorbs alpha, gamma and beta particles and it's cheap.

[–] [email protected] -1 points 1 week ago* (last edited 1 week ago)
[–] [email protected] 3 points 1 week ago (1 children)

You would need a pretty good thickness of water and it becomes complicated shipping it up into space.

[–] [email protected] 4 points 1 week ago

Well, the water is necessary for for life support and needs to be sourced somehow anyway. It kind of sets a minimum crew and passenger capacity if you want to make the most use of your shielding water.

[–] [email protected] -1 points 1 week ago (1 children)

Liquid and rockets is a death sentence.

Liquid and space vessels is worse.

Liquids on reentry is never going to happen.

[–] [email protected] 4 points 1 week ago (1 children)

Water doesn't have to be a liquid, but don't actual spacecraft typically contain liquids during wall of those cases? What do you mean?

[–] [email protected] -3 points 1 week ago* (last edited 1 week ago) (2 children)

You can freeze it before launch, but you'd have to freeze it again before reentry. Not possible, especially if you're talking about lining a craft with it during months of space travel. Water expands when frozen, and contracts when liquid. Metal does the opposite. How would you engineer that?

[–] [email protected] 2 points 1 week ago (1 children)
[–] [email protected] -2 points 1 week ago* (last edited 1 week ago)

Didn't think I needed to stoop to that level. Thought I was talking to about obvious things and didn't want to sound patronizing.

Thanks for clearing that up.

[–] [email protected] 1 points 1 week ago (1 children)

Build the hypothetical ship in space and you never have to deal with it except as ice, which is easier to move around and shape into what you need. The ISS has a lot of liquids on board in all sorts of forms, from chicken soup, to ink pens, to the urine inside astronaut bladders. I don't understand what you're trying to say.

[–] [email protected] -2 points 1 week ago

Do you even know what question you're responding to anymore? Wtf

[–] [email protected] 2 points 1 week ago* (last edited 1 week ago) (1 children)

Calm down, he was answering "how fast could we get there". It was never meant to be a realistic time frame.

[–] [email protected] 3 points 1 week ago

His disdain for NASA's caution is obvious.

[–] [email protected] 2 points 1 week ago (1 children)
[–] [email protected] 2 points 1 week ago

Because we (technically) can?