Calm down, he was answering “how fact could we get there”. It was never meant to be a realistic time frame.
Comment on How can we get to Mars faster
tate@lemmy.sdf.org 4 days ago
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.
eager_eagle@lemmy.world 4 days ago
tate@lemmy.sdf.org 4 days ago
His disdain for NASA’s caution is obvious.
CrimeDad@lemmy.crimedad.work 4 days ago
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?
verity_kindle@sh.itjust.works 4 days 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.
unlawfulbooger@lemmy.blahaj.zone 4 days ago
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.
knightly@pawb.social 4 days ago
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.
unlawfulbooger@lemmy.blahaj.zone 3 days ago
Ah yes, that’s the difference. Thanks!
skillissuer@discuss.tchncs.de 4 days ago
“remove” what exactly? water is not alive so it’s okay to irradiate it en.wikipedia.org/wiki/Food_irradiation
just_another_person@lemmy.world 4 days ago
Dude…wut.
Can’t tell if you’re joking or not.
SkybreakerEngineer@lemmy.world 4 days 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.
CrimeDad@lemmy.crimedad.work 4 days 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 anymore than a microwave oven does.
verity_kindle@sh.itjust.works 4 days ago
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.
verity_kindle@sh.itjust.works 4 days 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.
Bezier@suppo.fi 4 days ago
It doesn’t make it radioactive or something, if that was your thought.
Grimy@lemmy.world 4 days ago
You would need a pretty good thickness of water and it becomes complicated shipping it up into space.
CrimeDad@lemmy.crimedad.work 4 days 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.
just_another_person@lemmy.world 4 days ago
Liquid and rockets is a death sentence.
Liquid and space vessels is worse.
Liquids on reentry is never going to happen.
CrimeDad@lemmy.crimedad.work 4 days ago
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?
just_another_person@lemmy.world 4 days ago
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.