I really hope that they manage to figure out radiation shielding in time. Wasn't the idea of thin panels of liquid water discussed at one point?
That's because hydrogen is very good at absorbing radiation, so water has been a good candidate to be used as shielding for a long while. Lead is too heavy, of course.
We've known that trips to Mars will be highly radioactive for a long time, and even people on the ISS are subjected to a lot more of it than the average person. Hell, even air stewards are subjected to far more radiation a year due to flying at high altitudes where the Earth's atmosphere absorbs less of it.
NASA are a bunch of wusses lately. Elon Musk could do it.
transit time is a problem but mars's atmosphere is the bigger one since above ground structures are getting hit by radiation and spacesuits can't ever really have good radiation protection either.
Hold your horses folks, several parts of the study are pretty suspect.
First is the sample size was only 10 mice per group. That's pretty awful for any study.
I'd also be concerned about the radiation dose received. Converting 0.5 Grays (the lowest dose they used in the experiment) into Sieverts using a weighting factor of 20 (which is the weighting factor used for ions, xrays have a weighting factor of just 1) gives a dose of 10 Sv. This is a huge amount of radiation, the amount that would kill a human about 90% of the time with the best medical treatment available. A three year Mars mission is expected to give a dose of 1.2 Sv. On top of that, that dose is over three years instead of a few days which has a very real impact on its lethality.
I won't comment on the rest of it because I'm no biologist but radiation doses are pretty easy for someone to get a hold of.
Keep in mind that alot of interplanetary radiation consists of solar wind protons and heavier ions. Gamma and beta make only a small fraction of the dose composition.
Knowing that, Water is definitely a material that will be used on the craft but we have alot more materials we can use. Demron has been looked at as a viable material to be layered into IVA and EVA suits, its much more flexible, lighter and robust than a lead apron while still being a great personnel shield against alpha, beta, some gamma and some protons/ions.
There's also talk about placing a 2T magnet at Mars's L1 lagrange point to shield the planet and low orbit from most solar wind. Which is a very viable endeavour.
I thought anything above 7Sv was fatal always, so that shows what I know.
It might as well be. Without medical treatment it's pretty much garunteeded to kill you and even with treatment your odds are slim and you'll likely suffer debilitative injury for the rest of your life.
Even 1Sv is a lot to take for a human.
The typical dose for firefighters and other workers during Chernobyl was around 6Sv, and most of all of them died within a month.
Today, the reactor hall in there - if you ever go there - is probably spewing out about 15-20 Sv/H, which would amount to a lethal dose in about an hour - which would kill you in many months or even years later, depending how long you decide to hang out in the vicinity of the radiation 's source, like the Chernobyl reactor hall in this example.
You could die from radiation even faster, like no dosage all the way to death, in a matter of hours - it all depends how powerful the source of radiation is and how long you are exposed to the radiation. You could achieve this by challenging a blown reactor core spewing out 300 Sv/H to a dare, you could probably see the damage with your own eyes, before your eyes fail with the rest of your organs being ripped through on a molecular level by the violent, ionizing radiation.
1.2 Sv is still way way beyond any acceptable dosage. 50 mSv is considered the maximum acceptable yearly dose for a person under US regulations and 1.2 Sv over three years is almost 8 times that. That's one hell of a cancer risk right there.
I had a physicist friend who has been saying this for years. I’m surprised NASA never said anything about it earlier
Here's a handy chart, courtesy of XKCD:
https://files.facepunch.com/forum/upload/224422/2d956e9d-fd53-4e60-93e2-126609a29d2c/radiation.png
I thought this was one of the major challenges they were trying to figure out? When it comes down to it, we're still monkeys. Smart, hairless monkeys. We're made to survive in the forest and hunt, not travel into space. To really make this issue go away, we'd have to change how we work.
Nasa has a different acceptable dose level for astronauts from the rest of the US. It's 50 Rem (0.5 Sv) per year. There's plenty of evidence out there that our radiation regulations are far too strict being based on the discredited Linear No-Threshold (LNT) model. I won't say that the levels received by astronauts aren't too high because there is evidence it has caused them harm, but they're not walking tumours.
There's a huge difference between doses received over the span of days and doses received over years.
Yeah, its a shame hormesis isn't more publically known. There's been so much research done behind it for the past few decades across the human body to show the relatively low dose rates can be biopositive by stimulating the repair mechanisms that you'd think policy would change. However public perception is still unfortunately driven by fear and the media reinforces that with the LNT model.
I can understand where NASA is coming from though by still sticking with LNT in practice.. When you're in a life-critical risk averse line of work as an astronaut, especially deep space. You can't take any chances as it all just compounds.
Well Gamma rays are virtually impossible to block without shoving a big chunk of heavy element between you and the source. They aren't affected by magnetic or electric fields and are much harder to physically block than larger particles like proton or beta radiation. Neutron
Yeah but out astronauts don't spend any where near as much time in high radiation regions, plus there's the issue of the fact that mars itself doesn't offer much protection from radiation so you have that on top of it all.
Okay that sounds great and all but unless a major medical body comes out and declares it as consensus I'd like to keep my ambient radiation levels low k thx.
But the EPA said that radiation is good for you, what gives!
wouldn't be first thing to ruin my gut.
I don't believe the radiation in space is real. It's just to keep us on Earth and fullfill others dreams.
Couldn't they line the habitable part of the ships with tubes that run the liquid fuel through? Similar to the engines on the Orbiter of the space shuttle, the fuel is run through them before being burned which keeps the temperatures much cooler. I don't know if that would work the same as straight water, though
While that is a very interesting review article, it's also over 12 years old now. Science moves fast my man. I found a comprehensive review article published for free just last month on the same subject.
Elon Musk was fired m8
As chairman, he's still CEO.
Absolutely there is a huge difference.
I'm not even very well versed on the subject, just the basics really, but I felt like posting about it!
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