4 ms·
We've flown a radiation-blocking vest to the Moon and back, and it worked
- TheDudeMan 2mo agoWhy wouldn't it?
- rtkwe 2mo agoThe difficulty is making it protective but light enough to not significantly hinder the spacecraft or person wearing it, all of which is covered in the article.
- solarengineer 2mo agoPoor design, flawed assumptions, manufacturing defects, inability to bear the gravitational and rocket launch forces, inability of the jacket to last the duration of the radiation exposure - these are some reasons that come to my mind on why a radiation-blocking vest wouldn't have worked for the journey to the moon and back (i.e. your question "Why wouldn't it?".)
- deleted 2mo ago[deleted]
- alehlopeh 2mo agoThe use of “we” in this headline is really jarring.
- ButlerianJihad 2mo agoWe Flew to the Moon and Back So You Wouldn't Have To!
- antonvs 2mo agoYou're welcome!
- Am4TIfIsER0ppos 2mo agoScrew that. I want to go and I think it is horrible that we didn't bother for 50 years.
- xyzelement 2mo agoI agree actually. I understand the use of "we" to mean an achievement of humanity (like: we've been to the moon) but I find that often "we" is a substitute for "someone not me" - as in "we should make healthcare free" coming from someone who doesn't perceive a role in actually doing any of it. In this case it's kinda just confusing. The headline should be "Israeli startup + NASA ..."
- bcraven 2mo ago“It still gets people surprised,” Milstein says. “Everybody asks, what about the head? But we’re actually able to reduce the effective dose by 60 percent without protecting the head, the arms, or even the legs.” Whilst I understand the maths here, I can see why someone would be nervous!
- antonvs 2mo agoIt's ok, everything except your brain will be protected from radiation!
- clickety_clack 2mo agoYou’ll be cancer-free on average!
- weinzierl 2mo agoYour brain is quite robust against cancer and when it gets it, if is often a relatively fast death.
- weinzierl 2mo agoYou need to protect anything with relatively fast dividing cells best because this is where the cancer risk is highest. The brain with its slow dividing cells and fast killing tumors is the last thing to protect.
- ericd 2mo agoThis seems sort of interesting as a sort of emergency backup, but it seems like the real solution for any sort of long distance/long duration in space is just making mass to orbit dramatically cheaper and shielding the spacecraft.
- bell-cot 2mo agoA spacecraft with a 4m diameter spherical living space and 4m of water shielding around it will weigh about 1,000 tons. The propellant tanks needed to move it around the solar system will be similarly titanic. How many orders of magnitude were you figuring for your "dramatically cheaper"?
- ericd 2mo agoThat's 5 Starship block 4 launches, seems fine? Propellant, presumably for long duration voyages we're not relying entirely on chemical combustion. If we're using cyclers, once they're up to speed, you need barely any fuel for corrections, just to taxi to/from the cycler.
- dessimus 2mo agoMaybe when its actually demonstrated that it can actually launch with that payload. The largest payload they'd lifted so far is ~45 tons, and the claims I see on Wikipedia say its estimated 200 tons for LEO, not even for geosynchronous orbit much less a lunar trajectory.
- ericd 2mo ago20 launches would also be doable, though, if there's a reasonable launch cadence? And yeah, I don't expect they'd assemble for a Mars mission or other long range mission where they need a radiation shielded craft in geo or lunar.
- vikingerik 2mo agoAnd just for comparison on that number, the entire Apollo spacecraft (command+service+lunar modules) was about 50 tons to lunar orbit. And that took a gigantic Saturn V to launch.
- saltcured 2mo agoI remember reading, long ago, an assertion that most shielding ideas were counterproductive for astronauts. It was stated that most shielding would turn high energy photons into much more harmful showers of particles, worse than the original photon going directly through tissue. Was this an untested myth? HDPE has been around since the beginning of the space race, so it seems like someone ought to have considered this before? Has the understanding of particle interactions improved a lot since then, such that HDPE shielding would not have been considered before?
- wildzzz 2mo agoIt's not a new idea, here's an article from 20 years ago: https://www.sciencedirect.com/science/article/abs/pii/S0168583X06008822 https://www.sciencedirect.com/science/article/abs/pii/S01685... I can't find a good source but it seems that the radiation shielding properties of polyethylene were discovered some time after WWII. But I think this was an inevitable discovery, not some sort of accident. HDPE has a lot of hydrogen atoms which are perfect for blocking high energy particles without creating secondary radiation. A block of solid hydrogen would be ideal but that's not practical. Water works well but it's heavy and needs a container which adds more weight. Dense metals and concrete do a fine job but are heavy relative to amount you need to stop the same amount of radiation as HDPE. Plus you get the secondary radiation effects from metals that can harm humans or sensitive electronics. It's like being behind armor that's hit with a round. The armor may stop the round from getting through but very hot fragments of the backside of the armor (spalling) can fly off and injure someone. Now you need additional protection from the spalling too. Here's a photo from 2017 of a NASA facility using white HDPE sheets to attenuate high energy particles: https://www.flickr.com/photos/brookhavenlab/33642244296/in/album-72157678587953833 https://www.flickr.com/photos/brookhavenlab/33642244296/in/a...
- anonymars 2mo agoLong video but informative: https://www.youtube.com/watch?v=DJcbevbBzsc https://www.youtube.com/watch?v=DJcbevbBzsc (~26 min)
- anishvarghese 2mo agoThis targeted shielding is a classic aerospace mass tradeoff much like armoring a fighter pilot instead of the entire plane.
- roarcher 2mo agoI get your point, but fighter pilots don't wear armor. There is no reasonable amount of it that can protect against cannons and missiles, and the added weight and bulk of even a bulletproof vest would make high-G-force maneuvers impractical for the pilot.
- m4rtink 2mo agoBoth A-10 & SU-25 have an armored bathtub made form titanium to shield the cockpit (somewhat) from ground fire, aimed mainly against heavy machine gun and auto canon fire + splinters. Sure, those are ground attack aircraft, not fighter aircraft but IMHO good enough. Also IIRC some WW2 fighter planes had at lest armored glass front panel, to provide some protection from tail gunners when attacking bombers.
- wildzzz 2mo agoThe NASA Space Radiation Laboratory uses HDPE panels to attenuate neutrons, protons, and heavy ions. The lab sits at the tail end of a particle accelerator which is used to test radiation effects on various materials including electronics and mice. When I saw the plastic panels, I asked one of the NSRL physicists about it as we had just finished setting out some tungsten blocks to isolate the beam only a certain area on our experiment. Why plastic? Why not a dense metal? He explained that HDPE is dense with hydrogen that does really well against slowing down particles and that most importantly, HDPE is made from low atomic numbers that do not emit secondary radiation effects. This prevents radiation from hitting sensitive electronics outside the beam and also making nearby objects radioactive. When the beam hits an object with high atomic numbers (metals, especially dense ones), it can create very strong x-rays that can knock neutrons out of nearby stable metal nuclei and create unstable isotopes, effectively creating a bunch of unintended radiation sources. This isn't a big deal for the experiment, that goes away at the end of the day but not good for permanent equipment. You can see the HDPE sheets in this photo, they can be lowered or raised to adjust attenuation: https://www.flickr.com/photos/brookhavenlab/52979144013/ https://www.flickr.com/photos/brookhavenlab/52979144013/
- stevenwoo 2mo agoThought it might be useful for the untapped market for air crews on passenger airlines but the company said it does not block cosmic gamma rays.
- floatin 2mo agoCould use empty plastic water tanks in the walls and have a satellite in orbit that already has the water onboard and they just transfer the water back to the satellite before returning to earth. Water blocks radiation very well it’s the reason we use pools of it to store fuel rods when they are not in reactors.
- serf 2mo agothis is a common concept in space-craft thought experiments because of the dual-use nature; can shield yourself with a big water balloon essentially at the tip of the space craft to catch all those pesky extra energetic particles that are bombarding you against your fantastically high velocity, while also providing water to grow things in, or whatever. then neutron activation becomes even more nuanced because it affects not only your craft/infrastructure/armor but your semi-perishable goods.
- Sniffnoy 2mo agoIt's kind of buried in the article, but it's worth noting that this vest is meant only to guard against solar storms, not cosmic rays; those remain a significant problem. > The vest, though, does nearly nothing against galactic cosmic rays (GCR), which are the other major radiation source astronauts face. Unlike solar storm radiation, GCR arrive continuously at much higher energies, which makes them harder to shield against. “Using the vest against these rays would not be reasonable,” Houri says. “You’d have to wear it at all times.” See for instance this article on how the cosmic ray problem would affect a Mars mission: https://mceglowski.substack.com/p/radiation-tradeoffs-for-mars https://mceglowski.substack.com/p/radiation-tradeoffs-for-ma...
- hammock 2mo agoThe same protection against solar storms (which does nothing against cosmic rays) WILL also protect against exposure to the Van Allen belts. Remember the van allen belt radiation is what spawned a lot of fake moon landing theories that suggested transit thru the van allen belts was not survivable with the limited/no protection that our astronauts had at the time.
- m4rtink 2mo agoWell, those confused people mainly ignored the flight profile - Apollo spent a very little time in Earth orbit & boosted for Moon. As a result they flew through Van Allen belts very quickly, so the radio was not an issue. If for example you built a space ship on low Earth with efficient but low thrust ion drive & wanted to take it to Moon or Mars, it would take it possibly months to slowly (but efficiently) spiral out to higher orbit and eventually towards its destination. Many of those months would be spent inside the Van Allen belts. So for these mission profiles I have seen the suggestion of the ship being radiation hardened for autonomous flight & the crew arriving by a small fast craft only once it is out of the radiation belts.
- euroderf 2mo agoI remember reading about the Belts in the early 60s (IIRC). It most definitely spooked me. How will men (erm humans) ever get thru the Belts safely ? But then they disappeared from any and all discussions of spaceflight.
- ck2 2mo agothe longest human exposure ever to cosmic rays (which are physical particles with mass, not waves, moving at 99.999~9x21% the speed of light) which space is flooded with was set by the 75 hours of a lander on the moon with 22 hours of those in moon walks (space-walks in earth orbit, longest was 9 hours) when NASA inspected the helmets of the moon walking astronauts, they found deep microscopic grooves which often made it completely through the protection this is why moon walking astronauts reported seeing bursts of light even with their eyes closed when they simulated comic rays hitting mice for days, the mice slowed down, learned things much slower and forgot things much faster, their brains and CNS were being damaged humans will never make it to Mars, forget surviving on the surface, without advanced protection from cosmic rays, technology that does not exist yet this vest is a great start but it's not enough
- Ferret7446 2mo ago> humans will never make it to Mars Humans will never cure diseases, humans will never fly, humans will never go to space, etc.
- PowerElectronix 2mo agoBullet proof vest for really really small bullets. Nice.