Effects of One Year of Space Travel on the Human Body (2016)
theatlantic.com
theatlantic.com
How much worse does radiation exposure get?
No and no. Permanent magnets that would be strong enough to be effective would be too heavy. The power system to support effective electromagnets would be too heavy. It goes without saying that a thick lead layer would be too heavy.
One of the actual schemes discussed would be to have a solar flare emergency shelter that the astronauts could go to in case of a solar flare. This would use water as the shielding material, which would save weight, as water would have to be brought along in any case.
Too heavy for what? Anyway, you took the magnets or lead suggestions too literally. They were in the broad direction of using a material isolation or some kind of electromagnetic shield. Why permanent magnets BTW?
in the broad direction of using a material isolation or some kind of electromagnetic shield.
Water would work as a shielding material. 6' of lunar or martian regolith would work as well. As for "some kind of electromagnetic shield" note that a huge electric charge would be relatively easy to establish, which would repel particles of like charge. However, this would cause particles of the opposite electric charge to rush towards what you're trying to shield, so that particle flow would have to be managed with a magnetic field. This has been discussed and researched since at least the 60's, actually. Managing such particle flows would involve a whole lot of engineering research and not an insignificant amount of power.
A lot of engineering research? not an insignificant amount of power? too heavy? Do "cyclers" need realignement? Are they slow?
So what? Should we pack dozens of astronauts and hope at least a handful survive? That's the least realistic option IMO.
Heavy to shove out to sea from shore, but not if you've got a dock! (Read: build the craft already in space. And then have some mean engines.)
But this is all untenable; we need to become robots and cut out the malarkey.
So you're proposing something like Aldrin's cycler craft. Given our experience on Mir and the ISS, we are going to have to get a whole lot better at environmental engineering to be able to do that for human passengers. I've read that the inside of the ISS smells like some kind of porta potty.
we need to become robots and cut out the malarkey.
I hope we will still have "human fundamentalists." (To use Charles Stross' term)
One suggestion is to just line a ship with bags of water and then refill them with water recycled from urine and sweat. https://www.newscientist.com/article/dn23230-mars-trip-to-us...
As the article mentions, none of that is good enough to protect you from a solar flare, so for that, you can potentially reorient the ship to have its aft end pointed to the sun to block as much radiation as possible.
Basically, in an emergency if you need more fuel or oxygen you need to have extra. However, trading off some shielding can defiantly be worthwhile in exchange for some extra fuel and or oxygen.
(from this paper: https://www.researchgate.net/publication/252405981_OLTARIS_A... )
What you want is low atomic mass elements for galactic cosmic rays. Hydrogen is best, so you want fuel or plastic (polyethylene/polypropylene is the best plastic for radiation shielding). Water is also pretty good. As a zeroth order estimate, you look at the average atomic mass of the material to determine how well it shields galactic cosmic rays. So composites work better than aluminum.
Maybe the best economic option is to build a huge ship, that could be a captured asteroid, and place it in an permanent elliptic orbit near Earth's orbit in its perihelion and near Mars' orbit in its aphelion.
If you get to Mars in 3 months versus 9 months, your radiation dose during transit is just a third. And that also means you may be able to reuse the ship every synod (26 months) instead of every 2 synods.
That's the plan for SpaceX's BFR/ITS.
It seems more like a trade-off. A bulkier slower ship could offer better protection even for longer trips. Also you only need to power an elliptic orbiter once.
Cyclers need periodic re-alignment and are so slow that you'd need multiples in order to have one for each window. Also, you still have to catch up to one. Overall, not a fantastic trade.
Eventually we'll have faster transits, and Aldrin Cyclers, and the problem will become even more minute.
[1] Amazon: http://a.co/bL0Tavv
This means that a non-trivial building effort is required in space, as opposed to just attaching more cylinders together, ISS-style. Inflated structures have some promise here, but you probably also need something more solid to attach life-critical systems to, and something thicker to serve as a radiation shield, even while below the Van Allen belt.
This is of course doable, but it's a new, untried territory, which means expensive R&D and even more expensive orbital operations. Without a pressing need to keep humans in space for years, it's unlikely to be undertaken. It's cheaper to build more efficient shuttle craft for space stations, and e.g. more efficient engines for a rocket to Mars, to cut the trip time.
No, but a cable fits nicely into a rocket. Dividing up the ship into two pods would get you a nice long radius to minimize Coriolis effects. If one pod contains a nuclear reactor, for which you need separation from the crew compartment, then it's quite convenient.
https://en.wikipedia.org/wiki/Centrifuge_Accommodations_Modu...