Layman question: Is it possible to shield electronics against cosmic rays?
Or is it like a neutrino thing, where they just go through everything? (But neutrinos barely interact, correct?)
Or is it like a neutrino thing, where they just go through everything? (But neutrinos barely interact, correct?)
To answer your question, shielding is possible but it is much harder in space than it is under the magnetosphere. Even so, a stray particle can wreak havoc. Shielding for the purposes of data protection on earth is essentially a risk/reward analysis. Anyone could get hit by a cosmic bullet, but the chances are pretty low. The odds of an SSD flipping bits on its own are significantly higher.
Wow, I have to admit I always assumed cosmic rays to be gamma radiation but alpha particle radiation sounds a lot more scary.
Does anyone happen to know if computers engineered for the space station or shuttles have already some built-in (memory)redundancy or magnetic shielding to account for damage by cosmic rays? I imagine a system crash of the life support systems in space would be devastating.
IIRC nobody is currently using magnetic fields for shielding, I don’t know if that’s due to insufficient effectiveness, power consumption, or unwanted interactions e.g. with Earth’s magnetosphere.
This is what the James Webb is going to be doing, though for non-superconducting reasons.
The magnet in an MRI is a superconducting electromagnet. It needs power once, to charge it up, then you close the loop and it just sits there being a superconducting electromagnet. The only power used continuously is for cooling, which is to say, when ambient room heat leaks in, it has to be carried out again. The magnet itself does not produce heat; it has no electrical resistance because it is a superconductor.
Light ions, e.g. of helium, lithium or boron are also relatively abundant and heavier ions are less abundant. There are also electrons, but in smaller quantities, because they can be captured by ions.
The high speed protons collide with the atoms of the Earth atmosphere and the collisions generate a huge variety of particles, but most of them have a very short lifetime, so they decay before reaching ground level.
At ground level, the cosmic radiation consists mostly of muons, because they have a longer lifetime, so they survive the travel from the upper atmosphere where they are generated, until ground level.
Only extremely few of the particles from the primary cosmic radiation, i.e. protons, reach ground, because most are deflected by the magnetic field of the Earth and the remaining protons lose their energy in the collisions with atmosphere, by generating particles, which eventually decay into muons.
The point I was thinking about is a scenario where Starlink satellites communicate with each other via laser (already starting to happen), and then communicate with the end user via the satellite over them. Because we're talking about speed-of-light transmission between sats, data in the Starlink network can theoretically cover "ground" (aka miles/km) faster than ground-based ISPs.
Then it makes sense to deploy servers within that network so that two Starlink users can have extremely low latency from user to server to other user (the slowest part being the earth to sat latencies, one for each user).
It's easier to just code checks and balances to fix those errors instead. There's a famous story about a Google search bug caused by a comic ray and they implemented such error checking on their servers after that
The general solution here is to store multiple redundant copies of data and checksums of those data, in order that lack-of-consistency can be determined and the specific records which are considered suspect can be clearly identified.
In general, a record is a persistence of a pattern through time subject to entropic forces.[1] Given that modifications to records are typically random events, keeping (and continuously integrity-checking) multiple copies of those records is the best general defence, not guarding against one specific variety of modification in a single instance of a record.
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Notes:
1. The symmetric statement of signals is that they are persistence of a pattern through space subject to noise. See: https://news.ycombinator.com/item?id=27604073