Commission by CaptainPudgeMuffin

This week we’re talking about shields as they exist today and where we need them to be sooner rather than later. No fancy frills, just what we got or what wouldn’t take too too long to crack.

Active shielding is how you block out radiation without a dense wall of lead. Think of it like you’re throwing a baseball up in the air, you are actively causing the ball to defy gravity-and if you stop it will hit you in the face.

Now if you simply build a shelf the ball will stay there, until you make it move. Passive shielding is having a thick shell that absorbs and neutralizes radiation in space. The problem is that if you were to rely only on passive shielding, the mass you would need would require an insane amount of fuel to move. Picture having to move a small grocery store just to drive your car-a stretch sure, but not too far off when you start adding on flight time.

Getting back to active shielding, we are-right now-experiencing it courtesy of Earth, and if you are lucky enough to live far enough north or south you can see it get trippy at night. Our magnetic bubble has enough kick to keep the majority of charged particles away both from the sun and from the ever-present cosmic background radiation. We have made magnets so beastly that Earth itself quivered… nah not really but it does do really bad things to pacemakers.

But at what point does your intended protective field start to jack with your electronics and make

something break? Spacecraft Systems Engineering (fourth edition) defines Electromagnetic Compatibility by the following three principles

1. It does not cause interference with other systems or equipment

2. It is not susceptible to emissions from other systems, equipment or electrical environments

3. It does not cause interference within itself that can cause the system or equipment to malfunction or behave in an undesirable manner (pg. 527)

Yeah that last one I see all the time, it can be a real pain-but space does not give you the luxury of powering down for adjustments. I mean you can but do you really want to turn life support off? I sure don’t. The best path is to limit your complexity, the more things you have going on-the greater your chance for wires to get crossed or come loose… sounds silly, but just take my word on it.

One thing you have to figure on is that adding a magnetic field to your surroundings will throw extra juice into your gear, if you want to see what happens when this is taken to the extremes (we don’t deal in trifles here :D ) look up a picture of Tesla reading a book-it’s a shocker ;). This also bleeds into your ships wiring maps-how much water do you have to add to a trickle to make a stream? And how much do you have to drain to keep it from starting a flood, or in this case a plasma packed disco party of painful death?

Logically the best way of going about shielding is two fold, bear with me on this-flying saucer with accessories. There has been some development with high temperature superconducting magnets-more developing wouldn’t go amiss, but I digress. One of the best designs I have seen so far has a super magnet ring operating at 20 Tesla (Earths magnetic field is 3.1 × 10⁻⁵ Tesla for perspective) that surrounded a dough-nut shaped crew compartment which was then pushed by external equipment.

the walls of the crew cabin-doughnut-thingy would have to be lined with a double-helix conducting coil with the outer layer angled one direction and the inner coil angled the other. The reason why is that if a wave of radiation is polarized one way it could be mitigated by one coil but not the other, and vice versa; with all mixtures fitting in-between. Honestly this is limited by our knowledge of materials-sciences: copper is not good enough, but anything better than that needs more research to be feasible.

There is NASA’s “gossamer” configuration that claims to be 75% better than what we have now, but honestly I’d need to see flight data. It looks good on paper but I’m not sure how effective balancing the repellent forces of positive and negative energy will work in micro-gravity environments. It’s definitely off to a good start, I just hope the researchers are flexible in their development. What they want to do (as Google will show) is place four sets of beacons around the ship. The outer section is negative to repel the cosmic radiation, the inner section is positive to repel ions. And the man has math on his side, his paper passed peer review-and that is the standard… it just seems counter-intuitive.

Disclaimer, haven’t read the paper-it isn’t available to me so in the end I suspend judgment-but what gets me is that if you are putting energy output in your outer shell of the shield and then putting the exact opposite charge on the shell closest to the core, a portion of energy would jump from the outer shell to the inner shell. Degrading your outer shield and rendering your inner one practically useless. Now if the distance just happens to be enough to prevent that, now you have to cover more space in your outer shell.

Take two pool cues and cross them at their center; figure for the sake of argument that the tips would be where the negative ends would go and the intersection is your ship. No matter at what point in-between the center and the tips you pick for your opposite charge to be, there is a greater circumference out than in, which means more area, which means more nodes on the outside-which is more probable. Now this leans into particle physics and electromagnetic engineering which are not my fields of training, but it’s just giving me a bad vibe for now.

The most current design as put forth by NASA last year in their sixth IAASS conference is built around a six expandable solenoid coil plus one configuration. Think seven paper towel rolls stuck together side to side-not end to end-and you’ve got the gist. The ends of these tubes don’t protect against radiation and might just funnel more stronger stuff than normal, so the solution is to set up passive shield walls over the weakest parts. If we were to go with what we have today-this design is the best we have, that I am aware of. A form of this method of shielding is currently gaining flight data while attached to the ISS, the AMS02 which was attached on 20May2011 with NdFeB permanent magnets.

In the end developing a field strong enough to deflect cosmic radiation and weak enough so as to not harm the crew is a huge challenge, requiring a combination of electromagnetic theory, numerical analysis, engineering practicality, and an attitude of let’s push this shit to the limits to see what we find out! Ships will still no doubt have a “storm shelter” of solid armor in hopes of reducing exposure in emergency events, but what would be interesting would be a counter radiation generation system similar to what car companies use to cancel out the noise inside their vehicles, only instead of sound its pure energy.

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If you see something I said wrong please tell me, I would be honored to issue a correction, you have no idea how much that would mean to me-I don’t care so much about being absolutely right the first time around as I am that the end product works! Looking ahead, I’ve so far seen some amazing work coming the artists that have answered my commissions. For now I’m going to stick to general topics and get more specific as time goes on-as I learn which artists would be more comfortable with depicting different aspects of space adventuring.