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Comment by riobard | Hacker News Reader

Could they use a drone instead of manned aircrafts to address point 2? So there's no need to shield and thus saving the weight.

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IIRC some work was done to evaluate shielding only the relatively small area around the crew and avionics, saving considerable weight. However, it was soon discovered that radiation exposure can dramatically reduce the fatigue life of metallic materials. So, some (large) amount of shielding is still necessary.

Our computers are even more sensitive to radioactivity than our bodies.

Maybe yes with a drone based on TTL or some other "old" standard. Probably no with CMOS... Well, with a nuclear plant on board, I guess one can generate enough energy for a TTL computer.

But computers don't take up nearly as much space. You would only need to shield that one specific spot where the computer was rather than the whole cockpit.

Wouldn't you need to shield the wiring too? That stuff goes everywhere. Im not certain on the need for this though.

Yes, every particle crossing the copper can create an anomalous signal that can switch a 0 to 1 or visa versa. If you have enough of those, the program(s) will eventually crash. On the processors themselves the L1/L2 caches are vulnerable, but beyond that, the ROM could also get corrupted making hard resets impossible even after a crash.

Fiber optic cables aren't immune to this either : http://misspiggy.gsfc.nasa.gov/tva/meldoc/cabass/rad.htm

I think you are talking about SEUs.

http://en.wikipedia.org/wiki/Single_event_upset

Arguably, but the D-21 drone [1] was... a mess & a failure. Line Of Sight radio control was the only real option.

[1] http://en.wikipedia.org/wiki/Lockheed_D-21

I'm confused. The D-21 wasn't nuclear, and we've clearly fixed the problems with drones they had during that program. What's your point?

Unmanned aircraft were impractical during the Cold War, which is the only point in history when nuclear-powered aircraft were seriously considered. Drones are workable now, but political considerations alone make nuclear aircraft a non-starter today.

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