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Comment by vmarsy | Hacker News Reader

One of the issues with airplanes in general but especially with the Concorde at high altitude was radiation [1][2]. Would a carbon-fiber plane protect better or worse than an aluminum plane? My intuition tells me that aluminum is much better at shielding from radiation than carbon-fiber.

The Concorde was flying between 45,000 and a maximum altitude of 60,000 feet. If Boom flies at 60,000 feet, radiation is also going to be a bigger issue. I'm curious how the engineers are planning to address this.

[1] https://news.ycombinator.com/item?id=12785320

[2] http://www.nasa.gov/topics/earth/features/AGU-NAIRAS.html

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Well according to [1] crew of the Concord would get 50-150mSv/yr. US regulation is that a radiation worker can get 50mSv/yr and EU is 20mSv/yr. So this is clearly not acceptable.

Your intuition about carbon-fiber is correct.

What I would guess they are doing though is a layered system, as it is hard to make up the difference with just dopants. Other materials are good too, like Kevlar [2]. So you layer these materials together and get better overall protection. Lots of research being done for this right now actually. NASA has some SBIR phase II funding for low weight, structural radiation shields. Though on Earth you can get away with a lot more than you could in space (launch weight).

[1] http://www.aviationdoc.com/articles/Radiation%20and%20Aircre...

[2] http://esmat.esa.int/materials_news/isme09/pdf/3-ground/s3%2...

They aren't going to address it because it isn't an actual problem that needs to be addressed. You have far, far more to worry about with radon gas seeping up through cracks in your own home's foundation than a trivially-higher amount of cosmic radiation plinking you for 2-3 hours. BTW, it's the density of a material which offers radiation protection, not solely whether it's a metal or not.

I disagree. Concord crew surpassed US and EU regulations for allowed dosages (see my post above). Different materials have different attenuation lengths. So it isn't just density. Especially if we get into the whole neutron problem. But I'm keeping this brief: materials make a huge difference.

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