4 ms·

Extra radiation exposure is minor at those altitudes.

godelski 9y ago
For passengers, yes. Workers, no. The Concord had 12-15uSv/hr [1] (2-3x a long haul flight). The lower bound and best case, workers are fine. Upper bound and European (which are stricter than American, but we're talking international flights) standards are 1mSv (whole body) or 50mSv (effective to skin) [2]. So we're between 4166hrs/yr and 66.6hrs/yr working that would be allowed. Because it is international they'd probably go with the lowest common denominator, at 1mSv/yr dosage allowed (50mSv/yr for American radiation workers, 150 for Astronauts). And we're just talking flight, not adding the nominal background radiation, which is going to reduce the number of hours even more. So in short, no, the extra radiation exposure at those altitudes is not minor. It has to be considered if you are going to hire people to fly your plane and attend to your passengers. Airlines already consider radiation exposure. No one wants to do massive medical payouts 30 years from now. [1] http://aviationknowledge.wikidot.com/aviation:in-flight-health-cabin-radiation http://aviationknowledge.wikidot.com/aviation:in-flight-heal... [2] http://www.radioactivity.eu.com/site/pages/Doses_Limits.htm http://www.radioactivity.eu.com/site/pages/Doses_Limits.htm Addendum: 1Sv in a year is a 5.5% increase of cancer over your entire lifetime. 1Sv in an hour will probably kill you.
- techdragon 9y ago
  This is the most interesting question I've seen in a while. While I'm confident that material choices could provide some protection based on decades of spaceflight engineering and research into lightweight radiation protection methods. However it's the kind of hidden issue I can honestly imagine no one thinking about until it's far too late, which could make it a significant Achilles heel in terms of practical operation of these planes by airlines.
  - godelski 9y ago
    So I actually do some work in this area, hence me asking the question. The conventional method is aluminum. New methods include UHMWPE (polyethylene, same stuff grocery bags are made of) and Kevlar. There's doping methods to help some of these materials, but it can be really complicated. Carbon Fiber, what they are using, isn't really that great for shielding. I've personally run simulations on this, and untreated CF isn't that great of a shield. So my question is, are they treating their CF? Are they using dopants? What resins are they using? What altitudes will they be flying at? These things matter very much.
    - sapphire_tomb 9y ago
      Don't they have to use a fine copper grid over the surface of any carbon fibre used in aircraft? Otherwise you get a lightning strike on the wing, and it explodes? Does that help shielding from radiation too?
      - godelski 9y ago
        I asked some colleagues and they said no. CF is conductive btw. And at that high of a voltage... But my intuition would say that Cu adding to CF would not improve its shielding qualities. Especially if it is a mesh. No mesh is going to make the shielding characteristics better because the particles are at such a high frequency.
        sapphire_tomb 9y ago
        Not claiming this is 100% factual, but this YouTube video suggests the mesh thing is real : https://youtu.be/m37z5R2rJ5E https://youtu.be/m37z5R2rJ5E And I've seen similar on UK documentaries as well.
- johnm1019 9y ago
  The dose limits for radiation workers (which includes airline flight crews) is 20 mSv/yr. This is supported by the ICRP [1] and the EU [3]. British Airways carried out and published data from radiation monitoring of Concorde crews: "Supersonic transport (SST) flights The Concorde SST... was designed to fly at the... operating altitude of around 18 km (about 59 000 ft). Concern for potential hazards... led to monitoring equipment... being installed in all Concorde aircraft. Many data have been derived from this, including more than 20 years experience of the radiological environment. ...these flights indicate that the radiation exposure of Concorde flying crew is unlikely to exceed 6 mSv/y." [2] I will also suggest the interested reader look into "radiation hormesis" and what data really exists to support the linear-no-threshold (LNT) model, or the idea that any amount of radiation raises risk, below certain dose rates. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2889502/ https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2889502/ [1] http://www.icrp.org/icrpaedia/limits.asp http://www.icrp.org/icrpaedia/limits.asp [2] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1128520/pdf/oenvmed00079-0063.pdf https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1128520/pdf/oen... [3] http://eur-lex.europa.eu/legal-content/EN/TXT/PDF/?uri=OJ:L:2014:013:FULL&from=EN http://eur-lex.europa.eu/legal-content/EN/TXT/PDF/?uri=OJ:L:...
  - godelski 9y ago
    Thanks for that. I didn't see that paper when I was quick googling for Concord levels. That's not bad, 7.8hrs/day is the max (given the 7uSv/hr dosage they are estimating). So no flight crew is going to undergo that. Though it still begs the question, is Boom going to get that. As I understand it, Concord had nickel-aluminum throughout its body, which has better shielding properties than CF. They are also introducing more flights. Transpolar flights means more dosages. But given that paper I'm less concerned with the radiation dosages now. I'll still be interested to see what the data says when they start gathering it. We've also learned a lot more about radiation exposure, especially in flight since '96 [1][2]. And note that these values vary quite a lot. The real interest here will be in solar storms. I also wouldn't be surprised if NASA straps detectors to those planes, if Boom becomes commercial. I'd be very interested to see that. [1] https://www.nasa.gov/topics/earth/features/AGU-NAIRAS.html https://www.nasa.gov/topics/earth/features/AGU-NAIRAS.html [2] https://www.nasa.gov/topics/aeronautics/features/airline-radiation.html https://www.nasa.gov/topics/aeronautics/features/airline-rad...

For passengers, yes. Workers, no. The Concord had 12-15uSv/hr [1] (2-3x a long haul flight). The lower bound and best case, workers are fine. Upper bound and European (which are stricter than American, but we're talking international flights) standards are 1mSv (whole body) or 50mSv (effective to skin) [2]. So we're between 4166hrs/yr and 66.6hrs/yr working that would be allowed. Because it is international they'd probably go with the lowest common denominator, at 1mSv/yr dosage allowed (50mSv/yr for American radiation workers, 150 for Astronauts). And we're just talking flight, not adding the nominal background radiation, which is going to reduce the number of hours even more. So in short, no, the extra radiation exposure at those altitudes is not minor. It has to be considered if you are going to hire people to fly your plane and attend to your passengers. Airlines already consider radiation exposure. No one wants to do massive medical payouts 30 years from now. [1] http://aviationknowledge.wikidot.com/aviation:in-flight-health-cabin-radiation http://aviationknowledge.wikidot.com/aviation:in-flight-heal... [2] http://www.radioactivity.eu.com/site/pages/Doses_Limits.htm http://www.radioactivity.eu.com/site/pages/Doses_Limits.htm Addendum: 1Sv in a year is a 5.5% increase of cancer over your entire lifetime. 1Sv in an hour will probably kill you.

techdragon 9y ago
This is the most interesting question I've seen in a while. While I'm confident that material choices could provide some protection based on decades of spaceflight engineering and research into lightweight radiation protection methods. However it's the kind of hidden issue I can honestly imagine no one thinking about until it's far too late, which could make it a significant Achilles heel in terms of practical operation of these planes by airlines.
- godelski 9y ago
  So I actually do some work in this area, hence me asking the question. The conventional method is aluminum. New methods include UHMWPE (polyethylene, same stuff grocery bags are made of) and Kevlar. There's doping methods to help some of these materials, but it can be really complicated. Carbon Fiber, what they are using, isn't really that great for shielding. I've personally run simulations on this, and untreated CF isn't that great of a shield. So my question is, are they treating their CF? Are they using dopants? What resins are they using? What altitudes will they be flying at? These things matter very much.
  - sapphire_tomb 9y ago
    Don't they have to use a fine copper grid over the surface of any carbon fibre used in aircraft? Otherwise you get a lightning strike on the wing, and it explodes? Does that help shielding from radiation too?
    - godelski 9y ago
      I asked some colleagues and they said no. CF is conductive btw. And at that high of a voltage... But my intuition would say that Cu adding to CF would not improve its shielding qualities. Especially if it is a mesh. No mesh is going to make the shielding characteristics better because the particles are at such a high frequency.
      - sapphire_tomb 9y ago
        Not claiming this is 100% factual, but this YouTube video suggests the mesh thing is real : https://youtu.be/m37z5R2rJ5E https://youtu.be/m37z5R2rJ5E And I've seen similar on UK documentaries as well.
johnm1019 9y ago
The dose limits for radiation workers (which includes airline flight crews) is 20 mSv/yr. This is supported by the ICRP [1] and the EU [3]. British Airways carried out and published data from radiation monitoring of Concorde crews: "Supersonic transport (SST) flights The Concorde SST... was designed to fly at the... operating altitude of around 18 km (about 59 000 ft). Concern for potential hazards... led to monitoring equipment... being installed in all Concorde aircraft. Many data have been derived from this, including more than 20 years experience of the radiological environment. ...these flights indicate that the radiation exposure of Concorde flying crew is unlikely to exceed 6 mSv/y." [2] I will also suggest the interested reader look into "radiation hormesis" and what data really exists to support the linear-no-threshold (LNT) model, or the idea that any amount of radiation raises risk, below certain dose rates. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2889502/ https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2889502/ [1] http://www.icrp.org/icrpaedia/limits.asp http://www.icrp.org/icrpaedia/limits.asp [2] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1128520/pdf/oenvmed00079-0063.pdf https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1128520/pdf/oen... [3] http://eur-lex.europa.eu/legal-content/EN/TXT/PDF/?uri=OJ:L:2014:013:FULL&from=EN http://eur-lex.europa.eu/legal-content/EN/TXT/PDF/?uri=OJ:L:...
- godelski 9y ago
  Thanks for that. I didn't see that paper when I was quick googling for Concord levels. That's not bad, 7.8hrs/day is the max (given the 7uSv/hr dosage they are estimating). So no flight crew is going to undergo that. Though it still begs the question, is Boom going to get that. As I understand it, Concord had nickel-aluminum throughout its body, which has better shielding properties than CF. They are also introducing more flights. Transpolar flights means more dosages. But given that paper I'm less concerned with the radiation dosages now. I'll still be interested to see what the data says when they start gathering it. We've also learned a lot more about radiation exposure, especially in flight since '96 [1][2]. And note that these values vary quite a lot. The real interest here will be in solar storms. I also wouldn't be surprised if NASA straps detectors to those planes, if Boom becomes commercial. I'd be very interested to see that. [1] https://www.nasa.gov/topics/earth/features/AGU-NAIRAS.html https://www.nasa.gov/topics/earth/features/AGU-NAIRAS.html [2] https://www.nasa.gov/topics/aeronautics/features/airline-radiation.html https://www.nasa.gov/topics/aeronautics/features/airline-rad...