What I'm really curious about is how they're going to deal with radiation. At the required altitude your pilots and attendants can't do a normal routine. You'd get too high of a dosage, unless things are shielded. But that is heavier.
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-heal...
[2] 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.
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.
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.
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.
And I've seen similar on UK documentaries as well.
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/
[1] http://www.icrp.org/icrpaedia/limits.asp [2] 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:...
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
[2] https://www.nasa.gov/topics/aeronautics/features/airline-rad...