"The evidence you presented does not show what you claim it shows" is not a refutation?
Hans
No, it isn't. It at best raises question. A refutation requires PROOF to the contrary, not simply rejecting because you understand the source differently.
That canon explicitly states a requirement for 1 stateroom per person does refute your claim that canon doesn't state such. It specifies "within the Regency" for mid passage, and further specifies a type of passage unavailable with the regency. It categorically states in the section on steerage that the Regency is still under the old imperial regulations. It does so to explain why steerage is forbidden; the rules specify a number of other things as within the Regency, and while not explicit that they are regulation, that outside the regency they are different is so strongly implicit that it is a matter of regulation as to beg the question how one can see it any other way.
As for the NASA volumes, I'd have to check the specifics, which means finding the studies again. That said, that they noted problems at 3 days refutes your claim that NASA doesn't look at short term. Further, NASA has had missions under 8 days, both shuttle and Apollo, plus all Gemini and Mercury.
However, some interesting notes...
http://history.nasa.gov/SP-4225/long-duration/long.htm notes that underactivity is highly detrimental to astronaut morale.
An on point issue:
http://history.nasa.gov/SP-483/ch3-2.htm
confirms 11 cubic meters a minimum for space per person long term, and 1.5 cubic meters for 1-2 hours. this refers to open space; the machinery is not included.
While this is roughly one Td per person, that's also a minimum for persons with active duty schedules and at least ready motivation. In short, just about perfectly describing submariners and astronauts... but not passengers.
We can safely presume only a couple cubic meters of equipment; a stateroom represents all of these: a cabin, shared living space, life support equipment, food lockers, water storage, human waste handling, and minimal safety equipment (to wit, at least a bunk). the food locker for 21 meals is about 21 L... trivial... presuming dehydrated rations.
http://history.nasa.gov/SP-483/ch3-4.htm
There are differences among individuals in their perceptions of crowding. Altman (1975) reports that self directed, high self esteem persons have lower spatial needs than individuals searching for identity, and laissez faire individuals have lower spatial needs than authoritarian individuals. Similarly, subjects who report an external locus of control perceive a greater degree of crowdedness than do internal locus of control subjects (Schopler and Walton, 1974).
a 2:1 rate over crew would mirror the rough rates in commercial aircraft vs military fighterjets; those are, in fact, short term, but the other data appears to scale, so... commercial passengers generally have as much seat volume, half that much more as clearance, plus 1/3 that in aisle space, plus the shares of the freshers... and general principles would argue that the minimum be at least doubled for safety.
It also should be noted that 3 days is the transitional stress period; in confinement subjects, for the busy, it's a useful stress; for the bored, it can lead to anxiety and depression.
in short, the 2Td per person of HG's double occupancy rate is a reasonable military rate, 2x the NASA projected minimum for working crews, and not thoroughly dissimilar to current naval rates, when one considers all the relevant compartments allocated from Traveller stateroom space; most civilians would be unwilling to tolerate that volume for any length of time without tasks to distract them; passengers are almost by definition taskless... and bored humans are notorious for inventing "work" to the detriment of those around them. Which leads to the obvious comparison to prisoners.
Given that prisoners may have as little as 30 square feet (3.2 sq meters) each, in a 2.5m tall environment, why not use that as a basis? Because that volume is exclusively the room, and excludes the shower share, accessways (which add at least 50%), mess facilities, and gymnasium share, and because that minimal volume is intended to be a deterrent factor. In short, because it puts the occupant intentionally under stress. The actual volume per prisoner rapidly rises to nearly 250 cubic feet indoors, and another 250 in the yard... Further, studies have shown that confinements effects begin at 3-4 days in prisoners, with profound effects at longer durations. Lower stress prisons often have more than 4 times that space per prisoner; typically they also have lower violence, vandalism, and depression.
4 Td, roughly 2000 cubic feet, again looks to be a reasonable minimum for the passenger, tho for a highly motivated and busy crewman far less is adequate.
Me, I just happen to read TNEp219, and see that it's regulation within the regency, that regulation is specified as dating back to the 3I, and accepting that commercial ships have to have a stateroom per passenger, as is reiterated in MGT as well (sans explanation). Anything past that is into the realm of GM's whim.