The last thing I read on this site last night was someone telling me that testing a spacesuit with an astronaut in it was immoral.
Nope they didn't say immoral. They explained there were ethical issues to be considered when using humans when testing. It is always the duty of the scientist to reduce any testing on animals. A human is also an animal, we're part of the animal kingdom. So, a scientist will carry out several actions before carrying out human trials.
(a) Check whether the work has been done before (that's called research).
(b) Consider suitable simulation tests.
(c) Consider ways of reducing the number of humans taking part in a trial.
(d) Reduce the exposure of the human to the trial.
(e) Examine statistical techniques to reduce the number of human participants.
(f) Write an ethical protocol for the trial.
In the case of the sublimator you can test it using energy outputs that are representative of the human metabolic load. That would cover part (a) and (b) above, so there is no need to move to human trials. Metabolic loads for varying intensity of activity are easily found on the interweb... oh hang one, that means you looking. You're not much good at that. Anyway...
It's fairly simple to test a sublimator without a human, you could heat a coolant by passing it around a heated mannequin, run the coolant through a sublimator, and find the outgoing temperature of the coolant once it has passed through the sublimator. The sublimator could sit in a small vacuum chamber, maybe the size of a bell jar. I would consider that approach. Point being, I wouldn't even consider a human trial. Why would you, that is the real question?
Not only are there ethical issues with using human beings - there is also a cost and time issue. So as a scientist that has been involved with human trials; research into possible simulation are exhausted before moving to human trials. There are some cases where it very clear that one cannot pursue (a) and (b), and that applies to niche technologies or when one is looking at integration between man and machine. For example, the space suit would be tested for integration with the space craft. The integration plans I worked with are huge lists of activities that the user would normally perform while wearing the new technology under development. This would be part of the validation and verification processes.
