Earlier Jim dismissed the centrifuge on ISS. He is absolutely right. It would have been totally inadequate for these types of questions. Better way to do that is to put two Bigelows on a tether and spin them. Could be done in LEO but since we have SLS why not do it at EML, or enroute to Phobos, or an Athena type mission. Could be done with all of the above and needs to be because we have no clue how much gravity you need .1G, .16G, .38G, or 1 G. This would take multiple missions with multiple astronauts.
Thanks for your post, and very much appreciate your perspective as a practitioner.
In fairness, Jim objected to one form of centrifuge, or more precisely one form of AG experimentation on ISS; not sure he objects to all (and I'll leave it to him to clarify), but the gnomes of ESA and NASA appear to believe a short-arm centrifuge could be placed on the ISS without disruption.
If short-arm centrifuges are a promising solution (which they appear to be), what is the objection to proceeding down that path? It certainly appears to be a cheaper--and something that might be done on the ISS or similar sooner rather than later--alternative rather than constructing a large rotating torus or tethered arrangement.
Granted, that doesn't necessarily answer the question of what happens for extended periods between 0-1g (e.g., an extended lunar or Mars surface stay), but certainly if we can find a 0-g solution, that would hold promise for 1/6-1/3g environments?
It just makes things easier for the crew.
Though rotation rate is an issue a lot of people got sick if they spent more then a few minutes in a short arm hyper gravity centrifuge.
It doesn't necessarily make things easier for the crew if they have to transition (and re-adapt) between environments. Decreasing adaptation time and deleterious effects is the subject of much concern, altho admittedly we don't have much experience or effective facilities to make a determination.
Rotation rate and adaptation is an issue in some circumstances and for some people. However, a significant chunk of short-arm centrifuge research is determining how people adapt, how to improve that adaptation (both to and from), and how to decrease adaptation time. While the results are limited, they have been promising.