Why artificial gravity?

[Vultur]

My approach suggests that the easiest thing on the body be attempted, even though that means more mass to space.

I think that ends up being an argument for not doing it since you can always come up with more improvements to make it safer or easier.

Early exploration is always hazardous, there's little point in trying to get around that. Choose an acceptable risk level (probably much higher than we accept for ISS say... more on the level of early Antarctic exploration) and go.

[JohnFornaro]

My approach suggests that the easiest thing on the body be attempted, even though that means more mass to space.

I think that ends up being an argument for not doing it since you can always come up with more improvements to make it safer or easier.

Yes, it ends up being that argument if you don't want to go.  If you do want to go, you'll find a way to deal with the additional mass and its accompanying margin.

[JohnFornaro]

What happens if astronauts are kept in some kind of suspended animation? Would that also retard or suspend their skeleto-muscular atrophy?

There is no such a thing at the present time.

Not entirely true.

Over the last few years surgeons have been using a form of deep hibernation for many more complex operations that require the Heart to stop beating.  This usually lasts about 45 minutes.  They have also been able to induce a hibernative state with the use of low quantities of Sulfur dioxide and low temperatures, but have only maintained this for a few hours at best.

"A few hours at best" in the confines of a terrestrial hospital sounds like "no such thing at the present time" in space.

[alexterrell]

All rotation experiments that have been done have been done in Earth gravity.. with the exception of the minor tether experiments done on the Gemini flights.

For all we know humans have no problems with 10 rpm.. if there isn't a gravity field messing with the inner ear.

I wonder if they could knock up an outdoor experiment at the ISS.

What would be the cheapest format? You could have two freeflying modules, each big enough for 1 astronaut for 12 hours at a time. Or would it just be easier to use 2 manned Dragons away from the ISS? (One on the way to ISS, and one returning, for like 4 days of testing).

[Patchouli]

Though AG increases the complexity of the vehicle in some ways it can simplify the design of other parts.

Even partial G makes liquid gas separation a lot easier.
This would simplify at lot of the ECLSS design eliminating a lot of small high speed centrifuges and small passageways increasing it's reliability.

Partially true though bear in mind the ECLSS has to be able to work in zero-g as well. You cannot guarantee spin gravity for the entire voyage.

I thought about that and you just simply make use of a Skylab style open ECLSS during the microgravity parts of the flight.

The consumables would be sized to allow an abort back to Earth or the Martian surface hab if needed.

[Vultur]

My approach suggests that the easiest thing on the body be attempted, even though that means more mass to space.

I think that ends up being an argument for not doing it since you can always come up with more improvements to make it safer or easier.

Yes, it ends up being that argument if you don't want to go.  If you do want to go, you'll find a way to deal with the additional mass and its accompanying margin.

Except that missions will exist within financial limitations, which means limited numbers of launches thus limited mass. So you can't just "deal with" more mass. Early Mars missions will probably need to be minimalist.