Partial G Space Station

Radial rotation

One initial idea is to use Bigelow Aerospace Inflatable Space Stations for partial gravity research, because these stations have a much larger diameter than anything that fits in a payload fairing. A large diameter station can simulate artificial gravity by rotating along its axis.

I have not been able to find the dimensions of the largest Bigelow module, but the BA 330 appears^[1] to have around twice the diameter of the Galaxy, so 8 meters across.

The basic idea is to assemble a rigid "Ikea style" floor inside the inflatable walls, so the force of supporting equipment and astronauts does not hit the inflatable walls. There can be a ramp and/or ladder up to the airlock, which is on the rotational axis.

Pros:

Uses an off the shelf space station component.
The air lock is on the rotational axis, so craft can be docked without spinning down the station.
Can probably be launched in one go. The only on-orbit assembly will happen inside the already pressurized station.
There is a lot of living space inside a BA 330, possibly as much as 100 square meters of partial gravity floor.

Cons:

An "Ikea style" floor would need to be installed inside the walls.
The gravity level at the floor would be higher than at head height.
Matching the rotation of crew capsules to that of the station will complicate docking and supply stowage.

The killer here could be the difference in gravity level between floor level and head level. In a station with 8 meters diameter, an astronaut 1.70 meters tall would get approximately 60% of the floor level gravity at his head. This could be disorienting and might invalidate several experiments.

Doing some of the experiments while sitting down or lying down (eg. the daily 8 hours of sleep) could reduce this effect and make the experimental results easier to interpret.

Tethered/dumbbell configuration

Another proposal is to attach two components to each other with a tether or truss and rotate them around each other. This has the advantage that it can be done entirely using solid space station components.

Pros:

Uses off the shelf space station components, except for the tether or truss.
Uses all solid compartments.
Has been done before briefly, on a Gemini mission.

Cons:

Less living and laboratory space.
The station needs to be "spun down" before crew capsules can dock and undock. Does this have "life boat" safety implications?