This thread seems to have died, I guess because it has served its purpose because
the real thread has started.
However, I'm recycling the thread as a general forum for blue-skying AH manned orbital schemes for the 1970s-90s timeframe.
Specifically. musing on the interesting suggestion of making recoverable booster stages designed to use auxiliary rocket engines for maneuvering the stage back to a vertical rocket landing, I've been wondering about using some sort of rotor strategy to assist.
Critics will immediately say, "Ah, that's
Roton,
it doesn't work!" Says Encyclopedia Astronautica in particular, in a scathing and uncommonly judgmental article.
Well, first of all no, I'm not suggesting that the rotor be used to achieve any advantage in launch, as the original Roton proposal had it. I am suggesting using it for descent, which is what Roton did evolve toward. But second, no nonsense about a kerlox SSTO, certainly not a manned one!
As I was first thinking, there would be rotor blades, folded down to the side of the stage, perhaps doubling as insulation units. After stage burnout and separation, the blades would be deployed. Some
NASA studies, building on the suggestion of
M Kretz, May 9-12 1967, " Space Rotor - A French Concept for a Reusable Recovery System", SAE Paper Number 670391, Space Technology Conference Proceedings
(an article I have not found online and only cite for biblographic purposes, but have not read

)
suggest to me that rotor blades suitable for autogyroing lift in the lower atmosphere could also survive reentry heating from orbital speeds deployed and indeed serve as quite useful augmentation of the hypersonic drag desired to brake a reentering spacecraft; if that is the case then surely suitable blades for slowing and controlling the descent of a spent booster stage that reaches much lower speeds should be feasible.
These studies by the way are focused on the concept of using such rotors for return capsules from orbit. That's an intriguing idea in itself, but it seems unsuitable for either On The Shoulders of Giants nor Eyes Turned Skyward; the latter in particular with all the weight placed on the Apollo Block III+ that uses the old Block II method of the CSM turning around and docking with a Mission Module--whereas if there were a rotor landing system on a capsule it would have to be on the nose, so either no docking with Mission Modules at all or there would have to be a hatch in the heat shield a la TKS or the MOL. (Indeed with the nose taken up by a stowed rotor, the only ways such a capsule could dock with anything would be either to do some sort of sideways dock to a side hatch on the capsule, or to have at least a minimal MM a la TKS via a heat shield hatch, with the back part of the ship being where the docking ports are).
So again I'm at a tangent from the real-world publications. I'm talking strictly about booster recovery here.
Now I had a number of wacky elaborations on the idea, but keeping it to its essentials, I was envisioning these rotor blades being mounted to the upper end of the booster, so they are free to flap up and down but the whole booster has to turn with them. So it's not at all suitable for a manned descent! As for collective and cyclic pitch control one wacky notion I had was to use boundary/circulation control to achieve a blown flap effect and avoid physically pitching the blades, so they are only hinged to flap but otherwise firmly mounted; however that might be too elaborate.

So, either the dang things do have to be mounted with 2 degrees of freedom and the mounting suffers requiring more mass, or there are physical flaps all along the rotor trailing edge in lieu of moving the whole blade.
Given this though, I think the concept of the rotor slowing the descent and controlling it for crossrange under autogyroing descent is a worthy one.
With the simple concept of the stage itself spinning, I'm afraid we could hardly plan to have it land under rotor lift, because the stage would be twirling around on contact! It would be necessary to have it flare to a near-halt over the landing point, then fire up the engine per e of pi's notion; the rotor would be feathered to slow the spin, assisted by the engines, and as the rockets manage the final descent, the rotor blades collapse back to their stowed positions along the side, enabling a landing pad tower to be deployed to stabilize the vertical stage as it settles.
Alternatively--I wanted to avoid a more traditional helicopter-type rotor hub as these are heavy and complicated. But if it is not too heavy, conceivably such a mounting could enable the stage to avoid spinning. Then we might eliminate the rocket landing, with the rotor approaching the landing site unpowered but with tip jets or rockets powering it for final approach; the stabilizing tower could be attached while the rotor still spins and not only lifts the weight of the stage but gyrostabilizes it; then it could be gradually shut down, with the downswing of the rotor blades managed to avoid hitting the tower.
Conceivably we could detach the rotor blades, letting them scythe off through the air, and recover and reattach them later.
As I said, there are elaborations of the idea to be considered--or avoided!

One would be to recover upper stages as well as boosters this way. The NASA studies I cited were after all about bringing down capsules from orbit; upper orbital launch stages will be coming in at similar speeds and if the capsule rotors could survive and usefully brake the craft, perhaps something similar can brake something like a J-2S-based upper stage and its associated hydrogen/LOX tankage as well, soon enough to prevent damage to the engine and structure. Then the rotor gives quite a bit of crossrange, particularly if we can power it, and the upper stage might be recovered in mid-ocean by a dedicated ship pre-positioned based on mission profile and current weather predictions.
Thus, we might evolve a strategy for recoverable space launches using reusable versions of both the F-1A and J-2S, and not burden an orbiter with the need to bring down the upper stage engines which after all are just so much dead weight once the launch burn is complete.
Finally we might consider reverting to the actual focus of the NASA papers and look at a return capsule that uses the rotor landing system too, but frankly I'd rather not go there, being happy with spaceplanes or failing that, landers under parachutes.
Of course one reason I like spaceplanes is, with the boost axis 90 degrees off from the reentry axis, the problem of mission module docking is pre-solved; no need for a hatch through the reentry shield back to the MM when the shield is off to the side already, and no need for the launch/return orbiter plane to turn and dock with the MM, because it's already mounted back there.
If we don't mind hatches in heat shields of course a TKS sort of layout can work fine with a rotor-braked minimal return capsule.