It seems to me that if one were going for the nose down approach, permanent legs and landing engines could be attached after the vehicle is in orbit. A vehicle that will never again deal with atmosphere shouldn't have to worry about a sleek profile. It would eliminate one failure profile of things not extending during the landing maneuvers.
Quote from: mikelepage on 10/23/2023 04:21 amIf you're not so volumetrically constrained by the engines and prop tankage, you can afford to make the legs quite a lot bigger.Quick and dirty animation of the concept attached.Why is the nose so far off the surface? Bring it as close to the ground as you can. Get rid of the elevator entirely.Hell, if the engines are way-up-the-other-end, why not use the nose itself as the primary landing leg. Then the outer legs are purely for stabilisation rather than supporting the entire mass, hence their deployment systems can be reduced in size/mass.And given the way you've folded out the landing legs, those outer legs can also serve as ramps/stairs, leading to openings in the sides of the nose to the unpressurised cargo deck. (Hmmm, you could have two longer, two shorter legs, leading to two cargo decks. Increasing available cargo volume.)I mean, if you're going to do this, go all in.
If you're not so volumetrically constrained by the engines and prop tankage, you can afford to make the legs quite a lot bigger.Quick and dirty animation of the concept attached.
One disadvantage of the nose down concept, with landing thrusters pointing in the opposite direction of the main engines, is having both lit at the same time wastes propellant and maybe impractical due to settling.This means you likely have to commit to shutting down one set before starting up the other, on both descent and ascent. With the high-mount ring of landing engines, or even side-mount thrusters for a horizontal lander, you can easily start up the second set while the first is still running, and if they won't start, abort to orbit if descending, or abort back to the surface if ascending.