propulsive

One problem i see with spacex is their propulsive landing feature.

The final burn for propulsive landing only has to cancel that last little bit.

Compare that to a propulsive landing on the launch pad next to the assembly facilities.

They'll probably still be landing in depopulated areas --- you want to minimize damage on the ground if the propulsive landing system fails.

Sort of the 'go kart' versus an actual car. I'm sure a lot of that is just the resonance that Orion has with the Apollo capsule from the 60's and the modern look of Dragon 2 but the difference between propulsive landing vs parachutes is huge.

What else?Most non-chemical propulsive mechanisms considered for space travel do not have the ISP necessary to launch from the bottom of a deep gravity well.

"Dragon V2 will initially conclude missions under her parachutes, prior to a later switch to a fully propulsive landing.

In theory you could use 'chutes to slow the rocket for part of the descent, but to land vertically at a precise point you'd still have to add legs and use fuel for a propulsive landing.

Shroudless launch, 3D printed main engines, integrated LES using the main engines, propulsive landing, full reusability.

Both natural laminar flow and boundary layer control are utilized in the wake immersed propulsive integration.

There is not a complete Quantum Gravity Theory, so all what I will say are only educated guess, supposing that the final theory will mix gracefully with the current theories for the other forces.> [...] thereby producing a propulsive force thereon without having to expel propellant from the object.

The lithium liner provides some help as a neutron reflector but also acts as a propulsive medium, being converted to plasma which is then expanded against a magnetic nozzle for thrust.

Usually for ion propulsion systems you throw off positive ions and also include a rear-facing electron gun. Don't know the exact details, but if it's throwing off neutral waters, with some proportion of charged waters, those charged waters will find their way back to satellite via coulomb forces, but the uncharged water propulsive component will still make a difference.

I remain optimistic about the possibility of other propulsive or spatial traversal methods, notwithstanding the limitations from our current theories of physics, though this is a statement about faith in technological progress rather than a specific hypothesis.