What are advantages and disadvantages of powered landing (future Dragon) and aerodynamic (Space Shuttle, Dream Chaser) landing types?
Quote from: Archer on 02/21/2012 07:29 pmWhat are advantages and disadvantages of powered landing (future Dragon) and aerodynamic (Space Shuttle, Dream Chaser) landing types?Wings are orders of magnitude more efficient at generating lift than rocket fuel and engines are.
Over long distances, maybe. But not for small amounts of lift just for landing, especially if you have the rocket engines and tanks and everything anyway.
Quote from: Robotbeat on 02/22/2012 03:20 amOver long distances, maybe. But not for small amounts of lift just for landing, especially if you have the rocket engines and tanks and everything anyway.In that case, nearly all of the delta-V comes from aerodynamics, and that's because wings (even they they are low-aspect-ratio ones like capsules) are more efficient than rocket fuel and engines.
The trade is pretty close, though. Different folks are trying it different ways. I still sort of side with the vertical landing folks... Wings are dead weight in space.May the best design win!
One advantage of wings that has been mentioned is a potentially softer landing for ISS crew after 6 months on orbit. The Soyuz landing is pretty brutal.
Away from Earth, wings are a disadvantage almost all the time. SpaceX wants to have Mars capable hardware and systems (as much as possible).
Quote from: go4mars on 02/22/2012 11:14 amAway from Earth, wings are a disadvantage almost all the time. SpaceX wants to have Mars capable hardware and systems (as much as possible). I am taking the title of the thread to mean aerodynamic landing on Earth. There are other threads for discussing Mars landing techniques.
But there's no reason a powered landing can't be gentle -- consider the Apollo LM, for example.
...for extremely high Mars entry speeds, wings with their higher hypersonic lift/drag (used "negatively") can help keep the entry craft from skipping off into space. But that's a pretty extreme example.
Quote from: Robotbeat on 02/22/2012 04:03 pm...for extremely high Mars entry speeds, wings with their higher hypersonic lift/drag (used "negatively") can help keep the entry craft from skipping off into space. But that's a pretty extreme example.It is. And wings cannot be used for landing on Mars by themselves, of course. So I hold to my point that if we are talking about aerodynamic landing (I take that to mean winged landing, not parachutes), we are talking about landing on Earth. (OK, we might mention Titan, in which case we might make the lander a seaplane. Aerodynamic maneuvering is a different matter and can in principle be carried at any Solar System body (excluding the Sun!) which has an atmosphere.