Vertical Hook Landing - a Concept to be Discussed
1) Descend towards landing location
2) Ignition of rocket engine; fine-tuning of path to landing location
3) Vertical descend at landing location
4) Hovering aside of landing wire
5) Drift horizontally onto landing wire
6) Hook-on and engine off
Why?
- Save weight on landing gear. No legs, only a lightweight hook at a location where you would attach parachutes or crane for transport, which means: no additional structure penality.
- Soft landing. No or low shock on hook-on (formerly called touch-down).
- Lower precision requirements for hovering (depending on hook and wire design); just has to hit the landing wire.
- No or low ground effect problems like reflected rocket gas etc. You can land as high as you can put the wire.
- Can't fall over after engine cut-off. Can be used with traditional tall and narrow rocket design.
- Missing landing location will crash vehicle anyway with high likelihood. No big loss there. Cheap commercial air transport needs landing facilities too.
Why not?
The wire for hook landing could be mounted on an unmanned platform floating in the sea.
Hook landing may even be possible with a hypersonic parachute still attached to the vehicle
(klick here for modified schematic figure).
Notes:
X-13 Vertijet aeroplane demonstrated vertical landing on a hook with an air breathing engine in the 1950s.
The DC-X project did build a test vehicle in the early 1990s to demonstrate vertical landing with rockets.
Tailhook landing is used by some horizontally landing aircrafts to reduce needed runway length; this is rather different from vertical hook landing discussed here.