> I was thinking of something like a simple guided arrow, perhaps some fins that are extended on a telescopic shaft
It's one thing to say it, it's another to design it such it has a chance of working. Telescoping mechanisms with deployable aerodynamic structures sounds very complicated to me, compared to the thrusters they're using.
> You could possibly then put a tractor rocket at the end of this shaft to slow descent and keep the rocket plumes away from the main body and the ground.
The sky crane already does this.
> Regarding parachutes, is it not the case that if you need more performance, that you simply increase their size?
'Performance' is lots of things, presumably you mean drag. Increasing the diameter does increase the drag, but it also increases the opening forces, which requires a stronger structure, which means more mass. You don't have the luxury of much margin when every gram in your landing system has cost the us taxpayer thousands of dollars and is a gram that you can't use for science.
It's one thing to say it, it's another to design it such it has a chance of working. Telescoping mechanisms with deployable aerodynamic structures sounds very complicated to me, compared to the thrusters they're using.
> You could possibly then put a tractor rocket at the end of this shaft to slow descent and keep the rocket plumes away from the main body and the ground.
The sky crane already does this.
> Regarding parachutes, is it not the case that if you need more performance, that you simply increase their size?
'Performance' is lots of things, presumably you mean drag. Increasing the diameter does increase the drag, but it also increases the opening forces, which requires a stronger structure, which means more mass. You don't have the luxury of much margin when every gram in your landing system has cost the us taxpayer thousands of dollars and is a gram that you can't use for science.