Could you explain in what way orbiter does not have this?
I suppose you could write a Orbiter add-on with landing spacecraft, but it would be restricted to the add-on only.
SS allowed you to choose Flight->Spacecraft... and select spacecraft type from a list. (still does
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I would suggest underdogs. its another abandonware site that has it for free
I can't get to underdogs at all. If you can, I would be glad if you would download it for me!