The real nature of LV-223

Sorry if I´m repeating an older topic but... What I find weird about LV-223 is that albeit hostile, that world lacks any kind of orbital defense ring (or something like it). It seems defenseless. If Prometheus was a military ship, it could destroy the entire place "from orbit". What again makes me think that this world isn´t a "base" for some alien species. Also, it is so barren that doens´t seem to be the homeworld of any civilization. We don´t see any kind of lifeform over the soil. It´s a primordial world. Of course, the "defenseless" appearence would be in accordance with what one should expect of...a trap. However, I really think the story will be very different from these options and will spin in a different ant unantecipated direction. What you think?