Re: Spacesuit: You need a sealed piece of equipment over all your limbs, not just the head or body. So make sure the suit's on, the helmet's on, and all the sleeves and leggings. There'll be a little 'Sealed' flag on all equipment that's vacuum safe; there's also Hardened and Anti-beam, but the sealed is most common. Then make sure none of it's destroyed; if the little - besides the number in the upper left corner of the item description is grey (Well, in ASCII, anyway), then it's broke, not working, and you'll choke anyway.
Re: Hidden encounter. There's a difference between Rishiri spinner and Rishiri spinner exterior, just to make that clear. Rishiri spinner is when you leave through the 'door' of the building; exterior when you leave through the airlock (Yellow ! in th'spaceport, in ASCII mode. Some spaceports have more than one, and the rocks generally only give mecha scale missions on their exterior, which just the outside of the rock.). Exterior is th'space around the spinner, not inside it, etc, etc.
When you get to the area noted, if there's no marker, chances are it's either hidden or plot obscured; I believe in the case you're talking about, it's just hidden. You'll either need a (pretty high, in most cases) Awareness score or to systematically cover the entity of the map, until they deign to attack you. You'll find them when you either get within 1 square of the encounter, or you run over them and they attack.
/Aside/ Easiest way I've found is go to a corner, go horizontal or vertical to the other side of the map, go three spaces either up or down (if you went horizontal, or left or right (if you went vertical), depending on where you started, then repeat the horizontal or vertical movement. You end up being within one square of every tile on the map.\Aside\
If it's plot hidden, it'll be pretty obvious. Rumors'll say something along the lines of "X knows where Y is," and then you call up X and X tells you. There may be a diary involved, in which case you either hit it with insight or go hire an investigator. The raider one you're dealing with is a lot easier to complete if you try to schmooze a little with the non-rival NPC you get told about, just to give a hint. Depend on what skills you've got, though.
I think that covers it. It's a pretty simple operation once you get used to it, but yeah, the first few times can be a little confusin'.
