A quick internet search for the words "destiny public event" would have given you exactly what you're looking for. http://destinypublicevents.com . You -can- get Sleeper Simulant without a public event tracker; the game runs fine without using external sources of information, you'd just need to sit around in areas where the specific public events you're after happen and then wait for them to happen. Areas where public events happen have certain random events that occur outside of a few that have only a single public event; the areas where the warsats appear have multiple different PEs that occur, so what you get and if you get one is random, they're not guaranteed. The website above just makes it a bit easier to be in the right place at the right time if a public event does happen, but it still doesn't help you get the warsat public event, that's still entirely up to the game's RNG.

Sit in the areas that are known to have public events and DON'T MOVE. Literally, don't leave and you'll get the public events you need. ALSO: http://destinypublicevents.com/