Missions & Complexes

Yesterday i found (at first temptative) a mul zatahan. Started it, killed the overseer then had to dock for a while and when went back in there was a guy who finished it. My badness, ok...but now the question is:
Once disappeared, where does it respawn? Same constellation? Same region? Same solar system?
Thanks in advance

Being one of the people that is challenging this age-old belief, I will say that I used to believe respawns were by region. However, this belief was simply due to people repeating it enough times on the forums for it to become accepted fact. Recent evidence involving scanning with deep space scanner probes has helped to debunk this myth. In fact, this myth is extremely hard to prove and people had very little evidence to support it. Respawn by constellations is quite easy to disprove though and myself and others have confirmed that.

I will note though that some Ladar sites respawn by constellation and some by region. These are as far as I know, the only exceptions.

My current belief based on my findings in the last month or so is that all other sites respawn by two things: what security they can spawn in (high, low, null; specific security is irrelevant) and what faction they can spawn in (Gurista Watch will only spawn in Caldari dominant regions).

An easy way to show that my theory is correct would be to go to a region like Black Rise that has few high sec systems. Find a combat site (Gurista Hideout, Lookout, Watch, Vigil, sites that ONLY spawn in Caldari high sec) and run it. Then scour Black Rise quickly (DSP is where this helps) and try to find it again. You may get lucky but odds are you won't. The site has a much higher chance to respawn in a Caldari region with more high sec systems.

The counter argument is that someone may simply just beat you to it. However, with DSP this probability is very reduced. And if you have at it for a while, you can get some definitive answers.