it changes a little bit depending on which game version you are using (DL/DA vs TA) but generally speaking, Life Support is found in a Branch-off of the Logistics techs.

So you know though, you can create your very own survey ships once you have researched "Sensors" without the needed Survey Ship techs.

For example, I'll take a blank cargo hull, add some Impulse III engines, a Sensor Module, and then Basic Support and it'll be the pants off my Flagship in speed and range.  And you can be creating these within a few weeks into the game.