Exploration

Ships orbiting unowned or enemy (or allied) planets send exploration reports on those planets. A typical exploration message looks like this:

(-z0340)<<< Sub Space Message >>>

From: SWIFT HEART CLASS SC
At:Kamikachiadonia
Temp: 50 ( Temperate - warm )
There are enemy colonists
living on this planet.
The colonists are part of the
Fed race.
Sensors show that there are
1161 enemy clans.

A ship's mission does not have to be "exploration" to send these reports, it will send them regardless of it's mission and even fuelless ships send these messages.