What technology i need to start trade with other nation?
Xeno Commerce or its equivalent; whichever technology in your tree unlocks the cargo module should do it.
ship but only can send to my colonies or starbase.
Does your ship have:
- A cargo module
- Sufficient range to reach a foreign colony
Cargo modules are required to create trade routes, and your ships have to be able to reach the foreign colonies before you can trade with them. You can extend your range by colonizing towards your potential trade partner, building starbases in the direction of your potential trade partner, researching a tech or two that increases ship range (look for the life support techs in the Engineering tree), or by designing a custom trade ship with additional life support modules.
