Why cannot I capture the ships?

[Smiling_Spectre]

After some time in game my boarders stopped to capture anyone.

Or rather, they successfully capturing anyone - but ship always goes to self-destruct after that. I experienced it with two races already, and all sorts of the ships.

Why it's so? Is it some race option, or technology? And how can I prevent it?

[Zaimat]

Immaterial races, mission related ships, space stations will always self-destruct.

For other ships there is a chance based on Marine Strength attackers vs. defenders. If attackers are much stronger the capture chance is increased.

[Smiling_Spectre]

Immaterial races, mission related ships, space stations will always self-destruct.

Oh, I didn't knew this bit about stations. Thank you.

What about capturing planet, leaving station alone? Will it be transferred to me, or retain old owner?

For other ships there is a chance based on Marine Strength attackers vs. defenders. If attackers are much stronger the capture chance is increased.

Aha. Chance then. Ok, thank you.

[Zaimat]

You can't capture a planet without destroying it's defenses (eg: space station) but if you demand a system and it has a starbase it will transfer along with the colony.