Can I move my colony in the same planet ?

Yes you can relocate your colony to different coordinates in the same world, but not to different worlds.

Full guide found on our Wiki here: http://wiki.battledawn.com/index.php?title=Relocating_Your_Colony

To move your colony place an outpost where you would like to move it, then you must wait 24 ticks to have control over the op. Also if you do not have control over your colony you will need to wait a maximum of 72 ticks. Once you have control you simply click the op you would like to move to and hit the relocate button. It will cost you a flat fee of 50 energy as well as oil for every km you wish to move up to a maximum of 10,000 oil.

@Korupt: Not necessarily 10000 oil because it depends where you wish to relocate (If your outpost you wish to move your colony to is too near your original placement it will cost you less than 10 K oil)

Which I stated, every km costs 1 oil up to a maximum of 10,000.