why do ...
 

some planets start to hate me out of nowhere?
i just started a new game, got some nice progress. i made some missions and completed all, attacked and killed some pirates, looted some uninhabitated planets, but that's it.
is it maybe because i didn't always help other pilots when they asked for help? three of those planets are peleng, but i even saw one faeyan.
any ideas?

I think it is racial bias; if you kill pirates of a certain race the planet will hate you.

thanks for the reply. is there anything i can do to avoid this if i still want to hunt down some pirates?

Don't be in a hurry. Time heals all wounds... Meaning, relations will improve probably due to killing Doms... or helping the gov by means of quests (probably indirectly)... I'm not exactly sure, but I did have neutral (? blue face) relations with a half dozen planetary govs, but after killing numerous Doms and liberating a system or two, I found the relations had improved to excellent.

You can always payoff government officials. Do this before they go Hostile or the next time you visit (land) you will be imprisoned.

Of course, if a half dozen or more planets are upset then the cost of bribes is impractical. It might be better to go to jail. Unfortunately I have not tested this... yet.

If you kill Peleng pirates, the Peleng will hate you because piracy is common for them.
Not shure about the Maloq.
Humans,Faeyans,Gaalians, will appreciate that.

Also, if you take a "hit" mission and kill a group of innocent pilgrims that race will hate you and even issue a warrant for your arrest. If you fail a mission, that planet will hate you. Maloqs dislike humans to start with, until you do something to get on their good side. You can always check your status before you enter a system. Stay away from those with red frowny faces.