I can't conclude "Salvage" mission, help!

#1
Hi guys, I have a problem. When me and my friends retrieve the alien artifact, we tried to go back to the station where we began, but we didn't have the option to dock the submarine. I know we're supposed to go to the station to the right, but when we return to the one where we started we should at least be able to dock the submarine, even if it means failing the mission. Instead, we can't dock the submarine, we just see a white icon (kinda like a lamp) where the station is and even if we drive the submarine against it with a perfect angle, we don't have the option to dock, there should be a white line where we have to allign the green one of our submarine, but there is just the white lamp icon. Is it because we have to go to the station to the right? Is it because when we take the first artifact, another infrasonic signal appears and we have to retrieve a second artifact before the docking option can be unlocked? HELP US!
cron