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The series was about Earth battling these unknown aliens in space, the war was close to the alien's planet/planets. They wore dark body-suits with dark helmets, completely covering their features. They had better technology than humans, but we were somehow keeping them at bay with tactics. It happened then that one of our pilots crash-landed on one of the alien planets. There, the pilot discovered a pink alien, breeding eggs. They befriended each other and the pilot talked to the alien about Earth's war-tactics. When he got rescued, it came out that the pink alien is in fact one of the enemy aliens without the body suit, and that the alien had divulged the war-tactics to his leaders, causing the humans to start loosing all the battles.
I also remember that one of the humans tried putting on one of the alien's helmets. It made a sucking noise and the human nearly died from suffocation (the aliens breathed something else than air).
Any help with the name would be greatly appreciated.