In Helena's opening narration, she states that the surrounding stars are so close that the Alphans are "constantly bathed in a lovely blue light" (undoubtedly to provide an explanation ahead of time as to how they come across so many planets within a short time period). We see no evidence of a constant blue light, which would be most prominent when Koenig and Maya are out in space.
Petrov is shown to be a technician of the Technical Department. In other episodes, he's head of the Weapons Section.