When auditioning for the part of the holographic doctor, Robert Picardo was asked to say the line "Somebody forgot to turn off my program." He did so, then ad-libbed "I'm a doctor, not a light bulb" and got the part.
The character of Ensign Samantha Wildman was named after a little girl who died tragically in an accident. The girl's organs were donated to save the life of the wife of episode writer Jimmy Diggs. The real Samantha loved animals, so Ensign Wildman was written as the head of Voyager's Xenobiology Department.
Jeri Ryan has stated that she would become sick with anxiety at the thought of performing scenes with Kate Mulgrew. Most cast members have affirmed that their working relationship was quite strained during the first years of their cooperation. Mulgrew later admitted that she wanted to de-sexualize Star Trek in general and her Janeway character in particular (e.g. resisting attempts to have her engage in a relationship with a male crew member), so she disapproved when an obviously sexualized character like Seven was made the new center of attention. Mulgrew did later comment that Ryan "did a marvelous job in a very difficult role."
Many images seen on monitors on the wall in the Astrometrics Lab are actual images taken by the Hubble Space Telescope. The Cat's Eye Nebula and the famous "Pillars of Creation" from the Eagle Nebula can be seen in several episodes.
Garrett Wang does not actually play the clarinet. But anytime Harry Kim plays it, Wang chose (on his own) to learn the correct finger placements to match the music playing in the professional recording he was following, making the illusion more convincing.