The shield device Noss was trying to repair was used in The Pegasus (1994) as a Federation cloaking device.
Given Tuvok's birth year of 2264, his flashbacks are likely set in the late 2270s, between Star Trek: The Motion Picture (1979) and Star Trek II: The Wrath of Khan (1982).
The Doctor tells Tuvok, "I'm a doctor, not a battery" - a take on the original Star Trek (1966)'s Dr. McCoy often saying, "I'm a doctor, not a [fill in the blank]"
The type 6 shuttlecraft is seen for the last time in this episode.