Star Trek's Data had a field commission before attending Starfleet Academy. This website points out that Data joined Starfleet shortly (2341 CE) after being rescued but was still at the academy in 2378*. If both dates** are correct then perhaps Data didn't become a officer until 2278 because he joined as an enlisted man. At some point either he was required to serve on the bridge or as part of an away team. Both require an officer's commission to participate so I would imagine that Data was given a field commission by his commanding officer (the captain of the Trieste?) in order to do so. To be promoted further Data then had to attend the academy. It is possible that Miles O'Brien went through the same process but that he declined academy attendance in order to take the position of Transporter Chief on the USS Enterprise-D. On closer inspection I appear to be wearing loafers. *The first series of Star Trek: The Next Generation a...