Star Trek: Starfleet Academy brings Robert Picardo back as the Doctor for the first time since...well, since he voiced the character in 2024's Prodigy season 2. However, his first live-action Star Trek appearance since 2001's Voyager finale comes with a key omission. As far as anyone can tell, the Doctor no longer needs his mobile emitter to move as freely as he did in the 24th century. He was wearing it in Prodigy, but it's nowhere to be seen in Starfleet Academy's 32nd-century setting.
Originally brought back from an alternate 29th century in Voyager season 3's "Future's End" two-parter, the Doctor's mobile emitter transformed holographic technology when his ship reached Earth in the Prime Universe's 24th century. Star Trek: Picard proved that the device's design had been replicated a couple of decades later, which was likely only possible thanks to the Doctor's device being studied. However, Starfleet Academy hasn't yet explained how the Doctor has maintained his autonomy without a mobile emitter. I think I've figured it out, though.
SPOILERS ahead for Star Trek: Starfleet Academy season 1's first two episodes.
The Doctor's legend likely resulted in a greater presence of holographic emitters
When Voyager began, the Doctor's role as the ship's Emergency Medical Hologram meant he was restricted only to areas that were equipped with the relevent technology. This meant he could only access Sick Bay and Voyager's holodecks. The mobile emitter eventually allowed him far greater freedom, and when that happened, his journey toward sentience grew exponentially as he experienced new scenarios with which he was never programmed to be involved.
Even before his return to Earth, the Doctor's story started to circulate back in Federation space. He became something of a living legend, and in the centuries that have passed between then and Starfleet Academy's premiere, this status will have been cemented. He's not only earned a place in the history books for his role in helping the USS Voyager return from the Delta Quadrant, but also for becoming so self-aware, when that was never the plan.
When the Doctor's mobile emitter was being studied, he would have once more become reliant on pre-installed emitters. Without them, he can't be projected into spaces. To accommodate this sudden limitation, it's reasonable to assume that more and more emitters started to be installed in locations where the Doctor was most likely to be, including starships and other Federation/Starfleet facilities. While he would still require a mobile emitter at times, perhaps as a failsafe in case of a power failure, the less portable versions of the tech allowed him another way to explore his surroundings.
This possibility is heavily supported by Voyager season 4's "Message in a Bottle," which saw the EMH MK II, played by Andy Dick, aboard a ship called the USS Prometheus. Dick's character could move freely around the USS Prometheus due to the sheer number of holographic projectors. Therefore, by the time of the 32nd century, this is probably standard procedure to allow photonic lifeforms like the Doctor the same level of freedom. The USS Athena, on which he is stationed in Starfleet Academy, almost definitely has this accommodation, and the rest of the Academy's campus probably does as well. Considering Starfleet now also has its first photonic cadet in the form of Sam (Kerrice Brooks), it makes even more sense to prepare the campus and USS Athena in this way.
The Doctor probably also has a concealed mobile emitter (for safety)
Voyager included a handful of instances when it was smart for the Doctor to conceal his holographic nature. The device affixed to his upper arm often risked giving the game away, but the show proved it was possible to project an additional hologram around the emitter so that it just seemed like it was part of the Doctor's uniform. That could be what's going on in Starfleet Academy, only with a far more sophisticated version of the device.
Alternatively, the Doctor's Starfleet combadge could be doubling up as a mobile emitter. After all, the combadges do a lot more in the 32nd century compared to their 24th century counterparts. As well as being used for their traditional function of getting in touch with someone, they also serve as personal transporters that make getting from A to B especially efficient. Even Seven of Nine would be proud.
If a 32nd-century combadge is capable of all that, there's no reason one can't house the Doctor's program and project him into a space just as his original version of the device did. It's only a very small piece of tech, and the Doctor's program has likely ballooned since the 24th century, but Star Trek: Starfleet Academy's hyper-advanced sci-fi setting makes size no object.
Star Trek: Starfleet Academy is streaming now on Paramount+. New episodes will arrive every Thursday until the Season 1 finale on March 12, 2026.