Death Station is great, but consider this: It's a bit of a dungeon crawl. That could be good to help a D&D player transition to Traveller by showing them something familiar and then overlapping the elements of Traveller that are very un-D&D, but it also could hinder them if presented all alone.
What do you think about a trio of adventures, each of which introduces them to a different style of Traveller role playing? A more sandboxy adventure might be nice to include, and... a third type? I'm a big fan of both Flatlined and Islands in the Rift as intro adventures because they enable newcomers to play with most of Traveller's bells and whistles. Maybe those two as well.
I totally agree. on the Sandbox thing. Something along the lines of the original Phandelver sandbox seems like a good idea: it was a key part in D&D 5e's success, after all. A setting, initially constrained, with a manageable set of strongly differentiated NPCs and with a choice of 2-3 tasks along classic Traveller adventure patron lines, pretty heavily signposted. Those would then unlock another set of more involved (and challenging or dangerous tasks. Something to demonstrate how deadly unarmoured combat is would be handy, with a one-off safety net (maybe it happens in the foyer of a clinic with a TL14 autodoc

)
As one of the tasks the players are introduced to the (currently broken) spaceship that could possibly come from their chargen. But it is broken so 2 more tasks that get it fixed, before a final adventure offworld, or even making a jump to another system.
So a widening world with each set of tasks leading the players
and GM through how to run - and play in - Traveller. Justin Alexander has written well about the need to explain how to run TTRPGs for the new GM, since it is not as obvious as we all think!
Death Station is fun, and can work with an experienced GM knows how to play up the horror (it so happens that I run it again last week with a party in their fifth-ever session, and had to make a few additions and some changes to pacing). But there is a
lot of white space. As you say, it looks like a dungeon crawl but one with a lot of empty rooms out of the box, only a very few encounters, and those on only two notes. For a dungeon crawl it also lacks some of the tonal variation that a good crawl has, and the antagonists are probably challenging for a newbie GM (playing episodic drug psychosis is tricky!)
People often suggest Flatlined, too, but jings: three fights with as many as 20+ participants in each is tricky for the most experienced GM!