So then there is trade to regulate. Though a very sporadic and specialized sort. In which case the tariffs arent for nothing.
...Probably not gonna see a whole lot of return on it though tbh. I imagine its massive one off purchases at random and a constant trickle of relatively low cost supplies for the few people manning the bases.
You're not entirely wrong, but there is a point to be made: scientific instruments
do have a lifespan. Some instruments are mission-critical and
must stay put depending on what the nature of their task is, regardless of the advances made in science and technology. Others, however, generally have a lifespan of say... 10-20 years, maybe more depending on how resilient the instruments in question are. They also require upkeep, as the USA's
Harmonised Tariff Schedule, adapted from the World Customs Organisation's
Harmonised System, has specific provisions regarding machine parts for repair. Those provisions allow for repair parts to be imported/exported with minimal or no customs duties. The USA's own export control laws
do complicate things somewhat, depending on the country of origin and where those instruments come from, where they're going, etc. That's a whole other can of worms that I'm not remotely qualified to talk about, though.
Disclaimer: I am not a licensed customs broker, nor am I an attorney-in-fact who does customs entries for 3PL companies. I am adjacent to those fields, however, and the recent tariff madness requires me to stay up-to-date for my job duties IRL. Make of that what you will.