A friend took a uni course by a professor who'd been part of the cover mission for the Glomar expedition. Apparently, the professor was utterly unaware of either the true mission or the fact that there was a secondary mission and crew aboard the ship until after news broke well after the project had been completed. This is amongst the reasons that I find objectiosn from people within large organisations that some activity X, Y, or Z couldn't be happening "because they have seen no evidence of it" ... generally underwhelming: it often takes only a small group of people to actively organise such activity and even many participants may be unaware of the true goals or significance. The assassination of Kim Jong-nam, half-brother of Kim Jong-un, and the role of the two women who actually delivered the lethal binary nerve agent unwittingly (they thought they were participating in a hidden-camera prank television programme) also comes to mind:

<https://www.npr.org/2020/12/16/947261100/assassins-explores-...>

I'm aware of a few other instances of "scientific" missions whose actual (or at least massively significant) role was other-than-advertised:

- Manganese nodule mining. This was one of the putative scientific missions of Project Azorian itself.

- The US and Soviet space programmes. Both were in large part public demonstrations of various capabilities (lift capacity, reliability, targeting and control) associated with ballistic missile technology, and many space lift vehicles were themselves missile platforms (Mercury-Atlas, Vostok, Gemini, Delta). Communications and surveillance roles also developed, and of course the US Space Shuttle programme was highly influenced (and some argue greatly limited by) US Air Force requirements. <https://www.encyclopedia.com/history/encyclopedias-almanacs-...>

- Camp Century / Project Iceworm. I ran across a propaganda film years ago on YouTube, and immediately realised that this was not in fact some simple scientific programme --- there were far too many resources devoted to it. And of course it wasn't: it was instead a pilot test of deploying nuclear missiles on the Greenland ice sheet. The irony is that the project's failure, including ice cores collected during the mission did and still are contributing massively to scientific understanding of glaciation and climate change. So in fact the misdirection of a primary scientific objective does in fact turn out to be the most significant contribution of the project. I've commented on this several times on HN, going back to at least 2016: <https://news.ycombinator.com/item?id=12237745>. "As part of man's continuing efforts to master the secrets of survival in the arctic" indeed....

Video: <https://yewtu.be/watch?v=28NYczAuXl4>

- The Arecibo Observatory. Though it did have valid astronomical and scientific uses, the justification when built was to detect Soviet nuclear and missile testing by using the Moon as a mirror for activities which couldn't be directly observed from the US on Earth. (Later satellite observation platforms largely obsoleted this initial mission.) <https://www.thedrive.com/the-war-zone/37898/collapsed-arecib...>

- "Modern" art. At least in significant part, this was conceived of as a psychological operation (psy-op) by the US Central Intelligence Agency. <https://daily.jstor.org/was-modern-art-really-a-cia-psy-op/>

The fact that I was aware of most of these programmes before realising their dual nature, and was strongly and generally favourably inclined toward them as a child and younger adult, gives me pause when I run across contemporary phenomena with a similar shape and smell to them. (Camp Century would be the odd one out as I'd not known of it at all until seeing the YouTube video within the past decade or so.)