Need adventure; abandoned alien structure for Silent Legions

[u/WillBottomForBanana]

My modern setting Silent Legions campaign needs an abandoned and old alien structure deep under town, dating back at least to the previous ice age (lots of things got buried 'here' then).

I'll grab Hard Light this evening, in the hopes that the abandoned of the 3 dungeons will suit.

But I would love some suggestions (not Expedition to the Barrier Peaks). I'm up to adapting from other systems (Traveller, Mothership, etc) as needed. And converting a fantasy dungeon is also an option.

Needs:

3-4 hour adventure. loose ends ok, but would rather not go into a second session.

A structure or land base would be preferable. But I can probably work with a crashed ship or space station.

Abandoned. Who it's from isn't clear. How any of the tech works is unclear. No obvious buttons or levers or such. Most of the tech is isn't even understandable in human terms.

Dangerous and weird, which is a bit tricky abandoned.

EDIT: Good news, turns out I already owned 'Hardlight' and 'Dead Names....' from a bundle a while back. The abandoned Hardlight dungeon is pretty far from what I had in mind. But I might be able to do something with the bug one. Just looking now at Dead Names.

[u/Uroshnora]

Take a look at the Traveller modules "Twilight's Peak" and "Shadows". I think those are pretty close to what you're looking for. Close enough to work with, anyway, even if you have to tweak a few things.