It's been years since the last project but I'd say for about ten or fifteen years. I'm not sure I still have a security clearance, though. Those things need to be renewed every now and then.
There have been some interesting assignments from them, I have to say. It's a shame they aren't all that common these days.
Can you give a general idea of what you worked on? When I had clearances it either maintaining spy planes or doing depot level rework of Fast Attack submarines.
Generally speaking, it was either about documentation systems for various branches of the military or - in a few cases - information modelling for specific situations involving logistics during peacetime. Troop movements, supplies, the right equipment in the right place. That sort of thing.
And there was one really cool project where we modelled a lot more than that. That's about all I'm allowed to say about that particular project, though.
I was involved in one Navy project, incidentally involving subs.
I've also trained people for various information-related tasks.