Here's what a stardrive field "generator" (so-called in the popular press) looks like when it is (almost) ready to get to work. Coolant hoses have not yet been connected, retention rail and outer door are still off:
Pretty kewl, hey? The primary cavity, wrapped around the phantasmatron, is under the big cylinder and just above the fat electromagnet.
The thing we found in it is shown at right, not so far off actual size.
And here's the damage it caused. Gee, doesn't look like much, does it? It doesn't take much to gum up the whole works and there you are, a bajillion miles from nowhere, with a silly look on your face hoping the Captain is in a really happy mood and the Enviro gang hasn't messed up the greenhouse again.
The inside of a stardrive assembly is nasty -- oxidation and fine, fine, fine dust from the high-pressure filtered air, droplets of coolant and so on; so you wear nitrile gloves. Blue nitrile gloves, with heavier gloves over them so they don't get torn up quite as quickly. And you work in pairs. Just sayin'. (I swear I never chased no research subject or like that. It's a coincidence. Honest).
I'm reaching in through the hole left in the secondary cavity (after removing the tuning dome) with a hex driver to unbolt it from the primary. Note the ample, comfortable work space: that and the easy, short hours are a couple reasons why folks are not just linin' up to work in the Just-Barely-Faster-Than-Light Engine Room crew on this nation's starships -- or those of any other nation, most of which are, when compared to ours, frankly, goshawful.
5 months ago