A check

If we’re flying or floating – or driving – we need to maintain what we’re running in. Let’s start with flying. Here’s Qantas in 2016, on the fleet they fly.

Line maintenance happens regularly; basically just dipstick tests (and if we never land the ’plane, we might do without wheels entirely). Ye olde B check be for olde modells, replaced by a “heavy maintenance” schedule as needed. For a (very) long flying craft, “line maintenance” can perhaps be done in-flight; heavy maintenance and checks C and beyond will, still, be done in hangars. For C, Qantas talks about every 18 months to two years depending on type of aircraft.

Now: back to our gas planet, Venus. I'd been talking Boeing turbofans as the baseline engine to keep heavy flights aloft (short of the ramjet). These use fuel, so need to refuel. Let us here assume, instead, a battery-powered propeller. Currently such offers less thrust and lift, but should keep aloft for longer. It still needs to rest now and again.

Qantas’ C schedule aligns nicely with Venus’ real year, the 584 day E/V synodic period. I’ve already mooted a floating warehouse, for a scrapyard; mechanics' shops can work just as well for healthy craft needing a turn-off and tune-up. As for line-maintenance: that should be done in-flight, and Venus can even be where the process gets tested.

That leaves the A check. Qantas, for the B[oeing-]737 craft, will park that ’plane every 8-10 weeks: changing filters, lubing hydraulics (I had to look up how to spell that…), and inspecting all the emergency equipment. I’m running the turbine on solar-panels and batteries, so I'd check these too. Under current tech, high-power batteries are solid-state and, therefore, degrade over time. That’s like, what, ten doodz to swarm the ’plane for five hours.

I agree that the filters are a problem; even 70 km above the surface. This particular planet is Venus, quite volcanic and with corrosive gasses even on a good day. Let’s agree on starting the A schedule no less than twenty days, 480 flight hours.

Still: as Qantas describes the A check, that could be done in-flight, too. Spaceflight is all about fixing floaty things.

Those ten guys will harpoon over during the daylight hours, and when the warehouse is nigh. The normal crew and passenger-manifest 'poon elsewhere, not to get underfoot ('though the captain and chief mechanic might stay. . .). Balloons are brought to keep the thing afloat, for the phase when the engine needs turned off.