If they're not appearing, don't stay in one place and board flip. I'm not certain, but it's entirely possible that ascension missions are suffering from the same glitch that makes Combat missions refuse to spawn for certain factions while at War: some factions simply never spawn certain mission types, no matter how much you board-flip them. And it doesn't seem to be consistent between players, so don't rely on other players posting "Oh, just go to system Xxyyzz, they have plenty of ascension missions there" - because they might have them there for that player, but not for you. So, fly your spaceship around and visit other systems. Systems with multiple Fed factions in Boom are your best bet, to increase your odds - factions other than the ruling faction can offer ascension missions. Maybe flip the board two or three times to be sure, then give up and move on to the next system.
For several days, I was at 100% post-commander with the Feds. I'd been doing one of those wing-delivery missions (fetching 1500 tonnes of gold) so was too busy to detour to wherever the Feds wanted me to go for the rank-up; I was flying about all over the place looking for more gold (it's surprising how quickly a tiny little extraction facility can be drained of gold). Visited over a dozen Fed systems in the process. I checked the mission board at each one, and only saw Ascension missions at one or two of them. The others (including the system where I was dumping the gold, which I visited repeatedly and had two Fed factions), nothing, never. Yesterday when I finally completed my gold mini-CG I flew about to find an ascension mission. Took five visits before I found one (I should have made a note where I'd spotted them earlier). But I'm sure if I'd stayed at that gold dump system and board-flipped, I'd have never found an ascension mission.
I thought there was something wrong with the boards but you're still seeing them. Guess I was very unlucky.
