planet

Thanks for all of the useful suggestions. In the end I did this: I took the step to modify the physics.cfg to increase the pack and unload values after landing/splashdown to around 5km. It's not quite clear to me why it worked a few times without doing this, but maybe I was just lucky. I also set the capsule parachute to open higher than the cabins so it lands last. I added some extra boosters to give me more fuel for a deceleration burn and that allowed me to leave activating the decouplers to the last minute (about 20km); the parts then usually stay within 1.5km of each other. Finally, after touchdown I wait a bit for things to settle, recover the capsule and then the two cabins via the tracking station. This I do as quickly as possible (you don't even have to finish confirming the first before recovering the second). So far it has worked three times in a row without losing anyone, so fingers crossed!

I built a space tourism bus with two cabin modules stacked but I had problems with it on re-entry: it kept flipping and heading nose first and there wasn't enough drag to slow the whole thing and deploy parachutes. So I hit on the idea of using decouplers to split the whole thing up, attaching parachutes to each module individually. This worked the first time I tried it; the separate units floated down: the command module landed first and then I could watch the passenger cabins splash down and I recovered them and got my cash. Then on one trip I was a bit high when I split the modules. I was watching the passenger modules float down from the command module view and at some point on the way down (pretty close to the ground actually) the view flipped by itself and the passenger modules disappeared. When I went to the tracking station they had gone. The tourists were gone, nowhere to be seen. Not in the astronaut complex or anything. I concluded that the modules must have drifted too far away from the command module and that ksp "cleaned them up" or something, so on the next trip I waited until the last minute before splitting the modules. It worked and I recovered the passenger cabins fine. Next trip, I did the same thing. The cabins were never more than 1200 meters away from the command module, but this time the view flipped again and the passenger cabins disappeared. I went to the tracking station and they were there though, but some time after (before I could recover them) they disappeared from there as well. I am aware there is some problem/feature that prevents you from recovering parts, but I thought it was related to the distance between the part and the main rocket, but that appears not to be the case here. Any idea what is going on?