aww

the guy already said that they have it turned on
@SamTheFox

@Zenithspeed @Luckwut
man you guys couldn't figure it out?

turn on has terrain physics in the properties tab

hmm... i've encountered this issue before, where there are no collisions even with terrain physics on
the only viable explanation i have is that you made too large of a height change, which does make sense in your case due to that massive crater
i've had planets with a ton of really harsh elevation changes and that usually resulted in the collisions breaking and reducing the height changes usually fixed it, so really you just have to make the crater less deep, which unfortunately might ruin the look but there's no other option :/

I've noticed that "auto-update gravity" also doesn't work for some reason

@Luckwut i've uploaded the planet, here:
https://www.simplerockets.com/CelestialBodies/View/99IB5Y/Henerth

@ilprofs07205 Huh that's weird, can i have the planet? (you can unlist it).

@Luckwut That's my problem. "Has Terrain Physics" is already on yet the craft still falls through.

Go to 'Properties' (Place where you can add description, Radius, gravity, etc) > Scroll down > Toggle 'Has Terrain Physics'