My Mun base exploded while trying to land another craft near it...

[wildkittyv1]

Hey guys,

Firstly, I\'ll just toss up a picture of the first 'craft' I got to the Mun to begin establishing a base there.

Anyway, that thing\'s been stable up on the Mun for a few in game days (it exploded once earlier while switching to it from another craft -what gives?) and I built another ship to land a smaller capsule next to it. I got the new payload to the Mun and landed down the first time about 1 km away, but I brought enough fuel to do a second takeoff and maneuver myself closer - it\'s right on the ridge of the large crater on the Mun\'s equator to give you a rough idea, but the second vehicle landed on the inside of the ridge so I couldn\'t see the other base.

Anyway, I\'m kind of hovering the thing over towards it, and I end up over-estimating how much thrust I needed to get there, so I miss it the second time. I land and come back for my last try as I\'m low on fuel and I keep getting slightly closer, but not as close as I wanted - the second time I was about 600m away.

So I come back in for the final try and everything is looking pretty solid. I get to about 600m away (coming in mostly vertical), at about 20 m/s, and the game locks up. I figure the landing craft is going to end up hitting the surface and explode on me - no biggie, I wanted to try again and get it right the first time, anyway. When the game stops lagging, there is an explosion, but it\'s from the base already landed/established, and then the second craft comes in explodes since I didn\'t have time to slow down. I was probably about 150m away on the horizontal when the explosion occurred.

Anyone know what gives? When the base exploded the first time, I figured it was because I switched from an accelerating craft (or one in orbit at a constant velocity) to that one, and the physics engine was carrying over some of the momentum or something. No biggie, I got the 10 tons of dead weight back up there and landed in roughly the same spot. I don\'t get what happened this time though, does the engine get wonky when vehicles get too close to each other on non-Kerbin surfaces? How close is too close? If this is the case, how does that 'Community Game' work where there\'s upwards of 5 craft in a small area?

Any help is much appreciated. Thanks

[G Addict]

The preestablished base may have clipped into the ground or just been plain unstable to begin with - IIRC it\'s at about 600m that the game loads physics for other craft, so it basically just realised that the previously non explody thing had, from, its point of view, been explody all along. So it exploded.

[maltesh]

I call it 'Explodey Rover Syndrome,' primarily because most of the time when it happens, I\'m usually approaching the base in a rover.

What happens is that, for some unknown reason, the hgt = attribute in the persistence file on a landed craft gets incorrectly set. It\'s supposed to provide the height of the 0,0,0 point of the craft above the local terrain. When 'Explodey Rover Syndrome' occurs, it gets set to -1.

This attempts to put the craft entirely underground when the active scene comes closer than ~200m, resulting in its destruction.

If you\'ve got a backup or a quicksave from before the explosion occurred, you can fix it by reloading the quicksave or copying over the afflicted vessel, and, if neccessary, adjusting the value of the hgt = attribute until it\'s high enough that the base/debris/rover doesn\'t explode when you get closer than 200m.

[E. F. Kranz]

Yeah, it happens.

[wildkittyv1]

I call it 'Explodey Rover Syndrome,' primarily because most of the time when it happens, I\'m usually approaching the base in a rover.

What happens is that, for some unknown reason, the hgt = attribute in the persistence file on a landed craft gets incorrectly set. It\'s supposed to provide the height of the 0,0,0 point of the craft above the local terrain. When 'Explodey Rover Syndrome' occurs, it gets set to -1.

This attempts to put the craft entirely underground when the active scene comes closer than ~200m, resulting in its destruction.

If you\'ve got a backup or a quicksave from before the explosion occurred, you can fix it by reloading the quicksave or copying over the afflicted vessel, and, if neccessary, adjusting the value of the hgt = attribute until it\'s high enough that the base/debris/rover doesn\'t explode when you get closer than 200m.

I\'ve never really messed with the saves in this game, auto or manual. When I make a quick save does it make a copy of the persistence in the same folder with some sort of time stamp? Can I access this save at any time, or does the load feature only access the last save made, whether that save was made manually or automatically? I doubt I have a save of that time to access, but it\'s no biggie since landing that hunk o\' parts is actually a bit of a challenge, I would just like to avoid this happening in the future.

In regards to prevention, is there a way to 'safeguard' myself in a general way? If I went into the file and edited the heights to be 2 or 3 what the game saves them as, would they 'respawn' each time at that 2 or 3 above height (assuming its measured in meters and not by a coordinate measured differently) each time I got close enough to have the game load their physics/models? If this worked, would the game overwrite the edited height each time and, thus, risk this happening whenever I try to land something else nearby? I assume craft with proper legs would be able to survive a 3 meter drop from a standstill on the Mun.

Thanks for the suggestions, I\'ll look into what I can do. It\'s just a bit bothersome because I was really happy that I managed to get that close during a pinpoint landing on my first shot, and then it destroyed my most difficult payload to deliver. I don\'t mind bringing it up there once more, but I don\'t want to have to redo it too much since the decent from 50km takes me about a half hour because of its size and having to babysit it.

[maltesh]

Quicksave only makes one save, which is overwritten every time you quicksave again.

I really don\'t know what causes the hgt = attributes to be set to -1, so I can\'t really give any information on how to prevent it. And, if I recall correctly, if you set it too high, the base will drop from that height when the active scene approaches within 200m, which will result in its own problems.

IF you want to generally fix it if it\'s already happened, manually BACK UP the persistence file by copying the file to elswhere on your hard drive., find out what bases are afflicted by attempting to load them from the Flight Tracker screen, then restore from the backup and start tinkering. My general rule of thumb: All the parts that make up the vessel have a position = attribute with three numbers separated by commas, the second being the y- position. Find the Y-position of the lowest part attatched to the craft, flip the value to positive, and set the hgt = value a bit higher than that. If it explodes, restore from the backup and set it a little higher than that. If you screw it up, restore from the backup.

And yeah, if you\'re going to tinker with the persistence file, back it up somewhere safe first. I know, I mentioned it before, but it bears repeating. I edit it fairly often, and every so often, I still make a make a mistake that wipes the file and requires me to restore from the back up.