Huh? How could [inexplicable thing in KSP] happen?

[ShadowZone]

Today I had a very bad day in KSP. Yesterday I was almost successful constructing a rather charming looking Tylo lander which I wanted to use during my entire Jool 5 Challenge. Thing was stable, had enough Delta V (in theory) and did I mention I liked how it looked?

I even designed a cruiser in which the lander almost seamlessly integrates. Thing weighed 1100 tons. Had to design a completely new launcher system for that kind of payload. Guess what? In tests I managed to get 1200t into orbit. Everything looked peachy.

HOWEVER: Today I wanted to test out my lander again and guess what? For some reason beyond my understanding the thing (which worked fine yesterday) is suddenly horribly unbalanced. Why? Why? I didn't change anything! Just went to sleep, went to work, came back home and started the game up again. CoM and CoT line up nicely in the editor. How can this happen?

In other "Huh?" news:

• My entire 29 flights were gone after a game crash, 38 kerbals were MIA. Luckily it was only my sandbox game where I try out new creations.
  
• For some reason I could not leftclick on any buildings of the KSC after the game loaded. Could not even go back to main menu. Had to bring up Task Manager to close and restart. Same thing. Had to load the latest quicksave to finally make it work again.
  
• During ascent, a Tri-Stack Adapter simply fell off. Along with the three attached nuke engines. Crashing into the launcher vehicle below. Blowing up spectacularly.
  

So... what were you biggest inexplicable "Huh?" moments in KSP? I can imagine I am not alone

[worir4]

I wonder what causes the lock up. I think it happens when you fire kerbals but i am not 100% sure.

[Norpo]

When my thrusters on my skycrane just froze, and the ship wouldn't move (it had wayyyyyy more than enough TWR.)

It eventually worked... But then the EXACT SAME thing happened to one of my boosters on the lifter to Moho.

In the end, I removed Kerbal Joint Reinforcement, and it worked like a charm. Hm.

[MGCJerry]

I have the "it used to work" issues all the time. Build a wonderful plane, that flies great at all altitudes. Then suddenly, after a number of reverts, it careens of the runway, flips end over end, accepts no pilot input, etc. I have to exit KSP then reload it and 95% of the time, things are fine. The other 5%, I have to rebuild.

[SkyRender]

Today I had a very bad day in KSP. Yesterday I was almost successful constructing a rather charming looking Tylo lander which I wanted to use during my entire Jool 5 Challenge. Thing was stable, had enough Delta V (in theory) and did I mention I liked how it looked?

I even designed a cruiser in which the lander almost seamlessly integrates. Thing weighed 1100 tons. Had to design a completely new launcher system for that kind of payload. Guess what? In tests I managed to get 1200t into orbit. Everything looked peachy.

HOWEVER: Today I wanted to test out my lander again and guess what? For some reason beyond my understanding the thing (which worked fine yesterday) is suddenly horribly unbalanced. Why? Why? I didn't change anything! Just went to sleep, went to work, came back home and started the game up again. CoM and CoT line up nicely in the editor. How can this happen?

In other "Huh?" news:

• My entire 29 flights were gone after a game crash, 38 kerbals were MIA. Luckily it was only my sandbox game where I try out new creations.
  
• For some reason I could not leftclick on any buildings of the KSC after the game loaded. Could not even go back to main menu. Had to bring up Task Manager to close and restart. Same thing. Had to load the latest quicksave to finally make it work again.
  
• During ascent, a Tri-Stack Adapter simply fell off. Along with the three attached nuke engines. Crashing into the launcher vehicle below. Blowing up spectacularly.
  

So... what were you biggest inexplicable "Huh?" moments in KSP? I can imagine I am not alone

I would guess that you have a few mods installed? I've noticed that some of them don't play nice. In particular, Karbonite tends to cause the Space Center buildings to not respond to right or left clicks on occasion. As well, many of the aerodynamic mods out there (yes, even FAR) can cause weird CoM/CoL issues. Just a few iterations of FAR ago, you had to completely redo any wing setup on any spaceplane if you wanted to make changes after loading a craft from a save, due to some small calculation errors.

As for my own impossible occurrences, I'd count my self-destructive asteroid catcher as one of them. If Time Warp is ever activated near it, the moment speed goes back to 1x, it rips itself apart violently. No real reason, mind. The claw just has that effect on ships.

[Ikaneko]

When I entered Minmus SOI at 0 m/s, when I had been entering at 200 m/s (no time warp in SOI crossing)

That was good though, because then I could choose my inclination.

[ShadowZone]

As for my own impossible occurrences, I'd count my self-destructive asteroid catcher as one of them. If Time Warp is ever activated near it, the moment speed goes back to 1x, it rips itself apart violently. No real reason, mind. The claw just has that effect on ships.

Oh yeah, that happened to me as well. Been a while, though

[Nemrav]

When my apollo recreation bent over 180 degrees (after the launcher, ie. command pod and lander in relation to the launcher) it was scary.... and hollarious.

had a screenshot but it got deleted

[tater]

I've had a few ships lately that have become "sticky" when you dock them together. I docked a couple mini-landers to a munbase, then landed the whole thing. Perfect, and the contract was fine. I had done this before, but forgot a part that was required on that, so I landed next to the first one. In the first base, Jeb transferred to the mini-lander (beats a rover to hop around nearby, though it does run out of fuel), undocked it (they were pointing sideways, along the ground), and my design as it so that when I put the gear down it stands up). Perfect.

2d base lands, now with the part needed to fulfill the contract. Do the same thing… mini-lander now a new ship, it is undocked, but it won't fall. I hit time warp… BOOM blows everything up, the parts even hit the other base 400m away and wipe that out as well. Yeesh.

[InterCity]

The jets of my craft tend to get stuck in the launch pad. A couple of clamps fixes it, but it's rather annoying when that happens in early career.

Also I once set up for a pefect duna transfer and went coffee hunting. The game crashed in the meantine (inexplicably) and when I reloaded, it required a 25 km/s burn. So I grinded my teeth and pressed mod+F12...

[Pecan]

For me at least 'inexplicable things' usually come down to memory issues (oldish 32-bit machine). Nearly all mods have had to go, my campaign crawls with 30-odd flights in progress and I'm worrying that soon I won't be able to play at all. Have to hope there'll be another memory-optimisation pass pretty soon during beta.

[jman508]

i lost my favorite sandbox save file due to that lockup issue

[BagelRabbit]

Hmmmm...

I would have to pick these guys as the most difficult-to-explain events that happened in KSP:

Kraken-baiting:

How to get Five-sided Symmetry (though it no longer works, so far as I can tell):

...and a newer one: Floating RCS Ports.

I seem to find a lot of these things...

[Bill Phil]

When thrusting and you don't move relative to a nearby object at all...

[AbacusWizard]

A couple of versions ago I had an ion-powered interplanetary spaceship that had been on a tour of Duna and Ike (maybe Dres too? I forget) and returned to Kerbin orbit. I detached the crew/lab section, de-orbited, deployed parachutes, and was gently floating down to an easy landing...

...and then the ground vanished. The whole planet was just plain gone, replaced by a small blue glow at the core. I stared dumbfounded as the crew/lab section reached elevation zero and exploded, killing everyone aboard and losing all science data.

It was at that point that I decided it was high time for me to update to the recently released new version and start a new career.

[tg626]

I've had that on a simple apollo style mun landing return...

[LordFerret]

This is an easy one, I can answer this..... because it's Monday.

[moogoob]

0.25, career mode, no mods other than Mechjeb and Hot Rockets. I had the game freeze up right when Jeb's second capsule landed on Kerbin. Upon reloading I got the science back, but Jeb was apparently eaten by the Kraken or something because only Bill and Bob were left to do flights. :/

[Scrat]

Once in an older version I went accidently on eva on reentry and jeb could not grab the pod and fell down. I thought this was the end but he had enough horizontal speed to bounce of many times from the ground and stand up after a very long facebrake. My only thought were: okaaaaay?!?

[Janos1986]

Eh, just a couple days ago while on a landing approach in an earlier version of my SSTO, as I was closing up at a 100 meters just above the runway at no more than 70m/s, suddenly my frontal surface of the left wing literally EXPLODES out of nowhere, yawing the whole plane to the right in the process and making it smash into the ground.

At the same time, my launchpad also EXPLODES FOR NO APPARENT REASON, since it's not even near my plane and it's empty.

Single Stage to Orbit: A Michael Bay movie.

Edited January 13, 2015 by Janos1986

[Madrias]

I've lost the entire right engine and fuel stack once on a 3 engine 2STO I was using (me and my bloody drop tanks...) and managed to save the plane. Mostly. I did the only thing I could do, I shut down the left-most engine by closing the remaining air intake group (so that it'd shut down hard, not spool down), turned to find a landing zone, and realized I'm out over the ocean, and I'm bleeding altitude rapidly. I fire up my rocket (LV-N, breaking my house rules that nuclear rockets are not to be detonated below 14KM), point the nose up, and let the rocket burn, trying desperately to make land as my drop tank (Rockomax Orange) drains rapidly. I reach bingo fuel in the drop tank, immediately cut it loose, and it bounces up into the belly of the plane, breaks the rocket free, shears off my tail surfaces, and adds insult to injury by flipping the plane upside down. So now I'm falling rapidly, I have no ability to pull up, I have one engine mounted on the left of my center of mass, and to make matters worse, what's left of a very expensive glider is still over water.

I pop my parachutes, they go into drag mode, and I can already tell there's a problem: my parachutes are floating above the plane's wing and fuselage. I now have to make a hard decision: sacrifice the science to save my pilots (mind, this was back in 0.23.5 where pilots didn't matter, but science did in Career Mode), or lose my science and my pilots and any chance at recovering some pieces of my plane.

I flip the proverbial safety cover (remove the cardboard surrounding and covering the button) then slap the Backspace key (Bound to Action Group Abort). The decoupler fires, sepratrons fire at low power for as long as they can, and I press AG6 to deploy the Emergency Chutes after the sepratrons burn out. Chutes deploy, but the rearmost two on the twin cockpit stack are, again, floating and sliding away from the plane. At this point, I'm hoping the cockpits slow down enough on full deploy to not be a problem. Chutes full deploy, the rear two explode, velocity dips below 7 m/s. They'll live. And what do I see floating lazily down next to my pilots? The upper wing assembly, dangling by half the parachutes, along with all the science containers still intact (some were used in flight, admittedly. Hence being worried.), falling ever-so-slightly faster than we are, landing in the water just before we get there.

Perhaps my most profitable failure.

As for strangest occurrance? Tail on my propeller plane (Yay for Firespitter!) falls off, behaves like I've stuck it on a mile long rope and dragged my camera way out from both the tail and the plane, like it was stuck in the middle of a bungee cord.

[soulsource]

The most spectacular thing I encountered yet was a reminder that one shouldn't taunt the Kraken by using physics warp while landing.

An unmanned probe, built for testing the LV-N engine on a sub-orbital trajectory was just on its way back, and I didn't have the patience to wait for it to land using the parachutes, so I enabled physics warp. Well, obviously due to a numeric inaccuracy the Kraken the thing collided with the ground, the nuclear engine exploded, and the probe went back upwards. At first I expected it to slow down again and crash into the ground, but it didn't. Obviously the Kraken held it in its grip and pulled it away from Kerbin in order to devour it. It kept on getting faster and faster, and a few seconds later it passed the orbit of Minmus - on a trajectory that looked pretty much like a straight line out of the Kerbol system... Since one should not watch the Kraken in action for too long, or risk damage to the save file sanity, I switched back to KSP (what was luckily possible) and abandoned sacrificed the probe to the Kraken...

[Engineer of Stuff]

What the heck is wrong with my orbit?

My orbit line showed up in Scenic View.

Edited January 14, 2015 by Engineer Of Stuff