Why is my engine exploding on approach to Moon??

[ToThaMun!]

I've been building this rocket for awhile now to get me landed on the moon. Finally got it all together. It gets into orbit easily, it has tons of fuel on the final stage for manuevering to get to the moon and then again has enough to obtain orbit and land. The problem is, when I begin my final approach to the moon my damn engine just explodes all of a sudden! What could be causing this?

Engine is the LV-909 " terrier " engine. It happens just all of a sudden when I'm at about 595m/s going around the dark side of the moon. It is becoming really annoying because it happened twice now as I am doing final manuevers. I have tons of fuel too like 150 units. So I can burn for quite awhile to do anything I want. I want to try and land and then take off again since it is a Satellite type craft and no Kerbals. I'm basically just making sure I actually CAN land, problem is I can't even get to that point since my engine just goes boom

Edited November 2, 2015 by ToThaMun!

[Mastikator]

Press F3 to find out what caused the explosion. It will say something like "Terrier exploded due to overheating/collision with x/structural failure/the kraken"

[ToThaMun!]

Press F3 to find out what caused the explosion. It will say something like "Terrier exploded due to overheating/collision with x/structural failure/the kraken"

Thanks, it happened again and this time I checked. It shows the FL-T100 fuel tank exploded due to overheating.

And this was even before approach. I have no idea what is going on.

[Kerbart]

Did you stir the oxygen tanks?

[ToThaMun!]

Did you stir the oxygen tanks?

Didnt even know that was a thing! lol. How do you do that?

[fourfa]

It's an Apollo 13 joke (a good one)

[Plasmaburndeath]

Didnt even know that was a thing! lol. How do you do that?

[scifi6546]

That was a joke, before you land check for a red bar on your engine. If there is a red bar that means that the engine is over heating.

[Plasmaburndeath]

Anyway once my main post is posted, some engines are very touchy on being left on. I have had to add a radiator to a engine to prevent it from Going BOOM before. Best bet is to do small bursts at full blast (Z and X) trying to keep it cool as possible. I think cooling should do more since as Kahn said... Khan: It is very cold in space!

[ToThaMun!]

This run it happened during a manuever millions of miles from the Moon. I dunno. I don't get it. The skin temp is like 293.3 degrees. Is that too hot?

[Snark]

That's really weird. A few questions:

- Are you running any mods that mess with game physics?

- Is there anything weird or special about your ship design? e.g. parts clipped inside other parts

- If you turn on the thermal debug info, does anything interesting show up for that tank before it goes book? You can turn it on by hitting alt-F12, then Physics, subsection Thermal, there's a checkbox that if you turn it on makes various thermal data.show up on parts' right click menus.

(Update) I see from your comments about skin temp that you must already know about thermal debug info. 293 degrees should be no problem at all, most parts can take 2000 degrees.

Edited November 2, 2015 by Snark

[Guest]

Heat is broken.

Random things explode at random situations.

Try disabling it.

[Snark]

Heat is broken.

Random things explode at random situations.

Try disabling it.

Well, that's putting it a bit strongly. Yes, there are some bugs, but they don't seem random to me. The main thermal problem I've noticed is that cubic and octagonal struts like to overheat and explode for no reason, but if I avoid those parts, I've never seen any unexplained thermal explosions since 1.0.4, and that's with a lot of hours. Certainly I've never seen any problems with fuel tanks or Terriers. So if the OP is having a frequent, easily reproducible problem, then there's likely some specific thing about his game that's triggering the bug. Would be interesting to narrow it down.

[ToThaMun!]

That's really weird. A few questions:

- Are you running any mods that mess with game physics?

- Is there anything weird or special about your ship design? e.g. parts clipped inside other parts

- If you turn on the thermal debug info, does anything interesting show up for that tank before it goes book? You can turn it on by hitting alt-F12, then Physics, subsection Thermal, there's a checkbox that if you turn it on makes various thermal data.show up on parts' right click menus.

(Update) I see from your comments about skin temp that you must already know about thermal debug info. 293 degrees should be no problem at all, most parts can take 2000 degrees.

Yeah I found out about the debug menu mode last night. So I checked that today. The moments before explosion have typically been in the 293-300. I just checked temps during liftoff which I think would be the highest and that particular tank got to 306.3 degrees. But no boom. It actually seems to happen around the time of a manuever. Theres a little hitch that occurs when you transition into the Moon orbit and I dunno, maybe there is something stuck inside my ship or something that bounces with the physics engine? My ship is ... unorthodox, but it works. When it blows up and I " revert to launch " the ship will bounce when the screen first comes on and the whole ship will come apart and explode lol.

Here is the final lander craft. 210 units of fuel and my menuever is already done that will get me to a moon approach. So tons of fuel left.

[GeneralVeers]

I've had this random-explosion problem on one of my previous rocket designs, and it seemed to be the result of parts installed too close together and being "through" each other (apparently the SAS ring is just a bit larger than the ore storage tank, so the side fuel pods and engines mounted to the storage tank were sticking through the SAS ring).

If it's a dorsal engine that's exploding, you might try a standoff mount so there's some distance between the engine and the main hull.

[ToThaMun!]

I cycled the parts again in the assembly stage but didn't find anything stuck anywhere or anything. Everything is latched on as it should be. I even added panels just in case lol.

But we'll see how this approach goes. So far so good. 214 units of fuel left and on a collision course with the moon.

- - - Updated - - -

Captured orbit with 140 units of fuel left. With this little engine can probably burn for another full minute + easy. Hope my engine stays put!

[magnemoe]

Never run into issues who is not caused by engines or by atmosphere. Except some launchpad explotions because of overheating.

And 2.5 meter service modules summons kraken if anything is in their line of sight but that is not overheating.

My only issue is that the 1x2 fuel tank and engine combination get very hot if burning long, LV-N get hot after 5 minutes burns but that is known.

The 505 is safe as an house regarding overheating as long as you stay out of Eve and Jool atmosphere.

Edited November 3, 2015 by magnemoe

[Snark]

Service bays are one area that is known to be buggy if things are clipping (though that usually results in things just flying apart, not overheating, at least from the posts I've seen). Do you have anything in those service bays that's "iffy"? (i.e. doesn't fit easily with plenty of clearance between the thing and the inner walls of the bay)?

On a totally unrelated note to your overheating problems, a couple of things that I was wondering from your screenshot:

- holy smokes, that's a lot of monopropellant. Any particular reason why so much? (or why any, given that there's no docking port on the ship)

- any particular reason for the "upper" landing legs where they can't reach the ground? I don't see any stack decouplers that would make them become ground-reachable.

- I really don't think you need those little radiator panels-- if you're only running a Terrier and aren't going to Eve or somewhere, they're not going to do anything helpful. Whatever's causing your thermal blowups is something sudden, buggy, and catastrophic, and I really doubt that those radiators are going to make any difference.

[Kerbart]

I think cooling should do more since as Kahn said... Khan: It is very cold in space!

...but vacuum is also a good insulator. The only way to lose heat is by radiation which takes fairly high temperatures to have a significant effect. An engine might quickly drop from near-melting to a mere boiling temperature but after that there can be a lot of heat lingering, meaning that the next time you fire it up it'll be a lot quicker at critical temperature.

Having said that, an LV-909 should not be exploding due to overheating.

[cantab]

The thermal system shows evidence of using a fundamentally flawed algorithm for the purpose. In less technical terms, it's a crock of dung.

[Gahooligan]

This run it happened during a manuever millions of miles from the Moon. I dunno. I don't get it. The skin temp is like 293.3 degrees. Is that too hot?

I wouldnt think so, it's listed with a max temp of 2000 i believe. Could be a glitch, did you try putting radiators on/near it?

[DancesWithSquirrels]

There are known problems with the 1.0.4 heat model, including an issue where having many parts connected to one leads to overheating - the rate of heat transfer is computed for each object pair separately, rather then en masse for the many-one connection, and things can quickly go boom in a feedback loop. Also cubic struts are particularly nasty in this regard.

Try the Stock Bug Fix modules - there's a fix for at least part of the heat feedback loop in that package, along with a lot of other very useful stuff.

The Klaw fix alone is worth the entire mod.

[A_name]

There is no reason why a Terrier engine would overheat to the point of exploding during a Mun run. Not even the Nerv overheats to that point on such relatively short burns. It has to be a bug or glitch. Sometimes this will happen when a part is slightly clipping into another. I would just disable max heat in the debug menu altogether at least until you're done with this particular mission.