On the Health and Wellness of Solar Panels

[AndrewBCrisp]

I'm not entirely sure if this qualifies as a bug or gameplay question, but I suspect half the problem may be my overlooking something so I'll stick it here in hopes it's in the right section.

I recently sent a Kerbal on a mid-term mission to the Mun. This mission involved a series of experiments that would be reset and repeated, so I loaded the spacecraft with a fair set of batteries and two SP 3x2 shielded solar panels to keep the whole thing charged. Up until this mission I have used either the OX-STAT solar panels or the OX 1x6 nonshielded solar panels with no issues.

I put the spacecraft into orbit, set up my Mun transfer burn, and after completing the burn, deployed the SP 3x2 panels. (Around this time, I had to do a quickload as I found my Mun transfer stage was not going to impact Kerbin as the mission called for). Time warp to the Mun's SOI and jettison the Mun transfer stage (it swung past the Mun and burned up in Kerbin's atmosphere as planned). I set up my orbital insertion burn, executed the burn without incident, everything working as intended.

Then I opened the service bay to get at my science instruments and rolled the spacecraft 90 degrees - and watched the panels break off and fly away, leaving my craft with battery power only.

At first I thought the craft's insertion burn must have weakened them, so I quickloaded to just after the Mun transfer burn and repeated everything, this time making sure to retract the panels back into their shields before executing the orbital insertion burn. The panels folded up, and the burn went off without trouble, but after that the panels registered as "broken". Bwuh?

I was able to complete the mission and retrieve my Kerbal by truncating the science end of things and juggling power between the capsule and the service module batteries, but this has made me wary of using the folding solar panels again. I don't understand what went wrong. Both SP and OX panels show the same panel strength, and the OX-series are working just fine on my probes. However, any probe with OX-series panels make the ascent safe inside payload fairings, and although they go through the same maneuvers I put my ill-fated spacecraft through, they use smaller engines (either the 48-7s or the LV-1, as opposed to the LV-909 on my Mun mission).

Possible theories:

1) The casings on the SP series solar panels are not working as they should, and the panels are being exposed to drag forces on ascent.

2) The greater thrust from the LV-909 engine is breaking the panels.

3) Quickload is breaking the panels. Not sure how or why.

4) The roll broke the panels. Again, not sure how or why.

5) I am running one mod - DMagic Orbital Sciences. Somehow it is interacting with my 1.0.2 save to break the panels.

I'm at a loss on this one. Thoughts?

Edited June 9, 2015 by AndrewBCrisp

[cybersol]

Are the service bay doors crushing the panels?

[AndrewBCrisp]

I don't believe so. I checked on my second quickload to make sure the bay doors don't interfere with the solar panels and vice-versa. I might have to run some experiments to see if I was mistaken.

[cybersol]

The service bay door crushing the casings or the panels themselves seems to be the most likely explanation. It may even be crushing them indirectly though some other parts that are clipped into the bay or near the doors. I don't use DMagic so I can't help there, but the other 4 reasons seem much less likely. Quickload or switching to a craft can sometimes summon the Kraken, but its usually been primed by the claw, the service bay, or tons of close together or clipped light weight parts (or ...).

[Snark]

Can't say what your problem is, but have a few observations on what it isn't.

It's not the panels getting "weakened" by anything; I don't think KSP tracks degradation of physical strength. Any physical trauma they encounter either destroys them immediately, or leaves them unaffected.

It's not a problem of having passed through atmosphere during launch. I put unshielded OX-series panels on my craft all the time (not even inside fairings), and never have a problem.

It's not a problem with the engine being too strong. G-shock doesn't hurt deployed panels, as long as they don't collide with anything. I've made crash landings that destroyed the bottom part of the craft but left the deployed panels intact (at least until the craft flipped and they hit the ground). I've played around with the Karbonite+ mod, which has some engines that let me pull over 20 G's... no problem for panels.

If I had to guess, it would be what the other folks here have suggested, some sort of clipping issue.

[Two]

If it involves a service bay, it is usually a clipping issue. If even a single pixel intersects with the bay, many fun things will happen.

[Coga19000]

In addition to the aforementioned clipping, the OX 3-2 has a much wider profile than the 1-6. Therefor, even though it doesn't clip during deployment, it may clip while tracking the sunlight.

[viktor19]

Are the service bay doors crushing the panels?

Happened to me one time while opening the service bay. Praise the F9!

[Agate]

opened the service bay

opened the service bay

opened the service bay

Service bays cause spontaneous explosions of spaceships. If any part of the spacecraft is anywhere near the doors when they open, kaboom. Goes double for parts that also move. If a part is attached to the outside of a service bay, or really anywhere near the bay, the game may treat it as being *inside*, rendering it unusable at best, kaboom at worst. And objects attached inside the bay but in the wrong place may rattle continuously, causing control difficulties at best, kaboom at worst.

Edited June 9, 2015 by Agate

[AndrewBCrisp]

Thanks for the responses, everyone. The consensus appears to be the open service bay clipped with the panels.

I conducted some experiments this afternoon to check this. First up was bringing the Mun 4 spacecraft (sans launch vehicle) onto the launch pad and opening first the solar panels and then the service bay. Nothing broke, but then, the spacecraft was neither in motion nor were the panels actively tracking the sun.

Next up was putting the spacecraft in orbit and rerunning the tests there. I renamed the spacecraft Orbiter 13 and put it into a low equatorial orbit. Once there, I opened up the solar panels and performed slow, careful, maneuvers along the roll, pitch, and yaw axes. The panels remained intact and tracked the sun. I performed each maneuver after the panels had locked onto the sun and finished moving.

I then opened up the service bay, and repeated my maneuvers, again keeping things careful and no movements until the panels had finished lining up with the sun once more. Once again, no problems, the panels survived the experience.

One last test was to put the spacecraft into a 90 degree roll while the panels were still tracking the sun from a previous maneuver. That did it - both panels shattered.

So, taking all this into account with what everyone said about clipping, I would venture to conclude that a nearby open service bay, plus actively tracking panels, plus a maneuver, combined to break the panels during my Mun 4 mission. I suspect opening the bay while the panels are actively tracking might also have the same result. Going forward I will have to be more careful with panel placement - shifting the panels further back might do the trick. Failing that, limiting my maneuvers seems to be the safest course.

Thanks again for your advice, everyone. This has been a real learning experience.

[ajburges]

In addition to the aforementioned clipping, the OX 3-2 has a much wider profile than the 1-6. Therefor, even though it doesn't clip during deployment, it may clip while tracking the sunlight.

The 1x6 can also clip if you use narrow margins. The axle is mounted on the edge of the box. Drove me nuts when I was crafting my Mk2 cargo bay docking ring sub-assembly. (a reaction wheel, docking port with aesthetic adapter, large radial battery, KER module, and two solar panels)

[Coga19000]

The 1x6 can also clip if you use narrow margins. The axle is mounted on the edge of the box. Drove me nuts when I was crafting my Mk2 cargo bay docking ring sub-assembly. (a reaction wheel, docking port with aesthetic adapter, large radial battery, KER module, and two solar panels)

Well obviously, but the 3x2 had a shape that just makes it that much easier.

Oh, and another solution to the OP: you can always try retracting the Panels while doing critical maneuvers.

Edited June 10, 2015 by Coga19000

[mrclucks]

I've encountered a similar problem. Built an interplanetary science module design to reenter. There was a 2.5 service bay with a science Jr below it, 6 radially attached to the science bay, and parachutes on top of the radially mount science bays. Opened the service bay and the parachutes starting freaking out for a little, but then calmed down. Closing the bay doors did the same thing but nothing broke. After reentry I staged the parachutes but moat refused to open, so i reverted and added a battery block to lower the science bays, which solved the problem.

My solution is to move the solar panels away from the service bay

[Sharpy]

I don't know... my fuel truck, a fully unmanned vessel with no cargo bay, has a long row of 1x6 solar panels along both sides (to give the refinery an extra kick of power while picking fuel). And about 5 of those, at random, are stuck. Trying to open them results in a message "cannot extend solar panels while they are being stowed" or something along these lines. And really, there's a bunch of them but only these 5 are affected, at random locations in the lines. And I'm pretty sure I didn't hit them with anything, because the truck was launched with no stages above it, and it landed on its wheels on Minmus, rather softly too.