GIlly is eating my probes!

[wibou]

Soooo I like to keep a probe in orbit around each celestial bodies, so when I get contract to "Science data from ...", it is be free money.

However, I can't seem to maintain a probe around Gilly for a very long time... Right now I am down to the FIFTH probe there and they always end up crashing.

According to various sources, Gilly maximum elevation is 6400 meters; so I always make sure to be at least 6500 meters high. As example, my last (the fourth one) probe was on a PE - 7200m / AP - 8500m orbit.

I was never able to witness the probe crashing, I just realize at some point it is no longer there... It usually takes a while (more than 100 Kerbin days for sure).

Each time I had a probe, I waited several orbit just to be sure it was stable and it seemed stable. Yet they all ended up crashing so far.

My fifth one is in way higher orbit I'd like (PE - 21000m / AP 25000m) to give it a chance to last (but even then I wonder if it will...).

I feel like the problem may be caused by the various physic engine imprecision; a difference of orbital speed of 0.5m/s around Gilly would be enough to down a probe (20.5m/s -> ~6700m orbit VS 20.0m/s -> crash) but I was never able to prove that theory.

I also observed that the orbit of the probe is ALWAYS wobbly around Gilly. The very same probe is stable around Eve, Duna or Ike but around Gilly, PE and AP move back and forth (even if the orbit is NOT perfectly circular). So another theory is that each "wobble" cause imprecision that are eating decimals until the probe is not longer in orbit.

Am I the first one to experiment that kind of issues? Any tips?

Edited January 31, 2015 by wibou

[Taki117]

Each body has a Minimum altitude for deletion (on Kerbin it's 22km) This is the altitude blow which any object greater than 2.5km away from the current active vessel will be deleted as "crashed" in the game engine.

EDIT: After a bit of research it seems like 8km is about the limit for Gilly.

Edited January 30, 2015 by Taki117

[wibou]

Each body has a Minimum altitude for deletion (on Kerbin it's 22km) This is the altitude blow which any object greater than 2.5km away from the current active vessel will be deleted as "crashed" in the game engine.

Soooo what you are telling me is that the deletion altitude for Gilly is ABOVE the minimum altitude to maintain a stable orbit?

Are you _sure_ about that? If that's so, then it is CLEARLY a bug.

But even if what you say is true, that does not explain why a probe can last 100+days around Gilly (Note: I wasn't in control of the probe all the time) and someday just crash suddently.

[Tex_NL]

For what you're trying to do you don't need to skim the surface, any orbit will do. The answer to your problem is staring you in your face. Go higher!

Taki is correct. All bodies have a minimum altitude. All unfocused objects below that are deleted.

[wibou]

Taki is correct. All bodies have a minimum altitude. All unfocused objects below that are deleted.

No sorry, that doesn't make sense, my problem is NOT that my probe get deleted when I change focus... they survive a very long time while I am focused elsewhere THEN crash although they were in stable orbit. I highly doubt this has anything to do with the deletion altitude.

EDIT: After a bit of research it seems like 8km is about the limit for Gilly.

Where did you find this information? That might have been my problem since all my probes so far had their PE lower than that.

But then, something is buggy since 8km is too high for some science instruments (thermometer) to work. So Gilly would be the ONLY celestial body where you cannot put a probe with a thermometer into a stable orbit.

Edited January 31, 2015 by wibou
typo

[Taki117]

Where did you find this information? That might have been my problem since all my probes so far had their PE lower than that.

But then, something is buggy since 8km is too high for some science instruments (thermometer) to work. So Gilly would be the ONLY celestial body where you cannot put a probe with a thermometer into a stable orbit.

Inference from the wiki. The minimum altitude for 5x time warp (Which is a known safe condition) is 8km. Gillys small size means that there is likely a very small margin between that and the maximum altitude for deletion.

[LordFerret]

I have a SCANsat probe parked in a stable orbit around Gilly, 250km. After finishing the low-res and then hi-res scans, I parked it back down there... I do so with all SCANsat probes. It's been there for quite a long while, MET 31+ years. Moho is the one I have a problem with... it seems to eat probes at any orbit I park them at. Nobody seems to be able to answer the question 'why', other than to suggest it's related to time-warping and the Kraken. Clearly, a game bug which needs to be addressed.

[Vanamonde]

Orbiting vehicles under a certain altitude (which is unfortunately obscure and different for each world) will indeed be deleted. There's no telling how long they'll last, and I have no idea why, but this is a very old KSP issue, and it definitely does happen. I never leave anything I want to keep orbiting under 10,000m around any world.

[wibou]

I see... So unlike Kerbin, the deletion of vehicle is semi-random... well that's a bummer.

And that also mean that thermometer are useless around Gilly (because the threshold for deletion is apparently HIGHER than the thermometer lower bound), so I won't be of any use there...

Well, I hope this get fixed in further update.

[SpaceNomad]

And that also mean that thermometer are useless around Gilly (because the threshold for deletion is apparently HIGHER than the thermometer lower bound), so I won't be of any use there...

No, that does not mean that. Deletion only happens when the craft is unfocused. So, you can still maintain lower orbits with an active vessel, make your measurements and then put the craft in a higher parking orbit, so it won't get deleted when "on rails".

[Windspren]

Does this mean that a Mun base would be deleted?

[Tex_NL]

No. Landed objects are not deleted.

[Alshain]

Also, the minimum altitude on the Mun is below it's highest peak, so an orbit there would be ill advised anyway.