What happens with asteroids in-game once you "delete" them in the tracking station?

[TanDeeJay]

Just a question about asteroids.

I'm wondering what does the game engine do with them once you delete them in the tracking station?

It states that "you might not be able to find them again"... Space is big and finding an untracked object is of course like finding a needle in a haystack, or is it actually suggesting that the game engine removes them from the object list so you reallly won't be able to find them again?

I have this qestion because I have a number of ore-depleted asteroids in orbit around kerbin, and wondering what to do with them. if I delete them, does the game still internally track them, so that they could be a navigational hazard whenever I head away from kerbin?

I guess this all comes down to what are asteroids (at a technical game-engine level) are they objects that are created when you 1st start the game, and there are a finite number of them in the solar system? or do they get randomly generated everytime the game engine decides you "detect" an object?

[Superfluous J]

It never occurred to me that you could stop tracking an asteroid that you had clawed to. I figured that at the point you entered its physics bubble, it became a craft and you were stuck with it.

You can find out yourself by looking for it in the persistent file after you stop tracking it and it goes away from the tracking station.

[eddiew]

I imagine you could klaw a small probe to one and terminate it rather than stop tracking... that should make it go away properly.

That said, the chances of a collision between things in orbit is very small. If you manage it, post pics, you'd probably be the first to  

[Laie]

2 hours ago, TanDeeJay said:

I guess this all comes down to what are asteroids (at a technical game-engine level) are they objects that are created when you 1st start the game, and there are a finite number of them in the solar system? or do they get randomly generated everytime the game engine decides you "detect" an object?

They are created when you first detect them, and destroyed when you lose contact.

Asteroids pop up (are created) randomly, and, if you do nothing, they will just disappear (be destroyed) after a while. If you start tracking an asteroid, it will not vanish for as long as it's tracked. Once you stop tracking, it may disappear. Most (all?) asteroids are projected to enter Kerbin's SOI, and providing they survive the encounter, they are usually deleted soon after. I guess any asteroid that isn't expected to do a close flyby within a given time frame is up for deletion.

Once you stick a claw to an asteroid, it becomes part of a Vessel and can be destroyed like a vessel.

I honestly don't know what happens when you un-claw it. I expect that it will be treated like debris, but really don't know.

[TanDeeJay]

 

1 hour ago, eddiew said:

I imagine you could klaw a small probe to one and terminate it rather than stop tracking... that should make it go away properly.

That said, the chances of a collision between things in orbit is very small. If you manage it, post pics, you'd probably be the first to  

 

Thats just it, I have a couple of asteroids in orbit that have run out of resources, that I have declawed, which was why I was wondering what happens.  I have had a collision with some space debris, but that was because I was oriented in a prograde direction when I decoupled an empty 3.75 to 2.5m fuel tank adapter I was using for aerodynamics...  the decoupler ejected it quite a distance, and I promptly forgot about it and then started burning prograde, and the empty fuel tank then prompty took out a solar panel on my ship .  I've seen Mun and minimus get in the way when I've been trying to define maneuvers.  I imagine that a gauntlet of prograde orbit asteroids which don't show up when defining maneuvers could get in the way without you knowing until its too late.  Normally asteroids are not in a prograde orbit, so would be far less likely to be navigational hazards, but so far, all the asteroids I've caught I've pulled into a prograde orbit... thus poluting that prograde orbit space...

so... what happens when you launch prograde and retrograde into LKO?  2 ships flying past each other at 5k/s... 

[TanDeeJay]

49 minutes ago, Laie said:

Once you stick a claw to an asteroid, it becomes part of a Vessel and can be destroyed like a vessel.

I honestly don't know what happens when you un-claw it. I expect that it will be treated like debris, but really don't know.

That was why I asked the question... I have a couple of asteroids I've depleted the resources of which are in prograde orbits... 1500km and 2500k orbits so was wondering if I deleted them, they would then cease to be...

I just tried in the tracking station to delete the 2500k orbit asteroid, and it gave the warning about terminating a ship also killing any crew on board, so your right, it does treat them like debris. but tracked asteroids that have not been captured, just stop being tracked, and remain visible from the tracking station for a while.

[Loskene]

8 minutes ago, TanDeeJay said:

so... what happens when you launch prograde and retrograde into LKO?  2 ships flying past each other at 5k/s... 

If the intercept velocity is high enough there's a decent chance they'd "collide" in between physics steps and simply phase right through each other without registering a hit. This is usually the case for "head-on" collisions in LKO, and it makes testing these scenarios rather difficult at times. If you wanted to ensure a hit at a high velocity but not so high the physics calculations can't keep up, you can have both objects travelling in identical orbits but at a different inclination to one another. Can be hard to get the timing right but you're guaranteed quite the fireworks show at the crossover point, and the impact velocity can be altered by adjusting the relative inclination, so you can find out exactly where the clipping threshold is where the objects are moving too fast to impact each other. 0 relative inclination obviously has a relative velocity of 0, the objects would be in exactly identical orbits and never meet, and 180 degrees relative inc being the prograde-retrograde impact trajectory where, ironically, the objects may never meet either.

Although orbital debris strikes of sizeable objects in real life are quite rare, in KSP there are a few factors that make them significantly more common, and I've had a few very close calls myself as proof. Lack of axial tilts and most bodies in the system being on the same plane mean most of your vessels will tend to launch into the same orbital ranges with little deviation from the ecliptic, and Kerbin being so much smaller than Earth there's just a bit less space for everything to get lost in. Still though, unplanned encounters with spent rocket stages and debris in LKO are uncommon, though asteroids obviously present a much bigger target.

[TanDeeJay]

just tried 2 probes at 80km, one prograde one retrograde... velocity difference when they passed was a little over  4500m/s.  didn't have the camera angle right, so briefly saw about 3 frames with the other probe zooming past...

at that speed, once less than 4k, they are past you in less than a second... you might be quite right about moving so fast that the physics calculations miss the collision.   I have the Electric engine on my probes with 21k delta V, so plenty of dv to play around with

[eddiew]

2 hours ago, TanDeeJay said:

I've seen Mun and minimus get in the way when I've been trying to define maneuvers.  I imagine that a gauntlet of prograde orbit asteroids which don't show up when defining maneuvers could get in the way without you knowing until its too late.  Normally asteroids are not in a prograde orbit, so would be far less likely to be navigational hazards, but so far, all the asteroids I've caught I've pulled into a prograde orbit... thus poluting that prograde orbit space...

so... what happens when you launch prograde and retrograde into LKO?  2 ships flying past each other at 5k/s... 

Hitting Mun is easy - it's a couple of hundred km across.

Hitting another ship, maybe 10m across if it's a real biggie, with another ship, is very, very unlikely unless you decouple two vessels and then just leave them to float. In which case the eventually collision would be super slow because they're basically co-orbital anyway.

And while theoretically you could get to the point of Kessler Syndrome, I suspect KSP would grind to a halt and die before that happened. You'd need thousands of rocks in identical equatorial orbits before you had a significant chance of hitting one during an ejection burn.

Personally I'd call it an experiment. Leave them there and see if you can hit any  

[Loskene]

5 minutes ago, eddiew said:

And while theoretically you could get to the point of Kessler Syndrome, I suspect KSP would grind to a halt and die before that happened. You'd need thousands of rocks in identical equatorial orbits before you had a significant chance of hitting one during an ejection burn.

Personally I'd call it an experiment. Leave them there and see if you can hit any  

I had a career game where I decided not to clean up any orbital debris and see what happened first: Kessler cascade or the game refusing to load anymore.

It ended up being the latter, as you might have predicted, especially seeing as vessels outside render range are on rails and don't have any collision physics, so nothing can hit anything except the ship you're actively flying. But I did have some notable close calls. Now a bunch of rocks in mid/high equatorial orbits you're not likely to ever hit during an escape burn unless probability decides to play a joke on you, but in a low orbit (70-80km) even a single one can pose a serious hazard to rockets during ascent. At one point I had roughly half a dozen spent rocket bodies flying around this orbit, all within small fractions of a degree of 0 inclination. During one later launch I nearly had a heart attack while preparing for circularisation, as one of them belted past me in the blink of an eye, showing as a HUD element that briefly became a flash of metal streaking by before disappearing back into the distance. I couldn't tell you the exact closest approach, I was on ascent into the same orbit as the debris so the relative velocity was on the order of hundreds rather than thousands of m/s (still way too fast to track when you're not expecting it), but it was definitely less than 2km, I can tell you that much, probably closer. If it had been an asteroid, that launch would have been less close call more difficult letter to write to a Mrs. Kerman.

So yeah it's unlikely in general, but this game allows for a number of specific circumstances that'll shift that probability closer to 1 than 0, though you'd really have to do it "accidentally-on-purpose" to see it happen.

[Gapone]

I tried. You CAN start tracking them again :)

[TanDeeJay]

3 hours ago, Gapone said:

I tried. You CAN start tracking them again

Yes, as long as the tracking center remembers where they are. Once you stop tracking them it takes a while for them to disappear from the tracking station but they do eventually disappear... My question was about what happens to them after they disappear from the tracking station. Are they still there and a potential navigation hazzard or does the game truly delete them? My main concern was that equatorial orbit space getting poluted with depleted asteroids.

[MaverickSawyer]

There's a "signal strength" meter assigned to untracked asteroids... Once it ticks down to zero, they completely vanish from the game, never to be seen again.

[TanDeeJay]

10 minutes ago, MaverickSawyer said:

There's a "signal strength" meter assigned to untracked asteroids... Once it ticks down to zero, they completely vanish from the game, never to be seen again.

Is that signal strength based on when tracking was stopped or distance from the space centre?

But arent asteroids that you've docked with treated like a ship instead of an asteroid, so that whrn you delete it it truly deletes it and not just stop tracking with the signal strength decay? Which would mean deleting depleted asteroids would stop them being navigational hazards immediately

Edited January 5, 2019 by TanDeeJay

[MaverickSawyer]

If you've grappled the rock, it's handled as debris or a ship... Until you terminate it via the tracking station, it stays. Once you delete it, it's gone.

As for signal strength... No idea. I just noticed it last night while prepping for my upcoming ARM.

[Tyko]

This whole idea of "navigational hazard" isn't really a concern for me. The odds of accidentally hitting another orbiting body are astronomical NASA estimated that "more than 170 million bits of debris smaller than 1 cm (0.4 in), about 670,000 pieces of debris 1–10 cm, and around 29,000 larger pieces were estimated to be in orbit around the earth" Even with those incredible quantities collisions are very rare with only one major collision I'm aware of between two satellites.

With this in mind, having 1, 10 or even 100 asteroids floating around isn't going to present a risk worth worrying about. 

Consider that a object in a 100km orbit is traveling along a circumference of about 4400km. That object, at 100m across, is only occupying a given place along it's orbit 1/44000th of the time. For a collision to happen with it the craft's orbit would have to be within 100m of the object's orbit - any higher or lower and they'd miss each other anyway. So they have to be at that same altitude and in that exact 1/44000th portion of the orbit.