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Atmosphere doesn't take effect while in tracking station mode?


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Hello

I'm trying to land a vessel on Kerbin by using only the atmosphere to slow down. My PE is 61km and AP is ~300km. While orbiting around Kerbin my AP and PE slowly reduce as expected. 

It's a slow process and I'm trying to warp time but due to low altitude I'm limited to 4x. If I go back to the tracking station on Kerbin and monitor my vessel from there I can warp time faster but my orbit doesn't change. I tried a few passes and PE and AP didn't budge, as if there was no atmosphere to slow down my vessel. If I go back to flying the vessel then orbit changes as expected. 

Is this a known issue or am I doing something wrong?

Thanks!

Edited by traxtor
clarification
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4 minutes ago, James Kerman said:

Welcome to the forum, @traxtor.

When you leave your vessel, the game puts it 'on rails' - basically it is not affected by physics (or interactions with the atmosphere) anymore. I usually set PE to 50,000m or less to save time on aero braking unless I've run out of propellant.

Thanks, @James Kerman, that explains it. 

In my case i did ran out of propellant early. I could've improved my maneuvers on early save but figured why not try it. It's a fun game!

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Hi @traxtor

I think it as to do with the having to track all your hundreds of ships and debris at the same time.

The game just puts everything on rails. Easier that way.

 

And about that. One of my little frustration is having a ship refuelling with an ISRU.

It takes a long time so off to the station to warp time (The game won't know that there are night cycles and let the ISRU work full time). Simple enough.

But the station also doesn't update the mass of the ship so you don't know when it's fully loaded.

You have to be generous with time before going to go look (Have to remember to go peek daytime over there). And have to leave your little Kerbals extra months or years on some moon.

Maybe miss a transfer window.

 

C'est la vie.

 

ME

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If you want better Phys Warp Speeds, you could check out the Mod Better Time Warp. You can create custom warp speeds, noth for normal and physical warp. like 20x, 50x Phys Warp, etc.

Other than that you'll have to rough it out.

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17 minutes ago, 5thHorseman said:

You really haven't experienced KSP until you've spent more than 20 orbits cycling between physical and non-physical time warp.

God I once had a minor, uh, accident in LKO and had to aerobrake for a landing... with a 69km perikee (nice). 20 orbits? I wish.

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5 hours ago, traxtor said:

Hello

I'm trying to land a vessel on Kerbin by using only the atmosphere to slow down. My PE is 61km and AP is ~300km. While orbiting around Kerbin my AP and PE slowly reduce as expected. 

It's a slow process and I'm trying to warp time but due to low altitude I'm limited to 4x. If I go back to the tracking station on Kerbin and monitor my vessel from there I can warp time faster but my orbit doesn't change. I tried a few passes and PE and AP didn't budge, as if there was no atmosphere to slow down my vessel. If I go back to flying the vessel then orbit changes as expected. 

Is this a known issue or am I doing something wrong?

Thanks!

Whilst this has already been explained, I want to make an explanation that's a tad more detailed.

If you've ever used time warp while controlling larger vessels, you'll have noticed the game likes to lag. Not only that, but calculations are done less accurately leading to exacerbated wobbling and structural problems. If you set time warp to 100,000x while still doing physics calculations, then the game would probably crash, so at time warp levels over 4, the game stops calculating drag, joints, staging events, thrust and pretty much everything so all the game has to do is calculate encounters and escapes, and stop time warp when entering atmospheres so the game can calculate the effects of the atmosphere again.

If you stop the game from checking if the vessel is in the atmosphere by going into the tracking station then as a result nothing will be calculated and your ship will just remain in its current orbit until another celestial body captures the ship.

3 hours ago, Martian Emigrant said:

I think it as to do with the having to track all your hundreds of ships and debris at the same time.

The game just puts everything on rails. Easier that way.

Actually, if you don't time warp at all, anything that is outside of a certain radius of your vessel is not calculated. So, time warp is not needed for your vessel to be locked on rails.

Now that I think about it, I wonder what would happen if you entered the physics range of an object on the exact same frame said object entered another SOI.

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1 hour ago, Bej Kerman said:

Whilst this has already been explained, I want to make an explanation that's a tad more detailed.

If you've ever used time warp while controlling larger vessels, you'll have noticed the game likes to lag. Not only that, but calculations are done less accurately leading to exacerbated wobbling and structural problems. If you set time warp to 100,000x while still doing physics calculations, then the game would probably crash, so at time warp levels over 4, the game stops calculating drag, joints, staging events, thrust and pretty much everything so all the game has to do is calculate encounters and escapes, and stop time warp when entering atmospheres so the game can calculate the effects of the atmosphere again.

If you stop the game from checking if the vessel is in the atmosphere by going into the tracking station then as a result nothing will be calculated and your ship will just remain in its current orbit until another celestial body captures the ship.

Actually, if you don't time warp at all, anything that is outside of a certain radius of your vessel is not calculated. So, time warp is not needed for your vessel to be locked on rails.

Now that I think about it, I wonder what would happen if you entered the physics range of an object on the exact same frame said object entered another SOI.

Thanks, that makes sense, it is a physics simulator after all. Although this makes me think are calculations reduced based on performance or are they always reduced under such condition. That is, are calculation reductions the same between a low spec and a high spec PC for example?

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15 minutes ago, traxtor said:

That is, are calculation reductions the same between a low spec and a high spec PC for example?

Yes, the rules for when and how accurately to simulate physics are independent of PC.   A lower-spec PC will sometimes need more real time to simulate the physics, so the KSP internal clock slows down as needed.

Graphics can also be the limiting factor sometimes, which complicates things, but the approach KSP takes is to simulate physics with a time step of 0.02-seconds of KSP internal time, however long that takes in real time, so that physics simulation gives the same result for all of us when we share craft (link to Squad's explanation) .

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21 hours ago, traxtor said:

Is this a known issue

21 hours ago, James Kerman said:

When you leave your vessel, the game puts it 'on rails' - basically it is not affected by physics (or interactions with the atmosphere) anymore.

Minor(?) addition: the game still checks if your vessel collides with a celestial body. Actually, it ckecks if it's too close to a body: on Kerbin, anything with an altitude <25-30km will be deleted. Near the Mun, it's ~10km IIRC.

So the behaviour is that a PE in the atmosphere has no effect, except when it's so deep that the game destroys your craft it in an instant. Either way, there will be no gradual decay of the orbit.

Note that this only applies to unattended craft (that is, you're watching it's orbit from in the tracking station or another far away vessel).

 

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