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[old thread] Trajectories : atmospheric predictions

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Hi, I absolutely love this mod, thank you so much for it.

I just have one question, I'm trying to understand why I don't see trajectory information calculated past the atmospheric encounter on a fly-by.

The image below shows it, that altitude isn't pulling the vessel in for a landing (there's no 'X' anywhere), but there's no white on the far side of it (presumably that trajectory will carry me out of Laythe orbit).

I'm trying to set up an aerobrake on Laythe that puts me on course for Tylo, but fly-by's like this don't seem to work the way I would expect.

http://i.imgur.com/q6UiJPm.png

Thanks!

David

You may need to adjust some options to show more patches (under Settings) and/or select 'Complete' at the top of the menu.

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Well herp a derp, can't believe I missed that. Truthfully though, all mods should be available through CKAN packages.

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Hi !

Thank you for working on this awesome addon, it is very usefull to manage to land my launcher near KSC but since 0.90 it does not work properly.

Here is what happens when I try to land my ship :

- Trajectory before reentry, I mark the predicted impact as target :

F9341E5EB0ED7E2741483D2FED11988532FDEF54

But in the end, I land near KSC, on the wrong size of the montains :

2048x1052.resizedimage

Here is my ship :

2048x1052.resizedimage

You can download the ship there :

http://www.amis.tv/~pamynx/KSP/Venicia%2014.craft

You should not have much problem to launch it:

-In the beginning, just keep the liquid engine low to keep a TWR ~ 1.5.

-Go full power once solid boosters are off and start your gravity turn.

-You should read a circular orbit of 75x75 km.

-Drop the payload.

-To go down, brake to a 75x55 km orbit when at 90°E.

-Keep heading prograde.

-And you should hit the ground near KSC.

All along the descent, the landing prediction will move to go very far away from the real landing place and that is quite annoying because if I land on the wrong side of the mountain my connection will be cut and I wont be able to open the chutes, and the ship breaks when landing in the water...

I play with KSP 0.90.

Using the following addons :

FerramAerospaceResearch : http://forum.kerbalspaceprogram.com/threads/20451-0-90-Ferram-Aerospace-Research-v0-14-6-12-27-14

DeadlyReentry : http://forum.kerbalspaceprogram.com/threads/54954-0-90-Deadly-Reentry-v6-4-0-Dec-16-2014

Engineer : http://forum.kerbalspaceprogram.com/threads/18230-0-25-0-90-Kerbal-Engineer-Redux-v0-6-2-12%280-25%29-and-v1-0-14-1%280-90%29

PreciseNode : http://forum.kerbalspaceprogram.com/threads/47863-0-90-0-Precise-Node-1-1-2-Precisely-edit-your-maneuver-nodes

ProceduralFairings : http://forum.kerbalspaceprogram.com/threads/39512-0-90-Procedural-Fairings-3-11-manual-shape-controls-%28December-17%29

TriggerTech : http://forum.kerbalspaceprogram.com/threads/24786-0-90-Kerbal-Alarm-Clock-v3-2-2-0-%28Jan-11%29

TAC LS : http://forum.kerbalspaceprogram.com/threads/40667-0-25-TAC-Life-Support-v0-10-1-10Oct-No-Win64-Support

RemoteTech : http://forum.kerbalspaceprogram.com/threads/83305-0-90-0-RemoteTech-v1-6-0

SCANsat : http://forum.kerbalspaceprogram.com/threads/80369-0-90-SCANsat-v8-1-Real-Scanning-Real-Science-at-Warp-Speed%21-Dec-19

Trajectories : http://forum.kerbalspaceprogram.com/threads/104694

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Hi !

Thank you for working on this awesome addon, it is very usefull to manage to land my launcher near KSC but since 0.90 it does not work properly.

Here is what happens when I try to land my ship : {snip}

Known issue. It's because of FAR. Possibly also helped by not setting an AoA for trajectories to use in the calculations.

The newest version(s) of FAR and NEAR have changed the way drag calculations are done and Trajectories does not take every calculation into account for the entire trip through the atmosphere, so it gets more inaccurate the longer (and faster) you travel through the atmosphere. Work is being done to try to mitigate this without reducing performance.

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Known issue. It's because of FAR. Possibly also helped by not setting an AoA for trajectories to use in the calculations.

The newest version(s) of FAR and NEAR have changed the way drag calculations are done and Trajectories does not take every calculation into account for the entire trip through the atmosphere, so it gets more inaccurate the longer (and faster) you travel through the atmosphere. Work is being done to try to mitigate this without reducing performance.

Ok thank you ! Tell if I can help making some tests.

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Feature proposal: Allow to set the color of navball markers in configfile. I'm using a custom navball texture with dark colors, so the markers are barely visible.

Otherwise, awesome plugin - thank you!

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Feature proposal: Allow to set the color of navball markers in configfile. I'm using a custom navball texture with dark colors, so the markers are barely visible.

Otherwise, awesome plugin - thank you!

Uhm.. that has absolutely nothing to do with this mod.

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Exactly. Since this mod adds those, i'm quite sure it has something to do with this mod.

The standard KSP markers are easily visible... its just those which this mod adds, that are "dark marker on dark navball"

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Ah, my mistake. I've never seen those markers. Guess I haven't yet needed to be that precise on landings yet.

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Hey, I just wanted to drop by and say this mod is quickly becoming one of my core mods to make sure I get on each install. At first I couldn't see the need for it, but now, seeing exactly where my craft will touch down has let me maximize my returns on reusable crafts to help me stretch that KSP Funds.

Thanks a bunch for making this!

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Is there any difference between 180 and -180 degree slider in entry orientation settings? And is it related to surface or orbital prograde marker? Still trying to figure out why I never hit initial red X (using NEAR) :( It almost worked for spaceplane (reentry heat didn't let me to follow trajectory navball marker, so I missed), but for regular backwards reentry ships it's total mess, also instead of planned aerobraking it may end up with unplanned landing.

Edited by Mystique

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I've made a pre-release that should fix the accuracy issues when using FAR. It shouldn't change anything for NEAR or the stock model (which were already working fine, right?)

It's available for testing here : https://github.com/neuoy/KSPTrajectories/releases/tag/v1.1.3-rc1

Seems stable to me, but I've really not tested in-depth.

I tested, much better now... thanks.

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I've made a pre-release that should fix the accuracy issues when using FAR. It shouldn't change anything for NEAR or the stock model (which were already working fine, right?)

It's available for testing here : https://github.com/neuoy/KSPTrajectories/releases/tag/v1.1.3-rc1

Seems stable to me, but I've really not tested in-depth.

Only tested on a Kerbin landing so far.

Works fine for me !

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Is there any difference between 180 and -180 degree slider in entry orientation settings? And is it related to surface or orbital prograde marker? Still trying to figure out why I never hit initial red X (using NEAR) :( It almost worked for spaceplane (reentry heat didn't let me to follow trajectory navball marker, so I missed), but for regular backwards reentry ships it's total mess, also instead of planned aerobraking it may end up with unplanned landing.

180 and -180 should give the same output (especially with version 1.1.3-rc1 which solved a small bug about that). Make sure you set ALL sliders to 180 for retrograde entry though (each slider influences a different altitude). Next version will include more easily accessible "prograde" and "retrograde" preset buttons for convenience and to avoid confusions. Of course, make sure you actually follow what you've planned (keep pointed perfectly retrograde if that's what you've planned). Also, some bug fixes in version 1.1.3-rc1 may help prediction accuracy (mostly for FAR, but some fixes may improve NEAR predictions as well).

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Version 1.1.3 released on Kerbal Stuff, see the changelog there. Most important ones : fixes for FAR, various accuracy fixes for all models, added prograde/retrograde preset buttons, possibility to set target using latitude/longitude (and preset for KSC), added experimental auto-pilot.

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Apparently, there is a bug with the auto-pilot, if you enabled it in the settings (don't know if anyone has found that yet anyway), the game lags when you use your vessel controls (keyboard, etc.), even if the auto-pilot is not actually turned on. If this happens, you can just disable it back in the settings. I don't know yet what the problem is.

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Will check tonight. Love this mod, I am usually able to land within 3 km of the KSC with it.

Question: It doesn't seem like the mod shows a prediction for vacuum bodies? Places like Minmus rotate quite quickly, would it be possible to display the impact spot on those? (Or was that handled in the latest update?)

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Will check tonight. Love this mod, I am usually able to land within 3 km of the KSC with it.

Question: It doesn't seem like the mod shows a prediction for vacuum bodies? Places like Minmus rotate quite quickly, would it be possible to display the impact spot on those? (Or was that handled in the latest update?)

It does work. For some reason though the impact spot X doesn't show up sometimes. If you turn on "body-fixed" mode, you'd be able to see your flight path relative to the surface and eventual impact spot.

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Will check tonight. Love this mod, I am usually able to land within 3 km of the KSC with it.

Question: It doesn't seem like the mod shows a prediction for vacuum bodies? Places like Minmus rotate quite quickly, would it be possible to display the impact spot on those? (Or was that handled in the latest update?)

You don't see the X on Minmus because it's frequently hidden under the bumps. I think the mod is drawing it on the "flats" level at all times. If you switch to "fixed body mode" your Trajectories orbit will look a bit weird but where it ends on Minmus WILL be where you will actually crash.

Er, land. :D

EDIT: Oops, ninja'd by over an hour.

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