Trajectories¶

Download: https://github.com/neuoy/KSPTrajectories/releases
Forum thread: https://forum.kerbalspaceprogram.com/index.php?/topic/162324-131-110/

Trajectories is a mod that displays trajectory predictions, accounting for atmospheric drag, lift, etc.. See the forum thread for more details.

This addon is not associated with and not supported by the creator of Trajectories.

The Trajectories API is accessed through C# reflection, and is designed for the current version. This means that future Trajectories updates may break this addon, in which case ADDONS:TR:AVAILABLE will return false. It is also possible for future versions of Trajectories to remain fully compatible.

Note

Trajectories only predicts the trajectory of the “Active Vessel,” which is the vessel with the camera focused on it. IMPACTPOS, PLANNEDVEC, SETTARGET, and CORRECTEDVEC will throw exceptions if you try to call them from an inactive vessel or if Trajectories has not calculated an impact position. You should always check if HASIMPACT is true before accessing these suffixes.

For example:

if ADDONS:TR:AVAILABLE {
    if ADDONS:TR:HASIMPACT {
        PRINT ADDONS:TR:IMPACTPOS.
    } else {
        PRINT "Impact position is not available".
    }
} else {
    PRINT "Trajectories is not available.".
}

Trajectories does its calculation based on the vessel’s current orientation. Any tiny change in orientation will change the prediction.

Accuracy is not guaranteed.

See this repository for an example of this addon being used to land a rocket on the launch pad: https://github.com/CalebJ2/kOS-landing-script

Trajectories Version Compatibility¶

The Trajectories mod went through some changes between Trajectories 1.x and Trajectories 2.x. These changes alter the way that the kOS Trajectories AddOn has to communicate with the Trajectories mod, and added new suffixes that kOS could use. However, for backward compatibility kOS will try to support an older version of Trajectories if that’s what’s installed. Places where a suffix only works with newer versions of Trajectories are noted below in the suffix table.

Access structure TRAddon via ADDONS:TR.

structure TRAddon¶

Suffix	Type	Description
`AVAILABLE`	`Boolean` (readonly)	True if a compatible Trajectories version is installed.
`GETVERSION`	`String` (readonly)	Trajectories version string.
`GETVERSIONMAJOR`	`ScalarValue` (readonly)	Trajectories version Major.
`GETVERSIONMINOR`	`ScalarValue` (readonly)	Trajectories version Minor.
`GETVERSIONPATCH`	`ScalarValue` (readonly)	Trajectories version Patch.
`ISVERTWO`	`Boolean` (readonly)	True if Trajectories version is 2.0.0 or above.
`ISVERTWOTWO`	`Boolean` (readonly)	True if Trajectories version is 2.2.0 or above.
`ISVERTWOFOUR`	`Boolean` (readonly)	True if Trajectories version is 2.4.0 or above.
`HASIMPACT`	`Boolean` (readonly)	True if Trajectories has calculated an impact position for the current vessel.
`IMPACTPOS`	`GeoCoordinates` (readonly)	Returns a `GeoCoordinates` with the predicted impact position.
`TIMETILLIMPACT`	`ScalarValue` (readonly)	(only TR 2.2.0 and up) Seconds until impact.
`RESETDESCENTPROFILE(AoA)`	None	(only TR 2.4.0 and up) Reset all the Descent profile nodes.
`DESCENTANGLES`	`List`	(only TR 2.4.0 and up) Descent profile angles.
`DESCENTGRADES`	`List`	(only TR 2.4.0 and up) Descent profile grades (Retro or Pro).
`DESCENTMODES`	`List`	(only TR 2.4.0 and up) Descent profile modes (AoA or Horizon).
`PROGRADE`	`Boolean`	(only TR 2.2.0 and up Descent profile all prograde.
`RETROGRADE`	`Boolean`	(only TR 2.2.0 and up Descent profile all retrograde.
`PLANNEDVEC`	`Vector` (readonly)	Vector at which to point to follow predicted trajectory.
`PLANNEDVECTOR`	`Vector` (readonly)	Alias for `PLANNEDVEC`
`SETTARGET(position)`	None	Set Trajectories target.
`HASTARGET`	`Boolean` (readonly)	(only TR 2.0.0 and up) True if Trajectories target position has been set.
`GETTARGET`	`GeoCoordinates` (readonly)	(only TR 2.4.0 and up) Returns a `GeoCoordinates` with the Trajectories target position.
`CLEARTARGET()`	None	(only TR 2.4.0 and up) Clear Trajectories target.
`CORRECTEDVEC`	`Vector` (readonly)	Offset plus `PLANNEDVEC` to correct path for targeted impact.
`CORRECTEDVECTOR`	`Vector` (readonly)	Alias for `CORRECTEDVEC`

TRAddon:AVAILABLE¶

Type: Boolean
Access: Get

True if a compatible Trajectories version is installed. If this is not true, then none of the other suffixes listed here are safe to call (they can cause error and program crash).

TRAddon:GETVERSION¶

Type: String
Access: Get

Only gives the correct answer for Trajectries version >= 2.2.0

For earlier versions, it gives a hardcoded fixed answer, as follows:

For any Trajectories version earlier than 2.0.0, this returns the empty string “”.
For any Trajectories version at least 2.0.0 but below 2.2.0, this returns the ‘rounded off’ answer “2.0.0” regardless of the precise version number within that range.
If your Trajectories version is at least 2.2.0 or above, this returns the specific version string correctly.

For cases where you need to check for a known minimum Trajectories version, it is probably better to use the specific boolean suffix for that version (for example, TRAddon:ISVERTWO, or TRAddon:ISVERTWOTWO etc.)

TRAddon:GETVERSIONMAJOR¶

Type: Scalar
Access: Get

Only gives the correct answer for Trajectries version >= 2.0.0

For earlier versions, it gives a hardcoded fixed answer, as follows:

For any Trajectories version earlier than 2.0.0, this returns “0”.
If your Trajectories version is at least 2.0.0 or above, this returns the specific version major value correctly.

For cases where you need to check for a known minimum Trajectories version, it is probably better to use the specific boolean suffix for that version (for example, TRAddon:ISVERTWO, or TRAddon:ISVERTWOTWO etc.)

TRAddon:GETVERSIONMINOR¶

Type: Scalar
Access: Get

Only gives the correct answer for Trajectries version >= 2.2.0

For earlier versions, it gives a hardcoded fixed answer, as follows:

For any Trajectories version below 2.2.0, this returns “0” regardless of the precise version number within that range.
If your Trajectories version is at least 2.2.0 or above, this returns the specific version minor value correctly.

For cases where you need to check for a known minimum Trajectories version, it is probably better to use the specific boolean suffix for that version (for example, TRAddon:ISVERTWO, or TRAddon:ISVERTWOTWO etc.)

TRAddon:GETVERSIONPATCH¶

Type: Scalar
Access: Get

Only gives the correct answer for Trajectries version >= 2.2.0

For earlier versions, it gives a hardcoded fixed answer, as follows:

For any Trajectories version below 2.2.0, this returns “0” regardless of the precise version number within that range.
If your Trajectories version is at least 2.2.0 or above, this returns the specific version patch value correctly.

For cases where you need to check for a known minimum Trajectories version, it is probably better to use the specific boolean suffix for that version (for example, TRAddon:ISVERTWO, or TRAddon:ISVERTWOTWO etc.)

TRAddon:ISVERTWO¶

Type: Boolean
Access: Get

True if the Trajectories mod is at least version 2.0.0 or above.

TRAddon:ISVERTWOTWO¶

Type: Boolean
Access: Get

True if the Trajectories mod is at least version 2.2.0 or above.

TRAddon:ISVERTWOFOUR¶

Type: Boolean
Access: Get

True if the Trajectories mod is at least version 2.4.0 or above.

TRAddon:HASIMPACT¶

Type: Boolean
Access: Get

True if Trajectories has calculated an impact position for the current Vessel. You should always check this before using impactPos, plannedVect, setTarget, or correctedVect to avoid exceptions.

TRAddon:IMPACTPOS¶

Type: GeoCoordinates
Access: Get

Estimated impact position.

TRAddon:TIMETILLIMPACT¶

Type: Scalar
Access: Get

Did Not Exist in Trajectories before 2.2.0!

If :attr:`TRAddons:ISVERTWOTWO` is false, using this suffix will cause a runtime error.

Gives you Trajectories prediction of how many seconds until impact on ground or water.

TRAddon:RESETDESCENTPROFILE(AoA)¶

Parameters

AoA – Scalar

Returns

None

Did Not Exist in Trajectories before 2.4.0!

If :attr:`TRAddons:ISVERTWOFOUR` is false, using this suffix will cause a runtime error.

Resets all the Trajectories descent profile nodes to the passed AoA value (in Degrees), also sets Retrograde if AoA value is greater than 90 degrees (PI/2 radians) otherwise sets to Prograde.

TRAddon:DESCENTANGLES¶

Type: List
Access: Get/Set

Did Not Exist in Trajectories before 2.4.0!

If :attr:`TRAddons:ISVERTWOFOUR` is false, using this suffix will cause a runtime error.

Returns or sets all the Trajectories descent profile AoA values (in Degrees), also sets a node to Retrograde if it’s passed AoA is greater than 90 degrees (PI/2 radians) Note. also use with TRAddons:DESCENTGRADES to set a nodes grade if needed and passing AoA values as displayed in the gui with max 90 degrees (PI/2 radians).

List<Scalar>(atmospheric entry, high altitude, low altitude, final approach).

TRAddon:DESCENTGRADES¶

Type: List
Access: Get/Set

Did Not Exist in Trajectories before 2.4.0!

If :attr:`TRAddons:ISVERTWOFOUR` is false, using this suffix will cause a runtime error.

Returns or sets all the Trajectories descent profile grades, True = Retrograde, False = Prograde.

List<Boolean>(atmospheric entry, high altitude, low altitude, final approach).

TRAddon:DESCENTMODES¶

Type: List
Access: Get/Set

Did Not Exist in Trajectories before 2.4.0!

If :attr:`TRAddons:ISVERTWOFOUR` is false, using this suffix will cause a runtime error.

Returns or sets all the Trajectories descent profile modes, True = AoA, False = Horizon.

List<Boolean>(atmospheric entry, high altitude, low altitude, final approach).

TRAddon:PROGRADE¶

Type: Boolean
Access: Get/Set

Did Not Exist in Trajectories before 2.2.0!

If :attr:`TRAddons:ISVERTWOTWO` is false, using this suffix will cause a runtime error.

For Trajectories 2.2.0 True if all the descent profile AoA values are 0. For Trajectories 2.4.0 True if all the descent profile nodes are ‘prograde’

You can set this to have the same effect as clicking on prograde mode in the trajectories GUI. Setting this value to true causes TRAddon:RETROGRADE to become false. (They cannot both be true at the same time.)

Setting this causes all Trajectories descent profile nodes to be set to ‘prograde’ mode if True or ‘retrograde’ mode if False. Also resets all AoA values to 0.

TRAddon:RETROGRADE¶

Type: Boolean
Access: Get/Set

Did Not Exist in Trajectories before 2.2.0!

If :attr:`TRAddons:ISVERTWOTWO` is false, using this suffix will cause a runtime error.

For Trajectories 2.2.0 True if all the descent profile AoA values are 180. For Trajectories 2.4.0 True if all the descent profile nodes are ‘retrograde’

You can set this to have the same effect as clicking on retrograde mode in the trajectories GUI. Setting this value to true causes TRAddon:PROGRADE to become false. (They cannot both be true at the same time.)

Setting this causes all Trajectories descent profile nodes to be set to ‘retrograde’ mode if True or ‘prograde’ mode if False. Also resets all AoA values to 0.

TRAddon:PLANNEDVEC¶

Type: Vector
Access: Get

Vector pointing the direction your vessel should face to follow the predicted trajectory, based on the angle of attack selected in the Trajectories descent profile.

TRAddon:PLANNEDVECTOR¶

Type: Vector
Access: Get

Alias for PLANNEDVEC

TRAddon:SETTARGET(position)¶

Parameters

position – GeoCoordinates

Returns

None

Sets the Trajectories target landing position to the given position.

TRAddon:HASTARGET¶

Type: Boolean
Access: Get

Did Not Exist in Trajectories before 2.0.0!

If :attr:`TRAddons:ISVERTWO` is false, using this suffix will cause a runtime error.

The Trajectories Addon can be given a target position. This is true if such a position is set, or false if it is not.

TRAddon:GETTARGET¶

Type: GeoCoordinates
Access: Get

Did Not Exist in Trajectories before 2.4.0!

If :attr:`TRAddons:ISVERTWOFOUR` is false, using this suffix will cause a runtime error.

Returns the Trajectories target position if one is set.

TRAddon:CLEARTARGET()¶

:parameter None :return: None

Did Not Exist in Trajectories before 2.4.0!

If :attr:`TRAddons:ISVERTWOFOUR` is false, using this suffix will cause a runtime error.

Clears the Trajectories target position.

TRAddon:CORRECTEDVEC¶

Type: Vector
Access: Get

A vector that applies an offset to PLANNEDVEC intended to correct the predicted trajectory to impact at the selected target position. This vector does not use any aerodynamic prediction and is a very simplistic representation. It is also just a unit vector. It contains no magnitude information about how far off the selected target is from the predicted impact - just the way the offset points. Accuracy is not guaranteed, but it should at least help determine if you need to pitch the nose up or down.

TRAddon:CORRECTEDVECTOR¶

Type: Vector
Access: Get

Alias for CORRECTEDVEC