From 102139176b78fe2d67d250a46aa8b2cdf60ba662 Mon Sep 17 00:00:00 2001
From: Malin E <malin.ejdbo@gmail.com>
Date: Mon, 4 Oct 2021 11:02:41 +0200
Subject: [PATCH] Split trail into two, one with Earth as parent and one with
 L2

---
 .../solarsystem/missions/jwst/trail.asset     | 68 +++++++++++++++----
 1 file changed, 56 insertions(+), 12 deletions(-)

diff --git a/data/assets/scene/solarsystem/missions/jwst/trail.asset b/data/assets/scene/solarsystem/missions/jwst/trail.asset
index f62ce762c7..5fc3281a1c 100644
--- a/data/assets/scene/solarsystem/missions/jwst/trail.asset
+++ b/data/assets/scene/solarsystem/missions/jwst/trail.asset
@@ -1,39 +1,82 @@
 local assetHelper = asset.require('util/asset_helper')
 local transforms = asset.require('scene/solarsystem/planets/earth/lagrange_points/L2')
+local earthTransforms = asset.require('scene/solarsystem/planets/earth/transforms')
 local sunTransforms = asset.require('scene/solarsystem/sun/transforms')
 local horizons = asset.require('./horizons').horizons
 local kernels = asset.require('./kernels').kernels
 asset.require("spice/base")
 
-local JWSTTrail = {
-  Identifier = "JWSTTrail",
-  Parent = transforms.L2.Identifier,
+-- (malej 2021-10-04) In general, there is no trajectery data of JWST for the scheduled
+-- launch in December 2021, no horizons and no SPICE. Instead data from the 2018 launch
+-- is used, old data from an old launch time that never happende because of delays.
+-- If we can get our hands on the 2021 launch data, the jwst assets will be updated.
+
+-- Trail of JWST relative the Earth for the first month after launch
+-- Makes histroy of trail to stay at Earth, that a trail relative to L2 won't
+local JWSTTrailLaunch = {
+  Identifier = "JWSTTrailLaunch",
+  Parent = earthTransforms.EarthCenter.Identifier,
   TimeFrame = {
     Type = "TimeFrameInterval",
     Start = "2018 OCT 01 14:06:03",
-    End = "2021 OCT 01"
+    End = "2018 NOV 01"
   },
   Renderable = {
     Type = "RenderableTrailTrajectory",
     Translation = {
       Type = "HorizonsTranslation",
-      HorizonsTextFile = horizons .. "/horizons_jwst.dat",
+      HorizonsTextFile = horizons .. "/horizons_jwst_launch.dat",
     },
     Color = { 0.9, 0.9, 0.0 },
     StartTime = "2018 OCT 01 14:06:03",
-    EndTime = "2021 OCT 01",
-    SampleInterval = 3600
+    EndTime = "2018 NOV 01",
+    SampleInterval = 60
   },
   GUI = {
-    Name = "JWST Trail",
+    Name = "JWST Launch Trail",
     Path = "/Solar System/Missions/JWST/Trails",
     Description = [[
-      James Webb Space Telescope Trail relative to L2 based on horizons data from the
+      James Webb Space Telescope Laucnh Trail relative to Earth based on horizons data from the
       2018 launch.
     ]],
   }
 }
 
+-- Trail of JWST relative to L2 after first month to reach L2
+-- Gives a better trail history of the orbit around L2 than if it was relative to Earth
+local JWSTTrailOrbit = {
+  Identifier = "JWSTTrailOrbit",
+  Parent = transforms.L2.Identifier,
+  TimeFrame = {
+    Type = "TimeFrameInterval",
+    Start = "2018 NOV 01 00:00:03",
+    End = "2024 OCT 01"
+  },
+  Renderable = {
+    Type = "RenderableTrailOrbit",
+    Translation = {
+      Type = "HorizonsTranslation",
+      HorizonsTextFile = horizons .. "/horizons_jwst_orbit.dat",
+    },
+    Color = { 0.9, 0.9, 0.0 },
+    Period = 182.621099, -- About 6 months
+    Resolution = 4383 -- About a sample rate of once per hour
+  },
+  GUI = {
+    Name = "JWST Orbit Trail",
+    Path = "/Solar System/Missions/JWST/Trails",
+    Description = [[
+      James Webb Space Telescope Orbit Trail relative to L2 based on horizons data from the
+      2018 launch.
+    ]],
+  }
+}
+
+-- JPL Horizons doesn't have data of JWST relative to the Sun,
+-- instead a SPICE kernel with data from 2020 to 2024 is used.
+-- However, this SPICE kernel is (somehow) based on the horizons
+-- data of the 2018 launch anyway. Which mean that this kernel doesn't
+-- have any data of the launch, just the orbit.
 local JWSTSunTrail = {
   Identifier = "JWSTSunTrail",
   Parent = sunTransforms.SolarSystemBarycenter.Identifier,
@@ -61,7 +104,8 @@ local JWSTSunTrail = {
 }
 
 assetHelper.registerSceneGraphNodesAndExport(asset, {
-  JWSTTrail,
+  JWSTTrailLaunch,
+  JWSTTrailOrbit,
   JWSTSunTrail
 })
 
@@ -69,10 +113,10 @@ asset.meta = {
   Name = "James Webb Space Telescope Trails",
   Version = "1.0",
   Description = [[
-    Trail of James Webb Space Telescope in respect to L2 and the Sun
+    Trail of James Webb Space Telescope in respect to Earth, L2 and the Sun
   ]],
   Author = "OpenSpace Team",
   URL = "http://openspaceproject.com",
   License = "MIT license",
-  Identifiers = {"JWSTTrail", "JWSTSunTrail"}
+  Identifiers = {"JWSTTrailLaunch", "JWSTTrailOrbit", "JWSTSunTrail"}
 }