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GetLocationOrbitPlot, OrbitPlot3D

7.3 The OrbitTrackPlot Function

OrbitTrackPlot is useful for displaying the track of a low-orbit satellite onto the surface of the Earth.

Plotting orbital tracks.

Locations along the track are such that the object is directly overhead at some time between the given dates. The object will normally be an Earth satellite, but it can be a planet or any other object. The red regions indicate where the object is located overhead just after dusk in the evening sky. Similarly, the blue regions indicate the object's location overhead just before dawn in the morning sky.

If the object you are tracking is a low-orbit Earth satellite, then the red and blue regions represent the windows of opportunity to view the satellite. These are time periods of perhaps 5 or 10 minutes, while the satellite is still illuminated by the Sun but your viewing location is in darkness.

A sequence of tracks is displayed if you supply a list of objects, rather than a single object, as the first argument to OrbitTrackPlot. In this case, you can also use the option PlotStyle to set a different style for each track.

Enter the orbital elements of a Space Shuttle mission.

In[18]:=SetOrbitalElements[STS63,
ViewPoint -> Earth,
Date -> {1995,2,3,6+11,48,13},
OrbitalMeanMotion -> 15.82619484*Revs/Day,
OrbitalDecayRate -> 0.00000387*Revs/Day^2,
OrbitalSemiMajorAxis -> 6723.340*KiloMeter,
OrbitalEccentricity -> 0.0026128,
OrbitalInclination -> 51.6614*Degree,
MeanAnomaly -> 156.9459*Degree,
PerigeeArgument -> 202.9294*Degree,
AscendingLongitude -> 109.1408*Degree];

This graphic shows the track of the Space Shuttle mission for 6 hours, or about 4 orbits. Various evening passes are visible over parts of Australia, in addition to some morning passes over parts of North America.

In[19]:=OrbitTrackPlot[STS63, {1995,2,6, 8+11,0,0},
{1995,2,6,14+11,0,0},
PlotPoints -> 250,
LocationRing -> True];

The option setting LocationRing -> True draws a green ring around the current site location. If any track passes within that ring, then the object is above the local horizon. When this occurs the object may be tracked with radio equipment.

If the start and stop dates used by OrbitTrackPlot are sufficiently close, it makes sense to use the option setting Shading -> True. This option works just as it does in PlanetPlot, shading the night-time region.

Again, the option PlotRange is available if you need to zoom into a smaller region on the surface of the Earth. The default is PlotRange -> {{-180, 180}, {-90, 90}}.

This shows that visibility occurs around dawn and dusk only.

In[20]:=OrbitTrackPlot[STS63, {1995,2,6,8+11,0,0},
{1995,2,6,9+11,0,0},
PlotPoints -> 50,
Shading -> True];

The option PlotRange is used here to zoom into the area over Australia.

In[21]:=OrbitTrackPlot[STS63, {1995,2,6,8+11,0,0},
{1995,2,6,9+11,0,0},
PlotPoints -> 50,
Shading -> True,
PlotRange -> {{90, 180},
{-50, 10}}];

GetLocationOrbitPlot, OrbitPlot3D



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