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Apollo Lunar LandingsVoyager II Trajectory

Viking Mars Landings

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Viking Mars Landing Sites

During 1976, two Viking craft landed on Mars.

date long lat Location

Viking 1 {1976,7,20} 47.5W, 22.3N (Chryse Planitia)

Viking 2 {1976,9, 3} 134.3E, 47.6N (Utopia Planitia)

Viking 1 landed in Chryse Planitia, towards the left of following graphic. The landing took place in the martian northern summer - note the icecap around the south pole.

PlanetPlot3D[Mars,{1976,7,20},
     ShadingRuleFalse,
     PlotLabelRule"Viking 1",
     FeaturesRule{RGBColor[0,1,0],
     Point[{-47.5,+22.3}]},
     ViewPointRuleMars[0,0,1000000],
     ViewVerticalRuleMars[0,90]];1;

Two of the most visible features on Mars are the dark triangular shaped Syrtis Major, and the light Hellas basin. Syrtis Major is on the left, and Hellas on the lower left of the following graphic. Viking 2 landed in Utopia Planitia, slightly to the right and upper part of the graphic. The landing again took place in the martian northern summer.

PlanetPlot3D[Mars,{1976,9,3},
ShadingRuleFalse,
PlotLabelRule"Viking 2",
FeaturesRule{RGBColor[0,1,0],
Point[{134.3,+47.6}],
RGBColor[1,0,0],
Text["Syrtis\nMajor",
{70,10}],
RGBColor[1,0,0],
Text["Hellas",{70,-45}]},
ViewPointRuleMars[120,0,1000000],
ViewVerticalRuleMars[0,90]];1;

The large volcanic mountain Olympus Mons is on the upper left of the following graphic.

PlanetPlot3D[Mars,
ShadingRuleFalse,
PlotLabelRule"Olympus Mons",
FeaturesRule{RGBColor[1,0,0],
Point[{-133,18}]},
ViewPointRuleMars[-120,0,1000000],
ViewVerticalRuleMars[0,90]];1;

Note the object Mars[120, 0, 1000000] means the point 1,000,000km above the martian surface with a longitude of 120 degrees, and a latitude of zero. Similarly the object Mars[0, 90] means the martian north pole (with latitude 90 degrees).

Landing Dates

The two Viking craft landed in mid 1976. Mars was in opposition to the Sun eight months before that time; and eight months before that the Viking craft were launched from Earth. Hence Mars was close to Earth at the middle of the journey, which is efficient because it saves on fuel at the time of launch. Oppositions of Mars occur every 2.1 years.

Here is an animation showing the close approach of Mars and Earth.

In[7]:=Do[SolarSystemPlot[{1975,m,2},
ViewPoint -> GeoCentric,
Distance -> 3*AU,
Planets -> {Mars, Sun, Earth},
Moon -> False,
Text -> False,
MagnitudeScale -> 4.,
Epilog -> {
RGBColor[1,1,1],
OrbitTrack[Mars, {1975,1,1},
{1977,1,1},
PlotPoints -> 100]}],
{m,1,24}]

Note the option ViewPoint -> GeoCentric is used so that the morning and evening lines are suppressed. Those lines are only drawn if the viewpoint is explicitly the Earth.. However, GeoCentric is equivalent to the center of the Earth. Also note that the option Text->False is used to suppress the date text being printed.

Apollo Lunar LandingsVoyager II Trajectory



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