Celestia Forums

Jack or others,I have the xyz and ssc of Mars Express,but I didn?t find any model.Do anyone have it?

eh, mer_cruise.3ds you mean ?

Nope.This is about MER rovers

Raj wrote:eh, mer_cruise.3ds you mean ?

When I downloaded that addon a while ago, maybe it was never included?

Hi all,

Here is a 3DS model of Mars Express based on pictures found at ESA web site.



Model can be dowloaded here http://j.leboutet.free.fr/celestia/models/marsexpress.zip

I use this ssc file (based on JackHiggins's one), trying to describe MarsExpress's flight and orbits as shown on http://en.wikipedia.org/wiki/Mars_Express_Orbiter#Spacecraft_and_subsystems

"The orbit was adjusted by main engine firings to the desired 259 km ? 11,560 km near polar (86 degree inclination) orbit with a period of 7.5 hours.
Near periapsis the top deck is pointed down towards the martian surface and near apoapsis the high gain antenna will be pointed towards Earth for uplink and downlink.
After 440 days the apoapsis will be lowered to 10,107 km and periapsis will be raised to 298 km to give an orbital period of 6.7 hours.
"

"Mars Express flight" "Sol"
{
Class "spacecraft"
Mesh "marsexpress.3ds"
Radius 0.006
Beginning 2452800.366666667
Ending 2452998.446301042 # 2003/12/25
Albedo 0.7
SampledOrbit "marsexpress.xyz"
}

"Mars Express orb1" "Sol/Mars"
{
Class "spacecraft"
Mesh "marsexpress.3ds"
Radius 0.006
Beginning 2452998.446301042
Ending 2453438.446301042
Albedo 0.7
# Orbital elements are only very approximately correct
# These were taken from the ESA web site
EllipticalOrbit
{
Epoch 2452998.446301042
Period 0.3125 # 7h30min
SemiMajorAxis 9305.5 # 11560.0 + 259 + 6792 / 2
Eccentricity 0.6072
Inclination 86.3
AscendingNode 62
ArgOfPericenter 180.0
MeanAnomaly 200.0
}
}

"Mars Express orb2" "Sol/Mars"
{
Class "spacecraft"
Mesh "marsexpress.3ds"
Radius 0.006
Beginning 2453438.446301042
Ending 2553438.446301042 # who knows ?
Albedo 0.7
# Orbital elements are only very approximately correct
# These were taken from the ESA web site
EllipticalOrbit
{
Epoch 2453438.446301042
Period 0.2791 # 6h40min
SemiMajorAxis 8598.5 # 10107.0 + 298 + 6792 / 2
Eccentricity 0.5703
Inclination 86.3
AscendingNode 62
ArgOfPericenter 0.0
MeanAnomaly 0.0
}
}

But there is a "hole" between flight and first orbit.

And i can't found the right combination of RotationOffset, RotationEpoch , Obliquity, LongOfRotationAxis, PrecessionRate, to do "Near periapsis the top deck is pointed down towards the martian surface and near apoapsis the high gain antenna will be pointed towards Earth for uplink and downlink."

Help !!

jll
_________________________________
1.3.2p8:AMD Ath1800 256mb DDR:256mb DDR Nvid.GeF2-MX400
WinXPHome:FS1024x768x32:
Earth 8Kdds:Cloud 4Kdds:Night 4Kdds:Moon 4kdds:Galaxy ON

Nice job!...thank you!

I copied the code,and named it marsexpress.ssc,but this didn?t put the Mars Express into orbit,at least in Celestia 1.3.1.I think the code isn?t working actually,because when I deleted the Jack original code,the model disappear.The probe only appears near January24,2003.The xyz is in the Data folder and the model is in Models.I put the marsexpress.ssc in the Extras folder.And the code is this:
"Mars Express flight" "Sol"
{
Class "spacecraft"
Mesh "marsexpress.3ds"
Radius 0.006
Beginning 2452800.366666667
Ending 2452998.446301042 # 2003/12/25
Albedo 0.7
SampledOrbit "marsexpress.xyz"
}

"Mars Express orb1" "Sol/Mars"
{
Class "spacecraft"
Mesh "marsexpress.3ds"
Radius 0.006
Beginning 2452998.446301042
Ending 2453438.446301042
Albedo 0.7
# Orbital elements are only very approximately correct
# These were taken from the ESA web site
EllipticalOrbit
{
Epoch 2452998.446301042
Period 0.3125 # 7h30min
SemiMajorAxis 9305.5 # 11560.0 + 259 + 6792 / 2
Eccentricity 0.6072
Inclination 86.3
AscendingNode 62
ArgOfPericenter 180.0
MeanAnomaly 200.0
}
}

"Mars Express orb2" "Sol/Mars"
{
Class "spacecraft"
Mesh "marsexpress.3ds"
Radius 0.006
Beginning 2453438.446301042
Ending 2553438.446301042 # who knows ?
Albedo 0.7
# Orbital elements are only very approximately correct
# These were taken from the ESA web site
EllipticalOrbit
{
Epoch 2453438.446301042
Period 0.2791 # 6h40min
SemiMajorAxis 8598.5 # 10107.0 + 298 + 6792 / 2
Eccentricity 0.5703
Inclination 86.3
AscendingNode 62
ArgOfPericenter 0.0
MeanAnomaly 0.0
}
}

What I did wrong?

jll wrote:Hi all,

Here is a 3DS model of Mars Express based on pictures found at ESA web site.



Model can be dowloaded here http://j.leboutet.free.fr/celestia/models/marsexpress.zip

I use this ssc file (based on JackHiggins's one), trying to describe MarsExpress's flight and orbits as shown on http://en.wikipedia.org/wiki/Mars_Express_Orbiter#Spacecraft_and_subsystems

"The orbit was adjusted by main engine firings to the desired 259 km ? 11,560 km near polar (86 degree inclination) orbit with a period of 7.5 hours.
Near periapsis the top deck is pointed down towards the martian surface and near apoapsis the high gain antenna will be pointed towards Earth for uplink and downlink.
After 440 days the apoapsis will be lowered to 10,107 km and periapsis will be raised to 298 km to give an orbital period of 6.7 hours.
"

"Mars Express flight" "Sol"
{
Class "spacecraft"
Mesh "marsexpress.3ds"
Radius 0.006
Beginning 2452800.366666667
Ending 2452998.446301042 # 2003/12/25
Albedo 0.7
SampledOrbit "marsexpress.xyz"
}

"Mars Express orb1" "Sol/Mars"
{
Class "spacecraft"
Mesh "marsexpress.3ds"
Radius 0.006
Beginning 2452998.446301042
Ending 2453438.446301042
Albedo 0.7
# Orbital elements are only very approximately correct
# These were taken from the ESA web site
EllipticalOrbit
{
Epoch 2452998.446301042
Period 0.3125 # 7h30min
SemiMajorAxis 9305.5 # 11560.0 + 259 + 6792 / 2
Eccentricity 0.6072
Inclination 86.3
AscendingNode 62
ArgOfPericenter 180.0
MeanAnomaly 200.0
}
}

"Mars Express orb2" "Sol/Mars"
{
Class "spacecraft"
Mesh "marsexpress.3ds"
Radius 0.006
Beginning 2453438.446301042
Ending 2553438.446301042 # who knows ?
Albedo 0.7
# Orbital elements are only very approximately correct
# These were taken from the ESA web site
EllipticalOrbit
{
Epoch 2453438.446301042
Period 0.2791 # 6h40min
SemiMajorAxis 8598.5 # 10107.0 + 298 + 6792 / 2
Eccentricity 0.5703
Inclination 86.3
AscendingNode 62
ArgOfPericenter 0.0
MeanAnomaly 0.0
}
}

But there is a "hole" between flight and first orbit.

And i can't found the right combination of RotationOffset, RotationEpoch , Obliquity, LongOfRotationAxis, PrecessionRate, to do "Near periapsis the top deck is pointed down towards the martian surface and near apoapsis the high gain antenna will be pointed towards Earth for uplink and downlink."

Help !!

jll
_________________________________
1.3.2p8:AMD Ath1800 256mb DDR:256mb DDR Nvid.GeF2-MX400
WinXPHome:FS1024x768x32:
Earth 8Kdds:Cloud 4Kdds:Night 4Kdds:Moon 4kdds:Galaxy ON

Why are there two different orbits for Mars Express? On date March 8, 2005 MEX changes from orbit 1 to orbit 2. Why is that?