Celestia Forums

The Fermi Gamma-ray Space Telescope (FGRST), formerly called the Gamma-ray Large Area Space Telescope (GLAST), is a space observatory being used to perform gamma-ray astronomy observations from low Earth orbit. Its main instrument is the Large Area Telescope (LAT), with which astronomers mostly intend to perform an all-sky survey studying astrophysical and cosmological phenomena such as active galactic nuclei, pulsars, other high-energy sources and dark matter. Another instrument aboard Fermi, the Gamma-ray Burst Monitor (GBM; formerly GLAST Burst Monitor), is being used to study gamma-ray bursts... https://en.wikipedia.org/wiki/Fermi_Gamma-ray_Space_Telescope

FGRST is here...

hello toutatis,

here is my last born: satellite TRMM
This satellite was launched in Japan in 1997 (collaboration with Nasa) and returned to the atmosphere and was destroyed in 2015
I had a lot of trouble determining its orbit when it was active.
I collected the archive of Satcat for 1997 but I had nowhere semimajoraxis.
As its orbit is almost circular, I went through the parameter PericenterDistance which is the altitude (perigee) relative to the center of the Earth, and forcing eccentricity to 0 (circular orbit).
PericenterDistance: 6378.1 + 176/2 +174/2) = 6378.1 + 175 km

In the end, it seems to work.

here is my last born: satellite TRMM
This satellite was launched in Japan in 1997 (collaboration with Nasa) and returned to the atmosphere and was destroyed in 2015
I had a lot of trouble determining its orbit when it was active.
I collected the archive of Satcat for 1997 but I had nowhere semimajoraxis.
As its orbit is almost circular, I went through the parameter PericenterDistance which is the altitude (perigee) relative to the center of the Earth, and forcing eccentricity to 0 (circular orbit).
PericenterDistance: 6378.1 + 176/2 +174/2) = 6378.1 + 175 km

In the end, it seems to work.

Hello Gironde... Great work my friend... well, I will looking for TLE data of TRMM in the NORAD archive if there need to correct orbit... no problem with this...

this is from the NORAD archive...

Added after 24 minutes 28 seconds:
TRMM: Epoch - 2457064.46157 (10/02/2015 23:04:40 UTC) Period - 0.06360739682865741446 SemiMajor Axis - 6730.3524986523755476 Eccentricity - 0.0004267 Inclination - 34.9536 Ascending of Node - 347.4797 Argument of Pericenter - 261.2269 Mean Anomaly - 158.1517

Toutatis
Be careful, do not take the first 2 lines because they are pointing to a date before the launch.
I have used that ( 28/11/1997)
1 25063U 97074A 97331.94253462 .00000032 00000-0 00000+0 0 19
2 25063 33.4106 50.0079 0014571 240.8539 118.4586 15.64284004 13

The one you edited is too close to the end of the satellite.



Added after 1 hour 42 minutes:
Toutatis,

it will tell me where you found the semimajoraxis because it is not in the 2 lines of Norad Satcat
or how you calculate it.

it will tell me where you found the semimajoraxis because it is not in the 2 lines of Norad Satcat
or how you calculate it.

I calculate it from TLE... watch... let's use TLE you posted here... If (A) - semimajor axis.. then we can found it if we know only a Period (in seconds) (T) from this! A^3=μ*T^2/4*Pi^2

(T) - the time required for one revolution around the planet!!! You can find it from TLE data... See... 1 day = 1440 minutes = 86 400 seconds...

(T) = 86 400 / 15.64284004 = 5523.2937 seconds

15.64284004 is the number of revolutions per day!!!!

(Pi) = 3.14159265359

(μ) = 398 600.44158

4*Pi^2 = 4* 3.1416^2 = 39.47860224

5523.2937^2 = 30506773.29645969

30506773.29645969 * 398 600.44158 = 12160013307149.7846846699102

(A)^3 = 12160013307149.7846846699102 / 39.47860224 = 308015294797.57449195521239913078

then (A) = 6753.4252011656425266396584513163 Semimajor Axis!


How to find Period per day? Easy... 1 / 15.64284004 = 0.06392701053280092225503572943267


and that is all from TLE data!

Mars Atmosphere and Volatile Evolution Mission (MAVEN) is a space probe developed by NASA to study the Martian atmosphere while orbiting Mars. Mission goals include determining how the planet's atmosphere and water, presumed to have once been substantial, were lost over time...

https://en.wikipedia.org/wiki/MAVEN

Orbital Martian Spacecraft MAVEN...

for once, it's clear!
I had seen so much method that I was lost in the constants.

I integrated this into my Excel file, TLE edition
thank you Toutatis

I am adjusting the orientation of the CALIPSO satellite to finalize the addon

And congratulations on your latest addons

Hi Toutatis and Gironde.
I'm appreciating a lot what you are doing with spacecraft models, very nice and precious job, but (there is aolways a "but", alas!) I find just a small defect in all of them: they look too much "new", just like kids new plastic toys.
IMHO they miss the reality that they should have.
Can it be done something with textures or what else?
Sorry, I know nothing about 3d models, so may be I'm saying nonsenses.
Goofy

goofy

We are like you, novices in 3D
We have retrieved existing 3D files from the NASA website to convert them to a usable model in Celestia. NASA files are proposed by designers who have their own goal: modeling for astro software or 3D printer.
We are not yet well enough in modeling to understand how to modify the textures in Blender, Wings 3D, etc.
We must apologize. I hope that our work will inspire others to look into the issue. For the moment we are dependent on the existing and do with our knowledge.

for amateurs here is a site where we find tons of free 3D, especially on the science fiction universe:
https://free3d.com/3d-models/aircraft

good luck

Hi Toutatis and Gironde.
I'm appreciating a lot what you are doing with spacecraft models, very nice and precious job, but (there is aolways a "but", alas!) I find just a small defect in all of them: they look too much "new", just like kids new plastic toys.
IMHO they miss the reality that they should have.
Can it be done something with textures or what else?
Sorry, I know nothing about 3d models, so may be I'm saying nonsenses.
Goofy

Well Goofy... With time we will find a ways to modify them... but all models of spacecrafts in Celestia looks like that... maybe because all of them was made by people but not Universe...

Added after 2 minutes 10 seconds:

for once, it's clear!
I had seen so much method that I was lost in the constants.

I integrated this into my Excel file, TLE edition
thank you Toutatis

I am adjusting the orientation of the CALIPSO satellite to finalize the addon

And congratulations on your latest addons

Thank you too Gironde...

TESS again... ... Alternative add-on...

I'm appreciating a lot what you are doing with spacecraft models, very nice and precious job,

Anyway Thanks Goofy...

TESS again... ... Alternative add-on...

Ok!

Ok!

And in a galaxy not too far away, here is CALIPSO, Cloud Aerosol Lidar and Infrared Pathfinder Satellite Observations

Hi Toutatis.
About MAVEN, I had some doubt about the front solar panels color, shown golden in this #1 image from Celestia Origin last release:



and back solar panels color, shown flat silver in #2 image here:



so I made a search, and found a youtube movie with MAVEN solar panels deployment test, here:
https://youtu.be/oxxUUO4tgWs
As you see there is no gold, only dull black on the back and shining black on the front panel, as shown too in the attached image #3



Moreover the plate back the round antenna is covered with crunched gold leaf, not a flat silver panel, as you can see in the attached NASA drawing #4.



I have been unable to understand if the round antenna cover is silver or golden crunched leaf, anyway the actual one is too dark and "flat", IMHO.
Hope this helps to improve it, if possible.
Bye.

Goofy

Added after 52 minutes 57 seconds:
Hi Gironde and Toutatis.
Sorry, I apologize, I wrote the last message on MAVEN before reading your answers to my previous one.
I understand well the problem, and for this I appreciate even more the work you are doing, that anyway is very important and, BTW, was requested many times in the previous years, without answers.

So now I'm asking for help from whom have more experience on 3D modelling, Selden, John, Cham, anyone else willing to help a bit on these models, or at least some of them?
Please, someone can finish the work?
I hope so.
If not, anyway, thank you for what has been made available for all of us, very appreciated.

Goofy

Added after 51 minutes 42 seconds:
Hi Toutatis and Gironde.
Trying to give some help, I modified MAVEN textures, changing the antenna cover text with a new one, and modifying colors to the solar panels.
Well, while the panels show absolutely no change, the antenna cover accepted the new texture, and here the result:





This is the new texture I used:



Hope this can give some idea about possibility to improve something.
BTW, It looks weird that the panel textures don't appear, so I think them have not been merged in the model, may be or it's a nonsense of mine?
Moreover, the gold color is nowhere in the textures!
Bye

Goofy

About MAVEN, I had some doubt about the front solar panels color, shown golden in this #1 image from Celestia Origin last release:

Goofy... panels are black... they a bit looks gold because of the sun... but there no problem to change shininess of them...

satellite C-NOFS : without AscendingNode, ArgOfPericenter, MeanAnomaly

satellite MAVEN by Toutatis, colors and textures modified, blue solar cells

Toutatis, I think you put the diameter in the place of the radius.

Global Precipitation Measurement (GPM) or Global Precipitation Index (GPI) is a joint mission between JAXA and NASA as well as other international space agencies to make frequent (every 2–3 hours) observations of Earth’s precipitation. It is part of NASA's Earth Systematic Missions program and works with a satellite constellation to provide full global coverage. The project provides global precipitation maps to assist researchers in improving the forecasting of extreme events, studying global climate, and adding to current capabilities for using such satellite data to benefit society. GPM builds on the notable successes of the Tropical Rainfall Measuring Mission (TRMM), which was also a joint NASA-JAXA activity.
https://en.wikipedia.org/wiki/Global_Precipitation_Measurement

GPM-CORE

Added after 1 minute 58 seconds:
GPM-CORE