Celestia Forums

3 new addons on the spacecraft side:
IBEX, ICESat, Kepler

am sorry... found some mistakes in ssc file for the SOHO add-on.. so here use this new...

Added after 2 minutes 12 seconds:

Hello

3 new addons on the spacecraft side:
IBEX, ICESat, Kepler

Thanks Gironde...

Added after 2 minutes 12 seconds:
but I'm working with GRO now...

Gironde... SemiMajor Axis for IBEX can't be 202.811... and period..232.7017... that is impossible... and for ICESat .. SemiMajor Axis 297...

Added after 4 minutes 24 seconds:
but the models are great... ok... I will make ssc files for them...

Compton Gamma Ray Observatory (GRO) Add-on... the orbital elements of Comton GRO spacecraft by the historical TLE data which was taken from space-track.org.. I have an account there... so all is correct somehow... enjoy

Added after 3 minutes 28 seconds:
I got also the historical TLE data for IBEX and ICESat from space-track.org... so I will create a SSC files for them soon...

Compton Gamma Ray Observatory (GRO) Add-on...

Now you can download ICESat and IBEX SSC file... now these spacecrafts in the orbits around the Earth in Celestia but not inside the Earth... Enjoy..

Added after 11 minutes 35 seconds:
Kepler Observatory XYZV file... soon... ( about hour )... timeframe from 12-05-2009 to 28-12-2019

Kepler Add-on... contains XYZV-file in the "data" folder... also changed SSC file...

Hello Toutatis,

I was attentive to what you emphasize but that's what I find on wikipedia:

Half-major axis
a : half of the distance between the pericenter and the apocenter (the largest diameter of the ellipse). This parameter defines the absolute size of the orbit. It only makes sense in the case of an elliptical or circular trajectory (the half-grand-axis is infinite in the case of a parabola or a hyperbola) (rp+ra)/2

for Icesat :
apogee= 594 km perigee=586 km semimajoraxis = (594+586)/2= 590.5 km not 6973.1387446804838 (bigger than the apogee)

for period of IBEX : ok the unit is in day and I did not see that I had it in hours.

but maybe I did not understand everything!
I start on this kind of work.



Added after 1 hour 26 minutes:
Epoch
ICESat : 2455423.01238
IBEX : 2457916.04523


ra = apogee/2
ICESat : 594/2=297
IBEX : 330008/2=165004
rp = perigee/2
ICESat : 586/2=293
IBEX : 62855/2=31427.50
a = semimajoraxis = (apogee+perigee) /2
ICESat : 590
IBEX : 196431.50
e = eccenticity = (ra-rp) / (ra+rp)
or
e = 1 - 2/ [(ra/rp) +1]
ICESat : 0.006779661
IBEX : 0.68001568

I was attentive to what you emphasize but that's what I find on wikipedia:

Half-major axis
a : half of the distance between the pericenter and the apocenter (the largest diameter of the ellipse). This parameter defines the absolute size of the orbit. It only makes sense in the case of an elliptical or circular trajectory (the half-grand-axis is infinite in the case of a parabola or a hyperbola) (rp+ra)/2

for Icesat :
apogee= 594 km perigee=586 km semimajoraxis = (594+586)/2= 590.5 km not 6973.1387446804838 (bigger than the apogee)

for period of IBEX : ok the unit is in day and I did not see that I had it in hours.

but maybe I did not understand everything!
I start on this kind of work.

Well Gironde, all database I use for Add-ons is from NORAD ... or NASA and that is much more better...

The Aeronomy of Ice in the Mesosphere (AIM) is a satellite to conduct a 26-month study of noctilucent clouds (NLCs). It is the ninetieth Explorer program mission and is part of the NASA-funded Small Explorer program (SMEX). On April 25, 2007 AIM was boosted into a 600 km (370 mi) high polar orbit by a Pegasus-XL rocket, which was air-launched from the Lockheed L-1011 Stargazer aircraft operated by Orbital Sciences... https://en.wikipedia.org/wiki/Aeronomy_of_Ice_in_the_Mesosphere

Enjoy...

Added 26.05.2018, 13:47:
Added 26.05.2018, 13:45:

ra = apogee/2
ICESat : 594/2=297
IBEX : 330008/2=165004
rp = perigee/2
ICESat : 586/2=293
IBEX : 62855/2=31427.50
a = semimajoraxis = (apogee+perigee) /2
ICESat : 590
IBEX : 196431.50
e = eccenticity = (ra-rp) / (ra+rp)
or
e = 1 - 2/ [(ra/rp) +1]
ICESat : 0.006779661
IBEX : 0.68001568

a = semimajoraxis = (apogee+perigee) /2... NO... Gironde... read it here but attentive... https://en.wikipedia.org/wiki/Semi-major_and_semi-minor_axes

Toutatis,

I know but something escapes me

TOPEX/Poseidon was a joint satellite mission between NASA, the U.S. space agency; and CNES, the French space agency, to map ocean surface topography. Launched on August 10, 1992, it was the first major oceanographic research satellite. TOPEX/Poseidon helped revolutionize oceanography by providing data previously impossible to obtain. Oceanographer Walter Munk described TOPEX/Poseidon as "the most successful ocean experiment of all time." A malfunction ended normal satellite operations in January 2006. https://en.wikipedia.org/wiki/TOPEX/Poseidon

Today I want to start working with the main antenna for TESS... becoz at the 2 models that we have it looks not well in Celestia...

Added after 5 hours:
TESS Observatory with "new antenna"...

Hi Toutatis.
Can you please upload TESS ssc file?
And, just curious, why this one is 3DS only while your previous one was cmod too?
Thanks a lot.
Goofy

Hi Toutatis.
Can you please upload TESS ssc file?
And, just curious, why this one is 3DS only while your previous one was cmod too?
Thanks a lot.
Goofy

Okay Goofy... I will upload SSC file... and convert 3ds file to cmod file... just wait some mins plz...

Add-on TESS... SSC file from "Celestia Origin", I just changed it abit... + TESS (cmod model)...

Toutatis,

I looked at these 3 sites and I find that they give conflicting definitions even in their own lines.
They talk about the 2 focus points but we never know them.
If you know the definition of semimajoraxis that goes well with Celestia, I'm interested.

https://en.wikipedia.org/wiki/Semi-major_and_semi-minor_axes
https://en.wikipedia.org/wiki/Orbital_eccentricity
http://www.mathopenref.com/ellipseaxes.html

after I found Norad's SATCAT database:
https://celestrak.com/satcat/search.asp

with the last cmod of TESS, we gained the antenna but we lost the differentiation between the large cone of protection and the body of the satellite; now these 2 zones are defined at the same time. It's a bit embarrassing.

Thank you, Toutatis, very appreciated.
Bye

Soofy

I looked at these 3 sites and I find that they give conflicting definitions even in their own lines.
They talk about the 2 focus points but we never know them.
If you know the definition of semimajoraxis that goes well with Celestia, I'm interested.

Hi Gironde... problem only that I do not know English well to explain this... but I will try to explain... See...

a^3=μ*T^2/4*Pi^2 a - semi-major axis.., μ - standard gravitational parameter (for the Earth - 398 600,44158 км^3c^2).., T - orbital period of satellite.., Pi - 3,14159265358979323846

In celestial mechanics, the standard gravitational parameter μ of a celestial body is the product of the gravitational constant G and the mass M of the body.

μ=G*M
For several objects in the Solar System, the value of μ is known to greater accuracy than either G or M... The SI units of the standard gravitational parameter are m^3 s^−2. However, units of km^3 s^−2 are frequently used in the scientific literature and in spacecraft navigation...

So if you know orbital period of satellite, you can find semi major axis easy... T- period in seconds... then a - in kilometers