OHM OrbiComm Satellite v0.86 (hotfix)

[OrbitHangar]

Author: n_molson

OrbiComm Satellite (v0.86 - hotfix)

Nowadays, heavy communication satellites (up to 6,700 kg) are essential in our everyday lives and transmit flows of information all around the globe 24/24 & 7/7. In Geostationary Earth Orbit, 35,786 km above the Equator, those spacecraft can stay in duty for more than 15 years.

This addon gives you a chance to take the challenge of deploying one of those in GEO. While launches broadcasts gives us an impression of routine, planning such a launch requires an advanced knowledge of orbital mechanics.

The addon includes 5 scenarios ; 4 of them require Velcro Rockets + Velcro EELV. Launch from KSC with the Space Shuttle carrying the Centaur-G tug, Atlas V 551 or Delta 4H EELV, or even try your chance from Baikonur using a Proton-M/Briz-M, ILS workhorse !

v0.85 update log :

- Shuttle/Centaur-G (Velcro) scenario added.
- New Velcro Centaur-G tug (existing one was Centaur-G "prime", which is heavier).
- Proton-M/Briz-M scenario added.
- New Velcro Briz-M tug (core + torus, includes a full version and a partially-fueled version).
- Added helping information in the scenarios description.
- Some details added on OrbiComm mesh.
- OrbiComm D3D9 materials properties file now included.
- Re-designed OrbiComm thrusters, now uses real hardware for more realism (see '3-Specifications' in the Readme).

 

v0.86 update log :

- The .dll module included in the v0.85 package was outdated, which caused mesh animations issues. Also now really includes the RCS redesigned code mentionned above.

- Manual converted to .pdf for ERE (Enhanced Reading Experience).

 

Special Thanks to orbinaut 'Sputnik' for the very handy 'Velcro Rockets' addon !



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[PhantomCruiser]

First! Company just arrived so I can't mess with it ATM. Later though...

 

[N_Molson]

No worries, I realized that I forgot the .msh file. Fixed now

 

[Cosmic Penguin]

The Orbiter community really needs more comsats, and unfortunately most of them available right now comes from an incomplete series from the now inactive member Istochnikov (Boeing/Hughes BSS-601 & BSS-702 and Orbital Sciences Star-2).

Nicholas, I hope you consider making the other contemporary major comsat satellite buses, especially those from your own country! (Astrium/Airbus DS Eurostar-3000, which has just 1 satellite available on Orbiter; and Thales Alenia Space Spacebus-4000, which has none) Also I would like to see Space Systems/Loral's LS-1300 (probably the best seller of today) and Lockheed Martin's A2100 (which now is most commonly used by the US government). :tiphat:

 

[boogabooga]

Thorton's Proton includes an A2100.

I myself am partial to the 80s spin-stabilized designs like the HS-376.

 

[N_Molson]

Nicholas, I hope you consider making the other contemporary major comsat satellite buses

If you have information (various specifications, pictures of the satellites preparations before launch, 3D renders of the satellites in orbit), I'm definitively interested. :yes:

---------- Post added at 09:14 PM ---------- Previous post was at 07:16 PM ----------

The Shuttle/Centaur Velcro way :

I wish I could get rid of the airlock, not enough space in the cargo bay with it !

- Also next version will feature 2 engines instead of 1, for a bit less painful orbital maneuvers. Characteristics are now those of Aerojet's R-4D-15 (the R-4D was designed as Apollo/LM RCS thruster, and has been reused in a huge number of satellites or probes). Which now gives us roughly 890 N of thrust (Ve = 3168 m/s).

 

[orbitingpluto]

I wish I could get rid of the airlock, not enough space in the cargo bay with it !

Shuttle Fleet has the the external airlock/ODS as a option in the scenario file on a few Shuttles, being absent by default. Only problem is going to simviation.com instead of OrbiterHangar to download it if you don't already have it.

 

[DaveS]

Shuttle Fleet has the the external airlock/ODS as a option in the scenario file on a few Shuttles, being absent by default. Only problem is going to simviation.com instead of OrbiterHangar to download it if you don't already have it.

Well, another more realistic option would be to use the shorter Centaur G instead of the Centaur G Prime. The G Prime was 29.1 ft (8.86 m) long while the G was only 20 ft (6.09 m) long.

The G Prime was NASA interplanetary version, while the G was the commercial/DoD version for ordinary GEO spacecrafts.

 

[N_Molson]

Yeah, I'll shorten the G' tank by 8.86-6.09, it should fit the payload bay perfectly that way. Anyway the Centaur G' + OrbiComm stack had a mass of nearly 30 tons, far over the real-life Shuttle capabilities (though default Atlantis in Orbiter 2010 is quite overpowered and can haul 30 tons to LEO easily ).

 

[DaveS]

Yeah, I'll shorten the G' tank by 8.86-6.09, it should fit the payload bay perfectly that way. Anyway the Centaur G' + OrbiComm stack had a mass of nearly 30 tons, far over the real-life Shuttle capabilities (though default Atlantis in Orbiter 2010 is quite overpowered and can haul 30 tons to LEO easily ).

I'm not sure if the default Atlantis take in account the total mass of any attached children. This could explain the over-performance. Anyway, here's chart of the main differences between the G' and the G:

 

[N_Molson]

OK, played a bit with the Velcro Centaur-G' mesh, and changed the proportions of the main sections so that it looks like the drawing above. Checked the length with a 6.09 meters-long cylinder, we're good (I took the tank fore bulkhead as the starting point, not the payload adapter, which I think makes sense).

As you can see, it now fits the "stock Shuttle" bay perfectly :

Even better, the total payload mass (Centaur + Satellite) is 23,428 kg. Near perfection.

Well, I guess that in reality 3 other tons would be required in the payload bay for the CISS. But I say not bad for a speculative addon (and anyway, if the Atlantis module doesn't check the payload mass, that's irrelevant). I let those subtleties for you SSU guys .

Edit : Did it, Satellite in GEO using the Shuttle/Centaur G config. 800 kg of propellant remaining in the satellite's tank (which means 53 kg/year max consumption for corrections), could have done better (like aiming for a very low orbit with the Shuttle and spending some OMS fuel to smooth the Rinc to equator. Roughly, the Centaur G was able to send the 6,5 tons satellite in GTO, nearly canceling the Rinc. Then it was only a matter of raising the periapsis with OrbiComm engines, and refine the Inc, took two (long) orbits. Oh and I'm supposed to land the Shuttle too. Well, let's say the crew can enjoy 2 weeks in orbit for the same price !

---------- Post added at 11:38 PM ---------- Previous post was at 04:21 PM ----------

I realized we had no Velcro Breeze stage ! So I made one.

This mission has already failed because of wrong Velcro parameters : the toroid tank holding most of the tug fuel jettisoned at the first engine stop. Electronics failure ! :hmm:

Other than that the Proton-M/Breeze-M stack is quite interesting. Especially when you launch from Baikonur and accept the range constraints. Lots of fun.

So next version will include :

- Shuttle/Centaur-G scenario (with a new Centaur G Velcro vessel)
- Proton-M/Breeze-M scenario (with a new Breeze-M Velcro vessel)
- Important fixes on the satellite RCS and main thrusters layout, for more realism.
- D3D9 .cfg files to get the materials effects.

 

[N_Molson]

v0.85 updated !

A lot of new things, as listed below :

- Shuttle/Centaur-G (Velcro) scenario added.
- New Velcro Centaur-G tug (existing one was Centaur-G "prime", which is heavier).
- Proton-M/Briz-M scenario added.
- New Velcro Briz-M tug (core + torus, includes a full version and a partially-fueled version).
- Added helping information in the scenarios description.
- Some details added on OrbiComm mesh.
- OrbiComm D3D9 materials properties file now included.
- Re-designed OrbiComm thrusters, now uses real hardware for more realism (see '3-Specifications' in the Readme).

The propulsion section now features 2x 'Aerojet R-4D-15' (improved version of the Apollo/LM RCS thrusters) as main engines and 12x 'MOOG-ISP DST-12' thrusters (22 N each, 45°-canted) for attitude control.

Next version will focus on power management simulation and feature ullage burns (which is the reason why the DST-12 thrusters are 45° canted).

 

[IronRain]

Cool progress!

New Velcro Centaur-G tug

New Velcro Briz-M tug

Do you consider uploading these stages separately on O-H? I know a lot of mission where I would like to use those stages.

 

[DaveS]

N_Molson: If you need some further info on the Centaur G, this is the document for you: https://dl.dropboxusercontent.com/u/24122088/STSCentaur/CENTAUR G TECHNICAL DESCRIPTION.PDF

 

[N_Molson]

Do you consider uploading these stages separately on O-H? I know a lot of mission where I would like to use those stages.

That, with the quite extended russian 'Block-D' family, the KVRB, and there is that simple model of Ariane 5 I made some time ago as a static for a base. A Velcro Ariane 5-ECA would be an interesting addition, as this is one of the very few Equator-launched LVs. Also we need some textures and payload adapters for various existing Velcro upper stages. :yes:

N_Molson: If you need some further info on the Centaur G, this is the document for you: https://dl.dropboxusercontent.com/u/...ESCRIPTION.PDF

Thanks, I'll check my figures with this !

 

[N_Molson]

The mesh is horribly messed when you deploy the panels / the dishes, right ? Thanks to confirm.

Oh, and the modifications I did to the RCS code is the old one, too.

It seems that the .dll was not up-to-date. And of course the code is 620 km away now. :facepalm:

Well no problem, I'll fix that.

---------- Post added at 09:13 PM ---------- Previous post was at 07:20 PM ----------

v0.86 uploaded to OrbitHangar, should fix the mesh animation issue. And also improve the RCS. Oh and I converted the Readme.txt to a proper .pdf style.

 

[Cosmic Penguin]

I found that Orbicomm currently cannot be used with other add-ons that uses attachment points to actually attach it to other add-ons (such as BrianJ's Falcon 9R) - there is no attachment point on the bottom of the satellite, and if I manually add one in the configuration file and use it in a scenario the attachment did not happen and Orbiter ultimately CTDs. Nicholas, can you see if you can change the code a bit to include a bottom attachment point? Thanks!

 

[Cosmic Penguin]

I found that Orbicomm currently cannot be used with other add-ons that uses attachment points to actually attach it to other add-ons (such as BrianJ's Falcon 9R) - there is no attachment point on the bottom of the satellite, and if I manually add one in the configuration file and use it in a scenario the attachment did not happen and Orbiter ultimately CTDs. Nicholas, can you see if you can change the code a bit to include a bottom attachment point? Thanks!

OK nevermind, I found out that I was doing the new attachment point wrongly. Here's the new configuration file:

; === Configuration file for vessel class OrbiComm satellite ===
ClassName = OrbiComm
Module = OrbiComm

; === Attachment specs ===
BEGIN_ATTACHMENT
P 0 0 0  0 -1 0  0 0 1  XS
P 0 0.9 0.1  0  1 0  0 0 1  GS
P 0 0 -2.75  0 0 -1  0 1 0  F9
END_ATTACHMENT

:tiphat: