# ProjectVulcanCentaur

#### francisdrake

The VulcanCentaur is a two-stage-to-orbit, heavy-lift launch vehicle under development by the United Launch Alliance (ULA). Attached is an early development add-on, with limited capability.

For a launcher already in production, very little technical data can be found, aside from promotional stuff.
Specifically on the new Centaur V data are scarce. I would be thankful if somebody could point me to things like wet and dry mass of each stage, or a flight profile!

The idea is to include more functions and better meshes over time, but please be patient with me.

#### Attachments

• VulcanCentaur-04.zip
1.8 MB · Views: 10
Last edited:

#### Gargantua2024

##### The Desktop Orbinaut
For a launcher already in production, very little technical data can be found, aside from promotional stuff.
Specifically on the new Centaur V data are scarce. I would be thankful if somebody could point me to things like wet and dry mass of each stage, or a flight profile!
The new Vulcan Centaur addon looks promising already! In the version me and gattispilot made for the Artemis landers thread and later posted on OHM, I used the specifications of the rocket stages posted from the Space Launch Report site, while also taking guide from the official website of ULA itself:

The grey column is the specs for the Centaur stage used on Atlas V. I think both the current version and Centaur V will share almost identical performance, albeit of course Centaur V will carry a lot more propellant than the Atlas V version

Last edited:

#### Gargantua2024

##### The Desktop Orbinaut
Here's an SCN with Vulcan-Centaur positioned at Pad 41:

Code:
BEGIN_DESC
This is a test flight of the VulcanCentaur.

Launch the Peregrine Lunar Lander into an eastward trajectory. Pull backwards.
When in orbit, wait until the dashed node line, then restart the Centaur and perform the Trans Lunar Insertion (TLI) burn .
END_DESC

BEGIN_ENVIRONMENT
System Sol
Date MJD 61943.6945518604
END_ENVIRONMENT

BEGIN_FOCUS
Ship VulcanCentaur
END_FOCUS

BEGIN_CAMERA
TARGET VulcanCentaur
MODE Extern
POS 3.970000 16.180000 -42.570000
TRACKMODE Ground Earth
GROUNDLOCATION -80.58099 28.58409 46.26
FOV 40.00
END_CAMERA

BEGIN_HUD
TYPE Surface
END_HUD

BEGIN_MFD Left
TYPE Surface
SPDMODE 1
END_MFD

BEGIN_MFD Right
TYPE Orbit
PROJ Ship
FRAME Equator
ALT
REF Earth
END_MFD

BEGIN_SHIPS
VulcanCentaur:VulcanCentaur\VulcanCentaur
STATUS Landed Earth
POS -80.5828310 28.5834560
ALT 40.287
AROT 151.086 -8.299 94.537
AFCMODE 7
PRPLEVEL 0:1.0 1:1.0
NAVFREQ 0 0
MODE 0
FAIRING 1
ICPS
END
Peregrine:VulcanCentaur\Peregrine
STATUS Landed Earth
POS -80.5828310 28.5834560
ATTACHED 0:0,VulcanCentaur
PRPLEVEL 0:1
END
LC41_crewtower:Vessels/B_SLC41/b_slc41_crewtower
STATUS Landed Earth
POS -80.5829310 28.5835960
END
LC41:Vessels/B_SLC41/b_slc41
STATUS Landed Earth
POS -80.5828310 28.5834560
PRPLEVEL 0:1.000
THLEVEL 0:1.000 3:1.000
NAVFREQ 0 0
UMB 0 0.0000
END
END_SHIPS

#### francisdrake

In the version me and gattispilot made for the Artemis landers thread and later posted on OHM, I used the specifications of the rocket stages posted from the Space Launch Report site

Thank you for the data, these are really helpful! The values in your table are close to my ballpark-estimate. For example, for the Centaur I estimated a propellant mass of 52000 kg, your spreadsheet says 54000 kg. For the core stage I overestimated the propellant somehow, will correct this.

A question on the SLC 41 pad: Which one are you using? I tried installing the MRO addon, but got only an empty pad (no meshes).

A more general question:
What is the correct way to attach a 'spacecraft'-vessel to a dll-launcher?
I would love to fly the X-37B on this launcher, but it seems I miss out some lines in the cfg-file.

#### Gargantua2024

##### The Desktop Orbinaut
A question on the SLC 41 pad: Which one are you using? I tried installing the MRO addon, but got only an empty pad (no meshes).

A more general question:
What is the correct way to attach a 'spacecraft'-vessel to a dll-launcher?
I would love to fly the X-37B on this launcher, but it seems I miss out some lines in the cfg-file.
I'm no expert at this, but as far as I can tell, the payload should define at least one child attachment of its own to allow itself be attached on the DLL-coded launcher.

#### francisdrake

I tried the Starliner addon for the SLC 41 scenery, but had this strange 90° upwards effect, where the meshes are all canted sideways. Will give it another try later on.

The child_attach for the spacecraft vessel was an excellent tip!
I added a child attachment point to the X-37B.ini file to the rear of the vessel, and now it works.

For those who want to try:
I installed the Boeing_X-37B_110405.
Then modified the X-37B.ini file by adding
Code:
[CHILD_ATTACH_0]
POS=(0,0,-4.3)
DIR=(0,0,-1)
ROT=(0,-1,0)
TOPARENT=1
LOOSE=0
ID="XS"

#### Gargantua2024

##### The Desktop Orbinaut
I tried the Starliner addon for the SLC 41 scenery, but had this strange 90° upwards effect, where the meshes are all canted sideways. Will give it another try later on.
Strange, I thought I got the working SLC-41 pad from there. Have you tried installing from any of Abdullah Radwan's recompiles of MRO, MAVEN, GPS-2F4, or SDO? One of those mods should have the working SLC-41

#### DDasng1352

where the meshes are all canted sideways

#### Gargantua2024

##### The Desktop Orbinaut
This is the DLL of the SLC-41 pad that works for me, though I don't remember which mod I got this from. The crew tower is definitely from the Starliner addon, however.

If the pad is still 90 degrees off from where it should be, here's the state as saved from the (Current state).scn
Code:
LC41_crewtower:Vessels/B_SLC41/b_slc41_crewtower
STATUS Landed Earth
POS -80.5829310 28.5835960
ALT 2.000
AROT 60.301 -5.406 8.298
AFCMODE 7
NAVFREQ 0 0
END
LC41:Vessels/B_SLC41/b_slc41
STATUS Landed Earth
POS -80.5828310 28.5834560
ALT -0.183
AROT 151.079 -8.260 -175.462
AFCMODE 7
PRPLEVEL 0:1.000000
NAVFREQ 0 0
UMB 1 1.0000
END

#### Attachments

• SLC-41.zip
1 MB · Views: 4

#### francisdrake

Thanks, this SLC41 is upright! Tried it, everything looks fine, but the rocket gets a little 'side push' on launch. Maybe a side effect of the touchdown points. Will see if I can find the reason.

Focus at the moment is implementing the number of SRB's and fairing size (standard or large), controlled by a version designation in the scenario file. VC6L = VulcanCentaur, 6 SRB's, Long fairing.

#### francisdrake

Update 01: The zip-file in the first post was updated.

Made some progress on the launcher configurations. It can now have 0, 2, 4 or 6 SRBs, and either a standard or a long fairing. This is controlled by the configuration key, like "VC2S" for VulcanCentaur 2 SRBs, standard fairing.
Still have to hunt down several bugs in mass allocation.

Materials and textures made lighter, to improve the look while sitting on the launch pad. Still launching from pad 39A, as I did not look into the SLC41 scenarios yet.

Note that the launcher handles heavier now. In the previous version I forgot to add the Centaur propellant mass to the first stage dead load )

#### francisdrake

A short update: I found the payload bug! Took me two evenings ...
Reason was, it is necessary to call 'clbkPostCreation' to update the vessel after initialization.

Why I did not get the idea eralier?
In the API reference there is the chapter
8.2 The frame update loop and vessel module callback functions
8.2.1 Frame update diagram
... but there is no diagram!

I would appreciate if this diagram could be included in the next Orbiter release, or if someone could point me to a place where it is.

#### francisdrake

New version 02 in the first post of this thread.

Switched to BrianJ's fantastic SLC41 launchpad!
Caught several bugs, like mass allocation, touchdown points, crash on payload separation, etc.
Scenarios were renamed. Now an ISS-resupply scenario with a DreamChaser boilerplate vessel is included.
For the those who want of fly the 'real' DreamChaser, an Xperimental scenario is included.

General flight advice: After launch pull slightly back to achieve a heads-down attitude. Aim for a 120-150 km apoapsis with the first stage. When the first stage fuel is down to 70 ton, pitch up to 40°. This is to gain upward momentum. The Centaur has a very low thrust-to-weight ratio and will drop back into the atmosphere if not boosted upwards.

#### francisdrake

New version 03 on the front page!

Updated textures, flames and exhausts. Added support for the CST-100 StarLiner. The scenario is in 'Xperimental' and requires the Starliner addon CST-100-06.

#### Jeremyxxx

##### Active member
View attachment 26754

New version 03 on the front page!

Updated textures, flames and exhausts. Added support for the CST-100 StarLiner. The scenario is in 'Xperimental' and requires the Starliner addon CST-100-06.
That is what the launch of the Starliner would look like following the Atlas V's retirement

#### francisdrake

Yes, with all the delays of the StarLiner development, they may run out of Atlas V's before StarLiner flies.

#### DaveS

##### Space Shuttle Ultra Project co-developer
Donator
Beta Tester
Yes, with all the delays of the StarLiner development, they may run out of Atlas V's before StarLiner flies.
You might want to make the adapter between Centaur V and Starliner being that of the Starliner SM to ensure a smooth transition. The way you have it right now it creates parasitic drag being creating a low pressure zone between the Centaur and the Starliner SM. This not only reduces performance but also creates extra heating and structural loading.

#### Gargantua2024

##### The Desktop Orbinaut
Yes, with all the delays of the StarLiner development, they may run out of Atlas V's before StarLiner flies.
Out of the 28 missions left of the Atlas V, only 8 were reserved for Starliner flights (OFT-2, CFT, Starliner 1 to 6). So yeah, it could switch to Vulcan Centaur most likely starting with Boeing Starliner 7

#### francisdrake

On the adapter between the StarLiner and the Centaur:

The top of the adapter has the same outer dia as the SM.
This dark line may cause an optical illusion when looked at an oblique angle.
The StarLiner has a mesh finer than the Centaur, which causes some irregularities along the circumference.
This I have to improve to look better.

Unsolved is, how the vessel is supported internally on the PAF. On the Atlas V a cradle is used, which is 1.6 m high.
If the same is used here, the length of the adapter would nearly double, with a steeper cone angle.

I will probably make this as an alternative design and then compare the two, to find out which one looks more realistic.

#### MaxBuzz

##### Well-known member
Yes, with all the delays of the StarLiner development, they may run out of Atlas V's before StarLiner flies.
I a couple of weeks ago the news that Roskosmos sent its engineers to fix the errors of the raptor engine