Project VulcanCentaur

CurlSnout

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Where do I download the Alpaca ?

I hope someone corrects me if I'm wrong, but I think the ALPACA is/was (?) a work-in-progress. I creeped my way through this thread and collected the bits as I went - once again the happy beneficiary of others' (gattispilot, Gargantua2024, francisdrake et al.) talent and generosity:


ALPACA.jpg

Hi-Ho,

cs
 
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Sbb1413

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I hope someone corrects me if I'm wrong, but I think the Alpaca is/was (?) a work-in-progress.
IDK but the progress for the ALPACA lander is stalled as NASA has chosen Starship as the Artemis lander.
 

francisdrake

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The Dynetics Alpace was a project by Gattispilot and friends. For this test I used the Dynetics 102620 development version (attached). But this was only to see, if a Vulcan Centaur could lift a fueled Alpaca lander to Trans Lunar Injection. No, it can't.
The attached test version has drop tanks and landing legs sticking out of the payload fairing.
 

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  • Dynetics 102620.zip
    4.9 MB · Views: 16

CurlSnout

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Further adventures with the Vulcan Centaur - this time lifting a modified (recoverable?) S-IVB stage. This was a test-of-concept; the S-IVB is not in scale withe the VC. But, this way, it fits nicely on top and snug inside standard fairings.

VC_S-IVB_01.jpg

VC_S-IVB_02.jpg

VC_S-IVB_03.jpg

VC_S-IVB_04.jpg

VC_S-IVB_05.jpg

VC_S-IVB_06.jpg

Peace,

cs
 

Sbb1413

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Further adventures with the Vulcan Centaur - this time lifting a modified (recoverable?) S-IVB stage. This was a test-of-concept; the S-IVB is not in scale withe the VC. But, this way, it fits nicely on top and snug inside standard fairings.

View attachment 27983

View attachment 27984

View attachment 27985

View attachment 27986

View attachment 27987

View attachment 27988

Peace,

cs
Speaking of a recoverable stage, there is (was?) a proposal by the ULA to replace the Centaur stage of Vulcan with the Advanced Cryogenic Evolved Stage (ACES) in this decade, which is recoverable.
 

N_Molson

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was, and I strongly doubt it was recoverable, being by definition an upper stage that sends stuff on high Earth Orbit or escape trajectories...
 

Gargantua2024

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The new design concept of the crew version of the Dream Chaser omits the cockpit windows in favor of HUD screens like Crew Dragon has. This could mean on the outside, both crew and cargo Dream Chaser planes would look identically the same especially if Shooting Star modules are attached. No concept art though on what the crew version would look like while attached on the Vulcan during launch:
 

francisdrake

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Thanks for this interesting news!
It sounds reasonable, as the cargo version would anyhow land automatically.
It might scratch a little on the pilots ego, as they will only be passengers,
but given modern day automation this sounds very feasible.

And Sierra can focus on one vessel layout only. This should make human rating easier, as the same vessel type will have flown several times, before a crewed mission will be planned.
 

Voyager_VI

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Been playing around with the Peregrine mission and having problems with spacecraft landing on Moon. I've free-handed my descents to both the plain surface and also to Brighton Beach Landing pad. I also tried using Pursuit MFD and BaseLand MFD. Always with descent less than 1 mps on contact, but as soon as the spacecraft makes contact, it goes into a violent spin and shoots back up into space. Much like the bounce bug of earlier versions of Orbiter. Any sugestions of what to check? contact points in cfg file maybe?
 

francisdrake

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I have to confess that I did not land the Peregrine on the Moon. I just gave it the mass and very basic functions, to simulate the payload.
Congratulations that you made it to the Lunar surface with it!

Will have a look into the config file.

If you want to play around yourself, you could:

- Reverse the sequence of the contact points (e.g. TouchdownPoints 0 -3 -1 2 -2 -1 -2 -2 -1 )

- Make the contact points z-value unrealistic high so they surely point out of the size sphere.
The size sphere of this vessel has a radius of 3 m, and I am suspecting this interferes with the old-style contact point definition
Proposal: TouchdownPoints 0 -3 -4 -2 -2 -4 2 -2 -4
Or shrink the size sphere, but this affects the camera zoom in external view.

- Shut off Pursuit MFD in the last phase of the hover and land manually.
I sometimes had problems with Pursuit MFD starting a crazy tilt just before touchdown.
 

francisdrake

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Please try the attached cfg-file for the Peregrine lander.
Extract it from the zip-file. Then copy it to "Config - Vessels - VulcanCentaur", overwriting the existing Peregrine.cfg

Diagnosis: The vessel sphere was bigger than the radius of the contact points. So the vessel always fell over at landing, into a belly-down attitude.
Measure: Reduced the sphere to 2 m radius, and extend the touchdown points to -2 m. (They are extending sideways as well, now they reach outside of the vessel sphere.

I could land at Brighton Beach, but the vessel sinks through the pad until it touches the actural Lunar surface.
Also, the friction of the old-style touchdown points is low, so the vessel starts skidding down any inclined surface.

Let me know how it behaves on your side.
 

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  • Peregrine.zip
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Voyager_VI

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OK, thanks...will give it a try this week.
Been busy with family and work, so no time to jump into Orbiter lately.
 

Voyager_VI

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Made it to about 3 meter above and didn't get PursuitMFD turned off soon enough I think.
Hit and did the spin bounce straight up....
 

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francisdrake

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0071m.jpg0077m.jpg

It's been a while, but here is a - mainly cosmetic - update of the VulcanCentaur launcher.
Download is on the first page of this thread.

It now sports the red Vulcan logo on the first stage.
Tried to capture the bluish-red exhaust color of Methan engines.
The exhaust trail fans out above 20 km when the ambient atmospheric pressure gets low.

It has a very basic autopilot, activated with [V], which pitches the first stage slowly and ends in a KillRot.
Orbit insertion with the Centaur-stage has to be done manually.

As always: Have fun flying! :)
Comments welcome!

P.S: The Tenacity Dream Chaser on the first page is unchanged.
 

francisdrake

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0220.jpg

ULA has issued a user guide for the upcoming Vulcan Centaur launcher, so I updated the addon.
The new version 07 is available on the first page of this thread.

Changes:
  • Corrected a fuel bug of the first stage.
  • Improved the pitch autopilot. Now the Tenacity Dream Chaser can be launched to the ISS on VC4L.
  • Made a simple dll for the Peregrine Moon lander, to get proper the touchdown points.
This is still experimental and 'Moon bounces' are frequent.

Keys:
[E] Change camera view (up, down)
[J] Jettison payload
[V] Toggle launch auto-pitch pilot, 1st stage only
 

francisdrake

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0231a.jpg

The slightly improved version 07a is available on the first page of this thread.
This is mainly a dll of the Peregrine lander. It can now really land, without bouncing off the surface.
Keep the time acceleration at 1x before touchdown.

To reach the Moon I cheated and kept the Centaur attached until the Lunar Capture burn, where it ran out of fuel.
Maybe you can fly a better trajectory than me?

More detailed photos of the Centaur upper stage became available recently, so I made some cosmetic changes on the first and second stage meshes,
 

BrianJ

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....This is mainly a dll of the Peregrine lander. It can now really land, without bouncing off the surface.
Keep the time acceleration at 1x before touchdown.
Nice! I've been having trouble with the "bounce and spin" syndrome too, on the Nova-C lander. Especially at low frame rates <25fps, or with unexpected lags (due to touchdown dust effects, etc.). I'm still tweaking stiffness and damping values..:rolleyes:
To reach the Moon I cheated and kept the Centaur attached until the Lunar Capture burn, where it ran out of fuel.
Maybe you can fly a better trajectory than me?.....
I favour Jarmo's LTMFD all the way. Minimal course corrections required. Awesome piece of kit.

Cheers,
BrianJ
 

francisdrake

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I've been having trouble with the "bounce and spin" syndrome too, on the Nova-C lander.

The reasons for the 'bounce and spin' are quite unpredictable. Below I summarized, what I found by trial-and-error.
Maybe this helps for your lander:

Has Influence
No Influence
SetEmptyMass(220);
// Higher values are better; found this as minimum mass
SetSize(3);
// It does not matter, if the touchdownpoints are inside or outside of the size sphere;
SetPMI (_V(3, 3, 2.5));
// Higher values are better; found this as minimum PMI;
SetCOG_elev (1.1);
// No influence if touchdownpoints are defined
SetSurfaceFrictionCoeff (1, 1);
// Overriden by the touchdownpoints friction;

Touchdownpoints:
This is a hover vessel, so +Y points up.

static TOUCHDOWNVTX tdvtx_hover[ntdvtx_hover] = {
{ _V( 0, -1.19, 3.2), 1e7, 1e5, 0.9, 0.9}, // front leg
{ _V( -3.2, -1.19, 0), 1e7, 1e5, 0.9, 0.9}, // left leg
{ _V( 3.2, -1.19, 0), 1e7, 1e5, 0.9, 0.9}, // right leg
{ _V( 0, -1.19, -3.2), 1e7, 1e5, 1.0}, // rear leg
{ _V( 1.5, 0.8, 0), 1e6, 2e5, 0.6}, // top right
{ _V(-1.5, 0.8, 0), 1e6, 2e5, 0.6} // top left
};

Changing the stiffness (here: 1e7) or the dampening (here: 1e5) leads to unpredictable results.
I assume this may improve if mass and PMI were higher.

These touchdownpoints show the ‚restless legs‘ syndrome on the Moon. The vessel never achieves landed status, or does so only by chance after some minutes. It does very small micro-hops, which can be watched on the SurfaceMFD.

If the time acceleration is increased to >1:
„Warp speed, Mr. Sulu!“ 😳
 

BrianJ

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Thanks for the data - dropping the friction coeffs to 0.9 seems to have helped me a bit.

I just gave the Peregrine another flight. Used LTMFD all the way from launch to LOI. Only needed 5m/s dV for course corrections. Got the Peregrine down safely using PursuitMFD, at Ukert crater 1.4E 7.8N, with 255kg in the tanks.
All good.Thanks!

Cheers,
BrianJ
 
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