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[1.8x - 1.11.x] Stockish Project Orion v1.8.2 [update 12/29/2020]


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Only when physics warping. During normal conditions, there is an initial impulse from the recoil of the pulse unit being fired, followed by the impulse of the detonation, which is applied via a curve over 8 frames. Main problem is Orion supplies lots and lots of impulse, so it feels like an instantaneous application if you're, say, using 5kt pulse units in vac when your vessel only masses 400 tons - it's going to be 20-30 gees of accel over a short period of time either way.

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18 hours ago, SuicidalInsanity said:

the untextured wedges are radial cargo containers you can stuff in the spine trusses

From the shape, those parts seem very similar to the radial containers in SSPXR, as shown here.  SSPXR has lots of 3.75m parts too, including habs.  Not that you'd want your mod to depend on that one, but it feels like you're duplicating effort here.

You mentioned putting the spaceplane parts into a separate mod.  I'd suggest splitting out the hab/cargo stuff too, so people can pick and choose.  I'm interested in the engine and related fuel and structural parts, but less interested in crew and cargo parts since I already have plenty of those.

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7 hours ago, FreeThinker said:

Intresting mod, main problem seems you apply the huge force only in a very short period which result in extreme force applied to the vessel. So I suggest you try to spread the force over multiple frames, even if it isn't fully realistic, it would at least improve playability

Right. Continued use even with joint reinforcement and lots of struts result in bouncing all over the place. The idea of an engine which is hard to control is good, but the mod overdid it.

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I keep forgetting Autostruts is not enabled by default. Why is it not enabled by default.

Version 1.02 - GitHub | SpaceDock
Impulse code is changed, should provide a smoother, less vessel-destroying impulse.
Minimum Pulse unit yield is now 0.05 kT.

For further tweaking, there's two values in the Orion/Parts/Orion/part.cfg - KSPScalar and CollimationFactor. Increasing KSPScalar will reduce atmo impulse, and reducing CollimationFactor will reduce all impulse, atmo and vac - though this will reduce Orion Isp and dV.

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Yes. The denser the atmosphere, the greater the impulse from the bomb, and vice-versa in vacuum. On the launchpad even the dinky 0.05 kT pulse units are going to provide thousands of kN of impulse, you absolutely want lower yields; A 'standard" launch profile I found myself using during testing (~1500 ton test vessel) was 0.05kT on the pad, by about 10 km atmo density's a 6th of sea level, so increase yield to about 1 kt, then boost it again to whatever the optimum vac yield for ~1.5 TWR is about 15-20km - for 500 ton vessels, this will be about 1.5kT, my test vessel needed 2.5kT for an expedient orbits - lower yields will be slower and require more pulse units, but put less stress on the vessel; going for a 1.1-1.2 TWR ascent will cost you about 200-250 pulse units.
In the Orion Drive's Part Action Window there's an Impulse readout for the current impulse per bomb right under the yield selector that can be used to judge when a higher yield/throttle setting is needed.

An alternate method to orbit would be to use a booster to get the Orion vessel into high atmo/suborbital, then light the Orion drive - retracting the Pusher plate in the VAB toggles a bottom attach node that can be used to stick the Orion Drive on top of a rocket. Be warned, though, the engine won't activate while the plate's retracted, so staging will be a bit more complex than usual.

DeltaV calc ended up being dV = ((PlasmaVel/9.80665 * (((((NPUMass * CollimationFactor) * (yield * 0.2)) + ((1/3Pi*PlateDiameter^2) * DetonationDist) * 0.0012 * atmoDensity))) / NPUMass)) * 9.80665)ln(wetMass/dryMass) + ((NPUVelocity/9.80665)*9.80665) ln(wetmass/drymass).
tl;dr - Dynamic calculation of pulse unit Isp based on selected yield and atmo density fed into a standard dV calc+ second dV calc for the recoil from firing a pulse unit, since that's modeled too.
No, it currently doesn't account for staging, that's on the to-do list, but given the mass of an empty pulse magazine vs the mass of an Orion vessel, that's currently maybe a 1% discrepancy between reported and actual dv.

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1 hour ago, T.A.P.O.R. said:


Sweet mod. I'm not sure on the physics of it all, but it got me to Duna and had fun doing so.
Would have landed successfully too had my ship not  bounced and fallen apart.

I look forward to the rest of the updates.

Well, I'm not sure you can land with this engine as it works with strong pulse units

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On 4/3/2020 at 12:44 AM, münambulist said:

Anyone else seeing the magazines spontaneously fall off under acceleration? 

I finally tried this mod this morning and my magazines were falling off on the pad before I ever started the drive. 

Everything else seemed to work ok - just threw together a craft to test it with (which didn't work great) but other than the magazine issue it seemed to be functioning fine using the internal fuel.  I did not remember to autostrut anything, but I wasn't expecting everything to fall apart before engine start.

Edited by Cavscout74
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Update 1.7 is now up, and includes many of the other Project Orion parts hinted at earlier.
GitHub | SpaceDock


-New Parts:
*1.875m Orion Command Capsule
*1.875m RCS tank, 1,2m length
*1.875m radial fueltank, 1,2,4m length
*1.875m ISRU Smelter
*5m ISRU Uranium Processor
*2m radial resource contaners, 5 variants        
*5m Cargo Bays, 2,4m length
*radial cargo bay, 2,4m length, togglable endcaps
*1.875m Crew segment
*1.875m Lab            
*3.75m Crew Quarters             
*1.875m Endcap
*1.875-1.25m Adapters
*1.875-2.5m Adapter
*1.875-3.75m Adapters
*1.875-5m Adapter

*Further code tweaking to Orion impulse, should provide smoother impulse.
*2/4m spine Trusses now contain ISRU Workshops, now have internal storage/crew access/IVA
*Bomb magazine joint strength increased        
*Spine Trusses now have radial nodes
*ISRU added: Pulse Units can be made via the Workshop with resources produced from the Smelter and Uranium Processor    
*Stock and SMX ISRU compatibility patches for mining Orion ISRU resources

Adds CRP and Module Manager as dependencies.

Orion impulse has gone through a further code revision to smooth things out even further. Heavy parts like the Orion pulse magazines have also had their joint strength increased, and the payload spines now have radial attach nodes for stronger joint connections; together, vessels should be much less prone to RUD than before.

Also added is ISRU pulse unit fabrication. It's not as complex as something like MKS' systems, but it's also not the level of abstraction seen with stock fuel ISRU. Pulse unit manufacture is a 4 step process.
-Step 1 is mine the ore you need, Uranitite and MetallicOre: both can be found planetside or in asteroids, but are not guaranteed to appear in the latter.
-Step 2 is use the Smelter to process the MetallicOre into Metals; you'll need a Smelter, LF/O, and lots of radiators.
-Step 3 is process the Uranitite into EnrichedUranium; you'll need an Uranium Processor and Ec.
-Step 4 is combine intermediate resources into Pulse Units; you'll need a Workshop, EnrichedUranium, Metals, and Ec. Both Payload Spine Truss parts now include Workshops.

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On 4/19/2020 at 1:50 PM, Mekan1k said:


A Medusa wasn't originally on the to-do list, but with only minimal tweaking (mainly opening up animation/impulse cycle length to be configurable) ModulePulseEngine would support Medusae-class engines, so, maybe?


On 4/20/2020 at 12:21 AM, MonkeyCan'tDock said:

20m Orion

I really hope you mean 10m - 20m in the scaled down universe of KSP goes beyond gigantic into truly colossal. A 10m engine wouldn't be difficult to make, and could be included as an add-on mod to SPO, though it would more-or-less require tweakscale to use. You'll have to look elsewhere for Iowa-class turrets or Casaba Howitzers, though. Those are firmly in BDA territory.

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  • 3 weeks later...

This is the most impressive Orion I've seen in KSP. It really captures just how violent flying one of these things would be. :) Well done. The truss does seem to be a little hard to get things to attach to, though. And things tend to fall off it, though I presume the solution there is MOAR STRUTS.

Also launching this from KSC is hilarious. Not a good idea, but hilarious.

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  • 2 weeks later...

So... How do I make more bombs pulse units? Installed this mod in an otherwise stock KSP 1.9.1 and there doesn't seem to be a part for making the pulse units anywhere.

Having such a hard dependency on MKS for producing the pulse units would be a major blocker for me as I don't use MKS and don't plan to start doing so any time soon. It also doesn't help that this mod doesn't list MKS or CRP as dependencies either here or on CKAN so most of the resource parts don't work in an otherwise stock install. There should be some way to make pulse units out of ore, even if it requires a huge amount of ore and a huge amount of power to make them (1000 of each, for example).


Edit: after poking around in the mod folder it seems there's a patch to make the stock drills also able to mine metallic ore and uraninite, but that will still require CRP so that should be listed as at the very least a recommendation.

Edited by jimmymcgoochie
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Having played a bit with this mod, the yield strength "only" going up to 5 kiloton feels rather "weak" for an orion drive.

Although I may be a bit spoiled from Orion TD which had 15kt nukes and giant pusher plates

the DetlaV numbers also feel rather inadequate for going interstellar (Something envisioned for the real one).


However those points aside, It's still a far better option than Roverdudes Orion Drive

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After building an Orion ship with a lander I discovered a bug: the Orion drive does not work for me if the craft has retractable landing gear/legs. The drive consumes pulse units and makes a bright, persistent flash, but it does not play its animation or produce any thrust. I am using KSP 1.9.1 and v1.7 of this mod.

PS: a medusa drive would be fantastic


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On 5/21/2020 at 9:29 AM, jimmymcgoochie said:

So... How do I make more bombs pulse units?

A Smelter and a Uranium Processor - both in the Utilities tab - and a Workshop - integrated into the spinal trusses in the structural tab. There's a patch for stock drills to mine MetallicOre and Uraninite from asteroids, which are converted into Metals and Enriched Uranium, which are used by the workshop for pulse units. I'll see about getting CRP added as a dependency for CKAN installs.


On 5/23/2020 at 12:51 AM, Phoenix-D said:

Varying the KSPScalar in the part cfg doesn't appear to do anything at the moment

KSPScalar controls how much additional impulse pulse units generate when in an atmosphere. Setting it higher will give a smoother launch, conversely, setting it below, oh, 5 or so is going to be suicidal for a Kerbin ASL launch outside of the Unbreakable Joints cheat. For vac thrust modification you want collimation factor, which controls thrust and ISP.

On 5/27/2020 at 6:43 PM, GrandProtectorDark said:

Having played a bit with this mod, the yield strength and dV seem low.

Current numbers were based around the 10m ship intended for launch atop a Saturn V, as well as keeping in mind the reduced scale of KSP - 6 large external magazines + Orion internal mag can still give a 4000 ton vessel something like 100k dV at 5kt yield; but yes, yields and dV are lower than proposed values for full-scale Orions (That, and dV scaling with yield doesn't help, but is a consequence of going for a variable-yield approach instead of juggling n different types of pulse unit for different yields). But remember - 15tk yields were intended for 20m vessels massing in at something like 10-20k tons, and Dyson's 100-years-to-Alpha-Centauri proposal was even bigger.
Doesn't mean I can't open up yield values to let them be .cfg based instead of hard-coded, though.

11 hours ago, UberPig said:

After building an Orion ship with a lander I discovered a bug: the Orion drive does not work for me if the craft has retractable landing gear/legs. The drive consumes pulse units and makes a bright, persistent flash, but it does not play its animation or produce any thrust. I am using KSP 1.9.1 and v1.7 of this mod.

PS: a medusa drive would be fantastic

So that's what's causing it. I was wondering what it was; that simplifies my job trying to squash it. That said, until then, the times its cropped up for me reverting to launch fixed the issue.

As for people wanting Medusae - I was right about being being able to support them with minimal modifications to ModulePuseEngine:
Can't promise a Medusa release date, but they're doable. Scale will need some tweaking, though - that test article is has a 50m diameter when deployed. Semi-realistic, relative to KSP's scale? Sure. Does it fit in the VAB? Not really.

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^^ no and yes. There is no BDA dependency/interaction; Pulse units will not cause HP/armor damage. That said, they do have blast radii, and anything caught in the blast will be affected - KSC structures within the 140kPa overpressure zone will be destroyed (~300m @ 1kt), and parts will be subjected to impulse and flash heating - attempting to rendezvous with a station/base under Orion power will end in tragedy hilarity.
Update 1.7.5 is now up, grab from SpaceDock | Github. No Medusa yet, but the groundwork's there - this is mainly a bugfix update.

-Further revision to impulse code; 2-4x pyhsicswarp now properly uses impulse curves
-ModulePulseEngines now supports Medusa-class Orions
-Fixes landing gear NRE
-Reduced Nuke flash scale at sea level
-Fixes Orion firing when not active vessel and throttle > 0
-Min and max yield is now configurable
-Short Crewcan now has light emissives
-fixes crewhab IVA lounge table normals
-Adds some example ships


Edited by SuicidalInsanity
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On 4/10/2020 at 2:46 AM, FreeThinker said:

Intresting mod, main problem seems you apply the huge force only in a very short period which result in extreme force applied to the vessel. So I suggest you try to spread the force over multiple frames, even if it isn't fully realistic, it would at least improve playability

The suspension system that was intended by the project orion would have spread the impulse out over most of the time between pulses, with the forces felt by the upper craft never dropping below 0 during normal operation.  This was due to a combination of the sophisticated suspension and the pusher plate system accounting for a significant fraction of the vessel mass. That of course works against you when either shutting down or if there's a misfire, and suddenly there's an oscillating few hundred tonnes of craft linked to you.  That's when the real vomiting would start.  

In normal operation, even at minimum mass/max acceleration they were talking peaking at 4G (meaning +4G->-4G->+4G etc when shutting down) with normal operation peaking at around 2G, with averages only 1.2ish.


On 4/2/2020 at 12:24 PM, SuicidalInsanity said:

You've likely heard of Project Orion -


  Hide contents





Awesome work friend.

I love that it took me several reads through to notice the image above isn't the original, and it was the "in collaboration with Sean's Cannery" that wormed it's way into my skull with the hint.  :D


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Another thing I want to mention:
The Pulse Unit Storage Cans don't really make sense.

The Magazines are far too heavy. 
I did some rough math on the volume and density, and all 3 of the Orion Magazines are as heavy as if you filled them to around 4/5th with solid uranium.
I'm not quite sure if the Pulse units themself are too heavy, or if the Magazines fits more Pulseunits than they should, although I think it's a bit of both.
I've seen a numbers for 140kg per pulse unit, the ingame ones come out as around 640kg per unit.
The dimensions for the Pulse Units aren't really that easy to find. But with the numbers that I do could find, I got a capacity of around 180 units for the largest Orion Magazine (the 4 meter one).
This assumes the entire magazine is perfectly filled with pulse units and doesn't account for lost space due to the roundness of the units or space used for the feeder mechanism.

This actually also explains why I thought that the orion felt "weak". 

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