TiktaalikDreaming

[WIP] North American Rockwell Mars Excursion Module

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From Scott Lowther's USSP #04

Quote

In 1967, the Space Division of North American Rockwell produced a design for a manned Mars Excursion Module (MEM) that has in the years since become somewhat iconic. It was included in Mars mission planning by numerous aerospace corporations as well as NASA over about two decades, including the Boeing Integrated Manned Interplanetary Spacecraft (see USSP #03 for more on that).

The intention of this mod is to provide the parts to build said craft.  Keep in mind this was a module for landing on Mars and not staying for months.  It's small and cramped, used a fairly horrible oxidizer, and in short, wouldn't be used today.  But, the basic design has persisted.  See also http://www.projectrho.com/public_html/rocket/realdesigns.php#id--North_American_Rockwell_MEM

At the moment I'm just planning on the base MEM design itself.  The various logistics landing craft can mostly be put together with existing parts, especially the various procedural parts mods.  What sets the MEM apart is the way the various parts interlock.

Depends on (and repackages) Prop assets from https://forum.kerbalspaceprogram.com/index.php?/topic/166433-13-tiktaalik-dreaming-props/

Download from SpaceDock http://spacedock.info/mod/425/NKR's%20DEM

Dev things are available on github https://github.com/TiktaalikDreaming/NAR_MEM/releases  I use github to sync and backup my work, so the git version will usually be tga file textures instead of dds and a few other little things I tend to clean up for spacedock release not done.

Gratuitous pictures;  Parts available: https://imgur.com/a/epec8

rFNVZ2p.png

Now mostly updated for 1.1.  1.2.2  1.3

How to use this thing?

Here's a mission cycle starting from Duna orbit.  Real solar system versions would be similar but with larger numbers.

Click album link for the mission cycle; https://imgur.com/a/FGQa0

Edited by TiktaalikDreaming
added dependency

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A note on what's in progress and what I know isn't there.

The base is insanely too light, because I stole the config from a stock heat shield, hacked it about and haven't adjusted mass yet.  And it doesn't have RCS, RCS propellant, fuel/oxidizer tanks, the discarded centre piece of the heat shield, or the shell that covers the ascent stage.  But by god it has a lot of work sunk into it.  Those damned legs.

Although I've provided the Ballute and Drogue, they're expected to fit into a top mounted docking port that isn't yet in game (although I have a blender shape for it).  Once I have that piece, I'll start messing with how the drogue chute and ballute connect.  Current attachment points are best viewed as wildly speculative.  Many of the parts have a centre at the centre of the full MEM, although their attachment points are adjusted.  This could result in daftness, especially when trying to place them in the VAB.  And probably f'cks up the mass distribution.  Or in the case of this, unfairly makes the mass distro easy.

The engines both have stupidly large gimbals.  This is because the original plan was to have the engines canted at 13 degrees to counter the offset of the centre of mass.  So I set the gimbal to 15 degrees.  Without adding the gimbal speed option it's a bit silly though, so expect to see the gimbal get slower than infinitely fast soon.  And then it's still a band-aid solution to the core issue of the whole thing is a bit deranged.

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You're the man! I've been in love with the MEM since I was a kid. I'm not a mod developer, but let me know if you need help with finding data from the rockwell studies. Although something tells me you know more than enough already.

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I've converted the bases for the descent tanks to radially symmetrical.  As it was, you could match the planned look only by rotating every tank to match, which was a pain in the proverbial.

I'm also looking at how the descent stage's RCS, Legs and Lab all interfere with each other.  The original placement of the RCS and Legs would have RCS nozzles intersecting with leg components.  Rotating either by 15 degrees sets RCS to either across the leg components (in an OK way) or no-where near them.  BUT, if I rotate the RCS, it then occupies space used by the lab.  If I rotate the leg gaps, then placing the damned things will be a huge pain in game.  So, I'm going to rotate the lab and thus the ascent stage, 15 degrees clockwise, with the RCS.  All those Jeb damned radial stack nodes change.

Ascent Module rotated.  Thank Bob for spreadsheets with trig.  I think just a docking part and fixing the lab are next, then all the parts are basically functional.
I feel I should note here that, unlike virtually every stock (aka, non Realism Overhaul) mod with historical parts uses a scaled down edition of the original.  Partly because the VAB isn't really big, and partly because kerbals and kerbin are smaller than humans and Earth.  And so far, this WIP has been full scale.  So, at some stage soonish, I'll be embarking on half scaling this. Which will muck up any craft anyone has built with the full scale parts.  But seeing as the released zip is missing some significant parts, I suspect that won't really annoy anyone.

Edited by TiktaalikDreaming
Updates

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Descent tank stack node fixed.  And I've gone through and half scaled everything.  Thankfully, when you use the rescale attribute in KSP, KSP rescales the stack node positions.  Praise Jeb. Hopefully I got everything right with that.  I'm aware of an issue with the interstage decoupler not connecting without swearing while standing on one leg, holding your tongue just right and rubbing your hair counterclockwise.  I suspect that's due to mismatched stack node sizes, but I keep forgetting to test.  Maybe next version it won't be horrible.

Next version should have the docking port (I have to go back to some old stuff to try to reremember how to do docking nodes, it's a transform or sumfingk) and updated chute units that will fit in where they should now obviously be intended to fit.  And some week soon, textures!

But at least now, you don't have to try getting a 10m thing to Duna, a more kerbal 5m will still require some serious piece of work without other over-sized mods, but not like 10m did.

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I was just testing what I thought was a version with all the parts working when I realized the discardable outer shell used during reentry covers where I put the chutes.  I have a hairy descent for Jeb and co coming up, then a bit of adjusting. 

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OK, well, I sorted some issues and have uploaded a new version.

Now working:

The Lab's airlock/hatch.  It was being obstructed by colliders on the base/heat shield which have been rebuilt as they were massively over complex.

DeOrbit motor has a gimbal that should be enough to not spin like a crazy top.  Also, I fixed up the decoupler to increase the gap between stack nodes (when the stack nodes are really close is when it's hard to get the parts to link in the VAB, which I think you'll agree is insanely frustrating).

Interstage decoupler (between descent and ascent modules) has had it's stack nodes shifted apart, at the expense of burying the stock node into the ascent engine a bit.

Base/Heat Shield has been slightly redesigned, no stair to a lower level.  I WAS thinking of an outside stair, but seeing as a kerbal can almost jump over the whole landed craft it might not be necessary.

Next I'll be working on a basic shroud/hangar type thing for the DEM.  For either adding inline or sticking out the front of a craft (original plan was for this, but it mostly excludes single launch options)

 

Also, craft file: https://www.dropbox.com/s/rc5o3lpz3q0he4h/Duna%20Excursion%20Module.craft?dl=0

Edited by TiktaalikDreaming
Added link to craft file

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On 3/29/2016 at 6:52 AM, TiktaalikDreaming said:

Warning, I can't seem to get the docking node to work.  It may require adjustings.

Except that appears to have been a corrupt save or something.  Also couldn't use airlocks, ladders, etc

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I look forward to configuring this for Realism Overhaul :)

I've tried making something vaguely similar with procparts with little luck. Offsetting the CoM is also key for generating lift which is absolutely necessary on Mars, less so on Duna.

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3 hours ago, stratochief66 said:

I look forward to configuring this for Realism Overhaul :)

I've tried making something vaguely similar with procparts with little luck. Offsetting the CoM is also key for generating lift which is absolutely necessary on Mars, less so on Duna.

Well, the first step would be changing RescaleFactor from 0.5 to 1.0 and multiplying masses, resources, and thrusts by 8, because it's based on the real (proposed) figures half scaled.  Everything is hypergolic due to the FLOX oxidizer, although the ascent stage definitely has separately allocated RCS fuel which is more traditional, which is slightly baffling, but maybe they didn't want to be spewing out hideous corrosive fluorine clouds near the orbiting craft.

And 1.1 is increasing motivation for me to get off my poophole and make IVAs.  :-(

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I have a working update patch for prerelease 1.1 available here https://dl.orangedox.com/fwHMwGMo0A2iXdn3B6

It's just a zip of the parts updated.  I've started creating IVAs, and the Lab IVA is in the wrong spot/orientation.  I know that, sorry, tough. 

Legs: The only part that actually needed updating to work in 1.1 is the legs (feel free to just copy the legs in).  Due to the established issue Squad had with Unity5 wheel colliders not ignoring other colliders, even when they've been marked for ignoring, I've actually ended up removing the wheel colliders (and thus suspension, etc) from the legs.  Squad have a work around they're working on.  If that makes it into the prerelease, I'll mess with wheel colliders again before 1.1 release, but if not, I'll wait until 1.1 release before making the legs complete again.  The legs in the zip above do work.  They deploy and retract, although I found that there's a strange huge delay.  Most of the leg/wheel modules (there's four now) are commented out, but deploying still works, and these are pretty simple legs.

Other updated parts are the Ascent module, which has a partly done texture now and an IVA (although no props working just yet).  There's the very beginnings of a texture for the base/heat-shield.  And ditto for the lab, plus the aforementioned broken IVA for the lab.
 

Update: I've reverted the lab to stock IVA for the moment.  I'm re-aligning the lab and IVA in blender to reduce IVA orientation horrors in Unity.  This zip has a renamed thingy.

Edited by TiktaalikDreaming
Updated

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Lander I cobbled together based on this design using the parts I had available. Really cool someone is doing a proper model of this!

6SieoK1.png

Edited by tg626

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Wonder if this is Realism Overhaul compatible.  

Been wanting to do the Voyage Mars Mission for a long time, and recreating the MEM from procedural parts is a pain in the butt, plus I have no idea of the specs for the MEM.  Searching online hasn't yielded much beyond diagrams.  Also can't get a copy of Baxter's book so I can see if he made specs for his version of the MEM.  I asked @Chris P. Bacon about his lander in the comments of his video, but he never responded.

If this mod is RSS/RO compatible, it would save a ton of work recreating the mission as I could just mount this on a FASA (or whatever) Saturn-VB and go.

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3 hours ago, Nittany Tiger said:

Wonder if this is Realism Overhaul compatible.  

Been wanting to do the Voyage Mars Mission for a long time, and recreating the MEM from procedural parts is a pain in the butt, plus I have no idea of the specs for the MEM.  Searching online hasn't yielded much beyond diagrams.  Also can't get a copy of Baxter's book so I can see if he made specs for his version of the MEM.  I asked @Chris P. Bacon about his lander in the comments of his video, but he never responded.

If this mod is RSS/RO compatible, it would save a ton of work recreating the mission as I could just mount this on a FASA (or whatever) Saturn-VB and go.

It's not, but it's close.  I've been slowly working towards module manager config to trigger for RSS and RealFuels for all my mods.  But at the moment, I'm also trying to change scale from 50% to 64%, so there's quite a bit of work there for the MEM.

All the weights/fuel amounts/sizes are based on the published numbers where I could find them, but currently scaled to 50%.

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Cool.

Meanwhile, I can try to use the details from the Atomic Rockets article to rebuild the craft.  I didn't think about looking there until I saw your link.

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Well, I'm thinking of releasing a resized MEM with my IVAs in an unfinished state.  When I resize the parts, I'll take the time and do RSS and RF conversions.  So, not strictly fully RO, but then the plans were all using hypergolic propellant mixes, so it'll be fairly close.

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Given that this whole design was conceptual, I don't think you'll ever get it exact. If this thing ever got developed seriously, it probably would have gone through significant changes just like the LEM did.  A practical, functioning KSP equivalent would work better than a 1:1 recreation.  I imagine you might go through the same trouble making a working RSS version.

Plus, I don't think FLOX/CH4 is supported in Real Fuels unless I'm wrong.  RF does support a ton of fuels.

I'm no modder, so I can't imagine the amount of work you put into this, but you probably put a lot in given how close the final product is to the designs.

EDIT: If or when FASA gets updated for 1.1.2, I might do an RSS/RO install of 1.1.2 and put this on top of a Saturn-VB and test fly it (as best I can).  I know Scott Manley said in his RO series that RSS/RO has had issues with mods getting updated, so I don't know if or when there will be a playable state for RSS/RO 1.1.2.

Edited by Nittany Tiger

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4 hours ago, Nittany Tiger said:

Given that this whole design was conceptual, I don't think you'll ever get it exact. If this thing ever got developed seriously, it probably would have gone through significant changes just like the LEM did.  A practical, functioning KSP equivalent would work better than a 1:1 recreation.  I imagine you might go through the same trouble making a working RSS version.

Plus, I don't think FLOX/CH4 is supported in Real Fuels unless I'm wrong.  RF does support a ton of fuels.

I'm no modder, so I can't imagine the amount of work you put into this, but you probably put a lot in given how close the final product is to the designs.

EDIT: If or when FASA gets updated for 1.1.2, I might do an RSS/RO install of 1.1.2 and put this on top of a Saturn-VB and test fly it (as best I can).  I know Scott Manley said in his RO series that RSS/RO has had issues with mods getting updated, so I don't know if or when there will be a playable state for RSS/RO 1.1.2.

I have taken liberties.  :-)  I had to do some rotations as those RCS things were intersecting legs structures and things like that.  Also the propellant amounts for each module are given as a total mass, for RCS, main engines and fuel cell.  So I just arbitrarily carved that up into mono, and dual fuel.  But at least for most of the masses, there were references.  And in game, I haven't had to significantly change any.  I'm tempted to make some things heavier in the stock edition, as a lot of stock parts are a lot heavier than their real world comparisons.  Direct use of real world figures tends to make parts relatively more powerful and seems a bit cheaty.  :-)

And, Real Fuels might not support FLOX/CH4 directly, but it depends on Community Resource Pack, which has both CH4 (in liquid or gas) and three grades of FLOX.  There doesn't seem to be a way of making fuel systems horribly toxic and hypergolic in contact with anything though, so I'll just have to live with stock behaviour for the fuel.

 

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Actually, the more I think about it, the more I feel I should convert the stock vehicle to just using monopropellant.  It's not really claimed anywhere in the docs that I can find that there was a separate fuel store for the RCS, and they were using hypergolic fuels for the main engines (except the solid booster de-orbiting engines).  So the best match in stock would probably actually be the mono.

This means I'll probably break this some more.  :-)

PS: I have a resized to 64% mostly done.  But the old issue of hatch obstruction has come back to haunt me, and I'd like to get the legs working again.  They won't deploy in flight, which is a nuisance.  An "Oh my god, we're going to crash and die" grade nuisance.  They work in static tests, on the ground, attached to test rigs.  But they get stuck in "deploying" without actually deploying if in flight.  I suspect they've been like that since 1.1 and the leg/wheel breakinging.

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