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[WIP] North American Rockwell Mars Excursion Module


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Atomic Rockets says the lander uses ClF5 + MHF-5 for RCS, so it uses a different hypergolic propellant for the RCS than the main engines.  Maybe RCS is integrated somewhere in the ascent stage?  If so, just add mono and LFO in the stock version.  I would think that they would put RCS tanks in the ascent stage somewhere.  But hell, stock isn't supposed to be too realistic, so it's up to you.

For Real Fuels, the hypergolic behavior might come from the Engine Igniter mod (no ignitions required for hypergolic engines).  Otherwise, I don't think they simulate propellants breaking down the rocket (so much for storable) nor being toxic (not sure how Kerbals would get in contact with the propellants).

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8 hours ago, Nittany Tiger said:

Atomic Rockets says the lander uses ClF5 + MHF-5 for RCS, so it uses a different hypergolic propellant for the RCS than the main engines.  Maybe RCS is integrated somewhere in the ascent stage?  If so, just add mono and LFO in the stock version.  I would think that they would put RCS tanks in the ascent stage somewhere.  But hell, stock isn't supposed to be too realistic, so it's up to you.

For Real Fuels, the hypergolic behavior might come from the Engine Igniter mod (no ignitions required for hypergolic engines).  Otherwise, I don't think they simulate propellants breaking down the rocket (so much for storable) nor being toxic (not sure how Kerbals would get in contact with the propellants).

This is what comes from using multiple sources and then forgetting half of them.  That'd be why I didn't just go with monoP. 

I got the landing legs working.  I had a dodgy hack in place from when 1.1 was prerelease and never fixed it after 1.1.2 came out.  But now they even have (really stiff) suspension.  All the mod cons.  I need to sort my obstructing hatch, and do up some RSS and RF config and then it'll be update time.

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OK, fixed the hatch.  The collider didn't need to be as big anymore, as Kerbals are relatively smaller.  Still a bit of work to go, and I'm dead to the world right now, so I'm gonna head off to bed.  Hopefully less of that nasty work type stuff in future weeks.

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On 24/06/2016 at 9:06 PM, Nittany Tiger said:

Good luck.

Hopefully this works for 1.1.3.  Squad threw another update out even before some mods were updated to 1.1.2.  I actually started a new RSS install to test your mod in RSS and now I have to wait for RO to update first.

I've been meaning to answer this for a while.

The version I'm working on will work in 1.1.3.  The version currently available has an issue where the landing legs will not deploy while in flight.  Which makes landing tricky.  When 1.1 came out I was too distracted checking an assortment of parts and updating legs, decouplers, etc to notice, as the legs work on the launch platform just fine.

I'm about half way through adding in RSS/RealFuel MM code to the parts, so I don't want to release with that half done.  If someone desperately needs the legs, I can upload them somewhere as an interim measure.  Be aware that the next update will involve resizing, which will make a horrible mess of any saved craft using the parts, including those "in flight".

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On 27/06/2016 at 10:05 PM, TiktaalikDreaming said:

That ascent module has just about every module.  :-/

It's got charge, mono, dual fuel, reaction wheels, RCS, and a fuel cell. 

I managed to get all the parts apparently functioning with the 4 versions (stock, plus each combo of RSS + RF).  I'll need to run some more checks, but I think it's basically ready to go.  The stock sized IVA in an RSS sized craft looks pretty daft, so I might do up an expanded IVA with, um, a concert hall and cafe or something.  Rescaling doesn't rescale Kerbals, and they're tiny.

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OK, if you've subscribed to this mod on Spacedock, then you will have noticed lots of updates recently.  They're all basically the same.  But I was diagnosing issues with zip file folder structure v indexing on CKAN.  Most of my mods have ended up in CKAN using the find directive, to grab the folder to install, but this is just using file, which means when I built the zip for 0.8, with a different folder structure, CKAN didn't like it. 

If you're using CKAN, then you would have noticed nothing, except now there's an update.

The update has Module Manager config to convert for any combination of Real Fuels or Real Solar System.  Although, I've left the RCS running on Monopropellant as RF includes switching for systems using stock monoprop.

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2 hours ago, Jasseji said:

Hello,

 

Do you offer some guide on how to properly land/take off with this thing ? :wink:

Superb work but i'm having some issues

I need to repackage the prebuilt craft.  Having the staging right helps a lot.

Initially, the deorbit motor is used to (big surprise) take you out of orbit into a landing path.  Note, it's a solid rocket, so once it's started, you get a fixed burn time.  Once it's burnt, it should be jettisoned.

Descent is in 3 main stages.

1: Atmospheric braking using just the craft shape, down to about MACH 3.5 (Using MACH as a multiple of ~330m/s, not the actual speed of sound in local atmosphere)

2: Chutes.  First the drogue, then the ballute.  Chutes would realistically only slow you down to about MACH 1.5

3: Burn: The conical shell and the engine cover (the original plan called for the ballute etc to be cut at this point as well, but with KSP super safe chutes, I keep them all the way down) are jettisoned, and at a suitable time (theoretically at about 3km up), the descent engine is fired.  Landing legs are lowered, and, if you're like me, you then have a good 70% chance of landing upright, 20% chance of half crashing onto the side, and about a 10% chance of unplanned rapid disassembling.

Ascent;

The lab needs to be disconnected.  In my early attempts, I tried having the lab disconnect staged with the decouple and engine firing, but that never once worked well, so now I disconnect it first.

The ascent stage decouples and launches from the descent stage.  The plan is to exhaust pairs of ascent tanks and the jettison as the stage ascends.  That's a giant pain in the rear end in KSP.  You could link enabling each tank and jettisoning the last to an action group, but I find the ascent stage has plenty of oompf without the careful tank management.

Now, I've glossed over the decouple and fire ascent stage.  That's because it pretty much always results in exploding tanks, panic re-alignments, bursts of swearing, and using up a goodly chunk of you're docking monoprop.  I'll just say I'm aware of the joys, and am looking into what I can do better with the collision meshes so they don't interact as much during separation.  In the meantime, if you haven't done any base setup, what can work is relaunching the whole descent plus ascent.  Separating significantly above ground, then using KSP's super powerful reaction wheels, fueled by the fuel-cell, to turn right-way-up, and continue on your way.  The descent stage will then crash back to Duna/Mars, and hopefully you'll get back to orbit.

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1 hour ago, Nittany Tiger said:

I'm curious if you've seen Kottabos' video of your mod.  It's actually how I found out about it.  It's about six months old, though.

 

Yep. That's why the lab decoupler is called "Kottabos Memorial Thingy" or something like that.

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@TiktaalikDreaming do you have any plans to split the Ascent module into different parts ?

Let's say Command Pod + Conical Connector + RCS Struts + service module/fuselage ?

This would enable for instance some kind of return mission and using the pod only as ballistic Kerbin Lander

 

Also is the scale intended because of FASA Scaling ? It doesnt fit well with stock scale:

Mk 1-2 Command Pod is 3-Seat but is almost twice as big as the 4-Kerbal DEM's Ascent Module Pod

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I downloaded the mod and tested the ascent stage in a stock KSP install.  It really doesn't like flying straight with those tanks attached.  I had to either ascend at half-throttle, use RCS, or dump the tanks to get it to fly without trying to flip over.  I did fly it on Kerbin with hacked gravity, but I think the stability issue is in the CoM vs. CoT, which adding gravity back in wouldn't fix.

So, yeah, even with 8 degrees of gimballing on the ascent stage and strong reaction wheels, the thing doesn't want to fly straight.

Going to perform further test flights on Duna in stock (and possibly RSS/RO) and try to provide feedback for you.

Edited by Nittany Tiger
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I can second that, on Duna during entry, the whole ship starts tumbling around due to offset CoG, only hacking cfg's and adding 150 reaction wheel torque seems to stabilise the ship but only a bit :/

 

Pity, i really love the design

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5 hours ago, Jasseji said:

I can second that, on Duna during entry, the whole ship starts tumbling around due to offset CoG, only hacking cfg's and adding 150 reaction wheel torque seems to stabilise the ship but only a bit :/

 

Pity, i really love the design

I think I was able to hold attitude with the descent engine and SAS, though I may have had to use WSAD to keep it stable..

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9 hours ago, Jasseji said:

@TiktaalikDreaming do you have any plans to split the Ascent module into different parts ?

Let's say Command Pod + Conical Connector + RCS Struts + service module/fuselage ?

This would enable for instance some kind of return mission and using the pod only as ballistic Kerbin Lander

 

Also is the scale intended because of FASA Scaling ? It doesnt fit well with stock scale:

Mk 1-2 Command Pod is 3-Seat but is almost twice as big as the 4-Kerbal DEM's Ascent Module Pod

I won't be splitting up the ascent module.  While it might be handy, this is aiming at replicating an unbuilt historic design, which had independent earth reentry vehicles.
Scale is based on a recommendation by NathanKell for converting real world designs to Squad stock scale of 64%.  But, it was converted to that after the original scaling of 50% (IVA design not fully rescaled yet), and so the frame/shell pieces no longer fit stock sizes.  The original size (which you should get if you use Real Solar System + module manager) is a 5m diameter for the descent module, which makes it about 3.2m plus cargo shell.  So I'll later be adjusting the framework stuff to try to match 3.75m.

The seating arrangement in the ascent module suits 4 much better than a plain cone.  It's 2 sets of 2 seats one in front of the other.  That said, you'd need to be pretty friendly with the other 3.  Planned stay duration was 30 days as well.  So 30 days, with 3 other people in between the ascent module and lab module.  I think only that mercury mission for a week of orbit would be counted as more claustrophobic.

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7 hours ago, Nittany Tiger said:

I downloaded the mod and tested the ascent stage in a stock KSP install.  It really doesn't like flying straight with those tanks attached.  I had to either ascend at half-throttle, use RCS, or dump the tanks to get it to fly without trying to flip over.  I did fly it on Kerbin with hacked gravity, but I think the stability issue is in the CoM vs. CoT, which adding gravity back in wouldn't fix.

So, yeah, even with 8 degrees of gimballing on the ascent stage and strong reaction wheels, the thing doesn't want to fly straight.

Going to perform further test flights on Duna in stock (and possibly RSS/RO) and try to provide feedback for you.

The original plan was a thrust offset of 13 or 14 degrees I think.  The gimbal goes a bit nuts at 13, so I dropped it back to 8, but if that's not working for people, shoving back up will need to happen.  It has been working for me, but then I've been using some mods that help with gimballing, so I should probably disable and retest.

 

7 hours ago, Jasseji said:

I can second that, on Duna during entry, the whole ship starts tumbling around due to offset CoG, only hacking cfg's and adding 150 reaction wheel torque seems to stabilise the ship but only a bit :/

 

Pity, i really love the design

You can't keep descending without chutes.  I find about when you start going way off retrograde, just before it start tumbling, you'll also be about right to pop the drogue.

Also, the last few times I've used the drogue chute, it's been acting very daft.  Assuming it's not just me, I will be looking at that and I am aware of it.

Daftness; The part seems "attached" with invisible strings, ie, not actually attached anymore.  The chute waves around madly.  99% chance of flapping around followed by exploding.

Balute still functioning fine.

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4 hours ago, TiktaalikDreaming said:

The original plan was a thrust offset of 13 or 14 degrees I think.  The gimbal goes a bit nuts at 13, so I dropped it back to 8, but if that's not working for people, shoving back up will need to happen.  It has been working for me, but then I've been using some mods that help with gimballing, so I should probably disable and retest.

 

You can't keep descending without chutes.  I find about when you start going way off retrograde, just before it start tumbling, you'll also be about right to pop the drogue.

Also, the last few times I've used the drogue chute, it's been acting very daft.  Assuming it's not just me, I will be looking at that and I am aware of it.

Daftness; The part seems "attached" with invisible strings, ie, not actually attached anymore.  The chute waves around madly.  99% chance of flapping around followed by exploding.

Balute still functioning fine.

So here is what i did:
1. Deorbit burn with solid booster (Initial Orbit 250km with Hyperedit)
2. Decouple booster and prepare for Aerobrake
3. The tumbling starts, i pop the Drogue Chute and the Kraken hits (tumbling starts when hot air is flowing around the shell)
 

As for the scale, i modified it for the stock 1.25 rescale factor (so that on the Ascent stage top node you can place a normal-sized Clamp-O-Tron) - this has no effect on the aerodynamic behavior

 

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5 hours ago, Jasseji said:

So here is what i did:
1. Deorbit burn with solid booster (Initial Orbit 250km with Hyperedit)
2. Decouple booster and prepare for Aerobrake
3. The tumbling starts, i pop the Drogue Chute and the Kraken hits (tumbling starts when hot air is flowing around the shell)
 

As for the scale, i modified it for the stock 1.25 rescale factor (so that on the Ascent stage top node you can place a normal-sized Clamp-O-Tron) - this has no effect on the aerodynamic behavior

 

On step 3.  You need to deploy the chute much earlier than you would for Kerbin/Earth.  ie, at very high altitudes and with velocity still quite high.  Chute deployment is at MACH 3.5, which is ~1100m/s, which is sometimes greater than my deorbit pre-atmospheric speed.  So, the drogue should be popped way before the tumbling starts.  The craft is NOT stable without some drag tied to the nose.

Now, rescale.  Are you rescaling to match 1.25m parts, or setting "rescaleFactor" to 1.25?  The unity components are pretty much all at design sizes.  And Kerbals are small, so setting rescale to 1.25 will be enormous.  AND it won't rescale some aspects.  Chutes in particular have a fixed drag.

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1 minute ago, TiktaalikDreaming said:

On step 3.  You need to deploy the chute much earlier than you would for Kerbin/Earth.  ie, at very high altitudes and with velocity still quite high.  Chute deployment is at MACH 3.5, which is ~1100m/s, which is sometimes greater than my deorbit pre-atmospheric speed.  So, the drogue should be popped way before the tumbling starts.  The craft is NOT stable without some drag tied to the nose.

Now, rescale.  Are you rescaling to match 1.25m parts, or setting "rescaleFactor" to 1.25?  The unity components are pretty much all at design sizes.  And Kerbals are small, so setting rescale to 1.25 will be enormous.  AND it won't rescale some aspects.  Chutes in particular have a fixed drag.

Ok, will try that with the chute :wink:

rescalefactor 1.25 makes the front node fit a regular-sized Clamp-O-Tron, i have to try 1.0 as it might be enough for that too because as you said, at 1.25 kerbals seem small compared to the Lab Door

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28 minutes ago, Jasseji said:

Ok, will try that with the chute :wink:

rescalefactor 1.25 makes the front node fit a regular-sized Clamp-O-Tron, i have to try 1.0 as it might be enough for that too because as you said, at 1.25 kerbals seem small compared to the Lab Door

Just for the record, there is an included docking node that involved quite a bit of (unnecessary) research into docking node types and ages.

Kerbanauts should scale correctly (at least, that's the intention) when rescale factor is 0.64 as per the default config.  At 1.0, it's rescaled to "real life".  0.5 "works" but is pretty darn cramped, and your kerbanauts would be wanting IVAs so they didn't murder each other.

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36 minutes ago, TiktaalikDreaming said:

Just for the record, there is an included docking node that involved quite a bit of (unnecessary) research into docking node types and ages.

Kerbanauts should scale correctly (at least, that's the intention) when rescale factor is 0.64 as per the default config.  At 1.0, it's rescaled to "real life".  0.5 "works" but is pretty darn cramped, and your kerbanauts would be wanting IVAs so they didn't murder each other.

I know, i just don't like the drogue/probe docking ports for aesthetic reasons and use Cx's APAS on all my designs :)

I will be testing with 1.0 today and can share my findings :wink:

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17 hours ago, Jasseji said:

I know, i just don't like the drogue/probe docking ports for aesthetic reasons and use Cx's APAS on all my designs :)

I will be testing with 1.0 today and can share my findings :wink:

So, had some success, the 1.0 Scale also seems to be working OK - Clamp-O-Tron docking ports fit at the top and KErbals are not too small compared to the Lab Exit

Also i managed to land but the Drogue Chute behavior is sometimes erratic :wink:

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On 7/14/2016 at 3:45 PM, Jasseji said:

So, had some success, the 1.0 Scale also seems to be working OK - Clamp-O-Tron docking ports fit at the top and KErbals are not too small compared to the Lab Exit

Also i managed to land but the Drogue Chute behavior is sometimes erratic :wink:

 

9 hours ago, Jasseji said:

I'm also rerunning all my calculations on masses and thrusts etc.  I'm fairly sure errors have crept in as I've adjusted, as I never went back the the source figures and recalculated.  I know for instance that the current ascent tanks are absurdly dense.  There's an extra 45Tonnes of tank that shouldn't be there.

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