SM-25 Service Module: What for?

[dvader]

I just did the Munar 1 mission where they insist I should bring this huge SM-25 service module. It has a (poor) SAS module and tiny storage compartments. I thought I could put the MEM inside it just like the real Saturn V but there were these huge gray bars inside (and I have an aversion to clipping). So, it is huge and looks cool but what is the point of it?

[tater]

You are supposed to put all the propellant tanks, batteries, etc for the command module inside.

[Canopus]

4 minutes ago, dvader said:

I just did the Munar 1 mission where they insist I should bring this huge SM-25 service module. It has a (poor) SAS module and tiny storage compartments. I thought I could put the MEM inside it just like the real Saturn V but there were these huge gray bars inside (and I have an aversion to clipping). So, it is huge and looks cool but what is the point of it?

The LEM sat behind the Apollo SM. I put fuel, monopropellant, batteries and a fuel cell in there.

What's really annoying about this mission is that they force you to orbit the mun in such a low orbit with 0° inclination and then expect you to land way down in the southern hemisphere.

[Technical Ben]

13 minutes ago, dvader said:

I just did the Munar 1 mission where they insist I should bring this huge SM-25 service module. It has a (poor) SAS module and tiny storage compartments. I thought I could put the MEM inside it just like the real Saturn V but there were these huge gray bars inside (and I have an aversion to clipping). So, it is huge and looks cool but what is the point of it?

Is there not an option to remove the internals? I think if you right click and choose variations. Not in VAB this second so cannot test. XD

Nope, thinking of the other parts. As above, it's for other parts/equipment.

Edited March 15, 2018 by Technical Ben

[dvader]

@Canopus Aha... So, I should just fill it with fuel tanks then. Or just use a fuel tank... Since I couldn't figure out what it was for, I just put it below the entire rocket with a decoupler. It got staged and burnt to a crisp at take off.

I totally agree with the crazy mission parameters. It really annoys me when they force me to enter a certain orbit just to realize it was a waste of time and resources. The Blue Mun mission was worse since they explicitly told you to save fuel but then they want you to change to an equatorial orbit Kerbin for no reason at all. How can I plan for the dV requirements if I don't know what crazy things I'll be forced to do?

I tried the Munar 1 mission twice and the second time checked the conditions in the Mission Builder. They don't want you to do it efficiently or elegantly, just fast. So, the second time I just built a huge rocket with 8000 dV so I could do any crazy inclination change immediately. I got 8800 points but it felt like cheating

@Technical Ben I thought the same and clicked around but couldn't find any way to do it. My guess is that you can't. I guess it is just a much larger and much less practical alternative to the storage bays.

[tater]

 

[Just Jim]

I haven't tried the Munar 1 mission yet... which I probably should. But I did my own version of a Munar landing yesterday, and like both @Canopus and @tater pointed out, I crammed my Service Module with fuel tanks, and a couple fuel cells to keep the batteries charged, then stored my MEM behind the Service Module stage inside the fairings.

I don't have a cutaway of the service module, but here's the mission report I posted last night, which shows how I stored and then docked to the MEM.

 

Edited March 16, 2018 by Just Jim

[Kerbart]

Nice job, @tater. However the jury will detract points for that solar panel. You should be using the fuel cells instead!

[Just Jim]

OK, here's the inside of my SM... crammed with lots more fuel that I actually ended up needing, along with 4 small fuel cells, and an antenna on the other side.

I'm actually curious how far my Sarnus rocket can get. Last night doing a Mun landing I ended up with quite a bit of fuel left over in the third stage, and only ejected it so the screenshots looked right. And the SM had enough left for her final re-entry burn I hit the atmosphere doing only about 800 m/s before it finally ran out... 

I don't think a standard MEM can land and return from Duna because of the atmo... but I wonder if I could make it out to Ike and back with one of these?

Edited March 16, 2018 by Just Jim

[tater]

2 hours ago, Kerbart said:

Nice job, @tater. However the jury will detract points for that solar panel. You should be using the fuel cells instead!

I wasn’t making an Apollo clone, lol. 

Least I didn’t clip!

Edited March 16, 2018 by tater

[Delbrutis]

2 hours ago, Canopus said:

The LEM sat behind the Apollo SM. I put fuel, monopropellant, batteries and a fuel cell in there.

What's really annoying about this mission is that they force you to orbit the mun in such a low orbit with 0° inclination and then expect you to land way down in the southern hemisphere.

Don't know what your stance is on mods but STX has that awesome clam shell adapter for Apollo and also a kick ass N1 clone. STX is a Huge mod! Although most of the parts are really cool. If you don't want all the clutter it would be easy to cherry pick some choice parts "that's what I am going to do"  for Apollo they have a full size probe core w Saturn stripes and other good Apollo parts.

[Tyko]

I thought originally that the SM doors were meant to be open and closeable. Isn't there a way to do that?

[KerikBalm]

I think you can stage off the panels, but I couldn't seem to do it from the right click menu for some reason...

[tater]

Also, in my original MH, they staged off, then they mysteriously come back. Haven't tested the patch in that regard.

[Tyko]

On 3/15/2018 at 5:52 PM, Just Jim said:

OK, here's the inside of my SM... crammed with lots more fuel that I actually ended up needing, along with 4 small fuel cells, and an antenna on the other side.

 

I'm actually curious how far my Sarnus rocket can get. Last night doing a Mun landing I ended up with quite a bit of fuel left over in the third stage, and only ejected it so the screenshots looked right. And the SM had enough left for her final re-entry burn I hit the atmosphere doing only about 800 m/s before it finally ran out... 

I don't think a standard MEM can land and return from Duna because of the atmo... but I wonder if I could make it out to Ike and back with one of these?

Looks great! On your lander, how'd you get rid of the bottom shroud that appears as soon at you attach something to the bottom node?

[Just Jim]

Just now, Tyko said:

Looks great! On your lander, how'd you get rid of the bottom shroud that appears as soon at you attach something to the bottom node?

If I understand your question, look carefully at the bottom of the lander, and you will find 2 nodes. One will make the shroud appear, the other won't. 

[Tyko]

12 minutes ago, Just Jim said:

If I understand your question, look carefully at the bottom of the lander, and you will find 2 nodes. One will make the shroud appear, the other won't. 

Cool Thanks!... I was looking in the right click menu for a "shroud" button   

Edited April 8, 2018 by Tyko

[Just Jim]

1 minute ago, Tyko said:

Cool Thanks!... I was looking in the right click menu for a "shroud" button   

Ahhh, understood. I think the non-shroud node is a little bit above the other one, but don't quote me on that.

Edited April 8, 2018 by Just Jim

[Capt. Hunt]

IIRC, one node is supposed to be for your engine, and the other is for the decoupler to attach the descent stage.

[Tyko]

17 hours ago, Capt. Hunt said:

IIRC, one node is supposed to be for your engine, and the other is for the decoupler to attach the descent stage.

Yep, my thought too...if you use the shrouded version it's harder (I haven't found an elegant way) to EVA from the hatch with a ladder. Ladder placement is really problematic.

[EdwardB3020]

The fuel drained from one side of the tanks i put on and the others wont pump fuel into it. It's so weird. 

[klesh]

Yes, the service modules have a few strange bugs associated with them; I'm still finding new ones more than a year after their release.

[Ratwerke_Actual]

22 hours ago, klesh said:

Yes, the service modules have a few strange bugs associated with them; I'm still finding new ones more than a year after their release.

 

On 4/25/2019 at 6:14 PM, EdwardB3020 said:

The fuel drained from one side of the tanks i put on and the others wont pump fuel into it. It's so weird. 

I had so much trouble (about a week) figuring out a work around for every bug in the SM.

It's easier describing what SM will do. Nothing reliably.

To work around the fuel issue, mount a fuel tank on the bottom (outside). then offset it down temporarily to mount a couple of cubic struts on it. Move the tank back up and mount anything you want to work reliably on the inside of the SM to the struts.

Don't deploy the panels, use staging. That will let you click on objects inside.

Be aware that SM may actually hide Δv calcs for fuel inside or could spontaneously break the universe upon staging the panels, forcing you to the tracking station to reclaim your vessel.

The SM is nothing more than a pretty spacer in my build at this point.

Not bashing, but yeah I kinda am.

 

[Aeroboi]

The SM-25 seems to be very "Hydrodynamic"
Besides boats it seems to have a low to medium submerge ability meaning it doesn't have that much positive buoyancy. Meaning it requires not that much negative ballast to submerge.
Since everything inside is protected from drag you can stuff the content with seats, vectors or ore ballast and tbh really anything else and can do 60+ m/s underwater with proper tapered ends instead of 50m/s I could achieve on older stock designs without the SM-25 used. Put a stock impeller behind and you have a infinite range and fast submarine.

[lajoswinkler]

I can't get this thing to crossfeed fuel. My "Resource transfer obeys crossfeed rules" option is turned OFF and it still doesn't work. No matter what fuel arrangement I use inside, nothing. Sometimes fuel path shows in VAB as normal, sometimes it doesn't, but during flight engine on its bottom just doesn't work. No propellant.

I tried central node for tanks, two lateral nodes, lateral pouring into central by fuel pipes... nothing. It's been like this since "Making history" came out.