Duna Mission, Single Rocket or Assemble in orbit?

[AeroAviation]

I just want your guys opinion on what the best way to build an interplanetary rocket to bring and return kerbals from the surface of another planet it. I personally would go with docking as its less hassle IMO

[Montag]

Duna is not that hard to do with a single launch.  My favorite is to launch a large ship with a Mark 3 cockpit for a lander to land on Ike, land on Duna, and return to Kerbin.  I have the lander separate from a station that has a mobile processing bay that I leave behind.  The station has some Terrier engines and ferries the lander to and back from Ike.  It has enough fuel to ferry and refuel the lander.

[sketchfab]c0a139d53f854b89b2cdf115d402e54a[/sketchfab]
Duna Lander Open by Montag on Sketchfab

https://skfb.ly/FvYJ

Not sure if sketchfab works anymore, but the link will.  This is an older version, before the 10 meter parts.  I would refuel the main launch stage and then send it on its way.  Plenty of dV and excess fuel after Duna capture.  Leaving the station behind with the extra fuel would be an emergency reserve for the future.

 

[Foxster]

Personally I never assemble a craft in orbit. There is nowhere in the system you can't get to and back from starting at the surface of Kerbin.

If you do do it it tends to cost more, have more parts, takes longer, needs RCS plus docking ports and tends to be wobbly once assembled.  

[Pecan]

I prefer to build a space-only tug infrastructure that does the donkey work of taking satellites and landers backwards and forwards but for a one-off mission to Duna there just isn't any point in orbital assembly.

[Ultimate Steve]

If you are willing to go minimalist, Mk1 pod, heat shield, decoupler, parachute. Then, flt-400 tank and LV-909 engine. Copy-paste. Asparagus staging. You should now have 7LV-909 engines asparagus staged. Add detachable chutes and airbrakes and landing legs. Put it in a fairing and build a transfer stage out of size 3 parts. Then a lifter. Tada! you know have a ship that can do both Duna and Ike in the same trip, but only carries one Kerbal and its a bit tight on fuel if you do both moons. Launch it so that all LV-909's are full when you reach Duna's surface.

[Mycroft]

1 hour ago, Foxster said:

Personally I never assemble a craft in orbit. There is nowhere in the system you can't get to and back from starting at the surface of Kerbin.

If you do do it it tends to cost more, have more parts, takes longer, needs RCS plus docking ports and tends to be wobbly once assembled.  

If your orbital constructions are too wobbly, I would recommend the "EVA struts" mod. Works like a charm.

[Foxster]

1 hour ago, Mycroft said:

If your orbital constructions are too wobbly, I would recommend the "EVA struts" mod. Works like a charm.

Yup, tried that and it is good but I haven't done part or physics mods for a long time. Just felt a bit cheaty and I like the challenge of a doing a lot with a little. 

[Hodari]

Of the choices given, I'd go single launch.  There is also a third option which I used in my most recent mission(crewed Ike landing and return).  Make the first stage with just enough dV to get into orbit, then launch a second craft to refill that nearly empty stage.  You can then reuse that first stage to do your transfer and capture burns, so you'll only need the second stage for the final landing and return trip.  This approach is probably best if your refueler craft is some sort of reusable SSTO design or if you have an ISRU on Minmus and can get the fuel from there. 

[N_Danger]

 I voted for assemble in orbit. But that is for Duna orbit. I launch multiple payloads to arrive at Duna for assembly.

 It is more expensive(I also don't play career mode) but I generally build a station at Duna for long term exploration.

[steuben]

I've done both. These days I'm nicer to my kerbals and don't like keeping them in something with the interior volume of an average home fridge for more than a week. So I tend not do to one big lifts for anything beyond Minmus. Yeah... nicer and I've learned how to dock things.

[Thunder_86]

23 hours ago, Mycroft said:

If your orbital constructions are too wobbly, I would recommend the "EVA struts" mod. Works like a charm.

wait, what? There is such a thing??? I've wanted that in the vanilla game forever! I don't assemble ships up there BECAUSE I couldn't do that! Attaching 2 big parts with only 1 docking port is too wobbly, and creating designs that attach using multiple docking ports between 2 parts id too fiddly to align them right in the VAB... I'm getting this mod tonight!  Thanks for the tip!

[Mycroft]

1 hour ago, Thunder_86 said:

wait, what? There is such a thing??? I've wanted that in the vanilla game forever! I don't assemble ships up there BECAUSE I couldn't do that! Attaching 2 big parts with only 1 docking port is too wobbly, and creating designs that attach using multiple docking ports between 2 parts id too fiddly to align them right in the VAB... I'm getting this mod tonight!  Thanks for the tip!

My reaction precisely when I saw Kottabos' review of it!

[How to: KSP]

25 minutes ago, Mycroft said:

My reaction precisely when I saw Kottabos' review of it!

Alternatively, You could also use the struts from KAS mod

[MDZhB]

It really depends on how much you want to send. For small missions, launching from the surface is okay. For big things though, I like to assemble things in orbit, especially so I don't have to worry much about huge laggy boosters and lots of drag/added weight from fairings.

[the_Demongod]

If you're playing stock you can definitely go with single-launch, but if you have life support mods such as USI Kolonization, you need to build almost a mini space station with the capabilities to grow food and all.

Plus I just love assembling things in orbit but that's just me.

[Mycroft]

52 minutes ago, How to: KSP said:

Alternatively, You could also use the struts from KAS mod

Those struts are waaaayyyy the heck heavier and larger and less efficient to send up. In other words, clunky. Now the rest of the mod is not, but that one part is clunky. This mod I talked about is just like the stock strut, (except it's in the utility tab) and you can place it while on EVA. It is KIS/KAS compatible, actually 

[How to: KSP]

28 minutes ago, Mycroft said:

Those struts are waaaayyyy the heck heavier and larger and less efficient to send up. In other words, clunky. Now the rest of the mod is not, but that one part is clunky. This mod I talked about is just like the stock strut, (except it's in the utility tab) and you can place it while on EVA. It is KIS/KAS compatible, actually 

I see. I haven't used the mod but saw it in a mod review or have heard about it or something

[Thunder_86]

2 hours ago, Mycroft said:

My reaction precisely when I saw Kottabos' review of it!

dude they are so boss! I just tried them out, and they are absolutely incredible! This is now one of my favourite mods alongside MechJeb and Kerbal Alarm Clock!

[GarrisonChisholm]

This is how I did it.

It was a single launch- now mind I don't have a picture of the booster, but that's because it was A) ugly and B) busy, however Boosting something heavy into orbit is something that everyone learns, so I won't worry about that.

I'm particularly proud of the lander.  No refueling required, and it will carry 11 (12?) Kerbals to the surface of Duna and back again to Kerbin.  It re-entered safely from Duna return on its unmanned trial, losing no parts.  Now, the manned flight was a terrible tragedy, but it was not the fault of the design...   >.>

[AeroAviation]

On 6/22/2016 at 5:48 PM, Montag said:

Duna is not that hard to do with a single launch.  My favorite is to launch a large ship with a Mark 3 cockpit for a lander to land on Ike, land on Duna, and return to Kerbin.  I have the lander separate from a station that has a mobile processing bay that I leave behind.  The station has some Terrier engines and ferries the lander to and back from Ike.  It has enough fuel to ferry and refuel the lander.

[sketchfab]c0a139d53f854b89b2cdf115d402e54a[/sketchfab]
Duna Lander Open by Montag on Sketchfab

https://skfb.ly/FvYJ

Not sure if sketchfab works anymore, but the link will.  This is an older version, before the 10 meter parts.  I would refuel the main launch stage and then send it on its way.  Plenty of dV and excess fuel after Duna capture.  Leaving the station behind with the extra fuel would be an emergency reserve for the future.

 

Sorry for late reply but im not exactly sure how to download the file, I dont see any download buttons on sketchfab

[Montag]

1 hour ago, AeroAviation said:

Sorry for late reply but im not exactly sure how to download the file, I dont see any download buttons on sketchfab

Sketchfab is only a model viewer.  I do not think you can share craft files with it.  See the link below.   Double check the staging.  Pretty sure there is enough to do everything, but 100% if you refuel the Rhino engine stage before going to Duna you will have a ton of extra fuel.

Some things of note:

1. Mods used - MechJeb and KER
2. After achieving Kerbin orbit, you will want to disable the fins controls under the right click menu - will explain later
3. I was not able to aerocapture this completely at Duna.  There was insufficient control authority to keep the craft retrograde and the gigantors popped; however, I still had the fin controls active.  I have read that Mechjeb and maybe stock cannot use the fin controls correctly if the craft is retrograde.  This may be the reason for my problems.
4. Regardless, this is safe to have a periapsis of 20km in Duna and then a burn to capture.  You may be able to go deep enough with the fin controls disabled.  I believe 13.5 km should do it.
5. This is the next iteration using the 10 m  parts for the lifter.  It also has a heat shield for Kerbin return.
6. Use an engineer of level 1 or greater to repack the parachutes for Kerbin return.

 

https://drive.google.com/open?id=0B6u6wekQppUdX0doeDlmVURMTkU

[Foxster]

Just one more thought...Why would you want to assemble something in orbit for a Duna mission when you can do a manned return mission to the surface of Duna with a 24t craft:

 

[Montag]

15 hours ago, Foxster said:

Just one more thought...Why would you want to assemble something in orbit for a Duna mission when you can do a manned return mission to the surface of Duna with a 24t craft:

 

The scope of mission. Your craft does not have all of the science instrumentation.  The one I presented has all of the science experiments, can explore Ike,  and leaves an orbital space station.  Just comes back to where do you want to go today?

[Foxster]

1 hour ago, Montag said:

The scope of mission. Your craft does not have all of the science instrumentation.  The one I presented has all of the science experiments, can explore Ike,  and leaves an orbital space station.  Just comes back to where do you want to go today?

Sure but that's a small extra weight and as my craft had about 2000dV left over that wouldn't be hard to add to the mission. Unless the space station has an MPL or a refinery then that just adds unnecessary weight to the payload.  

I've seen a few Duna craft that start with too much unnecessary payload plus too much TWR and it all goes downhill from there. It ends with huge craft that are way over-engineered and need to be assembled in orbit because of this. I like lean, mean rocket machines.  

 

[W. Kerman]

If you are in science mode and don't have the right tech, then go space tug, if you are in sandbox then single launch is less work.