Duna Colonial Transport System

[DunaRocketeer]

I usually post images in the 'what did you do in ksp today' thread, but I'm coming to the end of the tech tree in this current play-through of the game, and I thought I'd share some pics of the vehicles that got me there. But mainly I want to share pics of the ongoing mission that will round out the tech tree, and keep me very occupied after it's done.

Derivatives of the vehicle shown below did the lion's share of the work. It got tweaked a bit as I unlocked better components, but essentially it is a way of recovering launch hardware to the KSC runway. It can put a small shuttle into orbit or a bare-bones manned Minmus flight:

 

Needing greater lifting capacity, but not wanting to change the booster, I decide to hitch two of them to a central disposable core. To keep costs down the core doesn't possess probe cores, SAS, RCS, batteries or anything really beyond a fairing, tanks and a couple of Swivels.

This launcher enabled a far more comprehensive exploration of the Kerbin-Mun-Minmus system. It could put a departure stage plus lander/rover surveyor into Munar orbit, or a space lab around Kerbin.

The next logical step was out into interplanetary space, and the Duna window was closest. I could've managed with the launcher I already had, but it would have been a pain to assemble a craft in orbit. It also wouldn't have been a particularly ambitious design, and since I had just unlocked all these 3.75m/mk3 parts, I thought I'd cook up something new....

 

 

Edited December 26, 2015 by DunaRocketeer

[DunaRocketeer]

As you can see, it is an evolutionary rather than revolutionary progression, but it still required an awful lot of testing to iron out all the bugs associated with controlling large vehicles in varied flight regimes.

The mission architecture owes a lot to the rumour mill surrounding SpaceX's Mars plans: several of the two stage vehicles are launched and refueled in Kerbin orbit by a tanker variant of the DCT, whilst the lower booster stage returns to launch site. For this opening salvo of flights, I've stuck to four DCT's: Two hab modules, and ISRU trailer that can be towed to the various DCT landing sites, and the Engineering Support craft, which contains the Engineer Kerbonaut's Mk1 Lander-Can plus life support, ramps for offloading cargo from the DCT's and a compact tractor-rover derived from my Munar surveying missions.

A steep ascent trajectory is a compromise between putting the upper stage on a good sub-orbital arc, and not going so far downrange so as to make booster recovery impossible:

Getting this barge of a vehicle on the ground is an interesting flying challenge. It also doesn't come to a halt on the runway easily.

 

Edited December 26, 2015 by DunaRocketeer

[DunaRocketeer]

Somewhat unusually, there is no monopropellant RCS system on the DCT - in order to keep things simple and light, translational motion is provided by the verniers that also handle attitude control during launch/entry.

The tanker offloads the vast majority of its propellant to the Duna-bound craft, and leaves just enough to get back home:

That's enough from me for now, I'll put the rest of the images up later. Of course, I also need to actually finish the mission...

[DMSP]

Nice!

[DunaRocketeer]

Thanks!

I needed an additional asset sent to Duna, one that didn't warrant another full DCT launch: An ore scanner satellite so I could figure out where my base should be landed.

All told, there were five spacecraft sent during the transfer window, all requiring course corrections at different times. KAC mod was indispensable!

A shot of a fully fueled DCT just prior to departure:

Goodbye Kerbin, hopefully see you in a few years!

300 days later, the fleet arrives at Duna. Some have to negotiate Ike, but there is plenty of propellant left for a landing. These are heavy vehicles, and aerocapture required a deep dive into the atmosphere and use of speedbrakes.

So that's as far as I have gotten up to now, the rest of the updates will follow on 'live'. I was confident of getting this far, but getting these big ships down to the surface through a thin atmosphere is going to be new for me. Likewise, getting all the cargo offloaded and integrated together could throw up some unforeseen challenges, even though it has been partly tested on Kerbin.

We'll have to wait and see how it pans out!

[Iago]

This is awesome! Dem launchers!

[DunaRocketeer]

That's very nice of you to say, lago!

I've made some progress today, although I find construction much more difficult than flight, and am currently troubleshooting a few unexpected issues.

So far I've got two DCT's on the ground, landed 2,1km from each other:

The engineering support vehicle touched down first, and I unpacked its cargo bay without much difficulty:

Once the rover was down the ramp, I packed it up into a trailer form so it could be towed to the second landing site (DCT Hab module 1):

I then rebuilt the ramp. Here's where it got more difficult: I needed to tweak the rover wheel's brake torque, grip multiplier, and disable steering on the aft two wheel-sets in order for me to make it up the ramp. This was a problem that didn't manifest itself in testing on Kerbin, so I'm enjoying the surprises, and the troubleshooting:

[Angelo Kerman]

Really enjoying the design of your craft and their use!

[Iago]

Will you make a full-blown colony on Duna?

[DunaRocketeer]

At this point I've no idea how big it will grow, depends on my free time after the Christmas break is over. I certainly want a lot more stuff than at present, which doesn't really resemble a colony yet!

[Iago]

But it's called Colonial Transport?

Edited December 27, 2015 by Iago

[DunaRocketeer]

What I mean is it'll look more like a colony the more I add to it all that I have on Duna right now are two hab modules, ore miners/processors and a rover. The vehicles are designed to take modules and crews to Duna a bit at a time, so the next transfer window will be an opportunity to further expand. Hope that helps make things clearer. 

[cubinator]

You must be using KAS for the ramp right? All in all, really cool stuff! 

[DunaRocketeer]

Kerbal Inventory System actually. I probably should have KAS because I'd like the struts and connectors, but it will have to wait until the next install - I'm still running a bugfixed v1.0 right now (I don't upgrade regularly), but will use a lot of different mods once 1.1 lands.

[Geschosskopf]

Some very impressive engineering here!  Kudos

[DunaRocketeer]

Thanks Geschosskopf, it is continuing to be an engineering learning experience, and a very rewarding mission

So I've unloaded the first Hab module, getting it down the ramp took lots of delicate maneuvering.

I attach small plane wheels to tow modules across the terrain - you can just about see the ones I have stowed in the cargo bay in the above image ^. The last DCT left in orbit contained the second hab, so I got round to bringing that down, and towing its hab to the one already on the surface.

The final major element to this mission is the In-Situ-Resource-Utilisation-Trailer which will mine and refine propellant for the trip back. It was stubborn in getting out of the cargo bay, and I needed to use KIS to wedge structural panels under it. This did succeed in unsticking the ISRU trailer, but I lost a large array in the process. I placed the remaining array on top and it seems to bbe working fine.

I'm about a year away from the next Kerbin-to-Duna window, and after reviewing the life support consumables in the Hab, I've decided to keep Bill on Duna till the next round of DCT's get here. There's more that I'd like him to be building before he heads home.

 

[Angelo Kerman]

How do you fly back multiple boosters at the same time? Are you using a mod that lets you go back in time to fly other parts of the craft? I forget the name of it..

[DunaRocketeer]

Yeah it's a mod called Burn Together. IIRC, it's not updated to 1.xx, but still works ok enough - in flight there is a little oscillation in the following vehicle that I haven't been able to damp out using the mod settings, but if you periodically swap who's the leading vehicle, you can get back to KSC no probs. I then release the following vehicle to fly onwards whilst I land the leader, then switch to the other still in flight, turn it around and land that one too.

[Angelo Kerman]

Oh cool, thanks! I just downloaded it. I knew I saw another mod.. it's called Flight Manager for Reusable Stages (FRMS). It lets you jump back in time in your save to fly separate stages. Found it here. Anyway, looking forward to seeing what you do next.:)

[SnakyLeVrai]

That's a good mission concept  well done  I like your ramp! Wings are great for engineering stuff!

[DunaRocketeer]

I had a bit of a setback a couple of nights ago: I lost one DCT to a game glitch. Best guess is that time-warp blew it up (I heard an explosion). In future, I'll make sure they're all outside each others physics radius, and see if that helps. Fortunately, the one that blew up wasn't the DCT with crew support, so Bill can still go home

Anyway, refuelling continues without any issues:

I'm starting to launch the DCT's once refuelled so that they don't glitch out. This is the first one - it got to orbit without incident and with plenty of margin for the Kerbin transfer burn:

So Bill's got a lot of time to kill now, and the couple of rover trips away from the landing site show that any other biomes are a long way away, so last night I sent him on a more ambitious sojourn:

I love the above pic, very SpaceX!

Getting to the North Pole took a surprising amount of fuel - it's easy to forget how much of a boost the planets rotation gives you.

I used KIS to bring the rover instruments with me, so there was a hefty science return from this little jaunt.

...aaand back again.

I've also started launching and refueling the next round of DCT's in Kerbin orbit, which will expand the base. It'll take a while for this to really come together since I have less free time now the holidays are over, but I'll get there eventually.

Edited January 13, 2016 by DunaRocketeer