Green Dunes: Reusable Long-Term Duna Base: Now with Part 3

[SofusRud]

After a long bit of procrastination from my preferred way of procrastinating,

I'm finally ready to throw myself after my latest big project. So without further ado, I give you:

Project Green Dunes: Reusable Long Term Duna Base Part 1

Intro

After a three years of operating their cargo SSTO, undertaking the construction of a space station in LKO and sending the interplanetary spacecraft "Tirek" on its maiden voyage to Duna, the bigwigs running Establishment Inc decided that the time was right for a new and bolder effort. The Tirek mission, which had carried Bill and Bob Kerman, along with a rover and a lander, to the surface of the big red planet Duna and back, had been set on a return trajectory back to Kerbin, which meant that the time would soon be ripe for new mission.

The Tirek leaving Duna (left) and Cloudbase Kerbin (right)

Fortunately as it transpires, the same thoughts must have crossed the minds of guys at KSC, and Establishment Inc soon were shortly contracted for a new mission. A mission to establish a sustained presence on Duna, and all that came with it, of course with the stipulation that no components be thrown away, and that everything be handled in as environmentally responsible a manner as possible. To do this, Establishment Inc will have to make ample use of its tried and tested cargo SSTO fleet:

The Thunderlane Mk-5 (Quadcoupler not standard equipment)

The Kylon-1

The Kylon-2

and various other smaller planes

Constructing Tugs

Hauling stuff to Duna will requires the use of space tugs, several of them. A while back, after many shouting matches between the main engineers, it was decided that the single-engined fuel-tank-pushing cargo dragging design of the Tirek would not adequately suffice. Instead, a design with two nuclear engines set out on pods, both its fuel tank and most of its cargo was decided upon. This design also takes advantage of the availability of the Kylon-2, which had not been developed back when Tirek was put together, and uses an orange jumbo as its main fuel tank.

This Tug design requires a total of three launches and three dockings to complete

first, the Tug core is launched, containing the power core, monopropellant tanks, and the ports for the engines. It needs to use a Kylon-2 due to its length, its weight is way lower than what the Kylon-2 is spec'ed for, making it very easy to get into orbit.

This design had already been built and tested once, dragging a survey station to minumus, and was now docked to the Kerbin space station, Cloudbase Kerbin.

three of these are launched.

Next comes the engines, two nukes a-piece. These are attached with delivery drones that then return to their SSTO and are then returned to Kerbin for reuse.

The first Tug has its engines delivered by a Thunderlane Mk-5

Tug returning

The other two were outfitted by a Kylon-1 in one go.

Then, all that's left to deliver are the Jumbo.

The Kylon-2 simply stops next to the tugs and detaches from the jumbo, and the docking is handled by the tug.

This process is repeated for each tug.

Now with all three tugs completed, they are then christened the completely random and non-related names "Discord", "Chrissy" and "N.Moon"

Slight Landing Complications

On its way back from delivering the first of the jumbo tanks, one Kylon-2 suffered landing complications.

It was as the aircraft came up over the mountains west of KSC, that the mission operators, at KSC noticed that an error had occured and that the aircraft was going to overshoot the runway by a significant degree. Somebody with a bit of Jeb in his veins decided that the best way to rectify this situation was to send instructions to the remote guidance unit in the Kylon, telling it to flip over and pull up as it came over the runway. To be fair, this could have worked had it been done a little later, but as it had to come almost straight down and pull up at the last minute. Too bad then that whilst the control authority that the Kylon-2 has is substantial it was not great enough, and the aircraft hit the ground at far too great speed to hold together.

Lacking a control unit, the remainder of the craft rolled across the length of the runway, a strange combination of perfect balance and wing surfaces keeping it going, with only the wheels touching the ground.

(In the end I realized that it would keep going until it reached the hills, so I switched physics warp on and off, causing it to bounce and the front hitting the ground, stopping it)

In the next part: Cargo!

Edited November 11, 2014 by SofusRud

[SofusRud]

Project Green Dunes: Reusable Long Term Duna Base Part 2

Lots of Docking

Back again, this installment is all about the docking, assembling the cargo that will be going off to Duna come next alignment.

Discord

First up we have the tug Discord. This was by far the most complicated cargo to put together, because it was no simply a matter of putting some pre-assembled payload onto the tug, part of the payload itself had to be put together as well.

You see, I find that in order to make the best kind of modular base part count needs to be kept to a minimum. This goes for space stations as well, and is why I don't put RCS systems on the individual space station components but instead have them assembled with smaller assembly drones and tugs and such. When it comes to a modular surface base on the other hand, maneuvering in space is not the issue, rather it's the landing part. Since this is a reusable space program we can't resort to disposable skycranes or disposable chute pods like I used to in my previous saves. Instead, this is what I came up with:

Skycrane

The core of the skycrane is basically identical to that of my nuclear tugs, with the exception of some wide and rather tall landing legs and the replacement of the bottom Snr port with a regular one.

Launching it was less of a hassle than I had anticipated, my Kylon-2 easily handled the fact that the landing legs offset the COM a bit upwards, and reaching orbit and docking with the Nuclear tug was a breeze.

Next up was adding a main fuel tank to the skycrane, not to mention the engines. I decided to go for LVT-45s, but if anyone has a suggestion for a more appropriate engine choice, then feel free to let me know.

N. Moon

An outpost on Duna requires a space station overhead, so as to prevent the space above the planet from being cluttered and as a storage depot for fuel, tanks, and other equipment. A suitably simple yet functional station core was thrown together, with five Snr docking ports, three regular ports, a large assembly drone and capacity for a crew of 4, all fitting snugly into the bay of a Kylon-2.

Once docked, I decided that this was probably enough for Discord, and decided to move on to the other tugs.

Now that we've seen how where going to ship stuff to the surface of Duna from orbit, it's time to see what that will be.

Habitation modules, simple Hitchhikers with legs and ports to attach each to three other components, as well as the top port for transport, and a bottom docking port so that the assembly rovers can attach.

Speaking of assembly rovers, here they come now, along with a pair of tunnel/structural segments. It wouldn't all fit in the cargo bay so it sort of sticks out the top in a slightly (IMO) comical way. After docking I undocked the rear segment, did a 180 roll and redocked, just so that I wouldn't have to deal with COM being out of alignment with the COT

After that, I sent up a big tank of with about 3000 units of RCS, and an MMU.

The MMU is worth noting, in that it has no probe core and can only be piloted with a Kerbal on-board. It is kinda big for an MMU, but that is what we have to deal with when making these things, at least when you feel that it needs reaction wheels and feel that a remote-controllable MMU kinda misses the point, at least until SQUAD adds probe-sized reaction wheels (pretty please). This MMU has been outfitted with a grabber, to facilitate engine switching, since you can't add more than one docking port to engines. Since the MMU needs a pilot, Jebediah got a chance to go into space today. All I had to do was add a command pod in the cargo bay that just stayed attached for the whole mission.

The MMU is docked on the back, behind the rovers.

Chrissi

The cargo of this tug consists again of mostly of surface base parts, and one rather special rover.

We'll go quickly through the two base parts: A lab module and a fuel tank

Now for that rover I promised you. Basically, the mission planners realized that a lot of things could potentially go wrong on an endeavor like this. More specifically, there were concerns that we would be royally screwed should an assembly rover or a base component flip or fall over. Also, if something underwent unplanned disassembly for whatever reason, it might be prudent to salvage what can be salvaged. Therefore, it was decided that some sort of contingency was needed, and that contigency is the Detritus Mk-2 Rover.

The Detritus Mk-2 is a basically a crane rover, using a CLAW to grab onto objects and some bendy parts being pushed by landing legs to lift them. It had to be light, have low part count, functional, and uniquely, due to it not being able to fit under the skycrane, able to land on its own with parachutes, hopefully intact.

I still have one more Tug left, docked to my LKO space station. I'll probably just load it up with a big fuel tank a few hitchhikers for crew transfers, unless anybody has any suggestions for what I could load it up with.

Any feedback/suggestions are much appreciated.

[Rhyunix]

I have yet to see a SSTO like that before, fascinating

[SofusRud]

All of my SSTOs have their own pages with dowloads and so forth if you wanna check them out

Kylon: http://forum.kerbalspaceprogram.com/threads/79535-The-Kylon-my-best-high-capacity-SSTO-so-far

Kylon-2: http://forum.kerbalspaceprogram.com/threads/82913-Kylon-2-The-Re-SSTOening

Thunderlane mk-5: http://forum.kerbalspaceprogram.com/threads/65968-Thunderlane-Mk-5-Becausethe-old-one-needed-an-upgrade

Kinda odd to think that I've been using the Thunderlane for about 6 months now!

[SofusRud]

Project Green Dunes: Reusable Long-term Duna Base Part 3

Part 3: Derpin' Duna

Its been a while but I'm finally back, exams and such can be such a drain on free time, but anyways...

Transfering Stuff

With all the stuff for the first shipment all assembled and ready to go, the next step was plotting four trajectories to Duna.

All fairly straightforward, only the one in the bottom left had troubles, seeing as how the COM of the crane thing wasn't totally inline with the COT and the arm by which it was attached was kinda bendy. That made attitude adjustments slightly trickier. They each took 2 burns to get their escapes and encounters with Duna, each arriving between 12 hours and a few days between each other.

Once there it was a simple task of doing a aerocapture, and then raising periapse, and then waiting for the next one.

I'll spare you the details regarding the subsequent numerous aerobrakings, and skip to the more interesting bits.

I decided to make 80km my baseline orbit, and where I would put the Duna station. Mostly so that I wouldn't have to deal with the ridiculously slow max time acceleration at lower altitudes, which make doing rendezvous an absolute chore.

The station was undocked, the skycrane docked to it and the tug was left somewhere around the same area. The tug doesn't really have much more to do unless more fuel is required and can basically wait around for the next time a transfer window with Kerbin pops up.

The Landing of Stuff

Now came the moment of truth, the question that would decide the viability of the entire project and which the whole project hinged on: Would the Skycrane work?

Right off the bat I noticed an issue that I had previously overlooked regarding the skycrane. It has chutes but they are placed on the central control section, and with the fuel tank on the top, the COM moves above the parachutes in all cases save for the heaviest of cargoes. This could be remedied by sending out a new fuel tank with chutes on it, but the next transfer window is a long way off, and Establishment Inc's heavy cargo SSTO fleet is grounded until they can redesigned with new parts following bankruptcy of old plane parts provider.

Eventually the mission controllers decide that the skycrane should probably still be capable of landing most of the components on engines alone, and that the decreased fuel efficiency is worth it. So first up are a pair of segments with assembly rovers, and as we'll see in a little while, this mission still has more woes to come.

The landing part is pretty straightforward. Skycrane detaches, scoots over, cargo detaches, and the two dock. Fits rather snugly in my opinion

And then the landing part. To save fuel I do my deorbit burn almost on the opposite side of the planet. I deobit at dawn, when the target landing area is at about late afternoon/early evening.

The landing zone had to be in a dark patch, as in as close to "sea-level" as possible in order to maximize amount of atmosphere that I'd go through and slow myself down in. Most options would put me in a big level plane type area, which would be easy to land in, but I decided that the scenery would be too boring. Had I gone into a more inclined orbit I'd have greater freedom to choose landing zone, but that's just another mistake we can add to the list. In the end I picked a canyon. It would require me to refine my precision landing technique, but I'd have plenty of time to fine-tune that.

The landing zone:

After the landing, the Skycrane, also named the Kevin Mk-1, takes off again redocks with the station and refuels before repeating the landing with the second segement and rover combo. I realized that it is incredibly important to remember the solar panels on the Skycrane. They need to be reopened the moment landing is complete, and closed before takeoff. The Kevin Mk-1 lacks any other form of power generation you see, but that can be another thing we stick onto a replacement fuel tank if we ever get round to shipping one in future.

Rover Troubles

Now for the bigger issues. The more observant among you might have noticed one of the big issues already. Thing is, if you look closely at the rover/segment assembly, the rovers are actually rotated 90 degrees from where they are supposed to be. As it stands, deploying the segment landing legs traps the rover between them, making it impossible for it to move out. The rover is basically stuck there until it can dock its segment to another, which would allow the segments to fold up one set of legs so the rover can escape.

Unfortunately this is where I derped up the most. Between the first and second landing, I tried a combination of fiddling with the landing legs and the rover, using frequent quickloads I might add, and finally managed to get the rover out. However, I then went and did the second landing before redocking the rover the rover the correct way round, which meant a great deal of time warp. Thing is, those segments don't have their own power generation, as I hadn't anticipated this problem and wanted to save on parts, so by the time I returned to it, the batteries were dead and the segment couldn't fold up its legs in order to dock to the rover.

This might have been fine, first solution that presented itself was to try to dock the other rover/segenmet combo onto the segment and use the other rovers' RTGs to refill the batteries. This is where the second problem presented itself. I don't know if its a bug or if Duna just has a tendency to make rover behave oddly, but I'll assume the former because I've never had this problem before, and not with these rovers which have an otherwise great track record. Basically the rover now handle like crap. I try to accelerate forwards and they start to slide backwards, regardless of the inclination of the terrain. At best the "go forward" rover command will decelerate the rover and only some of the time. Also the rover controls have gotten really unresponsive in general. I've tried switching where I control from, fiddling with the wheels, and nothing has worked. I can move around but the precision that surface docking requires is simply gone.

If anyone knows whats going on with this please let me know. A solution to this problem would be much appreciated.

So anyway, with that option gone I decide to turn to plan B: landing the crane and using it to restore power to the segment.

The crane is a unique craft on this endeavor. It's the only craft designed to land on parachutes and not skycrane, and it is designed to do some otherwise difficult tasks, like righting a flipped module and suchlike.

It took several attempts to get the landing right. It has the issue that unless properly adjusted, the force of the chutes opeing would rip the arm off, rendering the whole thing useless. also chutes were less than ideally placed, necessitating use of torque to keep it facing the right way up for landing. It was a tough nut to crack, I had to do a lot of fine adjustments to each individual chute so that they didn't open at the same time and I had to cut some before landing in order to keep it upright. I hope nobody holds that against me, but to be fair, it was basically impossible to get right the first time.

In order to deorbit I had to do the maneuver with the tug and everything attached, detach the crane, flip the tug and regain a stable orbit.

Unfortunately, despite my very best efforts, I ended up blowing a tire on the final landing. So plan B kinda hit an early roadblock.

This means that I have to resort to my final contingency: I have to land Kerbals to try and sort out this mess.

But that'll will be next time.

Again, if anyone has any insight or solution for my unresponsive rover problem, please let me know. I'd really appreciate it.

Also, any other feedback is much appreciated too.

Edited November 12, 2014 by SofusRud