Fendleton's Most Dashing & Intrepid Voyage of Discovery (WIPJool-5 Challenge Attempt)

[Fendleton]

Fendleton's Most Dashing & Intrepid Voyage of Discovery

Part 1: Assembling the mothership (Well, the back half of it)

Hello. This is my attempt to complete the Ultimate Jool-5 Challenge, where I must build a single ship that leaves Kerbin orbit, lands a kerbal on each moon of Jool, and returns. For this, I decided to make a nice big mothership, then deploy landers from it (which is fine under the challenge rules). The other method that works is to go ulta-minimalist, or to make a lander that can go anywhere and then attach a lot of fuel tanks to it. But I like large motherships, so that's what I'll be building and flying this tim. This thread is where I'll keep track of my progress, successes and failures.

But let's get this out of the way first. I am not a fantastic craft builder. My specialty is in aircraft, and I'm darned good at them (although I might not be taking one to Laythe, just to save on mass)....however my spacecraft are merely functional, rather than being genius material. But I've mastered docking in the past, and this isn't my first interplanetary mothership. I'd previously built one to get to Duna. It would have worked, had I not foolishly decided to use the 1.25m docking node for a few modules, causing the thing to snap in half at one point. The mission wasn't a failure (I got everyone back), but understandably I've tended to just use larger docking ports for most things since then. I'm also using a laptop, so there's no way in heck I wanted to have some massive cluster of orange tanks on my ship driving up the lag. They're also ugly. As a result of these two principles ("Don't break in half" and "No orange tanks"), my design is somewhat....unusual. Still. It might just be crazy enough to work.

The initial design for my propulsion module came about from a project I had to shift a space station to Duna. Lifting this thing into orbit was quite fun. When I decided to attempt the Jool-5 challenge, I decided to repurpose it. Unfortunately, it had very little thrust for getting out of kerbin's gravity well with the heavier load that would be required for the challenge. The final nail in the coffin of this design was when I discovered that I'd put the main docking node on backwards, making it useless. Back to the drawing board!

(Oh yes, and I'm running the Environmental Enhancement mod. No other mods, so I don't have things like autopilot, TWR, mass or delta-V stats)

The revised version had a working docking port, more fuel, plus 6 SRBs to get it away from Kerbin. No idea if that's enough fuel though. Probably isn't. I've got plans to deal with that later though.........note the SRBs to get it off the pad. The outer set of 6 aren't actually dropped...they overheat and explode, leaving the other 6 to give a little more power before being dropped. I'm calling that a design feature for now, since it worked.

Magnificent. Not the most efficient launcher, but it gets the job done nicely, and this is a really heavy thing to lob into space. The launcher is a basic onion design, with a lot of cross-feed.

And here we are on our way to our final 100km parking orbit waiting for the next module, with a tug attached so that we don't have problems with finding this shiny new transfer stage (it doesn't have a probe body). By the end of this update, the area between 70-100km is going to be absolutely full of space junk. Once it's in space, this module handles rather well by itself, and could probably have done a grand tour all by itself. But that's only the beginning of the Yet To Be Named Mothership.

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Science & Crew Quarters Module

Fairly quick build here....this was a far easier launch than I'd expected, and did almost everything I wanted it to. I didn't keep the massive onion-launcher from the last part, because it would have been horribly inefficient, and at this stage I still hadn't chucked up any debris....yet.

This module features my mobile lab, 2 hab modules (for a total crew of 10), some goo cans, the RTG array, some antennae, and the absolutely critical reaction-wheel array that will allow the mothership to turn around in mere minutes. Like the last module, it also features a tug for control, but it also has some probe bodies as backups (I think/hope). It also has 4 docking ports for the Advanced Dockable Science Packages that will be used on the landers (and for orbital stuff as well). The science packages need to come back to Kerbin in order to meet the more difficult versions of the challenge, and I think with some extra modules I can certainly manage that. However, this lab has no parachutes and thus each science package needs to be able to re-enter Kerbin's atmosphere and land safely. More on that later.

The docking went rather well for a ship of this size, and I topped-off the tanks in the mothership from the reserve fuel in the tug.

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Advanced Dockable Science Package

This was a set of 5 modules that I docked to the ship. I'm replacing these though, since I missed some stuff off them. I'll show the new ones in a future update. They're basically a probe body, RTGs, tiny RCS tank, 4 RCS quads (seriously high TWR on these things), a science-junior and all the sensors, plus a size 1 and a size 0 docking port and some parachutes for recovery back at Kerbin. They don't have goo though, so I'll be replacing them all for the future stuff.

This launch, having to lob a very wobbly payload, left a lot of bracing and staging debris in orbit. Not very nice, especially since I have to do it all again later. I really hope I don't hit any of this stuff.

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And that's it for now. I just lobbed up my Tylo lander, but this post is getting a bit hefty, and I'm pretty much at the halfway point of the build anyway so this seems a good place to stop for now. The remaining parts are the Reserve Fuel & Command Module, the Tylo & Universal Lander, the Laythe Lander, and the revised ADSP modules. Then I think I'm going to do something inventive and clever to add more fuel capacity to this monster of a ship. And then I can finally load it up with kerbals and send them off on my continuing Most Dashing & Intrepid Voyage of Discovery.

Edited June 30, 2014 by Fendleton

[Cmdr. Arn1e]

Wow, nice looking mothership so far! a couple of things to point out though: 1) why do you have the intercoolers on the nuke-engines? thought they only worked in-atmsophere for air-breathing engines?

and 2) you do know the full Science lab can reset experiments, allowing you to only take one science package that can be attached to any lander and reset once the science has been taken out and stored in the science lab? (sorry for wording on this last one, been another long day!)

Best of luck with it all, and if you need any more hints or tips don't be afraid to ask

[Fendleton]

Fendleton's Most Dashing & Intrepid Voyage of Discovery

Part 2: The Tylo lander

This was an absolutely horrible thing to design. I have never landed on Tylo previously, and couldn't find any guidelines on how to make a simple lander. So I guessed that if Tylo has gravity similar to Kerbin, then any spacecraft able to take off and get into orbit from Kerbin with fuel to spare should have a reasonable chance of doing the Tylo run. If I'm wrong on this, please correct me before I send this thing off on a suicide mission.

The main core of the lander is designed to be re-used for Vall, Bop and Pol, and features 4 LV-909s. Outside this, two skipper-powered boosters (hopefully) give the heft required to slow down for a landing on Tylo. Ejectable ladders and landing gear enable EVA on the surface without using jetpacks (which obviously do not work on Tylo). Just in case, I also added some smaller drop-tanks on the outside of these to give even more fuel.

Then I took the unusual (apparently) step of adding SRBs to these drop tanks. Why SRBs? Because for the initial approach to Tylo, I am going to be coming in fast. Very fast. And since I know that this thing barely has the TWR to get off the ground on Kerbin, having a bit more oomph will hopefully help out. Once they're burned out, I can eject them with the side-mounted droptanks and continue onwards on internal fuel. That's the plan.

Unfortunately this very odd design, as well as being quite unstable (lots of failed ground-tests before I got it nailed down right), is rather hard to lift. It can fly to LKO by itself.....but only by staging. Since I need thos stages for Tylo, I needed to build a medium-heavy lifter underneath it. But once I messed around a bit, it worked quite well. Those 6 SRBs get it up for a bit until the main lifter cores have the TWR to lift it by themselves.

Unfortunately after staging the first stages of the lifters, some part of the design glitched the camera, Nav-ball and made my remaining lifter spin alarmingly out of control. Things looked bleak.....and then normality returned and I was able to get the lander up into an orbit that would, eventually, take it close to the mothership.

A brief test confirmed that the landing legs were fully functional, and the ladders were long enough. At this point I realised I'd forgotten to add lights, and decided to leave them off to save on mass. I am quite certain that this decision will not come back to haunt me in future. This shot shows off the layout of the lander well, including the braking motors that will carry out the first stage of the landing burn. The drogue parachutes are left over from when this was going to be a Laythe lander as well. I'm keeping them so I can return this thing to Kerbin and get more science points out of it.

Next up: Docking the Tylo Lander (Unless I need to redo it), and Designing the Laythe Lander

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1) why do you have the intercoolers on the nuke-engines? thought they only worked in-atmsophere for air-breathing engines?

and 2) you do know the full Science lab can reset experiments, allowing you to only take one science package that can be attached to any lander and reset once the science has been taken out and stored in the science lab?

Fair questions!

The radial bodies are part of the "clipping parts without breaking the no-part clipping rule" tricks, which don't alter performance (if anything, it's less efficient than the alternatives) but allow me to have an extra docking port at the back of the ship, plus I think they look cool. They do add a bit of mass though......if I was building this from scratch again I'd replace them with FL-T400s.

And the science lab can reset experiments, and I use them for science-spam on Minmus/Mun missions regularly, but recovering the data for the harder levels of the challenge requires landing science packages back on Kerbin....and I forgot to add parachutes to my lab module. So I've had to improvise. I think the next version of my science-package will be a little different, so I can make things a bit simpler to work with. I think I'll carry a small tug/runabout with a claw module and some basic engines, which should let me dispense with the RCS and probe bodies in the original ADSP modules. I might not end up doing that level of the challenge (if I run low on fuel I'll take all the science into the lab module and eject the extra science modules, then try to land the module with a powered lander later, which will be fun).

I'm abandoning my reserve fuel module as well. It was a nice idea, but it fails the important "can actually be controlled" test. If I need more fuel, I'll have to just send another ship over and admit partial defeat.

Edited June 27, 2014 by Fendleton

[Fendleton]

Fendleton's Most Dashing & Intrepid Mission of Discovery

Part 3: I hate docking

I've genuinely lost count of how many launches this accursed ship has taken to build. Including the failures, reverts and abandoned versions of the savefile I've probably lobbed over 20 rockets into orbit to try to get this thing built. Anyway. Let's start with where we left off, with the Tylo Lander on its way up.

At this point, I realise that the design of the lander is such that unless I line it up perfectly, the magnetic effect of the docking clamps might cause the skipper-boosters to smash into the RTG array on the science module. So I figure a nice, careful approach is needed. Just in case, I quicksave. This turns out to be an excellent idea. Still, I line it up, optimistic that with a careful eye and a steady hand this lander can be docked.

Unfortunately, the lander only has RCS quads on the core, rather than on the boosters. It also only has one tank of monopropellant besides what's in the pod. This makes it....somewhat tricky to dock. I waste a LOT of fuel, partly because of stupid annoying control glitches that make the lander want to spin (the mothership actually has a similar issue when under power. I'm slightly worried by this).

After getting down to ~30 units of fuel, I decide that docking isn't feasible, and decide to rebuild the Reserve Fuel Module in a smaller form, designed to make docking easier, and more convenient. Or, at least, not fatal to the spacecraft if it goes wrong. I put the Tylo lander into an orbit that will gradually take it away from the mothership, but slowly enough that I can catch up with it.

Then I build myself a brand new Reserve Fuel Module and lob it up.

The launch goes fine

The rendezvous and docking goes fine......

But this thing WILL. NOT. MANEUVER PROPERLY. I'm not sure if it's lag from the insane partcount, glitches in the game, or just my bad piloting...but docking this thing was an absolute nightmare. Half the time the RCS didn't seem to do anything, and when it did, the craft would still randomly jerk around when thrusting (forwards and back. I know about translation balance). This thing was a write-off. Eventually I lost patience and reverted back to the quicksave I took when the Tylo Lander first reached the mothership

Eventually I get the confounded thing docked. There is literally no space at all for error when docking the full lander. I lost about 6 docking attempts due to having the RCS quads on the side of the science module deflect the boosters on the lander. No damage, but it'd bounce the damned thing away and I'd have to have another go at getting the angle right without smashing bits of the ship. Still....it's docked. And assuming I even make it to Tylo, the next time I dock this lander it will be sans the boosters that made this so damned annoying.

The problem now is that this lander only has a 1.25m docking port on it for the next module. So whatever I send to Laythe is going to be small.

Advanced Dockable Science Package Redesign

I've redesigned the ADSP, and I'm working to ship it out now. There's been a few failures and mistakes, so it's not up yet. The new version features all the missing sensors, and the final version will also have some extra Science Junior units so I can do orbital work from the mothership as well....since the orbital packages were going to be on the reserve fuel module, which has now been dumped. No pictures though. I de-orbited one of the old modules to see how well it fared for sample recovery. The good news is that it does fine. The bad news is that it's too big to fit under the Tylo Lander once the boosters are ejected...so I've still got some work to do to make sure the new modules will fit.

This version made it all the way to the mothership, before I realised that RCS fuels are useless when you've forgotten to put quads on the ADSP units as well. Revert time!

Minitug Module

This module will be a support system for the landers and ADSP packages. It has a bunch of fuel, 2 small engines, and multiple options for docking (a standard docking point, and also a claw). it can operate in the Reserve Tank mode using the docking port to stay inline with the center of mass, or it can grapple an uncontrolled payload for recovery with the claw. Refuel-to-empty (where the tug is dscarded) also uses the claw, because it's quicker to dock with and uses less monopropellant. It's launched with the standard launcher I've used for quite a few of the smaller modules now.

To try out the idea, I lobbed a prototype up. It seems to work well...I think I'll use this one to top-off the tanks on the Tylo Lander, then alter it a little. If I add a couple of seats, it can also serve as a lifeboat for lander crews in an emergency. This module will be docked behind the main engines of the propulsion module, so it may be a little radioactive. Hopefully those seats aren't needed.

Propulsion Module Stability Test

Remember that old prototype of the propulsion module that I couldn't use because the docking port was on backwards? It was sitting in a 200km orbit, and I decided to take advantage of this to see how it went. A full power burn would de-orbit the stage, keeping the orbit clear for future use. It would also give valuable data on the stability of the propulsion module, fuel consumption, and acceleration.

The tests showed that overheating is not a problem with the NERVA engines alone (although the SRBs on the actual stage may cause issues), but that stability and acceleration are critical issues for this module. Hopefully the extra reaction wheels on the mothership can point the ship in the right direction (although thus far it appears to turn pretty awfully), and the SRBs can handle at least the first major burn. However, this brings up the elephant in the room:

Fuel Consumption

Put simply, the de-orbit took a lot more fuel than I'd like. Sure, I had plenty of fuel left, but this module is a lot lighter than the Yet To Be Named Mothership. Combined with the slow acceleration that will probably force some inefficient strategies...and I need to find a way to add more fuel to this thing. But here's the thing: I can't. The last two docking ports are reserved for the laythe lander (which I still haven't got a design for yet)and the minitug....and the only other places I could put them are going to be used for the science payload.

This requires some experimentation..and that's what I'm going to do. I've got 6 SRBs attached to the side of the ship for boosting away from kerbin. I believe that the bracing on these parts is strong enough that they can be used to mount extra fuel. Unfortunately, they do not have any ports on them. So I'm going to have to use 2 claw units per fuel tank, and line the tank up absolutely perfectly before docking it. I'm planning to use the Mk.1 Minitug to test out the Claw. I've used them before for asteroid capture....once....and I broke spacetime with them once. So assuming I can quicksave enough to avoid the more horrible bugs, this idea might just work.

And if it doesn't...well....I guess I'll just go for the mission and see what happens.

Next time: The Laythe Lander, ADSP Mk.3, and Claw Chaos!