Kerbal Space Program: Let's Light This Candle

Second successful docking. My next task for this growing space station is an emergency re-entry vehicle, as I neglected to put any kind of parachutes on the original capsule.

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Tanstaafl: I am thinking of deorbiting my space station and starting afresh as well. The new larger and stronger docking modules seem like just the thing for a space station. I'm going to resist though, but I'm going to keep those in mind if I ever decide on a portable station to send off-world.

So I mentioned in the beginning of the post that I missed up fuel lines when I was swapping out RCS tanks. Everything on the launch vehicle was fine (I would have noticed something wrong their pretty quickly) but some of the lines in the payload section were wrong, meaning that fuel was being pulled in an unbalanced way, messing up my center of mass during burns. This led to some wild crazy swings until I realized what was happening. I then had to use tons of RCS fuel to hold the rocket straight during these burns, and some more because I started doing more RCS burns at delta-Vs I'd normally use the engines for. And of course I needed more corrections because the whole thing was so unwieldy.

So yeah. Here I am.

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No way I can perform a final docking approach with that little RCS. Looks like my little Tug will be called into duty after all. Unfortunately the refueler just has one docking port, so the Tug will just be refueling it.

My orbiting stations quickly get unweildy as far as the game is concerned. The framerate just starts to die. I need to get more disciplined and simplify them. Yonder, your refueling lifter is simply insane! It's so complex, how does your game handle it?

My refueling rig only gets 1 full orange tank into orbit, but it does it at 60fps

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It looks similar to the top of yours, but it doesnt have the rest, so it removes a lot of complexity. The Orange tank gets to 100km with the last 2 orange buddies still attached with enough fuel for rendevous with my station (275km). The one orange tank is pretty agile with
2 sets of RCS thrusters at each end and it is capped on both sites by the new Large docking ports, letting it extend the station its attached to as long as its fuel is needed.

I get around 3-4 fps at launch. Once the SRBs go it's up to 10-12 FPS, and it steadily improves from there.

So my rescue mission seems to be an abject failure. My tug only holds 80 RCS fuel, but the real problem is that I forgot how overpowered it is when it's not tugging anything. It burns RCS fuel super fast, and the smallest velocity corrections I can make are .2 to .3 m/s at the slightest tap. I spent a lot of fuel overshooting my docking attempts and aborting before I got smart and turned off 2/3rds of my RCS thrusters. So now I've docked with the Refueler, but the whole thing only has 23.3 monopropellant!

I know it's wasteful, but at this point I think I'm just going to deorbit them both. I can send up another replacement tug.

So my relentless optimization has now paid off:

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That is my Heavy Refueler in a (very low, perigee is 96 km) stable orbit with fuel left in the launch vehicle! This was accomplished simply by addressing the two biggest concerns from my walkthrough, lots of gravity drag at launch and as the central stages popped off. For launch I increased the total thrust by replacing each Large Radial Engine on the 12 outside stacks with 12 small radial engines. They were really packed on there.

I then changed my payload configuration to a 6 asparagus rather than an 8 asparagus. Each Poodle and Large Radial engine comes on as the large stack beneath them comes off, so now that whole section of flight is a lot better. (The craft still slightly decelerates when the last solid boosters go). I increased the fuel on each of the side stacks in the payload, so the whole thing still has 3 orange tanks of fuel, I did lose the two sets of engines and jettison struts though. I also anticipated that my increased performance would let me swap out my Payload's Skipper engine for a Poodle, slightly lowering weight.

Right now my biggest problem is that I didn't anticipate my LV surviving to orbit! It doesn't have a control unit, energy generation, or real attitude control. I'll have to bring my apogee up to my Station height, turn around to lower perigee below 67k km, and then separate and bring my payload up again.

After struggling with getting a heavy lifter to work I poked around a while and downloaded a "fueling tanker" design just to see how it worked. I tried it and...

IMAGE(http://cloud.steampowered.com/ugc/882983254884169017/AC9A5961B3BFBB30239AF3B27988D139BEF0686A/)

Not one, not two, but four full orange tanks in orbit (and the tank on the final stage is still half full). I can't even begin to figure out how it worked. Obviously I have a long way to go on my own.

Curse you internet!

Yeah, this thing is ridiculous. I've started modifying the payload to match what I want to do with it but...

IMAGE(http://cloud-2.steampowered.com/ugc/882983254885107634/24754F0121506FF66FA9465AFA427DE4C8FA3EDD/)

Outer ring is six stacks; two orange tanks and one of the grey tanks. Asparagus staged and dropping two at a time.

The inner ring is also six stacks; one orange tank and two grey tanks. Also asparagus staged from the outer ring and dropping two at a time.

The final, inner stage is also one orange tank and two grey tanks.

In the original design the four upper tanks have docking ports on each end. The upper ones are covered with the adapter shroud that connects to a probe core with a bunch of RCS units to control it. The shroud connects to the tank with a decoupler.

The way it looks like it would work is once on location the four upper tanks would be undocked from each other (they are connected by a docking port in the middle) and the individual probe core would use the RCS units to dock it to its destination using the docking port on the "bottom". The decoupler would then fire and the probe core would fly away with the shroud, leaving just the orange tank behind.

As I stated before, I set my task to be a lunar landing, with rover, and then a safe return to Kerbal.

(By the way, I love the maneuvers. If you haven't used them yet, that needs to be absolutely the first thing you figure out how to use.)

Lift off!
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There's a fatal design flaw that isn't visible from this angle.

Setting my intersect maneuver.
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The flaw: I added a taller engine and extra fuel tank and forgot to move my landing gear down to compensate. This is the result.
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I dropped the rover and it landed upside down.

Next design!
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Coming in for a landing. Note the nav glove and how far away the yellow crosshair is from the center.
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Yup, too much horizontal velocity. Called it a failure and aborted the landing.
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Next landing attempt.
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The eagle has landed!
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My first rover design, untested.
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Not only does the manifold extend through Jeb's head, the wheel angles cause it to only go in circles!
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Still, I consider it a successful landing and excursion. Happily, the Kerbals have enough fuel to return home and make a safe splashdown.
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I am so close to buying this game.

Do eet!

Xeknos wrote:

I am so close to buying this game.

Right? I'm watching like a hawk for a Steam sale...

It's so cool to see so much happening in this thread these days! Yonder, those paratroopers are awesome -- I'd never have thought to do that. Some of these tanker designs are great, too; the best advice I can give for those is to strip off any excess weight that you can (those aerodynamic nosecones, for instance, don't actually do anything at the moment apart from add weight), and think carefully about balancing engine weight and specific impulse. SRBs can be handy at the very bottom of your stack to give you an extra boost off the pad, but they become a burden higher up, since their specific impulse is so low.

There are some really interesting trade-offs to be between different engines; I really like the tiny Rockomax radial engine, for instance, since it has such a high thrust-to-weight ratio compare to, say, the LV-909, but the 909 has much higher specific impulse, so unless your spacecraft is very small, the extra efficiency of the 909 is worth it, despite the extra weight. Similarly, while the LV-N seems like an obvious win with its high specific impulse, it's insanely heavy for its thrust, so it only makes sense on quite large spacecraft, where you're going to end up saving enough fuel to justify several extra tonnes worth of engines.

Sometimes you just want to do something fun, though -- efficiency and weight-reduction be damned -- so I've been working on this:

IMAGE(http://wootangent.net/~lsd/blah/discoveryone.jpg)

I like the idea of keeping those LV-N engines away from the crew, even if there's absolutely no need for it; the same goes for all the crew space outside of the lander, so the crew has room to relax on long trips. The lander attached to the front is set up for Duna, though I think I should be able to land it on the Mün on this shakedown cruise. By attaching different lander designs and flying up fuel I should be able to take this just about anywhere

Yonder wrote:

Tanstaafl: I am thinking of deorbiting my space station and starting afresh as well. The new larger and stronger docking modules seem like just the thing for a space station. I'm going to resist though, but I'm going to keep those in mind if I ever decide on a portable station to send off-world.

Those new docking clamps are definitely worth using -- they're a lot more sturdy than the smaller ones for bringing large modules together.

pneuman wrote:
Yonder wrote:

Tanstaafl: I am thinking of deorbiting my space station and starting afresh as well. The new larger and stronger docking modules seem like just the thing for a space station. I'm going to resist though, but I'm going to keep those in mind if I ever decide on a portable station to send off-world.

Those new docking clamps are definitely worth using -- they're a lot more sturdy than the smaller ones for bringing large modules together.

Sweet. I've been wanting to try those but haven't had a chance yet

Oh I wouldn't wait too long for a steam sale. The price is probably going to go up when it finally comes out of beta and its been selling pretty well. Always in the top twenty or so on steam.

Sigh. My space station just experienced a spontaneous, unplanned, rapid disassembly. Had brought my next module into orbit nearby, hit "]" to switch to the station (I just wanted to turn on the lights!) and boom. Station is now a disconnected set of rapidly expanding parts.

Looking on the official forums this looks to be a known issue and there is speculation that it is related to the new cupola module. Be careful switching between craft.

Official support thread.

pneuman wrote:

(those aerodynamic nosecones, for instance, don't actually do anything at the moment apart from add weight)

I feel betrayed.

tanstaafl wrote:

Sigh. My space station just experienced a spontaneous, unplanned, rapid disassembly. Had brought my next module into orbit nearby, hit "]" to switch to the station (I just wanted to turn on the lights!) and boom. Station is now a disconnected set of rapidly expanding parts.

Looking on the official forums this looks to be a known issue and there is speculation that it is related to the new cupola module. Be careful switching between craft.

Official support thread.

So glad you mentioned that, I was just about to send up my new habitation module, and if the cupola's are buggy will this would probably set it off:

IMAGE(http://imageshack.us/a/img801/7001/2013052600010.jpg)

Norfair wrote:
pneuman wrote:
Yonder wrote:

Tanstaafl: I am thinking of deorbiting my space station and starting afresh as well. The new larger and stronger docking modules seem like just the thing for a space station. I'm going to resist though, but I'm going to keep those in mind if I ever decide on a portable station to send off-world.

Those new docking clamps are definitely worth using -- they're a lot more sturdy than the smaller ones for bringing large modules together.

Sweet. I've been wanting to try those but haven't had a chance yet

Oh I wouldn't wait too long for a steam sale. The price is probably going to go up when it finally comes out of beta and its been selling pretty well. Always in the top twenty or so on steam.

And they deserve your every penny!

pneuman wrote:

It's so cool to see so much happening in this thread these days! Yonder, those paratroopers are awesome -- I'd never have thought to do that.

I'm glad you liked them!

Here is my next External Command Chair foray, every Kerbal's favorite amusement park ride the Tower of Terror!

Unfortunately I have to pack for a trip and climbing the Kerbals up the Launch Tower is a huge pain, so we're just going to send up one.

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Jumping the gap, without rolling off the handrail-less edge is part of the fun!

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Strap in tight!

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And we're off!

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The separation can get a bit twisty.

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The SRBs are just the beginning!

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We'll actually break 45k km.

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And back down.

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He looks a little nervous.

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Probably because this ride has never landed in the water before and we have no idea what will happen.

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Oh God. I'm going to throw up.

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You're alive!

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It works better when it lands on the ground.

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I mean, obviously the engine explodes when it hits the ground, but that's just like the crumple zone of a car, it absorbs all the shock.

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See, perfectly intact!

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Aww, look at how sad he is that the ride is over.

Well, I caved and bought it. The first rocket I launched didn't quite make orbit, but I learned a lot. And playing the Enterprise theme song made it a special moment.

My tall multi-stagers keep getting terribly unstable, with tanks separating from each other without warning, sometimes on the launch pad. They are also very rough on my framerate. So I have started working on squat & wide designs consisting mostly of mainsail rockets each attached to only a single big orange fuel tank. Right now I've got I think 19 of them with a few solid fuel boosters just cuz. The payload then sits on top, in this case a ship designed to dock at my station, then land on Duma, unload rover car for some joyriding, then return home. I'll get some pics when I'm at home again.

Last night my attempt with this design failed because I ran out of monopropellent for my thrusters. I was so so so close to docking but could not do fine maneuvers.

A tug and an extra docking port in-line with the overall piece structure (on one end, basically) are essential for correcting for mistakes like that. Get yourself a small but heavy spacecraft with a good amount of RCS fuel and well placed thrusters and you can have it perform the last docking steps. My ships are becoming more and more modular due to stuff like that. I'm sticking the huge docking ports on both ends of everything now.

Edit: Im also finding that this technique gets progressively wobblier. I should check out the Quantum Strut mod. I wish Kerbalnauts could install struts in-orbit.

It was the best of times, it was the worst of times...

I made a whole new lander and spacecraft assembly (the thing I use to move things to different planets) using the new, big docking ports (so much more stable).

Got to Duna, aerobraked into orbit, sent down my lander which actually is flanked by two hab units, underneath each is a small one man rover. Landing was picture perfect (festooned with 'chutes). Unclipped by rovers, drove one around and quicksaved. When I then flipped my rover, re-loaded and my rover self-destructed :(. Tried re-loading multiple times but it just sank into the surface and blew up. Maybe the new wheels? Undocked the other rover and saved, re-loaded to test and the rover was gone... Blech.

Disconnected the two habs, talked one of my Kerbals into talking a brief walk and the other two blasted off without him, abandoning him on Duna.

The lander made it back into orbit like butter.

So the good, everything I made worked as designed. The bad, bugs destroyed my rovers.

I'll give the tug a shot. I'm actually thinking of scrapping my current station (skyfall in Australia maybe) and building one that's more docking friendly and doesn't cause such a framerate drop when I get close to it.

I went through that too. Its hard to get one that is fun to look at and doesnt kill framerate.

I am very curious, but I imagine this game would mostly be a rocket simulator in terms of showing off perfect arcs before my stuff slammed into the ground. For someone with only decent understanding of physics and such, how approachable is this game?

Demosthenes wrote:

I am very curious, but I imagine this game would mostly be a rocket simulator in terms of showing off perfect arcs before my stuff slammed into the ground. For someone with only decent understanding of physics and such, how approachable is this game?

It is a game of trial and error, probably even for Yonder still. It is pretty approachable IMO. The game comes with some default rocket designs to play with and understand how things work together. The wiki has some good info and tutorials. Most of my launches still end in explosions or aborts.

Got my proper station assembled in Duna orbit. It was in 2 flights. 1 with the orange tank, the other with the rest of the orbiter structure, just all in a line instead of the way you see it now. The ship you see attached was the engine for the main flight and was able to unplug all the bits to assemble them into the nice shape. That orange tank is about 80% full and all those RCS tanks are pretty full too.

IMAGE(https://lh3.googleusercontent.com/-tEQgX8rtZHU/UaVOhDWmLII/AAAAAAAAAsc/vKVW_DnWYeI/w777-h540-no/Duna+Base.png)

Most importantly, my framerate is sitting at a lovely 60fps. Now I need a relief ship to come and replace Bill and Jeb with C list Kerbals. No need to waste their mixture of stupidity and courage babysitting a space station. Those two were also the first residents of the Kerbin space station.

Well, bad news. My space station did not have the fuel reserves I thought. My Duma ship ran out of fuel setting up its orbit to reach Duma. Back to the drawing board for me, after I scuttle my station. I could just End Flight it, but I want something more spectacular if I can.

Worse news: my station escape vehicle was built on a PPD-10 Hitchhiker Storage Container to hold the crew. However, this is ridiculously fragile and shattered on landing, even with 4 parachutes. Apparently I should have used landing gear in conjunction with the parachutes, though I'm not even sure that would have worked.