The Circumnavigation of Pol

[Sutternalt]

The Circumnavigation of Pol

by land

This thread will chronicle my attempt to complete the Elcano challenge via a (wholly stock) circumnavigation of Pol. If you notice the "H" for hyperedit in the corner, it's because I was using it to test my rover on Pol. I didn't want to have to fly all the way there only to realize I'd forgotten a crucial part, or that my wheels were too far from the CoM, or something. Even so, I haven't fully tested this iteration of Noether's Revenge.

---

[TABLE=width: 350]

[TR]

[TD]Mass[/TD]

[TD]1.0813636×10¹⁹ kg (2/10,000 of Kerbin)[/TD]

[/TR]

[TR]

[TD]Joolean Periapsis[/TD]

[TD]210,624,206 m[/TD]

[/TR]

[TR]

[TD]Joolean Apoapsis[/TD]

[TD]149,155,794 m[/TD]

[/TR]

[TR]

[TD]Eccentricity[/TD]

[TD]0.17[/TD]

[/TR]

[TR]

[TD]Inclination[/TD]

[TD]4.25°[/TD]

[/TR]

[TR]

[TD]Equatorial Radius[/TD]

[TD]44,000 m[/TD]

[/TR]

[TR]

[TD]Circumference[/TD]

[TD]276,460.2 m[/TD]

[/TR]

[TR]

[TD]Max Elevation[/TD]

[TD]5590.2m[/TD]

[/TR]

[TR]

[TD]Lowest Elevation[/TD]

[TD]782.5m[/TD]

[/TR]

[/TABLE]

^{Information from KSP Wiki and KerbalMaps}

---

So far, I've made a rover called Noether's Revenge (so titled because Noether's Theorem is my favorite theorem, and, let's face it, every mathematician needs a tale of revenge).

It's got six wheels, eight RTG's, some batteries, a command pod, struts, and some emergency RCS for the inevitable 3km-long jump because of Pol's low gravity (and my proclivity for shaking things up when I get bored). Note that there's only four RCS ports; not enough thrust to actually lift the thing into the (air).

I've also made a lifter that should be able to get the darned thing to Pol. Because the challenge rules were all, "No, no, this is about the HARD way." and I was all, "How hard, exactly?" and they were like, "HARD. The HARD way." So I said, "Fine, screw it." I call it the KSS Valentina because, well, screw Jebediah. Valentina's way cooler. And obviously more attractive.

I started out with some careful delta v calculations. I knew I needed around 8770 delta v to get to Pol from Kerbin's surface, assuming I have to make the maximum plane changes on the way there.

[TABLE=class: grid, width: 500, align: left]

[TR]

[TD]Stage[/TD]

[TD]Mass[/TD]

[TD]TWR[/TD]

[TD]Delta-V[/TD]

[/TR]

[TR]

[TD]Pol[/TD]

[TD]12.3[/TD]

[TD]8.72[/TD]

[TD]1085[/TD]

[/TR]

[TR]

[TD]Interplanetary[/TD]

[TD]29.7[/TD]

[TD]0.21[/TD]

[TD]3736[/TD]

[/TR]

[TR]

[TD]Kerbin[/TD]

[TD]104.5[/TD]

[TD]1.66[/TD]

[TD]3208[/TD]

[/TR]

[TR]

[TD]Boosters[/TD]

[TD]Lots[/TD]

[TD]Hopefully >1[/TD]

[TD]No idea[/TD]

[/TR]

[/TABLE]

These, obviously, quickly dissolved at the Kerbin stage. I an idea on how to get 3000 delta-v on at least 30t of payload, but these darned newly rebalanced engines tripped me up. It's like I haven't even played this game for 666 hours anymore. Anyway, I finally decided to just send up the upper stages completely empty of fuel. That helped, and I ended up with 3208 delta-v. But then the boosters caused me problems. Finally, I just strapped on some of the newer 5m parts and the Apollo-inspired "really freaking huge engines" on top of my original four boosters.

I have no idea if the Valentina can even get to orbit, let alone do it safely. It probably can. But I do know it can get to Pol. Once it's refueled. It'll just take for-freaking-ever because Nuclear engines have a horrendous burn time. Really, I hate using them, especially since I only have one on my interplanetary stage. I'm an impatient person.

Javascript is disabled. View full album

[not pictured: the previous iterations, lacking the large spaceplane fins, flipping over in-atmo.]

Thank God, the Valentina made it to orbit. Holding (mostly) at (sort-of) 82,000m altitude, the next task was refueling it building a refueling craft calculating how much fuel I needed to lug up there. The Valentina has 3*5=15 jet fuel tanks. That means that, at 0.75t or 150u liq.f., we need to get 11.25t or 2250u of the stuff into orbit. On top of that, she's got three monoprop cylindrified's, three monoprop R25's, and a command pod. So that's 3*0.6[150]+3*1[250]+.06[15]= 1.8[450]+3[750]+.06[15]=5.4t 1215u of monopropellant.

In total, then, I need to haul 16.65t of fuel into orbit.

To accomplish this, I built the KSS Jebediah, following the Kerbal Way of MOAR BOOSTERS, MOAR FUEL, MOAR EXPLOSIVES. This behemoth, weighing in at 461.2 tons, is quite capable of getting said fuel into orbit.

[not pictured: the Jebediah, because my function keys stopped working at this point for some reason. I'll get you some pictures later, at not-four-AM.]

The launch proceeded perfectly.

Shortly I had docked.

Not so shortly afterward (WHY ARE THERE SO MANY FUEL TANKS. WHY.), I'd refueled the Valentina.

Next: Getting to Pol.

---

Edit: Oh, drat. I just realized - Valentina Kerman's a pilot. She can't fix wheels.

Edited May 15, 2015 by Sutternalt

[Fengist]

Oh, drat. I just realized - Valentina Kerman's a pilot. She can't fix wheels.

LOL... I'm not even going to go there. You cannot sucker me into getting my head smashed by my wife's frying pan.

[Sutternalt]

Getting to Pol

^{The Jump Cannon}

Well, I came up with a solution to my engineer problem. That solution comes in the form of the Jump Cannon, named after both its hilariously diminuitive size and Annie Jump Cannon, who actually spent the time to do the detail work and catalog a whole bunch of stars. At its core, the Jump Cannon is just a grabbing unit strapped to some monopropellant engines and an external command seat. I was very pleased. Bill, however, was... not ecstatic when he learned that he'd have to ride to Jool on the outside.

This wasn't my first solution. My first solution was to launch a KSS Valentina II with an external command seat on top of the Noether's Revenge. The problem was that Bill wasn't a pilot. With Valentina and Jebediah in space and only one pod and parachute capable of getting down, I'd have to do a complicated shuffling of personnel and spacecraft to get both Bill and Valentina on the Noether's Revenge II. Then I remembered about the grabbing claw unit, and figured, hey, why not?

Anyway, I did the math, and not only should I still have enough delta-v to get the Jump Cannon and Noether's Revenge to Pol, but the Jump Cannon will have enough delta-v to do some scouting and act as a beacon/waypoint.

That'll be especially handy, because I want to visit all the cool features of Pol. I'd been there once before.* I definitely want to visit the mountains, those can get pretty high, and there's lowlands and I think a space krak---. Hold on a moment.

I've been thinking of Bop this whole time.

Hmm.**

Well, my former calculations are correct; I used Pol's values to make them. And I did say I was going to circumnavigate Pol. Alright, let's do it. Cheeseball, you shall be mine!

Right, so, minor diversion aside, the launch of the Jump Cannon proceeded normally. The most interesting part was attaching the thing to a craft; not only could Bill not ride it up without a complicated ladder system, but I couldn't attach a decoupler to the bottom or top. So I had to do a strange off-centered solution. But eventually the Jump Cannon rendevouzed with the KSS Valentina, and after some orbital ballet, I managed to get the thing more-or-less perched on Noether's Revenge's top. Or the KSS Valentina's nose; however you prefer to look at it.

Javascript is disabled. View full album

Once I finally get to Pol, here's my planned route:

^{via http://www.kerbalmaps.com/?body=Pol}

It takes me through the most interesting variety of terrain available; I hit the high point, the low point, a ring of mountains, and some of the crumbly cheese pollen bits between.

Thus prepared, I launched the KSS Valentina from orbit. First, I deorbited the KSS Jebediah, and safely landed him back on Kerbin. Then I got the KSS Valentina clear of Kerbin's SoI, mostly to avoid the annoyance of timewarping to a transfer window at KSC. Given when Joolean transfer windows happen, I figure it'll be a while before I actually hit one.

Looking at the map, I only have to wait half a Kerbal year; much better than my usual two years or so. Everything was going smoothly until I tried activating the nuclear engine. It was then that I realized I'd forgotten a critical component: One fuel line. The structural piece that goes from three fuel tanks to one fuel tank doesn't transmit fuel, of all the completely ridiculous-! The KSS Valentina was dead in the water, far from Kerbin, in the middle of the ideal burn window.

Javascript is disabled. View full album

I've got three options at this point. One, use hyperedit to cheat my way to Pol. I mean, I know this craft can make it. But that's just so... cheaty. Two, learn how to edit part config files so that fuel can flow through that twice-blasted connector. I think that's an acceptable cheat. The craft works, it's just the stupid miserable fuel line that's missing. Three, rebuild, rescue Valentina and Bill, and relaunch. No cheats. But it'd involve a solar rendevouz, which would take... forever. And, as I've mentioned at one point, I'm impatient. No, I think I'll try my hand at editing the part file. After all, how hard could it be?

It came down to a little line that reads, "NoCrossFeedNodeKey = bottom". Apparantly, the stack tricoupler could have fuel crossfeed. But it only accepts fuel from the top. The documentation read something about this being a vital fix to prevent fuel imbalances or something, but I'm sure it'll be fine.

I've said how much I hate nuke engines before, right? Well, if I haven't, let me reiterate that. I hate nuke engines. Yes, their Isp is glorious, but the things are slower than throwing rocks out the window. On top of that, the fuel was only being pulled from one tank. Then parts started overheating, and my 20-minute burn (realtime 20 minutes, mind you) turned into a 40-minute one, because I had to shut down the engine to cool everything off. Of course, by then my trajectory was off, so I had to fix that. Then, with the new burn, fuel mysteriously was being pulled from two of three tanks, which made even less sense than only being pulled from one. In the end, I had to babysit the thing, transferring fuel as I burned to keep the CoM centered. Even after all that, my final trajectory is doing that wonderful thing where it flickers in and out of existence because of rounding errors. I'm either going to miss Jool entirely, aerobrake at 180,000 m (no idea if that's going to be a useful altitude), or crash into the planet. Guess I'll find out soon.

Javascript is disabled. View full album

Oh. Okay then. Aerobraking is out. Bill died immediately, which I guess I should've seen coming. Then the wheels popped off, and that's a mission scrub if I've ever seen one. Time for some more slow-as-ants nuke engine maneuvering. After five more maneuvers and a couple of quick loads (apparantly getting within 300,000m of Jool meant my craft was forevermore "under acceleration", thereby preventing time acceleration, or leaving the game without losing my progress), I finally have a stable "Pol"-ar orbit.

Javascript is disabled. View full album

Pol! At last! I never thought it'd take so long to reach you!

To get here, I had to dump my nuke stage. Now the KSS Valentina is barely different than the Noether's Revenge, so I went ahead and renamed it. I hope I have enough fuel to land. I should, but it's still nervewracking. The harder part will be correlating my map with the actual terrain to land in mostly the right place. Or at least somewhere close enough that I can navigate to my path.

I think I found the right mountain ring. Unfortunately, it was about to be on the night side. Even so, the landing went very smoothly. I even ended up with extra RCS fuel, which I ditched. The fuel promptly slid down Twilight Ridge, which is what I decided this place would be called.

Surrounded on all sides by strange cairns of pointy stones, Bill managed to (somehow) beat Valentina out of Noether's Revenge to plant a flag. They took a couple of nice pictures for the annals of history before boarding again. Jool was, cooperatively, in the sky, so the pictures were very good. Bill loaded up on snacks and fuel before re-embarking his command seat on the Jump Cannon.

Javascript is disabled. View full album

Next: Embarking!

As Promised: here's some photos of the KSS Jebediah .

_{*Pol was actually my first goal after the Mun way back when I first began playing this game; it was a complicated mission with a craft that had a detachable mining lander using Kethane that visited Ike and Dres on the way to Jool. I've no idea how I managed to get there, because I performed no delta-v calculations whatsoever. On second thought, yes, I do remember: quicksaves and revert-to-launches.}

_{**Let's see here. Noether's Revenge dry mass = NRm = 6.9t. Jump Cannon dry mass = JCm = 2. Jump Cannon fuel mass = JCmf = 1. Noether's Revenge fuel mass = NRmf = 1+(1/250)*15=1.06.}

_{TWR = Thrust/Force_gravity}

_{TWR_Pol = (20+20) / [(2+6.9)*0.37278] = 12.06}

_{TWR_Bop = (20+20) / [(2+6.9)*0.5886] = 7.636}

_dV=645.7

_{dV_Pol-Bop_max = 2556 <uh-oh.}

_{Hrmm. If I add four FL-R1's, that raises my dV to 2701 but only lowers my Bop TWR to 3.23. That's doable. Now, how to get four FL-R1's to Jool?}

Edited May 13, 2015 by Sutternalt

[Sutternalt]

Day 1: Embarking

^{Or: Bouncing Around, Mid-"Air" Repairs, and the Nadir of the Journey}

---

Before I start, I feel like I ought to explain why I'm doing this. First, I love Kerbal Space Program. But, if you're not careful, you can fall into the trap of only playing for the orbital mechanics. Planets are just points. Who cares what's on them? So often, Kerbin just becomes either "green field" or "ocean". Duna is just "red desert". The Mun is "middle of a crater". And that's boring. The planets and moons in this game are so much more diverse than we give them credit for, and you can only really see that diversity if you go overland; if you drive them. Second, rovers are next to completely useless in this game (especially on airless rocks where rockets are just... better), and I've got a strange drive to always try things that seem completely useless. Maybe it's just to confirm that they really are useless. Or maybe it's to try and find a use for them. Third and finally, even if you do like rovers, you aren't likely to use them on a low-gravity planet because they're "impossible to drive". I contend that they're not. I also contend that they're perfectly easy to control, so long as you've got a wide wheel base and low CoM.

As far as why pick Pol, I'll hazard that Pol is the least interesting body in the Kerbol system. It's not the smallest, it's hard to get to, there's no anomalies, the terrain is annoying but not particularly interesting, and it's just not... cool. I'd like to try and prove myself wrong.

---

First thing to do would be to figure out where I need to go. If I am where I think I am, I should go south to the lowest point on Pol. Probably a bit South-Southeast. So, I--wait, where's the flag?

Valentina couldn't find it. She'd just planted the thing not five minutes ago and now it had disappeared completely. Even Bill couldn't find it from his external seat.

Turns out it's 600m above the surface. With the discarded "spare" fuel tank. Oh, and somehow, it's daylight now. Bill chalked it up to eddies in the spacetime continuum. I think it's something to do with loading a save file on Pol's notoriously bumpy tiny surface, but I'm no astro-engineer.

Weirdness now safely explained, I started off down Twilight Ridge, moving South-Southeast.

Already I encountered a problem. With Jump Cannon jammed on top of Noether's Revenge, the CoM shifted upward enough for the rover to want to wheelie. But it's still quite manageable with SAS on. I set off down Twilight Ridge at a good clip, and then bounced. I landed fine, though; the tires can take it.

But I bounced again.

And again.

At one point, I hit the ground too hard, and a tire broke. Of course, however, I'd bounced into the air again. Problem being that if one tire broke with the previous bounce, presumably, more tires were going to break with the next impact. It looked like it was going to be a particularly long bounce this time, so Bill did what he came to do: repair some tires. In mid-air.

Javascript is disabled. View full album

As I predicted, once I'd landed that bounce, even more tires broke. But this would be okay; as long as I fixed the tires before the craft hit the ground, I could maintain control. Bill got to work again.

This time, however, Bill couldn't get back onto Jump Cannon before Noether's Revenge bounced. Bill hurriedly used his jetpack to arc skyward again, but Noether's Revenge was spiralling out of control rather badly. If it landed on anything but its wheels, it'd be a mission scrub.

So there wasn't much choice. I had to switch to Valentina, and hope Bill bounced instead of dying. I brought Noether's Revenge to a juddering, broken-wheeled halt. Bill was speeding past the ship into the air. Apparently he'd survived the first impact. Now that Noether's Revenge was stable, I switched back to Bill.

He juuuust barely managed to gain altitude quickly enough to pull out of his dive. I landed him next to Noether's Revenge to repair some tires, refuel in the command pod, and plant a flag.

Javascript is disabled. View full album

It had been a long and eventful five kilometers.

I named the place "The Last Bounce". It seemed appropriate.

After deciding to set out again, I immediately got sick of the Noether's Revenge's tendency to wheelie. I pulled her to a stop and detached the Jump Cannon. I was going to find the lowest elevation point and park there. Unfortunately, that'd cripple my ability to repair Noether's Revenge, because Bill would be far, far away. No more mid-air repairs. But that's okay, because there weren't any mountains between me and the lowest elevation point, so there'd theoretically be fewer bounces, and therefore fewer broken tires. Bill was excited to stretch the Jump Cannon's legs, or rather, rockets. So, he set off to find today's goal: the point of lowest elevation.

Javascript is disabled. View full album

I managed to land at 317m altitude on a downward slope, about 22km from Noether's Revenge. If the bottom of this valley isn't the lowest elevation on Pol, I'll be surprised. Jump Cannon performed beautifully; no complaints there. However, when I switched back to Noether's Revenge, the recently-planted flag was mysteriously floating 1000m up.

I wonder if this is the beginnings of a trend....

As I started off again, I realized that there was going to be a mountain in the way.

Drat. Oh well. At least Noether's Revenge was much easier to control, although it still tended to wheelie. This was disappointing; my previous (hyperedit tested) iteration of Noether's Revenge didn't wheelie, but it did scrape the bottom and explode when it landed large jumps. As I roved, I learned quickly that the best method of accelerating and braking is to make like an Antilock Brake System, and do it in rapid spurts. Turning can be surprisingly well effected by rotating the whole rover in mid-(air). So long as the angle from your heading isn't too great, Noether's Revenge just bounces forward in the right direction at that point, and then eventually settles down. Land-based turning happens both surprisingly effectively and shockingly normally. Also, whatever you do, don't press the brake button on landing. That'll lock your wheels for sure, and then flip the rover.*

Coming to the top of previously-mentioned smallish mountain,

I decided that I'd take this one slow to try and spare the wheels. With luck, I could avoid being airborne for too long. The sheer cliff at the bottom of this thing makes that unlikely.

Though I took the descent gradually, the cliff proved too much. Four wheels broke. And Bill was 20km away. I debated getting Bill back to Noether's Revenge by EVA jetpack, but then I had a better idea: drive Noether's Revenge on the remaining front two wheels by listing starboard. It worked, though it slowed my average speed from 10 or 15 m/s to 6m/s.

Javascript is disabled. View full album

Finally, the front wheel popped. That left me with one wheel in the middle of the starboard side. Time for repairs. Bill jetpacked in from 12km away, repaired Noether's Revenge and refueled, and then sped off back to the Jump Cannon. As I was flying back, I really started to appreciate just how alien Pol is. It's just me, Bill, and Valentina here. I really feel exposed; I regret not making room in the delta-v budget for some kind of permanent base for my Kerbals to relax in. Poor Valentina's been cooped up in that one-kerbal capsule for years. Bill hasn't even had that comfort. Jeez, what have I done to these poor Kerbals?

I made some good headway in these "flat"lands, far from any mountain range. Or should I say "mountain ring"? My average speed was up somewhere around 19m/s, and I spent a good deal of that, unfortunately, airborne between bounces. These hills can be quite annoying; I don't think there's a lick of flat land anywhere on Pol.**

^{I slowed the video down to 1x near the middle so you could experience what 20m/s on Pol is like. For those too lazy, the answer is "bouncy".}

Without much further incident, I caught up to the Jump Cannon. Bill launched the Jump Cannon and efficiently re-grabbed the Noether's Revenge. Then I ventured down into the valley, trying to find the lowest point on Pol. Eventually, I abandoned Noether's Revenge, and travelled about 700m on foot to where I think it is - 82m in altitude.

Javascript is disabled. View full album

I made about 28km today. That means it'll take just about 12 days to get around Pol.

Casualty report:

-1 SAS Module (Fore Starboard) <Wait, shoot. When did that happen?

-1,5,6,1 tires (in four events)

Progress so Far:

Next: The Zenith of the Journey

*^{Hmm. I think this is an ideal place and vehicle to do stunts. I'll have to investigate that.}

**^{Well, maybe at the poles. I'm going to keep pretending that that's the case until I can't any more. Hope is a good thing.}

Edited May 15, 2015 by Sutternalt