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The starry heavens above me, a sturdy rover enclosing me 3; blast from the past


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This is going to be my third report of this series, dedicated to rover circumnavigations. What? You've been looking, and there is no second installment? That's true, because my second rover circumnavigation - of Wal - is still halfway. It's going very slowly, because it turns out Wal is a lot uglier than I anticipated. Meanwhile, I got an idea and I wanted to at least started it.

The idea was to run a circumnavigation of Polta, another OPM moon of Urlum. Back when I landed there in the A'Tuin mission (chapter 9.5), I really liked Polta. I went as far as calling it my new favourite solid body. So, perfect place to circumnavigate. But I couldn't do it in that mission because it was inside a radiation belt.

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Here exploring it with the rover I had for that mission, the Horseshoe

For the occasion, I also wanted to bring back from retirement my old first rover, the Dancing Porcupine

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So called for its strut armor devised to protect it from the consequences of reckless driving in low gravity, this rover was my first major accomplishment in this game, and I did drive it for thousands of kilometers - especially in my Jool 5 science challenge. I'm still very fond of this rover, and it still offers a fun driving experience.

As I adopted kerbalism to make the game more difficult, I tried to adapt this rover, but I couldn't. Dancing Porcupine is made to be self-sufficient in a long trip. Once you add in the requirements for food, decent housings for the crew, and replaceable spare parts, the whole concept couldn't hold. I would need to couple it with a mothership, but that defies the whole purpose of this rover. Also, Dancing Porcupine relies on its rockets to climb steep inclines, because it has low wheel power; and without the easy ISRU offered by stock, this function just couldn't be sustained.

Now I'll get a chance to drive again on that moon I like so much, using this rover I like so much. Or at least, I will get a chance once I finish my current Wal circumnavigation (which will probably get its own report eventually).

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Part 1: Pit stop amid the rings of Sarnus

Dancing Porcupine doesn't have enough fuel to reach Polta in one go, so I decide to stop for refueling in the tiny moonlets of Sarnus.

Turns out, Dancing Porcupine didn't have enough fuel for that either; I had to pull off some tricks to barely manage it.

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About to land on Ovok

Spoiler

Dancing Porcupine can do many things, but one of the few things it cannot do is orbit from Kerbin's surface. So it's got its own dedicated launcher.

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Launcher on the launchpad. It is slightly tilted because it is optimized to orbit without manual steering

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Losing the first boosters

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Next stage is a mastodon engine. I don't think I ever used it for anything else

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Remove the aerodinamic cover. It could have been quite spectacular, but the one on Tamarromobile was a lot better

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Jettisoning the last piece of the launcher, now Dancing Porcupine is on its own

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And it finishes circularizing

I made a few modifications to the rover. First, as I'm going very far from the sun, I took away all the solar panels and I put in more rtgs. Second, I strapped a relay satellite on its back. Wait, why am I using a relay satellite? The stck game doesn't give any benefit from it. Well, all my circumnavigation missions so far brough relay satellites, so it's for the sake of tradition. It also has the rovemate probe core to detect anomalies.

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The trajectory to Sarnun. Pretty straightforward. After months of rss, I'm surprised by how cheap are manuevers in the stock game

I could have gone to Jool, refueling on Pol, or on Sarnus, refueling on Ovok. The first is cheaper, but the second offers the better view.

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Capture at Sarnus by gravity assist from Slate

For capture at Sarnus one can use a gravity assist from Slate, or aerobraking on Tekto. A'Tuin went aerobraking because it was supposed to stay around Tekto, which is the only moon outside of the radiation belt. Here I'm using the stock game, I don't have to worry about radiations, and Slate is closer to my target.

Unfortunately, as I get closer to Sarnus and start planning a route for Ovok, I realize my mistake. Ovok is close to Sarnus, I need a lot of apoapsis lowering to get there. I don't have enough fuel. So I start using the other moons for gravity assists.

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Trajectory around Sarnus, part 1

In this first part of the trajectory, after gravity capture from Slate I reduce apoapsis a bit with rockets - yellow manuever, 86 m/s, cheap enough to get more convenient trajectories - to get an encounter with Tekto, shortly after the purple manuever - which is mostly plane change. I will use Tekto to raise periapsis, because if I take another gravity assist to lower my traajectory at this point, I end up colliding with Sarnus. Tekt ejects me on the red dotted trajectory, which is suited for a Slate flyby later.

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Arrival at Sarnus. Slate is clearly visible. The smaller moon is Eeloo, which the OPM mod moves in this position

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Slate flyby. Dancing Porcupine is Flying over the Muil Plateau, straight above the path taken by Tamarromobile so long ago

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Passing close to the rings, and very close to Ovok. But too fast, obviously

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Ovok and the rings seen from the driving cabin. I didn't take many picks of the rings because the ones I got with Arrowhead in the A'Tuin mission are better

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Tekto flyby

Tekto is another world I'd like to expore in detail one day. Possibly with a propeller plane. Unfortunately, I couldn't do much with Arrowhead because a bug caused the propellers to not produce thrust. So I'm wary of trying it again. I considered landing Dancing Porcupine there, aerobraking is free and if I launch from a tall mountain I may be able to get to orbit without spending too much. Then I remember the terrier engines don't work at all in thick atmospheres.

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Trajectory around Sarnus, part 2

Time for an update on the trajectory. Tekto send me in this high orbit just touching Slate. A small correction manuever (yellow, 3 m/s) ensures a Slate encounter in 43 days, which I'll use to lower orbit so that periapsis falls eactly on Ovok. From there, circularizing orbit is less than 600 m/s, and I have 700, so I won't need to try and use Eeloo to further reduce Sarnus apoapsis. I'm simulating the capture burn in Sarnus space because Ovok is so tiny (even smaller than Gilly) that it has no significant Oberth effect.

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I didn't take many pics of the rings, but I took some. Last time I was here, radiations were strong enough to kill the crew in three hours; this time I can relax and enjoy the sightseeing

I made a small mistake there; there was still an inclination difference with Ovok, that I had to compensate for with a burn. A small one, the inclination was only 1.5°, but it was enough to eat up my limited fuel. So as I approach Ovok...

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Approaching Ovok with a severe fuel shortage

... I have 543 m/s left of fuel, and I'm speeding against the moonlet at 553 m/s. Well, not all is lost. Ovok's gravity is so tiny, it won't accelerate me further; and if I use all the fuel I have to slow down, I should fall at about 10 m/s. The wheels are rated to survive impacts up to 12 m/s, I should barely survive.

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Run out of fuel at 9 m/s

Indeed, Dancing Porcupine survived the impact.

A bit of clarification here: Dancing Porcupine can easily survive losing control at 40 m/s while driving, but that's a kind of skidding-along-the-ground kind of impact. Your speed is mostly parallel to the ground, and you're mostly bouncing. A straight, direct impact like this is a lot more dangerous, and the porcupine armor is of limited use against it.

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Landed on Ovok!

At least now I can get new fuel.

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Posted (edited)

Part 2: the rover that went to circumnavigate Polta and ended up circumnavigating Ovok instead

Since I'm already there with a rover, and I need to get to another biome for refueling, and this moon is so small, I decided I may as well run an Elcano on Ovok too.

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Spoiler

The main biome of Ovok, where I landed, didn't have enough ore to mine for the small drills of Dancing Porcupine. I need to move 10 km south to find another biome.

I thought, since I'm here, with a rover, without worry about radiation, in one of the most spectacular places in the whole game, I may as well run a circumnavigation here too.

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Starting the rover

Driving in such small gravity is a unique experience, but I was prepared for it because I already did drive on Gilly (with Stool, in the Bolt mission). The thing is, of course you can't go fast, and you can't accelerate much. You just have to live with it.

Pushing the accelerator, the rover moves forward, but it also starts to roll upwards. It's ok, stop the accelerator, reactivate reaction wheels to stop spinning, now you're moving at 1 m/s. Wait to come down from your bounce, stop reaction wheels, waiting for the rover to touch on the ground with all wheels again, and you can accelerate some more. Eventually, you can pick up some speed.

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Picking up some speed

Except, of course, you can't pick up too much speed, because with 20 m/s I'd go orbital. Already at 5-6 m/s Dancing Porcupine takes long bounces that encompass several degrees of latitude on this tiny moon. On Gilly, I coulndn't ever go faster than 4 m/s, but Ovok is much smoother, so I could accelerate more.

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So this was what the average driving experience looked like

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I got close to 12 m/s occasionally. And at that speed, you're not much driving as taking suborbital jumps; here the longest in all the circumnavigation

And that's basically it. Ovok terrain is very flat and very uniform, so it was just a matter of going forward. It took a bit less that 6 hours for this circumnavigation. I tried using 2x speed, but it made problems when the wheels touched the ground. I could have activated it when airborne, but really, I found more convenient to just put the game in background for a few minutes.

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Without light amplification. You can't see much, but then, there are no obstacles on Ovok

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Reached the next biome, planted a flag and stopped for fuel. Notice the radiators extended

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Refueling for 26 days

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I got very fast. That's more than half orbital speed

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Stopping the rover and accelerating again takes very long. To avoid it, I send out a kerbal to plant flags with the rover still moving. Then I catch up with the jetpack

I planted a flag every 8-10 km, but I almost never stopped the rover.

Now that I have fuel, I could have actually used the rockets to push downward and drive more easily, but I didn't want to do it. This is supposed to be an Elcano challenge, and in this tiny gravity it's already hard enough to distinguish a wheeled circumnavigation from a low orbit. I only used the rockets twice to assist braking; once in the south pole, because I was about to drive through the terrain glitch. And the other in the end of the circumnavigation, because I wanted to stop right next to the first flag.

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Some stunning pics of slate crossing the rings

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The south pole, with its glitch

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Still the south pole

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And this is the north pole instead

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More from the north pole

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There's a sort of butterfly-shaped terrain here

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I planted a flag right over it. Also, Eeloo and Slate looking gorgeous

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And Hale, the last moonlet of Sarnus

I actually cheated for that last pic. You can only see Hale like that when it's passing next to Ovok, and you need the right conditions of light, so I stopped after the circumnavigation and started time warp until I got just the right position and illumination.

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Returning to my first flag, finding another glitch: it's hovering in mid-air. Or mid-space, since there is no air here

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And there we are, circumnavigation complete

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The bunch of flags planted around the moonlet

Edited by king of nowhere
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On 8/27/2022 at 1:37 AM, king of nowhere said:

Since I'm already there with a rover, and I need to get to another biome for refueling, and this moon is so small, I decided I may as well run an Elcano on Ovok too.

Nice!  Once again, I really like your use of the Cupola!  Ovok looks every bit as frustrating as Gilly, but then it would also be every bit as rewarding once you finish.

I've added a leaderboard section to the Elcano challenge for mod planet entries.  I would call it a work in progress.  I think we have a similar idea on doing that, simply having a single category for mod planets, and stating the planet (or moon) circumnavigated next to each entry.

My memory isn't perfect- I only recall you having an entry for Slate, and now Ovok.  (With another one coming soon!).  If I have missed one, please let me know.  

I have not started working on a badge yet.  I'm thinking the badge would be similar to the other badges, but perhaps with a '?' question mark or 'X' in the center.  I'm open to additional ideas regarding the badge, if you have any thoughts I'd love to hear them.

I think you are the first player to submit an Elcano entry for a mod planet.  Those entries have always been welcome, but we just have never had a leaderboard for it.  Now that a leaderboard is in place, I find myself wondering why I didn't do that sooner.

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1 hour ago, 18Watt said:

My memory isn't perfect- I only recall you having an entry for Slate, and now Ovok.  (With another one coming soon!).  If I have missed one, please let me know.  

slate and ovok are the ones I completed.

On Wal I recently crossed the halfway line, but it will still take months.

In this continuity I'm planning to also do Hale (again, since I'm already here and it's small and it's got good sightseeing) and eventually Polta. but those will take a while, because I'm still running my main kerbalism rss grand tour, and I just couldn't resist picking up also the speedrun challenge.

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  • 3 weeks later...

Part 3: through sleet and Hale

Having just circumnavigated Ovok, I can't skip Hale.

The terrain is a lot harder, but the view is even better.

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Spoiler

I'm on Ovok, Hale is literally just a stone's throw from my position. The sky from Hale looks even better than from Ovok, because the inner moonlet is stuck right between the two ring systems, instead of on the outer boundary.

The previous time I went to Hale, it was a daring stunt in a highly radioactive environment that required all the deltaV I could muster, some exotic trajectory to minimize exposure, and still almost killed the crew. I was too busy looking at the geiger counter and trying to be fast to admire the view. But this time there are no radiations, so I can enjoy it at leisure.

Almost feels like cheating.

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Leaving Ovok

Most of this post will just be pictures of the rings, and for once I won't bother with captions unless I have something specific to say. Writing "here's yet another amazing view of Sarnus rings" several dozen times wouldn't add much. Following a bunch of pics taken during the trip to Hale. I took over 100 screenshots, I'm trying to only include the best.

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I tried to capture the exact moment of crossing the rings, which really are one pixel thick. This is the closes I came to it

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Hale is even smaller than Ovok, which is itself smaller than Gilly. Its nominal radius is only 6 km. Gravity is supposedly slightly higher than Ovok, due to a higher density.

In practice, though, most of Hale sits at an elevation between 2500 and 4500 m. Which, when added to the diminutive radius of the moonlet, nearly double its actual size. And since gravity decreases with distance, and the nominal value of 0.023 m/s refers to datum level, the actual gravity is often half of that.

It's still higher than Phobos, now that I think of it. And Phobos even had glitches due to the low gravity.

Anyway, while on Ovok I was able to pick up some speed due to the flatness of the ground, Hale is very irregular and bumpy. So I couldn't ever accelerate more than 2.5 m/s with wheels alone. I could go slightly faster while falling down cliffs. To speed things up, most of the circumnavigation was run at 2x speed; any faster than that, and it would mess the wheels. Still, near the end I was having troubles climbing a cliff with anything resembling speed, and I decided to "cheat" and use the rockets to push Dancing Porcupine against the ground (for the sake of the Elcano challenge, I clarify that every forward push was provided by the wheels, and the rockets were only used to simulate some gravity).

An act that crushed the wheels, even though I was using low thrust. Looks like another glitch of the game. But after reloading and figuring out the trick (no, there isn't any special trick to avoid breaking the wheels, just keep trying until it works), I dared to push my rover to the ludicrous speed of 7 m/s. Which is close enough to orbital speed that when I went EVA with Bill to plant a flag without stopping the rover, on catching up to the rover I sent Bill past orbital speed and the visual changed, rotated by 90 degrees. I ended up in some terrible limbo where the smallest touch of the jetpack would change the trajectory from orbital to suborbital, with subsequent visual rotation. It was quite annoying to get back to the rover in those conditions.

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This is the south pole. On Hale there are no major terrain artifacts, though a close look will reveal those three pieces of terrain aren't well connected

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The circumnavigation took roughly 9 in-game hours, for a distance somewhere around 60 km. It was slow because of the terrain, though the last third using thrusters to simulate gravity increased the average speed.

Hale is definitely worth a look, if you don't have a killer radiation mod.

 

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