totm may 2023 Elcano IV: Circumnavigate all the things!

[damerell]

On 7/20/2022 at 12:01 AM, damerell said:

Alas however all is not joy: I stopped 2km away because I am on the edge of a tremendous drop into certain death (if the slope is so steep I gain speed with the brakes on, I can't drive down it; my main false start on Eve was discovering this) - I'm not sure where I go from here and I fear the answer may be "back the way I came and make a semicircle around the pole".

It turns out to be not entirely clear if I have the torque to go back the way I came.

[Pouicpouic]

6 hours ago, damerell said:

It turns out to be not entirely clear if I have the torque to go back the way I came.

This is very sad news...
I tried to warn you about this hellish situation, but I should have scared you even more...

I really hope you can do it !

[damerell]

Fortunately I remembered that the Kerbal Foundries wheels can have their gear ratio adjusted, producing more torque but with a lower maximum drive speed. (I wonder if I should write a bit more kOS to adjust the gear ratio either in response to action groups or automatically based on groundspeed?) Armed with this approach it was still a godawful struggle to back off the way I'd come but eventually I made it back to around 88 degrees north and could then drive west through only moderately ghastly terrain.

The KF wheels break from prolonged overstress, not like the stock behaviour, and alas are not really quite up to scratch in Eve's gravity; if I stop on a steep slope one of the downslope wheels will break after a while. This puts extra load on the others and, well, Jeannette Kermana has to get out the airlock and go and fix several wheels, something she has done approximately a hundred times on this little jaunt.

There was a lot of this kind of thing. I hate driving down this kind of wedge because, sure, it's OK for now but goodness knows what you'll meet at the end and you can't steer away if you don't like it.

Map seen from above as we're about to turn south. I think I can probably squeeze through West of the Crater Lake, making the northbound and southbound legs as close to opposite sides of the planet as I can.

And shutdown. The terrain is easy again and Kerbol is just peeking over the horizon to the east which I think means I have have a full day of roving in the daylight, but this polar problem has been pretty hard work and I'm done for today. Also the altimetry map is still stretched but has gone from "will it just crash if I have it on with the pole itself onscreen" to "not really useful" to "not too bad".

 

Edited July 22, 2022 by damerell

[damerell]

The weather here recently has helped to keep the Eve circumnavigation experience authentic since I am sitting in a small space for long periods of time wishing for more temperature control, just like the kerbals.

80 degrees north:

A flag planted at 70 degrees:

Skirting a lake at 66 degrees. The terrain has been very easy here close to sea level compared to the Peaks where I started out, but it does run the risk of the occasional diversion around water.

Checking the map. Given the lump of Peaks coming up, I think my plan is to run around the edge of the Crater Lake and cut south through the gap in the mountains.

Another lake coming up at 50 degrees:

Podpont planting the 50 degree flag:

So far, the course looks good:

And 40 degrees, having skirted the now-traditional lake (the large dark red blob on the altimetry MFD is all water):

Pretty easy going right now; I haven't had time to play much but when I do I'm going as fast as anyone could reasonably expect given the gravity turns every up slope into something of a slog. Also, Kerbol is setting gradually and I'll need to decide when to shut down for Eve's night.

[damerell]

Slow progress recently, in spite of relatively easy terrain. I think this is partly down to the need for a lot of navigation to keep the terrain easy and a certain amount of purple rock fatigue.

I did shut down for the Eve night - a good call since in the morning I was going to experimentally verify I could cross shallow rivers. Exactly how deep a river I can cross without pumping ballast in remains an interesting question.

I tried to steer around this enormous crater's edges, not entirely successfully - I hate veering too much off my heading, even if it would be quicker to drive West into flatter terrain then go South much faster. I was tempted to drive up to the rim and have a look, but sense prevailed - I'm not sure if I'd even have the torque to make it up there, and if I did, getting down might be catastrophic.

Podpont planting the 30 degrees North flag. Plenty of daylight left. I know in KSP the ground isn't always where it seems to be but I'm a bit alarmed at my front right wheel just hanging in the air like that.

My plan was to turn Southeast here, cross this saddle pass, then drive due South at 10 degrees West which I think will let me skirt the Crater Lake without either having to make large diversions around bits of it or get anywhere near the mountains to the West.

20 degrees north; first glimpse of water.

I went a little further but it didn't produce any interesting screenshots. I know once I get around the lake I'll have to veer some way East to get through a gap in the mountains around 2 degrees East. Then perhaps I'll have an easy run towards the South Pole.

I'm kind of torn between "hooray, almost half distance" and thinking, coo, even after this slog, only half distance?

Edited July 27, 2022 by damerell

[damerell]

Here's Podpont, inveterate flag planter, at 10 degrees North. And one of the smaller bodies of water this area is riddled with.

The equator! Half distance (plus a princely half-degree latitude since I started just south of the equator).

And a shot of the map with all its flags, just because:

I appear to have driven quite a long way around the crater lake without ever capturing its likeness. Ooops.

Edited July 28, 2022 by damerell

[damerell]

Here's the crater lake. It looks exactly like every other body of water on Eve. Oh, well.

I had come some way East around the shores of the lake to drive through this pass. This worked OK, but the terrain beyond was still well above sea level.

Here I wondered if the lake ahead was above sea level. It's not, I'm just about to rove down a very long way. It's further away than it looks.

20 degrees South:

It was clearly getting dark and I'm not short of supplies / habitation anywhere, so I shut down for the night, then set off again at dawn.

30 degrees South:

 

[damerell]

Now I'm out of those lakes and mountains, I've been making good progress with few problems - so here are screenshots of 40, 50, 60, 70, and 80 degrees South:

It is late here IRL and I expect the South Pole to be challenging (although I may resist the urge to even try to get very close to it) so I'm stopping for the night, but I'm past 2/3 distance and 3/4 distance is in view.

[damerell]

Within 3 degrees of the Pole the terrain took a turn for the awful:

After a bit I decided I'd had enough of one Pole and I'd plant a flag and circle around it to the West, where the altimetery map looked flatter.

It turned out to be flat because it was water. The good news is that the KF wheels apparently serve as quite functional paddle wheels. (This wouldn't work with Scatterer waves especially since I have no yaw authority to speak of, and it would be cheeky for a water circumnavigation, but I can live with it as a happy development on this trip.)

Here I turned to the North having circled around the pole mostly in the drink but partly on land.

And here's the 80 degrees South flag on the last leg. I waited a bit for dawn (but failed to account for the fact that if you drive North from a South Pole in perpetual light you may actually drive back into darkness); Kerbol hasn't quite risen yet but the terrain is easy and I'm happy to continue in the dark.

 

[damerell]

By the time I got to 70 degrees South, Kerbol had risen.

60 and 50 degrees South:

And 7/8 distance. The end is in sight.

I did get to 40 degrees South tonight, but forgot to screenshot before shutting down. I've done most of Eve this weekend, but I fear it will be a few days before I have time to finish up.

[damerell]

I never did get a screenshot of 40 degrees south, oops, but I dropped a flag there.

30, 20, and 10 degrees didn't post any difficulty.

However, I discovered then that with unerring accuracy I had started on top of a sodding mountain. This was particularly annoying since my ascent vehicle doesn't need to take off from as high an altitude as possible. It was considerably difficult to find a route I could climb at all, and I had to pause more than once on the way up to brew up more electric charge.

Also I fear I did break my personal quickload rule when I flipped the rover about 500m from the finish. Sigh. I guess I can tell myself the kerbals could have _walked_ to the flag from there.

The intrepid team of Podpont, Sally, and Jeanette. Another oddity is that when I started this save in KSP 1.1.3 or so, Sally was not a pilot. Weird.

And finally, a map of flag icons.

The next thing is to see how close to the rover I can land the ascent vehicle. It may be that the roving is not quite over. Then I can do Gilly, which I suspect may not take _quite_ as long.

[damerell]

I must remember to make the rover kOS script a bit keener to run the fuel cells. I barely used 20% of my fuel getting around Eve.

How do I get back from Eve? This ascent vehicle, which has a realistic lift airship envelope, a Mk2 rocket stage, asparagus-staged aerospikes, and a heatshield.

Here it is having jettisoned the main engine and inflated the heatshield.

Dangling from a chute. There's then a slightly tricky transition between chute and inflating the airship envelope so we land legs-down.

Not as close as I'd hoped to land, but only about an hour away - and mostly downhill.

Here's the rover arrived at the ascent vehicle. The kerbals will stay in the rover until it's time to return to orbit - it's much more spacious.

Gilly will not be entirely easy - I'd made it most of the way around when this happened for no readily apparent reason. A fresh attempt will be needed tomorrow.

Edited August 6, 2022 by damerell

[damerell]

So, what's up with Gilly? This sudden rover disintegration is caused by the suspension bottoming out and banging the rear of the rover on the deck. You might ask, how can this happen in no gravity? The answer is that if you drive up a steep slope on (say) Kerbin, you won't be going all that fast when you get to the top. On Gilly, your entire forward velocity can be converted into mostly-upward velocity and with no control of the resulting arc you are going to slam back down at the same speed, mostly-downward.

The other thing, of course, is that the challenge rules permit "brief" jumps which is tricky to respect when a kerbal could launch themself into orbit by breaking wind. However, downward facing engines are permitted; I wrote a kOS script which managed the throttle on the engines on the top of the Mk VII to try and make sure whenever I left the ground my upward velocity was zeroed out (made slightly tricky by the way that the actual shape of the ground matters - there are some multi-kilometre drops and ascents on Gilly, and it's no good kOS cancelling out vertical velocity relative to sea level if this is actually slamming you down on the ground rising under you); I'd then descend under Gilly's gravity, but from a modest height.

I also upped the spring strength and damping on the wheels to the maximum and turned off the antiroll mechanism entirely. Some combination of this and restricting speed to 15 m/s (somewhere between 15 and 20 m/s hitting a bump on Gilly goes from "a big jump" to "you might come down 15 minutes later") got me around without any unplanned rover disassembly, and the kOS script did make the journey more "jumps" and less "three suborbital trajectories spliced together".

I landed near one of the poles (why?) and so took a polar route. 45 degrees north:

Crossing the Equator. The 6 minute impact time here will be reduced, but it's still a big jump.

45 degrees South. Absolutely typical of Gilly - I am less than a metre above ground and 8 minutes to impact. (In practice, I took control of the throttle and got it back down on the deck...)

45 degrees South on the way up again. I don't know why there is no screenshot of the Pole or why this image is labelled "equatoragain", sorry - some confusion on my part.

Really the Equator. I had remembered something from my Kerbin circumnavigations - if you have and turn on a Scansat BTDT, you get a solid record of your path on the small Scansat map.

45 degrees North.

About as close to the North Pole as I came. Even on Gilly, the terrain is kind of awful.

Around there I did take a big jump, flew clean past the pickup craft, and had to approach it from the South. Here it is just coming into view.

And finally back home. I would like to tell you I came to a controlled halt and didn't just whack into the Hangarmoth at 2 m/s, but I would be lying.

I now have to, sigh, load this rover back aboard (fortunately, I can use RCS for _that_), suck it dry of LFO, MP, and uranium, and - since there's a resupply rover en route to Duna - drop it back out again.

[damerell]

To Duna! Well, first to get off Eve and Gilly.

Here's the Eve ascent vehicle again, which happily I have discovered has enough shove to rendezvous with the Queen Agaster itself. It drops the base ring of landing legs and the heavy monoprop tank as soon as it's rising straight up under the airship envelope. Yes, that is a huge and scary ladder to climb in Eve's gravity; the thing basically brings its own launchpad and gantry.

When the upward speed drops to around 100 m/s, I undock the envelope. It shoots upwards and because we pitch over a bit, we don't fly into it later. I don't use Mechjeb's ascent guidance until later in the climb - it seems a bit too keen to stooge around in Eve's atmosphere.

Rising under power - there's a pretty normal asparagus engine and tank arrangement here.

Into orbit (and soon to raise our periapsis out of the fiery death zone).

And at the QA. Sadly, there's no way to deorbit it - it has no control parts at all.

Getting the Hangarmoth off Gilly was very easy since if I release the ground tethers, just putting down the landing legs propels it into the air for a minute or so, giving time to retract them and activate the Orion units. It wanted around 66 days to fill the LFO and MP tanks, and I had 40 days on my habitation timers, so the supply situation is much healthier than it was. Taking off with the Ore tanks full was difficult (since as discussed some idiot didn't put them diagonally opposite each other) but I realised I could pump as much LFO and MP as possible to the other end of the Hangarmoth and then it could be balanced about the thrust axis. It's en route to rendezvous with the Queen Agaster now. (There aren't any screenshots of this because KSP apparently decided to ignore me pressing the F1 key, sigh.)

Edited August 8, 2022 by damerell

[damerell]

And I'm en route to Duna. I wonder what new difficulties it will pose?

Incidentally, I got an Eve-Duna transfer window 10 days after docking up in Eve orbit. I wish I could say I planned that.

Edited August 8, 2022 by damerell

[damerell]

I spent a restful few hours sending some of the remaining scan satellites and rover deliveries on their way, then the Duna rover resupply came to say hello, popping its box hangar open to disgorge, well, a rover.

Unsurprisingly, it is not so easy to use RCS added as an afterthought for on-ground attitude control (which is forbidden) to fly this rover into the cargo bay on the Hangarmoth in zero-G.

[18Watt]

On 8/7/2022 at 8:12 AM, damerell said:

I would like to tell you I came to a controlled halt and didn't just whack into the Hangarmoth at 2 m/s, but I would be lying.

Yep!  Once you manage to actually get moving on Gilly, it's hard to stop!

Congratulations on getting the crew off Eve!  The poor crew I sent to do an Eve circumnavigation is still there..

[damerell]

1 hour ago, 18Watt said:

Congratulations on getting the crew off Eve!  The poor crew I sent to do an Eve circumnavigation is still there..

Planning to do it all in one go makes kerbals not at all expendable (and two of my kerbals are survivors of my earlier missions). I started with 3 complete pilot/scientist/engineer/engineer crews; I need six kerbals on the Hangarmoth or the QA to control probes directly in a RemoteTech world (ie without waiting out the lightspeed lag from Kerbin) - if I lose one crew I can't do that if I have a crew on the surface, if I lose two crews I can't do that at all, and of course if I lose three crews that's game over.

Another unwelcome discovery is that in the reset to start Moho afresh, the special vehicles for Laythe simply did not get launched. I'll have to start them up when I'm done with Duna and/or while parked up when dark.

The rover delivery vehicle had quite a lot of LFO and MP left. It was the very devil of a job to get it close enough to attach to with a KAS arm (why did I not put a docking port on it?) and Hersel Kerman, the specialist EVA engineer, had used over half his suit endurance before the operation was completed - but it was worth it to pump that precious fuel out of it. (I also had to deal with an obscure mod incompatibility between KIS and USI Konstruction).

The regular landing kOS script worked well enough with a few modifications to account for Duna having an atmosphere, but this was not one of my better landings. A Hangarmoth II should just have some side landing legs. However, in the low gravity no harm was done and retracting the landing gear set the Hangarmoth back down on its belly.

The rover about to set off! Except I am about to discover if I run the arrays of Ore and MetallicOre drills on the Hangarmoth at the same time a single thermal control system can't even remotely keep up, so engineer Arald Kerman will recover two more from the large KIS containers on the Hangarmoth and fit them where he can find space; I don't have a shot of it yet, but the resulting configuration is, ah, less aesthetically pleasing.

I landed further south than I hoped so I am driving about North-East until I hit the Equator. Duna being smaller than Eve, I plan to screenshot/flag every 15 degrees, and since I had to shutdown here, I'm declaring this close enough.

The good news is that Duna is - so far - a pleasure to rove on; rolling dunes and light gravity mean the Mk VII can just be given its head.

Edited August 9, 2022 by damerell

[18Watt]

18 minutes ago, damerell said:

The good news is that Duna is - so far - a pleasure to rove on;

I also really enjoyed Duna.  Except for the poles..  Duna has some extremely high elevations, most of which are easily reachable. 

[damerell]

I got a bit distracted by the question of absurdly fast boats and a way to do Gilly without leaving the ground, but here I am at the meridian. I'd shut down shortly after, since it was getting dark, and go to relaunch the Laytheboat.

I did start roving a bit before sunrise, though, the terrain being so easy.

Sunrise on Duna.

30 degrees East.

45 degrees East.

I should at least rework the Laythe jet delivery vehicle before doing more roving.

[damerell]

Flag at 60 East:

 

I regret my usual image presentation workflow broke down here. I stopped in the dark to drop a flag at 120E, then went to launch the Lathe recovery jet. This was slightly awkward since it involved a huge heavy sail on one side of the rocket.

Basically, there's a tank with two LV-Ns on it which roughly balances out the jet and its two LV-Ns and smaller tanks. Of course as the fuel burns off there will come a point where the empty tank can't balance out the jet, but a) I think I have surplus dV and b) kOS can dial down one set of engines appropriately.

The upper stage LFO engine is in the middle here (so you can't see it, sorry, bad picture-taking) but once it runs dry both it and the nose tanks pop off, leaving jet and ventral tank attached to a monoprop tank and reaction wheel.

 

Edited August 20, 2022 by damerell

[damerell]

Dawn on Duna. I know these screenshots are mostly here to document progress but even so, this one is pretty boring, sorry.

A flag, and an illustration of how the ScanSat BTDT provides a neat track on the map of where you've gone. I dipped into the Eastern Canyon for a bit until it strayed too far from the Equator, then had some tougher terrain in the Highlands.

Here I am taking a big jump into, unfortunately, a region characterised by ugly Z-fighting.

And finally past 180 degrees East... well past halfway, then, since I landed at 25 degrees West.

However, I had a realisation that was obvious in retrospect. KSP's small worlds mean on many of them the dawn moves at a speed comparable to roving speeds. On Duna, it moves at almost exactly 30 m/s - travelling east means this about halves the roving day, whereas if I'd travelled west Kerbol might barely seem to move in the sky at all. This is the first time this has caught me since Moho barely spins at all and I took polar routes on Eve and Gilly.

In the hope this is of interest to other circumnavigators I present the speed of dawn for Kerbol-system bodies. Note this is a bit imprecise for moons because it depends on the moon's position in its orbit about its parent body, and only for Moho have I bothered to distinguish sidereal and solar day.

• Moho: 0.6 m/s
• Eve: 55 m/s
• Gilly: 3 m/s
• Kerbin: 175 m/s
• Mun: 9 m/s
• Minmus: 9 m/s
• Duna: 31 m/s
• Ike: 12 m/s
• Dres: 25 m/s
• Laythe: 59 m/s
• Vall: 18 m/s
• Tylo: 18 m/s
• Bop: 0.8 m/s
• Pol: 0.3 m/s
• Eeloo: 68 m/s

There's a whole range there from too slow to care about to too fast to keep up with, but it seems pretty clear in retrospect that the direction to set off in is West not East. Oh, well.

[damerell]

I found myself roving down this canyon.

I resolved to rove on into the night, having spent some time rewriting the kOS speed control script, and being concerned about being able to go to Ike or have to recover to the QA to reset habitation timers.

And now it's dark.

Darker still, but by keeping the speed reasonable I can drive over these gentle dunes.

 

[damerell]

I ploughed on through the night, or rather, spent about half the time driving and half the time rewriting the anti-overspeed kOS script (which handled the case where the desired maximum was more than the maximum drive speed so it just needed braking downhill well, but not slower roving at night; it took several iterations to reach a point where it wasn't alternately letting me go full throttle then braking to waste all the input energy). Flag at 120W:

Could have sworn I hit screenshot as I got past 105W, but I've got nothing, so here's a flag at 90W:

This puzzled me - was it a huge grey mountain? Does Kerbol look really weird because of some odd property of the Dunanian atmosphere?

Oh, wait, it's Ike.

75W, and an impressive view in the sky. With only 50 degrees longitude to go, I should be home before dark. A pity to have set out the wrong way and done an unnecessary night roving leg, but I seem to have survived it.

 

[damerell]

I resolved to try and rove into the "Western Canyon" biome I'd seen on the map. From the last screenshot at 75W there was some nasty Highlands terrain, and the bottom of the Midland Sea was pretty bad, but I got into it here and tried to just steer straight down it.

Here I am much further down - zoomed out, the rover as a tiny blob, and showing the vast mountains the canyon is defined by. The canyon was smooth going.

My track on the Scansat map is wiggly because I followed the canyon to its easternmost extent, then decided to continue to 45W before turning towards the Hangarmoth; here is that moment.

Heading towards the Hangarmoth, and in smooth terrain for a change.

The last flag on Duna at 30W. I'm pleased the KSC thought to supply us with this semi-infinite supply of flags.

Once nice thing about the resupply mission that was necessary is that the Hangarmoth sticks up a long way because of the extra tanks being in this tower when the thing is landed. I'd seen it a bit before, but this shows it from a distance.

And home!

I have not checked the ISRU situation on the Hangarmoth, let alone loaded the rover up and set off for Ike - but I am done with Duna at last. Much smaller than Eve, but I've been distracted by other matters and it's taken a while. The Laythe vehicles are coming up to transfer out of Kerbin and I will have to make sure they hit those windows.

Edited September 13, 2022 by damerell