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Stars to stones: my nanocristalline diamond caveman attempt


king of nowhere
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Part 25: Spinoff challenge: Jool 5

Vall

Landing on Vall. Also, taking a dip into Jool's upper atmosphere

Spoiler

Assembling the Vall lander had some unexpected problems, caused by kraken attacks. Namely, some docking ports refused to undock (I even asked for help here). If I can't undock stuff, I can't complete the mission. Well, apparently the only thing I could do was hack the save. I took an old save, from before this problem happened, I made sure to have the same crew in the ship, I discarded all the pieces that had to be discarded until I got a perfect replica of NSN how it is now (I checked that there is the same amount of parts and fuel), and then I copied all the parts data from the old saved game into the new one. I basically swapped NSN with a perfect replica, without the bugs. And it actually worked!

But not completely. Some docking ports are still stuck. Which is why I put the expendable experiment between the lander and the lander pod here: I could not detach them

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The Vall lander, with some 4 tons of fuel; one of the tanks is almost empty

This causes a loss of efficiency, because I will have to carry dead weight up from Vall; but it's a minor issue, and fixing it was already annoying enough the first time.

So, once more I try to estimate the correct ejection deltaV from the alexmoon planner, and this time I actually got close, a 40 Mm Jool periapsis. A few correction manuevers later I got the trajectory ready for Vall intercept. This time I learned from the Laythe lesson, and I kept my periapsis a bit higher than the planet, to avoid smashing in the middle of it.

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Heading to Vall

By coincidence, there was no need to take the times, because I already met Vall on the first passage. Periapsis was -160 km, which is a lot better than -300; I suppose keeping a higher Jool periapsis helped.

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Approaching Vall

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I always liked Vall. Perhaps it's time to drive a rover on it again?

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At periapsis, flying close to the icy plains

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Releasing the lander

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Some geysers seen from IVA while flying over them

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Landed

The whole landing operation went without a hitch. Perhaps I was too paranoid skipping this landing in the ncd challenge, but after those landing struts crapped me, I really felt unsafe.

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Going back to orbit

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Jettisoning the lander after squeezing all the fuel from it

Now I still have a fair bit of fuel left. And one expendable experiment, why did I carry four?

I decided to also try to collect more science, see if I can get a mention for that category too (I mean, technically I have the record for science collected in caveman from a Jool5, because nobody else tried it that I'm aware). And since I had a safe amount of fuel left with NSN, I decided to also explore low Jool. For that I must raise apoapsis a lot, so, leaving Vall with high speed

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Not high enough. Must burn more

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Now it's good

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And now that orbital speed is very low...

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I can do a 90° plane change and periapsis lowering for little cost

Lowering periapsis is a lot cheaper if done in high orbit. As for the plane change, it was the only way to make sure I wouldn't hit one of the inner moons by accident.

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Dipping in the atmosphere of Jool

It was only a 700 m dip, or I would have risked destruction. Now it's time to return, by performing the opposite manuever

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The fuel canister run out, going on emergency fuel. Luckily, it's enough

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Matched Pol orbit, with 200 m/s left

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Returned to Pol

This went perfectly at the first attempt, except for the docking port bug. Now I only have to return

 

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Part 26: Spinoff challenge: Jool 5

Return

Coming back to Kerbin. With a lot more efficiency than the last time.

Spoiler

As I've already done in the ncd career, I discard most of the habitat part to make Navis Sideralis Neanderthalensis lighter.

This time too I got hit by the no-undocking bug, even worse than before; not a single docking port could undock. Again, I did the editing trick on the save to fix it - again being careful to keep exactly the same parts. Using up fuel in discrete tanks that get jettisoned helps with this.

This time rearranging NSN was easier because there was less stuff attached.

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Jettisoning the taxi and the command pod for the Service Probe (which I ended up never using, by the way)

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Two of the lateral crew pods expelled. Still the struts remained, though

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Job completed

Even though I used up more fuel than the previous time, I've still got over 4000 m/s. It's a lot more than required.

This time I am making full use of the alexmoon tool. I check which orbit is best to leave Jool: a low periapsis gets more Oberth effect, but it takes more fuel to get there in the first place. While a higher apoapsis is cheaper to reach, but it gets less Oberth. Some experimenting conclude that the ideal orbit to launch from Jool to Kerbin is between 100 and 200 Mm above Jool - the difference is minimal within those extremes, but it quickly goes up. I eject from Pol with the minimal amount of speed, because Pol has already the best position to leave for Kerbin.

I wonder if it was intentional, because a lot of things about the Jool system are so incredibly convenient. Two big moons you can use for a gravity capture, one with an atmosphere you can use to aerobrake. You enter in a low orbit, either by using Oberth effect for the injection - it only costs a few hundred m/s - or by using the moons, then you work your way from the inside to the outside. And on the outside, you are in the best place to leave for Kerbin. The other gas giants explored in OPM were nowhere near this convenient.

Anyway, I got out with a 120 Mm Jool periapsis, aligned more or less where I wanted it to be to exit retrograde.

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The parking orbit around Jool

Now, the tool says I should have a 1270 m/s ejection burn, and my speed where I perform the manuever is 1520 m/s, so I assume I'd need to reach 2790 m/s.

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By the way, now NSN is symmetrical and incredibly stable in its thrust. Here I am jettisoning the last asymmetrical tank

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After the ejection burn

I decide to stop at 2700 m/s, it's a bit less but my orbit is deviating away from a perfect Jool retrograde; also, this way of manuevering is not very accurate, if I make a mistake I'd rather make an ejection burn too small, so that I can make a correction and fix it. If I burn too long, then I wasted fuel for the longer burn and I have to waste fuel again to fix it.

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Resulting solar orbit

I got a 12 Gm solar periapsis, so I did indeed burn too much. Even though I was 90 m/s short of the calculated speed. Yeah, I didn't account that the tool assumes circular orbits, and I was already elliptical, I had some additional speed. Which more or less compensated with the ejection not being perfectly parallel to Jool retrograde. Anyway, 1 million km is a relatively small course correction to make

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And here the plane change. Not that the orbital plane of Kerbin is very easy to see

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And the two pics to take the orbital time

There are 63.5 days between the two passages. Running some calculations on my datasheet, NSN orbital time is 2415 days, and the closest way to syncronize orbits is to get it to 2492: 6 Kerbin orbits by 426.1 days, minus the 63.5 that I have to recuperate. This method is robust enough that I can approximate the fraction of days.

To get the desired orbital time, I must raise apoapsis by a couple million km, which this far from Kerbol is cheap.

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And I also perform a second, more refined planar correction to match planes more exactly

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Six years later, coming for intercept

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I actually got within 1600 km!

Yep, this strategy is very robust. I had no idea you could get such precise periapsis just with a datasheet. If I had tried earlier, I could have gotten a much better Jool intercept, saving much fuel. Which wouldn't have mattered in the slightest, because I skipped some landings not for fuel shortage, but for safety, and now the fuel is enough anyway. Maybe I could have launched a few less canisters.

I believe this method of calculating intercepts is so robust for a few factors. When NSN is coming down to periapsis, its orbit is matching closely the orbit of Kerbin for a few days. NSN moves some 2 km/s faster than Kerbin, so every day it recovers 43200 km over the planet. With the orbits matching for several days, even missing Kerbin by half a million km is not a big deal. And once in Kerbin's SoI, the planet will pull towards the center, so small mistakes are corrected this way.

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Getting close to Kerbin

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Kerbin capture!

I still had over 2 km/s, so I figured, why not make a proper injection and save what's left of the ship? I parked it in a stable orbit, where it could potentially be used again. No, not that I'm planning on it. While I feel confident I could now land everywhere in caveman style, the amount of work required is staggering. If I do a caveman Eeloo landing, I will get infinite money and alt-f12 the fuel tanks in place. 

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NSN captured around Kerbin

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Only thing to do is deorbit the reentry pods one at a time

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First one takes a bit of damage falling on water, the Cetotheriums have a hard landing. But the capsule is made to survive it

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Second one, I took the chance for some nice pictures of the crew with internal overlay

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It landed in a pleasant grassland

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The lander pod needed the Service Probe to deorbit

I've already shown those vehicles getting deorbited from much greater speeds, nothing of note in the landings.

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Science collected

Removing the "recovery of vehicle returned from Vall surface" (I wonder why it picked Vall), I'd have gotten 1139.5 science at 10% return, equivalent to 11395 with normal science. In case this gets a mention in the Jeb category.

Edited by king of nowhere
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