The KSP Caveman Challenge 1.11.x - 1.12.x

[Blaarkies]

I added the newest adventures about my Diamond run. From the first Mun flyby that almost went horribly wrong, to stealing some rover wheels, and finally some simple orbits around Minmus.
Big things to come!

[paul_c]

Great write up!

Regarding leaving Mun/Minmus SOI, if you research the radius of the SOI then burn so the Ap is beyond this, you will leave it. If needs be, do that burn just to leave the moon's SOI, then if the orbit of Kerbin is near circular (ie the Pe is not low (enough)), wait until the Ap and burn retrograde to set your Pe.

To avoid hot re-entrys, you can set the Pe to something like 60km then do a number of orbits! However it will wear down the ablator more than a single, hot, entry (but not heat other components which might blow up).

[Blaarkies]

11 minutes ago, paul_c said:

Great write up!

Regarding leaving Mun/Minmus SOI, if you research the radius of the SOI then burn so the Ap is beyond this, you will leave it. If needs be, do that burn just to leave the moon's SOI, then if the orbit of Kerbin is near circular (ie the Pe is not low (enough)), wait until the Ap and burn retrograde to set your Pe.

To avoid hot re-entrys, you can set the Pe to something like 60km then do a number of orbits! However it will wear down the ablator more than a single, hot, entry (but not heat other components which might blow up).

Thanks!

For leaving the moons, it saves a lot of fuel by doing a single burn at moon PE that puts the craft on a course that exits the moon's SOI such that the craft ends up in a highly elliptical orbit around Kerbin. From there, it should ideally already be touching Kerbin atmosphere (Im not that lucky though ). I did learn that its much safer to put your AP intercept below the moon's orbit line, it avoid nasty slingshots.
An alternative could be to exit prograde direction, ending in a very high orbit with AP at Kerbin's SOI edge, and fixing it there? I haven't tested the costs on that though

I was really afraid of the 120% re-entry heating, but its really not that dangerous as long as you have a heatshield. I always empty mine of any ablator, and the temps were reasonable with PE at 30km.

[paul_c]

Yeah definitely more efficient, but without the nodes, very imprecise (at least for me). Thus, I did it in 2 stages - inside and outside Mun's SOI.

I did in fact, burn at more/less the correct ejection angle (guesstimated), with more/less the right amount of deltaV (from my vague memory of other flights in better times). I guess for my caveman challenge, I can do a bunch of research and build up a table of "get you home" ejection angle/dv from a range of circular Mun orbits? Then use it as a ready reckoner for my blind attempts. Obviously elliptical orbits are another thing entirely though.

The other strategy might be to consistently do docking, so there is excess fuel available and that makes things much safer.

[paul_c]

Anyway, here is an update. 

Thanks to a brilliant idea of using the reaction wheels, this is my "science roller". Bob is checking out resetting the Science Jr and Goo. Note the 4x science storage - every last scrap of science was to be gathered!!!

The elusive flagpole science:

So......that didn't earn me enough science, so to the sky again. My research on dV & TWR stats meant I could build a rocket to squeak into space:

Other nearby surface biomes too:

The easy ones are done, now for the more risky highlands/beyond:

I have just enough to buy that elusive Terrier engine, which has wonderful efficiency and should get me into orbit, to the Mun and beyond:

[paul_c]

With the science value of "crew report" not being that high, and the risk of losing an astronaut, my focus will now be on remote probes again. I can't afford the OCTO yet so its Stayputnik stuff for now. Also, I don't have solar panels. This is the prototype:

Next job is to develop a stopgap relay network - it will be 3x satellites on the equator. They'll need to just be on batteries for now, later on the network will be upgraded with solar ones.

[Blaarkies]

3 hours ago, paul_c said:

With the science value of "crew report" not being that high, and the risk of losing an astronaut, my focus will now be on remote probes again. I can't afford the OCTO yet so its Stayputnik stuff for now. Also, I don't have solar panels. This is the prototype:

 

Next job is to develop a stopgap relay network - it will be 3x satellites on the equator. They'll need to just be on batteries for now, later on the network will be upgraded with solar ones.

Remember the hibernate feature in probe cores, it saves a lot of electricity. Do you know if relays still work after the batteries run out?

Like if you focus the vessel again, it will certainly shutdown, but if you never focus that satellite again, would the out-of-focus comms work well after the battery lifetime?

Edited February 2, 2021 by Blaarkies

[paul_c]

Not sure......but I'll just send another relay up if one runs out of batteries. AFAIK KSP doesn't do the normal power consumption simulation when a signal goes through a relay, unless its in focus. But whether it allows one with a dead battery to still relay....not sure! I'll keep an eye on them! It almost feels like a cheat though if it does.

[paul_c]

The relay network is in place, let's hope the batteries don't run out too soon:

The theory goes that if you set the altitude to the radius of the body, then the phases at 120deg, an equilateral triangle network will form. I've gone for a bit more (711km; radius of Kerbin is 600km) to allow for a bit of leeway and in the above screenshot I've also highlighted/thickened the CommNet vessel links.

[Popestar]

2 hours ago, Blaarkies said:

Do you know if relays still work after the batteries run out?

No, they don't.  If the probe loses power, everything on the probe is out of order until power is restored. 

[paul_c]

With the 3x relays and another spaceship for science (contracts), my funds are once again low......so its back to contracts. I am now able to pick and choose which ones to do, ie the higher paying or those with science bonus too; but that are fully recyclable for parts. My diligent recording/research before means that I can now reliably do those of the style "test/haul a part between wwww-xxxx m altitude, at speed yyy-zzz m/s" and hit the parameters - or see that its out of reach. 

One tip, if you're asked to test a part by staging, but want to actually use it before, you can set up the staging for the test but manually activate it earlier. For example in the above, the test wanted the Skipper engine activated thru staging while splashed down, but I was also able to use it beforehand to arrive there. (The decouple stage is my emergency eject, but it wasn't needed).

[Blaarkies]

On 2/1/2021 at 7:22 PM, paul_c said:

100% reusable but with an "emergency" capsule decouple with its own chute, just in case. The flight plan is to go up vertically, then flip horizontal to maximise drag

Haha I just realized you made a rudimentary mini Starship here, nice! 

 

[Mr. Peabody]

6 hours ago, paul_c said:

The relay network is in place, let's hope the batteries don't run out too soon:

The theory goes that if you set the altitude to the radius of the body, then the phases at 120deg, an equilateral triangle network will form. I've gone for a bit more (711km; radius of Kerbin is 600km) to allow for a bit of leeway and in the above screenshot I've also highlighted/thickened the CommNet vessel links.

That comnet constellation is so nearly equilateral that it makes me feel happy just to look at it. Brilliant stuff!

[paul_c]

4 hours ago, Mr. Peabody said:

That comnet constellation is so nearly equilateral that it makes me feel happy just to look at it. Brilliant stuff!

Thanks! Its actually not too hard to align it even with caveman controls, because you can see the lines between the relays so you put the relay into a slightly-different orbit then wait as the shape alters from a skewed triangle to an equilateral triangle.

I suspect I might be raising their orbits a bit, too allow for some deviation, rather than keeping them at that altitude and tweaking phase again and again. One has a splash of fuel, the others have a good reserve.

[JAFO]

On 2/2/2021 at 1:03 AM, Popestar said:

Question:  why is it now disallowed?  Is it due to the potential for abuse?  Or does it have something to do with 1.11 (which it doesn't work with)?

Basically, it was always disallowed, ever since the very first Caveman Challenge. (With the noted exception of the 1.3 - 1.10 iteration of the challenge. Just why @Mr. Peabody failed to explicitly disallow it in that instance, I don't know.)

As for the reason, I would say partly for the potential for abuse, but mostly because it can be used to provide considerably more information to the player than the stock game provides. For instance, even the relatively innocuous "Time to Ap" feature makes it possible for a player to perform a much more efficient gravity turn launch and circularisation than someone relying on just the stock game feedback, resulting in a significant advantage in terms of available dV once in orbit. It has nothing to do with the game version in question.

Edited February 3, 2021 by JAFO

[Popestar]

5 minutes ago, JAFO said:

Basically, it was always disallowed, ever since the very first Caveman Challenge. (With the noted exception of the 1.3 - 1.10 iteration of the challenge. Just why @Mr. Peabody failed to explicitly disallow it in that instance, I don't know.)

As for the reason, I would say partly for the potential for abuse, but mostly because it can be used to provide considerably more information to the player than the stock game provides. For instance, even the relatively innocuous "Time to Ap" feature makes it possible for a player to perform a much more efficient gravity turn launch and circularisation than someone relying on just the stock game feedback, resulting in a significant advantage in terms of available dV once in orbit. It has nothing to do with the game version in question.

Thanks for the explanation,  I fully support not using it for the purposes of transfers, docking, and landings.  I just didn't realize some of the visual information wasn't part of stock.

[JAFO]

18 minutes ago, Popestar said:

Thanks for the explanation,  I fully support not using it for the purposes of transfers, docking, and landings.  I just didn't realize some of the visual information wasn't part of stock.

You're very welcome. There was a time not long ago when even basic dV information was not part of stock. Until recently, cavemen used to have to calculate their dV by hand (and TWR, for that matter), by noting down the wet mass of the craft's stages, draining all the tanks to get the dry mass, then, after making the calculations for the various stages (which also involves using the various Isp values for each engine), they had to remember to refill all the tanks before lauch!

Edited February 3, 2021 by JAFO

[JAFO]

On 2/2/2021 at 4:22 AM, paul_c said:

The flight plan is to go up vertically, then flip horizontal to maximise drag

Ahhh.. The famous "Starship" re-entry profile in action!

 

18 hours ago, Blaarkies said:

I was really afraid of the 120% re-entry heating, but its really not that dangerous as long as you have a heatshield. I always empty mine of any ablator, and the temps were reasonable with PE at 30km.

Thanks for this.. good to know that even with no ablator at all, the heatshield is still useful. That's something I've never experimented with.

Edited February 3, 2021 by JAFO

[paul_c]

A bit of progress yesterday. With the crippling 20% science multiplier in Diamond, we are very much technology-limited. Some of the elements of tech level 4 and 5 are irrelevant or easy to work round, so they will be earned much later (in the "end game" phase of the challenge). 

However, there is a delicate balancing act to sniff out and scrape together enough science to buy the tech needed for Mun exploration. The problem I am having is, once the command module is "on top" as the payload, the 18t limit really bites and the deltaV possible is really limiting. Fortunately I am using remote probes now (with the Stayputnik) but it needs the command capsule for stability control - I can't afford the small reaction wheels yet. Its a bit of a chicken-and-egg situation.

So......as an example, I made a burn for the Mun, in as good a free-return-trajectory I could estimate, and got a 1.2Mm Pe, but once out of Mun SOI it left me with a Kerbin elliptical orbit with Pe ~1.5Mm. And I had about 49m/s of dV left, not enough to lower it for aero-reentry. I was able to transmit "Mun high" science though. Another tweak/design iteration and a splash more dV, try again and this time the same 1.2Mm Pe Mun encounter, but with ~100m/s fuel left. It was enough to get the Pe down to 18km and a successful, if scorchy, reentry was made and some returned science:

So, a test flight was made without the command module, which will save a lot of weight, but leave me with no reaction wheels. It was only semi-possible to control the vehicle, it was tumbling all over the place and only engine gimbal to determine direction. But it was possible to eject the heatshield/science storage box/controller/chute and at least recover this part. I did log some atmospheric science but no gains left there. So, I NEED the reaction wheels! And more money!

The next few hours were grinding away doing contract work. Some are better paying than others and about 1/3 the time, a +1 science one comes up too. Also some are a bit higher or more involved, so no longer trivial to do.

I am going to need to choose between reaction wheel OR solar panels/OCTO controller for my next iteration of remote probes, hopefully with actual control and a better dV so I can point it at things and it will actually go there. Maybe orbit the Mun soon? Or even land on it??? Who knows???

[Mr. Peabody]

19 hours ago, JAFO said:

(With the noted exception of the 1.3 - 1.10 iteration of the challenge. Just why @Mr. Peabody failed to explicitly disallow it in that instance, I don't know.)

TBH I completely forgot about mechjeb. After it crashed my lander into the munar surface I deleted it and it never returned to my data folder. I always enjoyed piloting my crafts by hand. Additionally, it was well understood that the challenge should be attempted with a "vanilla" (unmodded) version of KSP. This understanding was somewhat muddled by recent game updates and the release of expansion packs.

Edited February 3, 2021 by Mr. Peabody

[paul_c]

The tech tree square to unlock reaction wheels was purchased, and duly incorporated into a modified design without a Command Capsule for more performance. It took 8 iterations to achieve a stable, controllable craft - the problem being aero drag balance front-rear, rather than reaction wheels etc. 

Anyway, after a number of flippy ascents, I succeeded in a smooth ascent and LKO with 1906m/s dV left:

A very average/poor encounter with the Mun, but now in orbit with some low (<60km) passes to gather science:

Return was looking promising with the remaining fuel, and the caveman components didn't explode on re-entry:

Laundry out:

It did the "let's roll down the slope" thing but didn't gather speed and eventually settled:

36.2 returned science (plus some world first stuff and an "explore the Mun" contract):

I had hoped for a smooth progress but its taken a bit longer, and more money, than anticipated. So, back to contracts for now.....

[paul_c]

With another design iteration, I was able to have +270dV more once into LKO, so it was time to go for the Mun. 2 contracts popped up - "land on the Mun" and "science from space around Mun". I nearly forgot to transmit the science from space! The landing....went as well as I could hope. Its not really designed for landings but it landed ok on the engine, then I let it topple (it was never coming back.....). Managed to transmit 1 piece of science (the most points) before the battery went dead so definitely more potential once I have solar panels (which are not too far out of reach now).

[paul_c]

Nearly there for the next wanted/needed upgrade on the tech tree, so once again its off to explore Kerbin. The Science Jr hadn't been to some places. Highlands:

Mountains:

Best of luck recovering that, lads:

Day out to the beach? The shores of Kerbin are close enough to drive/roll to:

[fourfa]

FYI on your classic 2x Mk1 science roller - the Mk1 pods (actually, all command pods) are also science containers, so to keep four copies of experiments you only need 2x Mk1 + 2x science box.

I definitely aim to bring 3x back from missions with good science returns.  My favorite is Mk1 pod, 1.25m service bay, with 2x science boxes clipped just barely inside.  Still leaves room for the small experiments and a solar panel

I'm a little more lenient with clipping than some (3000 hours ago I was against it FWIW) but I got good mileage out of this armored model:

Girders have really high impact tolerance and allow some crazy Duke Boys shenanigans

Edited February 4, 2021 by fourfa

[JAFO]

2 hours ago, fourfa said:

Girders have really high impact tolerance and allow some crazy Duke Boys shenanigans

I like that idea.. I usually use radiator panels for protection, but yeah, these would be way tougher!