PunkyFickle

Moar Boosters Challenge - To the Mun and back, speed competition

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28xhHQz.png

Hello Fellow Kerbonauts,

We know from the Impact the Mun challenge that it is possible to fly to and crash something on the Mun in a mere 12 min. This is a great first step towards adding boosters to stuff in order to go fast, but only shooting the Mun isn’t that useful, right? This challenge aims at proving that our rockets can be fast and useful. So for this challenge, you’ll not only need to reach the surface of the Mun as fast as possible, but to also bring a rock back to Kerbin as a proof you got there and to demonstrate the scientific relevance of adding moar boosters.

Rules :

  1. Depart from KSC
  2. Reach the surface of the Mun
  3. Take a surface sample
  4. Bring it home
  5. Your place on the leaderboard depends on your mission time when the sample lands on the ground
  6. Challenge ends on the 28/02/2019 at 00h00 UTC (just one month; how handy)
  • Not limit on the number of boosters used (obviously)
  • Rockets or planes, It doesn’t matter
  • Undock/dock as many times as you want
  • Launch as many vessels as you want, but the timer starts when the first vehicle takes/lifts off and ends when the sample gets to the ground (show METs on the tracking station screen if you used multiple vessels)
  • Land, bounce or lithobrake on the Mun, as long as you manage to take a sample and bring it back
  • Only the surface sample has to make it to Kerbin’s surface (but the Kerbal can land as well)
  • No Kerbal should be armed in the process, though. This includes the command chair; no prolonged use, not in harmful environment.
  • The surface of the ocean is part of Kerbin’s surface
  • We need the sample (mostly) intact for the science we’ll get from it, so smashing it on the ground doesn’t count if whatever contains/carries it gets destroyed/killed
  • No fiddling with the cfg files, hyperedit, Kraken exploit, etc. Stay fairplay.
  • Latest versions of the game only (when was the last aerodynamics update? 1.0.5?)
  • No DLC engines or fuel tanks
  • Pictures are good, videos are good(er). In any case, make us understand and enjoy.
  • Multiple submissions are allowed.
  • Mods :
    • If you used any, provide the list
    • Stock aerodynamics
    • Stock engines and fuel tanks
    • Modded fairings and wings are allowed
    • Nothing that messes with the physics engine
    • Ask the permission to use anything else than mods that blatantly do not interfere with the challenge (RemoteTech is OK, Alcubierre drive is not OK)

Awards :

  • Precision delivery : Have the sample landing next to the KSC facilities so that our scientists can start analyzing it as fast as possible.
  • Relay race : Bring the sample back with a different ship that the one which brought your Kerbal to the Mun
  • Sepratron : I like the separation (who doesn’t?). Use sepratrons as a significant source of thrust in your design to please me and earn this award.
  • Full throttle : Do it the most kerbal way and maintain full throttle for all the duration of the mission (with empty stages for the landing?). It probably is not possible and certainly is not reasonable, but I know how crazy some people are.
  • Vanilla addict : Stock and only stock. No mod award.

 

Temporary leaderboard (last edit : 04/02) :

  1. @Laie - 1h 19m with a good amount of boosters and an interesting packaging design. (Prev. time : 1h 30m 43sec)
  2.  
  3.  

 

Rewards : No pics, no submits
Nice badges like this one :

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I will make some with medals and awards when I find the time.

Feel free to recommend other awards if you think of any. Same for rules amendment if I missed anything.
Also, if anyone else feels like remaking/improving the badges or making medals, please go ahead, I’m not that confident with Gimp Photoshop.

Fly fast!

Edited by PunkyFickle

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...and 43 seconds, but hey.

I guess I've wasted several minutes by starting the deceleration too early, also, aerobraking took a lot longer than expected. A 2.5m heatshield might actually be worthwhile. Or, of course, MOAR boosters -- but this is as big as I'm willing to build.

 

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That's a decent amount of boosters. Well done!

5 hours ago, Laie said:

I guess I've wasted several minutes by starting the deceleration too early, also, aerobraking took a lot longer than expected. A 2.5m heatshield might actually be worthwhile. Or, of course, MOAR boosters -- but this is as big as I'm willing to build.

You started reentering at 7700 m/s. Be happy that the science container did not vaporise. You had quite a bit of ablator left, though.

Could you provide your list of mods for the records, please (GameData screenshot will do)?

Edited by PunkyFickle

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Around 8km/s is where any heatshield will fail instantly. I don't know the exact limit, but 7.7km/s is still on the safe side.... obviously. It also helps to have a lightweight payload and an oversize heatshield for quick deceleration to saner speeds.

Hmpf. I forgot to check the peak g load at the end. I occasionally looked at my data display and the highest value I noticed was a little under 20g.

This is probably about as fast as it gets with economic engines and sheer delta-V. If you check the timestamps, I was only coasting for a few minutes on my way to the moon before I hat to turn around and brake again. Substantial improvements can only be had by bringing higher TWRs, which also rules out nukes and and and. I guess that doing it in 75min will require 3x as much rocket.

Modlist:

Spoiler

$ ls -1 GameData/
000_ClickThroughBlocker
000_Toolbar
001_ToolbarControl
CommunityCategoryKit
EasyVesselSwitch
EditorExtensionsRedux
Firespitter
houserules
KAS
KerbalEngineer
KIS
kRPC
MechJeb2
ModuleManager.3.1.2.dll
ModuleManager.ConfigCache
ModuleManager.ConfigSHA
ModuleManager.Physics
ModuleManager.TechTree
RCSBuildAid
RetractableLiftingSurface
Squad
SXT
toolbar-settings.dat
TriggerTech
ZeroMiniAVC

 

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8 hours ago, Laie said:

Around 8km/s is where any heatshield will fail instantly.

Oh, I didn't know that. But I exclusively play with FAR, so I guess that I'd have to push a bit further to find that limit.

8 hours ago, Laie said:

I forgot to check the peak g load at the end.

You cut the relevant part in the video. You might still have the whole footage, though, if you are really curious. (Centrifuge award : start preparing the sample for analysis by applying more than x g to it upon reentry.)

8 hours ago, Laie said:

This is probably about as fast as it gets with economic engines and sheer delta-V. If you check the timestamps, I was only coasting for a few minutes on my way to the moon before I hat to turn around and brake again. Substantial improvements can only be had by bringing higher TWRs, which also rules out nukes and and and. I guess that doing it in 75min will require 3x as much rocket.

Yes, I'm rather puzzled as to why you went to the cautious nuclear reactors approach, when the challenge clearly favors brute force and piling up boosters (thus its subtle title). You missed the full thrust award by not much, by the way.

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13 hours ago, PunkyFickle said:

Yes, I'm rather puzzled as to why you went to the cautious nuclear reactors approach, when the challenge clearly favors brute force and piling up boosters (thus its subtle title). You missed the full thrust award by not much, by the way.

Well, once upon a time there was a Reddit challenge for a fast Minmus-and-back mission. My mission report has long since been lost, but my concept was similar to what I did  above and scored among the fastest. There, nukes were a good compromise -- you spent a good amount of time coasting in any event, so speedy acceleration wasn't *that* important. On couldn't afford to dawdle with ions, but nukes were fine.

Put differently, I didn't really plan for a mun mission but just repeated what I did before in a similar challenge, with only minor modifications.

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I can't leave good enough alone...

downdowndown.jpg

So I tried using chemicals all the way to the Mun, and nukes only for the way back. The LV was five times as heavy, lag was horrible, I kept restarting KSP when things became altogether too bad. Getting as far as the picture was 15 minutes of real time. Of course, it took several attempts... and I had to restart KSP for every launch lest random bits would fall off, on the pad or at the first staging event.

And the result? 79 Minutes. I don't think I'll bother making a gallery for that, much less a video. All in all, not a Sunday well spent.

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11 hours ago, Laie said:

The LV was five times as heavy, lag was horrible, I kept restarting KSP when things became altogether too bad.

That's the spirit! Haha, this challenge is stupid...

11 hours ago, Laie said:

not a Sunday well spent.

Sorry, I am responsible.

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3 hours ago, PunkyFickle said:

Sorry, I am responsible.

No you're not. It was my decision to put ever more effort into that project.

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I couldn't quite let go.... some findings:

  • flying a gravity turn (like I did) is definitely worthwhile. It reduces gravity losses throughout.
  • beyond take-off, TWR isn't all that important -- at least not with the velocities I reached.

I was constrained by part count more than anything else, with my last rocket being ~1600 parts. No launch clamps, rolled out on the runway where it would barely fit, the game took a two-minute break for the moment of takeoff . Literally. I staged first, then it took several seconds until all engines were active, and only then did I turn up the throttle. As TWR went across 1, the game stalled for minutes. Presumably because that was the moments when all the joints were strained.

Dialling in a gravity turn at like 1fps was an interesting experience. First stage had a long burn time of 80 seconds and required 27 minutes of real time. Once that was gone, the pace improved quickly and noticeably.

But! I wonder if there's something about TWR which I never noticed. Two youtube videos I found show people going straight up for the Mun at TWRs that never drop below 3, using stages that ought to be TWR 1.2... how? I guess I'll take that to the gameplay forum.

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Fun challenge.

From experimenting with heating I"ve done a while ago it seems a deflated inflatable heatshield has the most heat resistance. All you have to do is make sure that all the stacks are 2.5m or smaller and have the heatshield mounted on the side of the heatblast.

The deflated heatshield is also draggier then most nosecones so should have some stopping power. My idea is to make a very narrow thin aerofoil using a proper fairing shape so I can punch through the atmosphere ASAP to waste as little seconds getting through the atmosphere back to the surface.

A deflated inflatable heatshield should be able to survive ~2000m/s near sea level as long as it covers the frontal cross section. All you need is a few elevons and one parachute activated prior to impact. I expect this could shave of ~30-60 seconds from your normal flight time.

 

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4 minutes ago, Aeroboi said:

punch through the atmosphere ASAP to waste as little seconds getting through the atmosphere back to the surface.

Using an oversized heatshield for quick deceleration, then diving tip-first in a mk1 pod, I could bring it down to 3 minutes from hitting the first air until the eventual landing. I guess this can be improved upon, but doubt that it's worthwhile to carry an inflatable shield.

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21 hours ago, Laie said:

I couldn't quite let go...

I don't feel responsible for this weekend. Now it's entirely your will to waste them!

21 hours ago, Laie said:
  • flying a gravity turn (like I did) is definitely worthwhile. It reduces gravity losses throughout.
  • beyond take-off, TWR isn't all that important -- at least not with the velocities I reached.

But! I wonder if there's something about TWR which I never noticed. Two youtube videos I found show people going straight up for the Mun at TWRs that never drop below 3, using stages that ought to be TWR 1.2... how? I guess I'll take that to the gameplay forum.

Well, you have your answer here. There is no point in fighting with your weight (literally the effect of gravity) if you already are in orbit, where you use gravity to negate your weight. If I'm not mistaken, the real matter regarding acceleration once in orbit is the exhaust velocity which you get through your Isp. But we'll need a bit more thinking, indeed.

18 hours ago, Aeroboi said:

Fun challenge.

Well, not so much, actually (nor very original either). You'll probably spend quite some time watching at 2 FPS launches of overweight rockets. I imagined one could get a bit creative with multiple launches, science containers and such, but that'd be quite impossible or suboptimal to pull out.

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8 hours ago, PunkyFickle said:

Well, you have your answer here.

Nah, much simpler: Eventually I noticed that they were using bicouplers to mount two (clipped) mammoths to one stack of tanks. So while the stacks were similar in size, those youtubers had twice as many engines.

Also, the great Manley took off with 6000+ parts, something I most definitely will not try to emulate.

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