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SCTO | Smallest Craft To Orbit

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bulletrhli

bulletrhli

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The SCTO Challenge!

By BulletRHLI

Why hello there! This is my first challenge thread after the forums crash and I want to start it off with a simple, yet tedious challenge. I myself have been trying this the past few hours, and after many failed attempts, I have managed to achieve my own challenge to myself. My personal goal was to create the lightest lifting stage to bring a extremely tiny probe into space. I changed it though, I wanted the create the lightest OVERALL craft to get into an orbit. So, I used mechjeb to give me my information for launch mass and final mass once in orbit. My challenge is for you to get ANYTHING you want into orbit with the smallest launch mass.

What do I need to qualify?

That is simple. Create a ship or plane with the lightest initial mass and provide pictures and the craft file. In my trials, my best was 4.3t as shown in the proof below.

Can I use any mods?

I would like for you to use stock parts, but I can run two categories, Mod and stock SCTO leader boards. MechJeb is allowed for both information and flying though I challenge you to fly without it!

Lets kick it off with my attempt!

Launch Mass: 4.3t

Final Mass: 0.1t

Orbit: 100km give or take 200m

yf5q5XL.png

Good Luck Kerbonauts!

Edited by bulletrhli
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soranno

soranno

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I see your 4.3

and raise you a 1.966

I don`t have a mechjeb to show those windows, but I have two images taken with engineer open.. and the navball used to cunningly conceal my craft design. Rest assured it is all stock.

3BiHilZ.png

DwFNFM1.png

Into orbit with over .3

also I panicked right at the end and ended up with a hugely elliptical orbit, as the only panel on the thing is right on the front, and taking off the sun was behind me. As I reached apo the charge was like 0.12 or something, so I just burned and then flipped it around to get some sunlight :D

There is a lot of refinement to be done on this little design. Methinks I`m not finished..

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soranno

soranno

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found an old mechjeb version that at least still works in part, also I didn`t see that you asked for craft files and images, I was thinking to keep the design secret for the challenge hah!

refined down to 1.874

anyway, here on the launchpad for real

1dB97BT.jpg

and into orbit, for some reason all the other ascent stats are bugged out.. I guess it`s just the old version or something

dRAZtHg.png

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tavert

tavert

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This was done pretty much to death before the forums died. The answer is 1.26 tons: http://imgur.com/a/IbXlv#0

You really only need 3 parts, a probe, an FL-T200 tank, and a single Rockomax 24-77 engine carefully rotated and mounted so the center of thrust lines up with the center of mass. The positioning is a little tricky. I added MechJeb, and 2 cubic struts at the bottom so it doesn't fall over on the pad. A launch clamp could also work for that, and you might want to add a battery and/or solar panels if you can't get to orbit in 5 and a half minutes.

And here's the craft file, without MechJeb: https://dl.dropboxusercontent.com/u/8244638/MinOrb%206a%20stock.craft

You'll notice if you fly it manually that the thrust is still a tiny bit off-center, but it's easy to correct for.

Edited by tavert
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soranno

soranno

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1.238 and I`m so damn close... I foresee a long evening ahead.

Historical achievement being what it is, perception of something having been `done to death`, is not a reason to discount the possibility of new innovation. After all, Kerbal is a game whereby its very nature involves stretching the bounds of creativity and imagination, in ways unexpected and perhaps thought impossible.

Although I have several projects ongoing, I don`t think I`ll set this one aside quite so easily, just yet ;)

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soranno

soranno

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It`s a hell of a precedent. I hadn`t thought it would be so low. But learning about that has just encouraged me to try and beat it :)

1.238 and I got 74x24km.. I`m sure it`s in my piloting but I can`t get that close again hah!

Don`t worry, I have lots of beer and smokes to sustain this effort

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tavert

tavert

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1.238 and I`m so damn close... I foresee a long evening ahead.

Historical achievement being what it is, perception of something having been `done to death`, is not a reason to discount the possibility of new innovation. After all, Kerbal is a game whereby its very nature involves stretching the bounds of creativity and imagination, in ways unexpected and perhaps thought impossible.

Although I have several projects ongoing, I don`t think I`ll set this one aside quite so easily, just yet ;)

Your number got me curious, and I just proved myself wrong. I guess most of the entries in the past challenge were done in 0.18, so the lightest probe core was 0.01t heavier and this would not have been possible. Did I just fly your design? http://imgur.com/a/dqOI6#0

Because of the staging-from-the-top, I had to turn around to ditch the first 6 tanks. So I flew the ascent semi-manually. I had MechJeb doing "Show navball ascent path guidance" with gravity turn starting at 10km, ending at 50. I also had the throttle control set to limit to terminal velocity and limit acceleration to 40 m/s^2. Turned off the acceleration limit after hitting 70km apoapsis and had the maneuver planner do the circularization burn, though MJ2 doesn't get quite as perfectly circular as MJ1 did.

Oh, and I got to orbit quick enough that I could've even gone without the solar panel.

Edited by tavert
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numerobis

numerobis

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Posted (edited)

The best I'd done before was:

1.125 small tank

0.04 tiniest probe in 0.19 (lower than the Sputnik)

0.09 engine (single 24-77)

0.01 for a battery and solar panel required by the rules of that challenge.

0.00 for extra struts (cube struts are actually weightless)

So 1.265 total.

Beating that is impressive; I'll have to look more closely at it!

By the way, MechJeb wastes about 40 m/s from flying too fast. I had a patch but I doubt it made it in. The acceleration limit should not be relevant; let 'er rip!

Edited by numerobis
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tavert

tavert

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The best I'd done before was:

1.125 small tank

0.04 tiniest probe in 0.19 (lower than the Sputnik)

0.09 engine (single 24-77)

0.01 for a battery and solar panel required by the rules of that challenge.

0.00 for extra struts (cube struts are actually weightless)

So 1.265 total.

Beating that is impressive; I'll have to look more closely at it!

By the way, MechJeb wastes about 40 m/s from flying too fast. I had a patch but I doubt it made it in. The acceleration limit should not be relevant; let 'er rip!

The 1.26 I initially had was stealing someone's design, probably yours, I forget who originally posted it in the old challenge. I seem to remember seeing the patch you refer to, but again I forget where... was it on the MechJeb 2 github? I was limiting acceleration to avoid going too ridiculously fast down low.

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numerobis

numerobis

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It was an evolution between three of us. Someone (I forget who) made a two-stage design, I improved it marginally by putting the stage on top, and I mentioned I was about 80 m/s short when flying the simple SSTO. Zarakon flew it better but dropped a required piece (that challenge required solar and battery). Finally, I noticed the lighter probe core when 0.19 came out.

I'll have to see the state of MJ 2. I had some patches I was testing that would improve the throttle control yet again. I thought only my air-breathing work went in.

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tavert

tavert

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Your airbreathing code has been unbelievably useful, thanks for contributing that! I found a strange quirk with intake management that probably stems from KSP's general bugginess when it comes to nested symmetry, I have an issue filed on Github but it's minor since you can workaround it by rebuilding with symmetry arranged differently...

I've also been playing with your KSP-scripts a bit, some good stuff in there.

Back to the topic at hand, I've developed a gut feeling that there can be such a thing as too high a TWR on planets with atmospheres, and these tiny things get there with 20 kN of thrust as they use up fuel. I should go back and test this theory with the 1.26t SSTO, since that can be repeatably flown with MechJeb to compare settings.

Oh and I realized that the MechJeb2 part provides 5 units of electric charge but doesn't draw as much power as a probe, so it's unfairly lengthening the lifetime of the probe without using any batteries or solar panels.

Edited by tavert
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numerobis

numerobis

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It's on github now, awesome!

So yeah, definitely my improved speed control is not there. I'll try rewriting it (I lost the original: went on vacation, and my laptop bricked itself on the first day).

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numerobis

numerobis

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Good luck! I'm sure there is way to get it even lighter with the use of aerodynamics or something XD I know the crazy inventive people here, they will figure it out, I sure wont XD

I think it was Nao who built one that fluttered itself up to an escape trajectory using just some control surfaces and the smallest probe, less than 0.2 tonnes overall.

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  • 3 years later...
Ourworldalpha1

Ourworldalpha1

Posted
Posted (edited)

I like to enter a heavily modded craft

it is Remote tech capable

has science,Control,Maneuvering,RCS,SAS,LF-O Engine,300m/s

 Grand total of 0.060 Tons,120 pounds

Launcher included is 2 Tons,Costs 14000 VF

Edited by Ourworldalpha1
WARNING TWEAKSCALE WAS USED
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Vanamonde

Vanamonde

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Hello @Ourworldalpha1, and welcome to our forum. :D

Our forum has been around for a while, and some of the threads are fairly old. This one, for example, is no longer current, so the thread will be closed now. We do hope you will participate in other challenges, though. 

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