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Lowest start weight challenge (optimal construction)

ako

By ako
in KSP1 Challenges & Mission ideas

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ako

ako

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Challenge is build lowest start weight rocket, land on Mun, do eva and return back to Kerbal.

Challenge has two nomination - "Command Pod Mk1" (1t total mass) and "Mk-1-2 Command Pod" (4t total mass)

Rules:

1. Use "Fuel Consumption Bug Fix"

can get here: http://kerbalspaceprogram.com/forum/showthread.php/16439-0-16-0-Hacky-Fuel-Consumption-Bug-Fix

or here: https://dl.dropbox.com/u/62695719/KPS-MPL/Fuel%20Bug%20Fix.zip

bug description: http://kerbalspaceprogram.com/forum/showthread.php/15196-0-16-MAJOR-Fuel-consumption-is-wrong-at-low-throttle/

2. Stock parts

3. No cfg change

4. Show screenshots

5. Attach craft file

And of course be truthful.

Allowed mods: MechJeb - Autopilot (this a constructor challenge)

intermediate results for 2012-09-03:Command Pod Mk1 (1t total mass)

  1. Apotheosist "Minimun 16 IV" 9.8 tons link to post
  2. Apotheosist "Minimun 16 III" Stages: 3 11.0 tons link to post
  3. Nao "Rock Solid B Rocket" Stages: 8 16.6 tons link to post
  4. adammada "Nowy" Stages: 4 15.4 Tons link to post
  5. Apotheosist "Minimun 16" Stages: 3 17.3 tons link to post
  6. ako "Novosibirsk" Stages: 3 39.6 tons link to post

"Mk-1-2 Command Pod" (4t total mass)

  1. adammada "Potrojny" Stages: 4 53.9 tons link to post
  2. ako "Krasnoyarsk-2" Stages: 5 57.3 tons link to post
  3. Apotheosist "3 Kerbal Minimun 16" Stages: 2 64.8 tons link to post
  4. ako "Krasnoyarsk" Stages: 5 145.4 tons link to post

Edited by ako
add intermediate results
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Apotheosist

Apotheosist

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Great job!

But i'm forgot about aerospikes. :-)

At this time try build craft with this engines.

PS: You use for travel about 300-400 m/s dV less then i. :-)

Hehe, yep, aerospikes have a very good performance ;) Many people think they will get nerfed.

After some practice, it's possible to fly much more efficiently than mechjeb can. I usually try aiming for a total delta-v for a Mun return mission of 7500m/s, but with my MK-1-2 command pod I managed to to do with 7242m/s :)

So did you say aerospikes are not allowed? If so, maybe you should edit your post to say that. But I'd be very happy to go do the challenge again without aerospikes :D I just love designing rockets!

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ako

ako

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Hehe, yep, aerospikes have a very good performance ;) Many people think they will get nerfed.

Yep. I think so ;-)

After some practice, it's possible to fly much more efficiently than mechjeb can. I usually try aiming for a total delta-v for a Mun return mission of 7500m/s, but with my MK-1-2 command pod I managed to to do with 7242m/s :)

I trying design new rocket with aerospikes. At this time i get 51 tons and about 7200 dV. But with this rocket i cannot complete flight. And i try get bigger dV by add 2-3 tonns.

So did you say aerospikes are not allowed? If so, maybe you should edit your post to say that. But I'd be very happy to go do the challenge again without aerospikes :D I just love designing rockets!

Oh no. I not say what aerospikes not allowed and that means they are allowed. My mistake is only my mistake.

But I'm interested to see your rocket without aerospike. :-)

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martscht

martscht

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Just a quick question: does the Mk-3 Cockpit count in the category Mk-1-Pod (it weighs the same)... because then I'd probably have a fully reusable entry weighing in at 24.735 tons (I know, I'd still not beat the entry by Apotheosist, but that dear sir simply cannot be beat when it comes to minimalism).

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Apotheosist

Apotheosist

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Oh, ****. I assumed that i have to USE that fuel bug, not that i have to use "Fuel consumption bug" FIX. Sorry.

That's allright :D we all read things wrongly from time to time. There is a challenge somewhere where you have to use the bug, if you'd like to try that one.

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adammada

adammada

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After some practice, it's possible to fly much more efficiently than mechjeb can.

I see that this still is more piloting thant construction challenge. I tried to use your construction and eneded with 6L of fuel when trying to break to land on Kerbin... So what is most efficient way?

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Apotheosist

Apotheosist

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I see that this still is more piloting thant construction challenge. I tried to use your construction and eneded with 6L of fuel when trying to break to land on Kerbin... So what is most efficient way?

Which one of my ships did you use? And if you have some fuel left to brake on Kerbin, you're doing well. When braking to land on Kerbin, you need to thrust the engine right at the very last moment, but you only have to slow down to about 70 m/s. The engine and tank beneath you can usually absorb the impact from that speed and your capsule will survive intact. That only works if you land on solid ground, of course. Water landings tend to swallow the whole ship up even at relatively low speeds.

As for the rest of the mission, my flight plan to orbit is very simple in both craft. Full power all the time, at 12km, pitch over 45 degrees. At 30km, pitch over 90 degrees. Circularise the orbit at about 70km. Then do the rest the usual way. When landing on th Mun, I try to be as efficient as possible, by doing my retro-burn as close as possible to the surface of the Mun, usually about 2500m, but 3000m is efficient enough sometimes. The same applies for when lifting off from the Mun. I try to pitch over fairly soon, and get into about a 3000m circular orbit. Then I wait for the right time to do my burn to send me back to kerbin. The time at which you do this burn affects the efficiency. I use Munar landmarks as visual guides to tell me when to start the burn. You want to try to time it so that after your trans-Kerbin burn, your apoapsis is as close as you can get it to 11,400km. 11,400km is the altitude the Mun orbits at. I found that I used least fuel when my apoapsis was at this altitude. Try to get your periapsis at 30km. Any lower and you're wasting fuel, any higher and you might not get caught by the atmosphere. So your return trajectory back to kerbin should be a 30km x 11400km elliptical orbit. Then the landing would be as I described previously.

I have learnt most of my efficiency techniques from Kosmo-not, and specifically by watching his video: http://www.youtube.com/watch?v=GzEEcNnBxqM&feature=plcp

I then replicated the mission using his craft and using his video as a guide. It isn't in version 0.16, but the principles and technique shown there could still be helpful.

Other things I have learnt from guides and challenges on these forums, such as the optimal ascent (goddard problem) challenge, and optimal descent (to the Mun) challenge.

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ako

ako

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Apotheosist, "3 Kerbal Minimun 16" well designed ship!

Then more i try, the more I realize how :-)

At this time i working about 52-55 tonns. but my ships is more complex. You can realise best fuel to construction ratio. By design ship with more stages i lost this advantage. :-)

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adammada

adammada

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Nomination: Command Pod MK1

Ship name: Nowy

Start mass: 15.4 Tons

stages: 4

KSP: 0.16

Screenshots: http://imgur.com/a/loIWm

I'm aware that this design can be beaten - for example hard landing without parachute, cause there is lots of fuel left. I also created once ship without aerospike stage, and I almost returned (but ship didn't had parachute and i wasted too much fuel on retrograde, so he hit Kerbin too hard), but it needs really good piloting skills to use.

So i'm proud of this - it has less weight than Apotheosist's and it forgives mistakes :).

Edited by adammada
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Apotheosist

Apotheosist

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Nomination: Command Pod MK1

Ship name: Nowy

Start mass: 15.4 Tons

stages: 4

KSP: 0.16

Screenshots: http://imgur.com/a/loIWm

I'm aware that this design can be beaten - for example hard landing without parachute, cause there is lots of fuel left. I also created once ship without aerospike stage, and I almost returned (but ship didn't had parachute and i wasted too much fuel on retrograde, so he hit Kerbin too hard), but it needs really good piloting skills to use.

So i'm proud of this - it has less weight than Apotheosist's and it forgives mistakes :).

Bravo adammada! :D You managed to beat my design by quite a bit. Something I often tell myself is, no matter how well you do something, there will almost always be someone who can improve on it :P

On that note, I'm going to try to see what I can do using jet engines like you have.

I have also been thinking about what we might be able to do about how easy it is to fly these craft. Perhaps there could be a rule saying that the ship must have a certain amount of delta-v, or maybe categories for different ships with different delta-v, and maybe categories for use of certain components, like parachutes, or even an ASAS. This would make it easier for those who are less experienced at flying to find a small mun ship they are still able to fly.

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adammada

adammada

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Nomination: MK-1-2 Command Pod

Ship Name: Potrojny

Start mass: 53.9 tons

Stages: 4

KSP: 0.16

Screenshots: http://imgur.com/a/pfwEI

Thank you Apotheosist.

I have also been thinking about what we might be able to do about how easy it is to fly these craft. Perhaps there could be a rule saying that the ship must have a certain amount of delta-v, or maybe categories for different ships with different delta-v, and maybe categories for use of certain components, like parachutes, or even an ASAS. This would make it easier for those who are less experienced at flying to find a small mun ship they are still able to fly.

Yes, i also was thinking about something like "mandatory parachute", or even landing legs.

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Nao

Nao

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My nomination for: Command Pod MK1

Ship Name: Rock Solid B Rocket (codename 15 - c) :P

Start mass:16.6 tons

KSPver 0.16

Pics:

UG1XO.jpg

3bZmk.png

vYMO2.png

s6id0.png

IE7Am.png

the lower SBR are exploded by engaging next stage 2s before fuel runs out, no decouplers required.

Also, @adammada unfortunately you are still using fuel bug, just less known, the two Jet engines are draining the top tank of bottom stage at half value. Its caused by the presence of toroidal engine on the stack (you can try do a fuel flow test with and without it) also this bug affects all tank except the lowest one of the drained stack).

The effect is pretty minor since Jets eat fuel so slowly. The bug has been reported from what i know.

I'll try one more design, Jet powered that is :3

Edit: using Jet engine in my design i managed to get to the moon with same lander WITH parachute and around 20l more fuel with a craft weighting 11,85 t. Error on my part caused a crash landing on the Mun, but I'm sure i can come back to Kerth, and land safety with parachute! Ill do the mission when time permits.

What's more i rise a question could lower fuel load before launch count ? I launched my craft after static burning of 120l of fuel which equals 0,6 t. This would make my craft weight 11,25 at launch. :P

Cheers , Pozdrowionka :P

Edited by Nao
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Apotheosist

Apotheosist

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So I decided to see what I could do with jet engines. Here is the result:

Nomination: Command Pod Mk1

Ship name: Minimun 16 III

Start mass: 11 tons

Screenshots: http://imgur.com/a/qa4mA

Craft file: http://www./?al19s36r421091j

Complete with parachute and landing legs! :D

As you can see it is quite heavily based on adammada's design, and what he said about almost making it without the aerospike stage. Thanks adammada!

Edited by Apotheosist
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Apotheosist

Apotheosist

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Yes, you are really good pilot. Can you make a movie? Also, you could try this one:

JfljZ.jpg?1

Thanks, but most of the flight i use mechjeb! I could make a movie if I knew how, but I don't know how :(

I initially disregarded such a design, thinking the thrust to weight wouldn't be enough. But...it might just make it. I will try it.

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