OpenWorldAddict

Do the Impossible: Two burns to the Mun

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After completing the 'Get Rid of Jeb' challenge, I decided to post this one.

Story: Ever since the start of the kerbal space program, kerbal's have been yearning to go to the Mun. No matter how many people came to Gene Kerman to ask to be sent to the mun, he kept saying no each time. "In these early days of the program, it is just too expensive."

Everyone knows that to get to the mun would require 5 burns. One to take off and get into space, a second to get into orbit around Kerbin, a third to do the transfer between kerbin and the mun, a fourth to orbit around the mun, and a fifth to actually land on the moon. The fuel required to do all those burns just costs the program too much money.

However, one kerbal named Jebudiah was very persistant, and was constantly arguing with Gene. One day, Jeb came in and said that he thinks that the mun can be reached with only two burns. Gene first initial gut reaction was "Impossible!". After arguing about it for several hours, Gene gave in and (after arranging for Jebudiah to take an extended vacation in kerbol orbit) sent out a challenge to all the engineers in the program.

Rules: Build the smallest, cheapest, and lightest rocket that can get to the Mun in only two burns; one burn to take off from Kerbin, and one burn to land on the Mun. The rocket must include a probe computer and an empty Mk 1 Command Capsule. It must also land safely on the Mun (no crash landings). Then fly it to the mun unmanned to prove it to Gene that it can be done.

Smallest:

Cheapest:

Lightest:

Least amount of fuel burned:

Final Score: (your combined score for the smallest, cheapest, lightest - the amount of fuel burned.)

Edited by OpenWorldAddict
edits

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One, it's Jebediah.

Two, does this "two burns" criteria allow for simultaneous staging (ie. boosters that burn at the same time as the first stage and are dropped before actually finishing the first burn)?

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This definitely seems possible. :)

I'm also wondering if staging counts. Because if it does, all you need to do is line up the transfer angle and boom you're headed to the Mun.

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I can easily see a single burn from launch to TLI.

What I don't envision is a single suicide burn at the other end.

Although... *strokes beard...*

How would one go about proving that they *didn't* do additional burns?

Best,

-Slashy

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I just did a test run with a very simple lander, and it's absurdly easy to do a two-burn maneuver to land on the Mun. From a fresh start save, the Mun is perfectly aligned for a straight-to-Mun transfer. As long as you can regulate thrust throughout the flight, of course; lock that to a fixed rate and suddenly it becomes a LOT more challenging.

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To clarify: the first burn means everything from the initial 'lift-off' to the 'main engine cutoff'. This includes boosters, secondary engines, whatever is used to get the rocket into space. The only requirement is that when you do the 'main engine cutoff', your orbital trajectory has Mun encounter.

Also to note, the only other burns allowed other than the 'lift-off to MEC' burn and the 'suicide burn to land on the moon' are course corrections. However, remember to try limit the total of amount of fuel burned because it reduces your final score.

Edited by OpenWorldAddict

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Is it possible to do it in one with an ion lander?

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For insane difficulty, do it with only SRBs!

lol this reminds me of some of abysal lurker's videos such as going to minmus and back on SRB's with no searing. That said its not all that difficult to put yourself on a munar impact trajectory on a single burn from the launchpad. Bit more tricky to do it with an ideal accent path but still just comes down to timeing and pratice.

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Did it long time ago for some other challenge (link in the descriptions of the videos). SRBs only and also returning, it would be much easier with a small lander, if you don't have to return.

Launch

Landing

I think this count as two burns.

And here you have the return, it took two more burns (last one to slow down for the landing).

Return

PS: I'm sorry for sounding like a ...... in the videos.

EDIT:

HAHAHA, didn't read it properly at first, just saw the last few comments about SRBs.

Smallest:

Cheapest:

Lightest:

Least amount of fuel burned:

... if those are the scoring criteria .... I guess I'm not going to win this challenge. xD

Edited by Aphobius

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Is it possible to do it in one with an ion lander?

I don't know. Try giving it a shot.

For insane difficulty, do it with only SRBs!

If people really want to all do additional scoring category that is by itself, but for the main challenge, no.

Did it long time ago for some other challenge (link in the descriptions of the videos). SRBs only and also returning, it would be much easier with a small lander, if you don't have to return.

Launch

Landing

I think this count as two burns.

And here you have the return, it took two more burns (last one to slow down for the landing).

Return

PS: I'm sorry for sounding like a ...... in the videos.

EDIT:

HAHAHA, didn't read it properly at first, just saw the last few comments about SRBs.

... if those are the scoring criteria .... I guess I'm not going to win this challenge. xD

I am looking forward to seeing some actual entries.

I am also trying to do it myself, but that will take some time. I am first going to try going to the mun with the one burn with a small probe. In that try my only requirement is that I get to the Mun, which means as far as I am concerned, the probe can crash into the mun and as long as got there on one main burn. Next attempt will be to try to land a probe on the mun with only two main burns. (I haven't landed anything on the Mun since 1.0 came out, so this will take quite some time for me to figure out) If I accomplish that, then I do my first test run of the unmanned command pod landing on the Mun with only two main burns as required for the challenge. Once I am able to do it, I will do a couple more test runs before recording the mission for upload to YouTube.

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I made it using a single burn, some very complex gravitational assists, and a ton of torodial tanks to keep the kerbals alive at the end!

I hope i still have those pics of it!

 

 

 

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I propose a version of this challenge for the truly insane KSP players out there. 

1. Throughout the mission the only allowed throttle commands are "full" for launch and "stop" once that's done. Then "full" for the landing burn and "stop" once that's done. No shift or ctrl.

2. The craft must return. Sounds impossible? It isn't.  If you are very good with timing your suicide burn and use steering losses for fine tuning you can touch down relatively softly and immediately lift off again without cutting the engine, from there it would be easy to get an intercept with Kerbin's atmosphere.

I have no intention on trying this for myself, mind you. Just throwing it out there (*cough* @hazard-ish *cough*)

Edited by KerbonautInTraining

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29 minutes ago, Jhawk1099 said:

Is it just me or does this seem really easy?

Oh its a walk in the park! Super simple stuff.

... if you're a computer. It sounds easy but I think our F9 keys are gonna take a serious beating.

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So what exactly is "one burn" for landing? One perfectly timed full thrust suicide burn? This will propably lead to a lot of (semi-)crashes. (I assume no autopilot, since the space program is lacking that kind of money?)
Or are we allowed to change the thrust while landing to make necessary adjustments, as long as the engine is not turned off? Is changing the thrust limit ok? What about RCS?

Also, is returning home at all relevant for Jeb?

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53 minutes ago, KerbonautInTraining said:

Oh its a walk in the park! Super simple stuff.

... if you're a computer. It sounds easy but I think our F9 keys are gonna take a serious beating.

There once was a challenge to get to minmus and back in less than six hours. I made it in 4:23. Even though the suicide burn started well outside of Minmus' SOI, it only took some back-of-the-envelope math and two (or at most, three) F9 iterations to get it right. I certainly have throttled down towards the end, but it's likely that I didn't kill them entirely until I touched the surface -- stopping early and waiting for the fall in Minmus' gravity would have cost me a lot of time.

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1 minute ago, Laie said:

There once was a challenge to get to minmus and back in less than six hours. I made it in 4:23. Even though the suicide burn started well outside of Minmus' SOI, it only took some back-of-the-envelope math and two (or at most, three) F9 iterations to get it right. I certainly have throttled down towards the end, but it's likely that I didn't kill them entirely until I touched the surface -- stopping early and waiting for the fall in Minmus' gravity would have cost me a lot of time.

Holy %! $*, obviously our definitions of the bolded are not the same

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32 minutes ago, KerbonautInTraining said:

Holy %! $*, obviously our definitions of [back-of-the-envelope math] are not the same

Nah, it really was no more than a ballpark figure, rounded down to be on the safe side. I got lucky in that I was too careful and came to a halt far above Minmus; adjusting my estimate was a question of dividing that distance by the speed as given by the navball, then wait that many extra seconds until I start the burn.

Fine adjustments were made by throttle, keeping the "suicide burn timeout" around zero seconds until the very last. For all I know, I may have gone at 90% throttle for the last minute -- I really can't remember. But if you have a) a throttle b) enough fuel and c) a mod to tell you the suicide time, then this is easy.

Of course, that was the milkrun challenge which emphasized speed, while this one asks for the most lightweight vessel -- so packing extra fuel will cost you.

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This is easily possible with even the most minimal information mods. Heck, with a brachistochrone trajectory (which I did some envelope math advising on for whackjob in another thread. It's entirely possible.) you could do it in one burn.

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In the USSR times, they used the 'hot-fire' separation: the second stage ignites few seconds before MECO and first stage separation. We can use this as a method to save fuel and accomplish the misión.

Example: Gamma observatory.

KSP History: http://imgur.com/a/TvBhU

I hope this helped.

 

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On 2/23/2016 at 5:22 PM, KerbonautInTraining said:

I propose a version of this challenge for the truly insane KSP players out there. 

1. Throughout the mission the only allowed throttle commands are "full" for launch and "stop" once that's done. Then "full" for the landing burn and "stop" once that's done. No shift or ctrl.

2. The craft must return. Sounds impossible? It isn't.  If you are very good with timing your suicide burn and use steering losses for fine tuning you can touch down relatively softly and immediately lift off again without cutting the engine, from there it would be easy to get an intercept with Kerbin's atmosphere.

I have no intention on trying this for myself, mind you. Just throwing it out there (*cough* @hazard-ish *cough*)

Well... landing on the Mun is technically possible with one burn...

I'll see what I can do ;)

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Tip: If you time perfectly you can get to munar orbit with one burn. you must have about as much horizontal speed as the mun and enter the soi almost at ap.

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1 minute ago, superstrijder15 said:

Tip: If you time perfectly you can get to munar orbit with one burn. you must have about as much horizontal speed as the mun and enter the soi almost at ap.

With N-body physics that's possible, but not in stock KSP. You have to make some sort of burn once in the SOI to capture with patched conics.

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2 minutes ago, KerbonautInTraining said:

With N-body physics that's possible, but not in stock KSP. You have to make some sort of burn once in the SOI to capture with patched conics.

Yeah, sorry. but a sub-orbital should be, I've seen comets do it in my own saves.

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