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I need some help to get to mun .......


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So , the problem is , i tried to get to mun many times (about 10) and every time i face the problem of insufficient fuel  . I add extra fuel or even push in some fuel tanks using offset mode but i cant do it . If anybody got some tips pls reply explaining how to overcome this problem .

 

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There’s a small but useful mod called “Where can I go” which you can use in the VAB to find out exactly where your rocket can or can’t get to. It’s based on average values for launches, so getting your launch right will give you more range once you’re in orbit. A gravity turn is the best launch profile, there are guides on how to do those and even a dedicated mod (called Gravity Turn, oddly enough) to automate them; just launching up out of the atmosphere and then sideways to orbit is very inefficient and wastes fuel.

There’s a difference between sending a crewed mission and a probe or lander, in that generally you want to bring crews back again, so you’ll need a lot more fuel. Probes are cheaper and expendable, so start with those and build your rocket from the top down:

At the top is your probe, probably an OKTO or a HECS, with an antenna and some power (batteries and, if you have unlocked them, solar panels) and some science experiments. If you have small parts unlocked, use Oscar-B tanks and the Spark engine for their low weight which will give you better range, if not go for the Terrier and FL-T100 or 200 tanks which are slightly overkill for a small lander but which will also have a lot of range. Under that, add a decoupler and a payload fairing to cover the probe up during the ascent, and build a transfer stage that uses a FL-T400 tank and a Terrier engine, which will do the job of finishing off your orbit around Kerbin and then carrying your probe out to the Mun. Check Where can I go (WCIG for short) with ‘payload only’ mode on to make sure you can get to the Mun and land with fuel to spare (the numbers are green) in case your launch isn’t as efficient as it could be.

Your main booster should be made of FL-T400 and/or 800 tanks and a Swivel engine with some basic fins just above the engine for stability. Add some radial decouplers (2-4 should do it) and enable crossfeed, then add some solid boosters like Hammers or Thumpers with a FL-T200 or 400 on top: the extra fuel tanks will help you go further and will drain first so they’re empty when the solid boosters burn out and get dumped; add nosecones to the boosters, then make sure the solid boosters and main engine are in the same stage and if so check your thrust to weight ratio (TWR) on the first stage- if it’s above 2, reduce the power limit on the solid boosters to make them last longer and reduce wasted thrust from atmosphere, anything between 1.4 and 1.8 should be OK. Check WCIG again without ‘payload only’ and make sure you can still land on the Mun with fuel to spare. If you can, great; if not, you may need a bit more fuel, but just remember more fuel on the upper stages will need more fuel and then more thrust on the lower stages to get it into space.

If you’re in orbit and want to go to the Mun, you need to time your transfer burn right. It takes one day to get out to the Mun and 4 days for the Mun to orbit Kerbin, so you need to aim for a spot 90 degrees in front of it. This makes it pretty easy to time the transfer burn as this will need to be on the opposite side of Kerbin, so 90 degrees behind where the Mun is. This means that you’ll be pointing straight at the Mun, so when you’re pointing prograde and the Mun is straight ahead, fire those engines! You can use manoeuvre nodes to help your aim, but make sure you end up in orbit and not on a direct collision course as you will most likely crash if you try to land directly from a transfer burn without orbiting first.

Minmus is a little bit harder to aim at due to its inclined orbit and greater distance, but is actually a lot easier to land on as it’s lower gravity means lower orbital speeds and so less delta-V needed to slow down and land.

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2 hours ago, Zishan fj said:

So , the problem is , i tried to get to mun many times (about 10) and every time i face the problem of insufficient fuel  . I add extra fuel or even push in some fuel tanks using offset mode but i cant do it . If anybody got some tips pls reply explaining how to overcome this problem .

Welcome to our little club!

I can't tell you a lot without more details (as others have said), but if you have insufficient fuel, then the problem is going to be one of two things:  either you need more skill at flying the rocket or you need a better rocket design.  'Skill at flying' does not necessarily mean controlling the rocket during a burn, but can also extend to navigation and planning for your manoeuvres.

If we knew the design of your rocket, then it would be easy to tell which is the problem; if you have a rocket that is capable of reaching the Mun but you can't seem to get it there, then we can help with that.  On the other hand, if your rocket is not capable of reaching the Mun, then it really doesn't matter how much skill you have or lack--but we can help with that, too.

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3 hours ago, Zishan fj said:

So , the problem is , i tried to get to mun many times (about 10) and every time i face the problem of insufficient fuel  . I add extra fuel or even push in some fuel tanks using offset mode but i cant do it . If anybody got some tips pls reply explaining how to overcome this problem .

 

Hey - it may not be fuel.  At least not entirely.  It may also be choice of rocket engine.  Check out this thread where people tried to help me understand the difference between "fuel economy" of different engines.  Hint: the answer turned out to be very different from what I thought it would be.

 

 

 

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Multipling the request for pics... assuming you are not on the console version. And you are playing near stock KSP.

But getting something to the Mun or Minmus and back is really two problems, well three but landing is a trivial one to deal with. With slightly different design goals. The first is making orbit. The second is getting to the Mun.

Tackle the second one first. You will need a craft that has a vacuum delta-V of about 2400 m/s, and a TWR of about one-half. The delta-v is a _very_ conservative number, and assumes that you want to make orbit. With careful orbital planning and practice you can shave that down. But, it will give you lots of slack to learn how to do things. This will be the place to shave as much mass as you can. It will help with solving the second problem.

You need to get your Mun-craft to LKO. For that you will need a craft with a ASL delta-V of about 4000 and a TWR of about 2. Don't go for elegance here. You're going for pure LIFTING! POWA! Mua-ha-ha-ha! *cough*

If you want to refine the design...

Once you can reliably get things to orbit without needing to use the engines on your mun-craft. Take a look at the fuel you have left in that last stage. Revert back to the VAB and pull that much fuel and oxidizer out of the tanks, without pulling out more than that. You'll want to repeat it a few times, I'd recommend about three. Don't forget to downsize the fuel tanks as you go along.

You can use a similar process for the mun-craft as well. Once you have that suitably tweaked you can go back and refine your lifter again.

There are paper based approaches to this. But, I've never really been able to wrap my head around them to any great degree.

 

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Thanks to all , for the kind response.

As you have requested , I am attaching the screenshot  

Screenshots is given below, it is the latest rocket , 8 in the series.

If you require more information please let me know. SvHEnC.png

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Scrap the RCS, most of the function of it you can replace with reaction wheels for less weight. You can trim one of the batteries you've got. Move the launch clamps to the first stage. And don't throttle all the way up on launch; wait until the solids have burned out to do that. 

I don't recognize the nose come you've got. What mods are you using? Or is it one of the DLC parts?

Edited by steuben
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3 hours ago, steuben said:

I don't recognize the nose come you've got. What mods are you using? Or is it one of the DLC parts?

0.625m nose cone, adapter (tank) 0.625m to 1.8m, adapter (tank) 1.8m to 2.5m

Last two are from making History DLC

Edited by Draalo
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I don't see dV info, what version are you running? You should enable that if you're on ... whatever version they added it. 1.7 I think? Anyway, enable that in the settings, then click the dV button in the VAB that you'll get (It'll be down by the "i" and the wrench and the wifi-looking icons) and click "Vacuum" and then post again. And then also get your ship into space (assuming you get that far?) and post a pic of it orbiting Kerbin so we can see those dV numbers there, as well.

dV is an important factor in how far your rocket can get.

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40 minutes ago, Superfluous J said:

I don't see dV info, what version are you running? You should enable that if you're on ... whatever version they added it. 1.7 I think?

Delta-V info was added in 1.6, as were the new 1.25m nosecones (the screenshots we've been shown have the pre-1.6  "old" ones). If I had to take a wild guess, I'd say that @Zishan fj is playing KSP on a 32-bit machine, and as such is stuck back in 1.4.5.

Edited by IncongruousGoat
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“Simplify, then add lightness.” Your lander is far too big and heavy so the launch rocket is also far too big and heavy. A much smaller lander will allow you to use a much smaller rocket to launch it. You can land on the Mun for far less than 110 thousand funds!

Here’s one I made- it isn’t designed to do landings as it’s a replica of a real launch rocket, but when I tested it I landed on the Mun AND flew all the way back to Kerbin (but no parachutes :rolleyes:). Smaller top stages require less effort to get them moving so your fuel will last longer, meaning you don’t need such a massive booster to get into orbit in the first place.

There are many different ways to land on the Mun, here are some threads to give you inspiration.

For getting to and from the Mun for minimal cost:

For the cheapest possible landers (that still work):

 

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A quick mock up based on the pic in a stock ksp, and guessing at a Mailsail at the bottom of the stack, and a poodle in the middle.

KER reports ASL/VAC dv

S3 1139/3193
S2 1911/ 2079
S1 821/3193

The RCS is really hurting you though. Pulling that out added 1200 m/s ASL dv across the whole stack.

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Thanks for the kind replies , 

I've done whatever you have asked , i removed rcs and added the reaction module and i removed one of the batteries . Well , I launched the rocket and it reached mun orbit , landed on mun but i couldn't come back to kerbin  . Any tips to save fuel during the landing procedure ?

 

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You may not have enough for the trip. Mun landing and return to orbit takes about 1800 m/s 600 up, and 600 down with 600 for fighting gravity on the down trip. Again conservative numbers.

You might want to consider another stage, or drop tanks for the mun-craft.

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9 hours ago, Zishan fj said:

Thanks for the kind replies , 

I've done whatever you have asked , i removed rcs and added the reaction module and i removed one of the batteries . Well , I launched the rocket and it reached mun orbit , landed on mun but i couldn't come back to kerbin  . Any tips to save fuel during the landing procedure ?

 

If you use the fuel in the adapters on top of the rocket before the main lander tank, you can jettison the adapters so you won't have to haul them the whole way.  It should save you some fuel.

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I built a lookalike and had plenty of delta-v to get to the Moon land at a couple of locations and return even with all the monopropellant so it might come down to piloting efficiency and launch and landing profiles. The rocket could certainly be much more efficient but if it's a flight profile issue you'll just be brute forcing your way out of the problem. If it helps, my early Mun ships were massive and massively inefficient so we've all got to start somewhere.

You could try practicing with the stock Kerbal X. Flown well it can get you to the Mun and back and you can practice different ascent profiles and mun landing techniques like suicide burns and constant altitude burns.

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