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hello guys. uhm i have a small issue

i just found out that moho is a tad harder to get to then i anticipated, let alone landing.

this is what i have already shot into space

unknown.png

i have tested it and i think it could get an encounter before running out of fuel.

as you can see it has docking ports.

so i could add these 2 fuel tanks

 

unknown.png

i should also add these are the current planetary positions, kerbal alarm clock suggested these conditions as optimal transfer time. but i have my doubts

 

unknown.png

so what should i do?

would i make it? the odds in my favour?

or should i just redirect the mission to another planet?

because i am doubting my chances reaching moho.

 

as for my flight history

i am adept i guess at orbital transfer stuff.

have been to duna with some probes and had a rocket going to eve and then duna to drop a probe at eve and a rover and probe at duna. made it.

and i know the rules that: at low periapsis you burn to quickly change height at the other end. at high apoapsis you burn to most quicly change angle of flight.

 

i had the first rocket intended to do the eve-duna mission go to jool instead as the rover had a defect having no solar panels or batteries.

i sorta made it. i was lucky that the low tech cummonatrons were with me and gave me enough connection to do it.

with some gravity assists via i believe laythe i got into a stable orbit. though i think laythe shortly after threw me out of jool orbit again.

but since the save broke i can't be sure.

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Without having all information: Looks good, give it a try.

There are still some things to optimise:

Build the vessel with the 2 tanks cheaper and lighter.

Top-Down:

- dockingport + tank (without RCS thrusters and monoprop tank!)

- (maybe an in between structural part with additional RCS thrusters - depending on your docking skills - +decoupler)

- again dockingport + tank (again without ...)

- decoupler

- strong reaction wheel + probecore + RCS thrusters + monoprop tank

- fairing and rest of rocket

No need to carry the weight of thrusters and monoprop tanks to Moho. Probecore, tanks and thrusters will be left in Kerbin orbit.

Also empty the Lander Can - transfer the monoprop to the docking probe. (40kg less)

Docking ports can act as decouplers too, no need for additional decouplers. Fairing can be build taller, less drag, less weight.

Of course empty the attached tanks first and ditch them when empty.

 

The lander itself is fine - but i doubt it has enough dV for the returntrip. But lander should reach a low orbit again after landing. Use the gained science to unlock the NERV engines and then send a new vessel to bring the Kerbal back.

 

Or send a refuelprobe with a claw into low Moho orbit, refill the lander after it has done the job. Pretty sure a refilled lander can encounter Kerbin again.

 

Consider installing

it calculate and displays the dV of your vessel (go into the VAB, klick on settings in the KER window, select partless - it will show you the values for your allready flying vessel too when flying it)

Take a look at: http://wiki.kerbalspaceprogram.com/wiki/Cheat_sheet

Compare the given values with the dV requirements.

If the goal is only to land on Moho: Go for it (with the 2 docked tanks)

 

PS: If you install KER leave Cybutek a like - he deserves it :wink:

Edited by Draalo
typo
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10 hours ago, jevry said:

i just found out that moho is a tad harder to get to then i anticipated, let alone landing.

It's weird, isn't it? :)

But turns out, when you do the math, landing and returning from Moho is the second most dV-hungry planetary exploration task you can do in the stock solar system. Only landing and returning from Eve is harder, and that is quite obviously a special case. Among airless worlds, Moho is the king of fuel thirst. It just barely scrapes out ahead of Tylo, although the actual landing process itself is easier.

Then, you add to that the fact that the difference in orbital period between you and your target, the actual speed of your target, and the distance to it, determines the difficulty of hitting the transfer just right. It's easy to hit Duna, because its orbital period isn't that much different from Kerbin. It's also easy to hit Eeloo, because it is just that far away and moving so slowly. Just burn sometime in the correct week, in the general direction of prograde, and you can have your encounter served on a silver plate. But Moho? Not as far away as you think, drastically different orbital period, and screaming along its path at a huge speed. Trying to hit that with a Hohmann transfer is like a minigolf trick shot by comparison. Being an hour off the optimal transfer window already incurs noticable extra cost in dV.

Because of this high cost and low margin for error, people have devised an alternative way to visit Moho, which trades increased travel time for an easier and slightly cheaper trip. Make your ejection burn when Kerbin's position lines up with Moho's apoapsis, which conveniently also corresponds to the (I believe) ascending node. Put your periapsis on top of Moho's orbit, make sure the inclination ia matched, then time warp forward and loop around once or twice in solar orbit. Then you will be able to make a maneuver node at periapsis that finds an encounter with Moho without much trouble.

(Of course, that method usually doesn't work all that well when you have a life support mod installed, but I don't see any in your screenshot.)

 

Edited by Streetwind
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thx for the advice of you both. ehm i will definitly rebuild the extra tanks to save weight. probably do the middle part as a tug.

appearently i am too late now to do streetmans transfer advice as kerbin has already past moho's apoapsis. but nontheless, should be able to get it then. i was already planning to get jeb back in a later mission though.

i will try and see if it works

 

but one last question, is kerbal alrm clock lying to me or is moho really at the optimal position to transfer?

because i want to be sure i can trust kerbal alarm clocks transfer window advicements.

 

anyways thanks on the advice how to do moho.

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I found KAC to be reasonably reliable, but not exact. It is the right time to leave, but not down to the hour or minute. You can definitely get an encounter when the mod claims you can, but for Moho specifically you might want a little more precision.

Try alexmoon's launch window planner, or the ingame mod adaption, Transfer Window Planner. It's a bit more technical, but also lets you set up an extremely precise node. The ingame mod has a function to show you the spot where the node should go; for the out of game website, I've previously written up a guide here.

 

(Note: this planner gives you single transfer orbits. What you're doing with the apoapsis departure is essentially a delayed bi-elliptic transfer, which means two transfers chained back to back, and the planner can't give you that in one go. It could give you each of the two burns individually, but that would require you setting up your interim solar orbit as a custom vessel in the planner, which is more work than the result is worth. You can fly the apoapsis departure without pre-planning.)

Edited by Streetwind
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To be honest - i dont use kerbal alarm clock for the transfer windows - i eyeball it.

Various missions to Moho proofed that i m not totally wrong :wink:

 

Easy way to test it for yourself:

Complete your vessel and make a savegame ("Moho setup ready")

Do the ejection burn, inclination change and see if its easy possible to encounter Moho with a node.

If you are too early, reload, wait a bit and try again.

If you re too late just wait longer and retry.

With ALT-F5 you can name your quicksaves, with ALT-F9 you can choose a specific (named) quicksafe to load.

 

1 hour ago, jevry said:

i will definitly rebuild the extra tanks to save weight. probably do the middle part as a tug.

^^thats fine.

Edited by Draalo
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got the file for kerbal engineer first of all. seems me pretty usefull yes

for the rest i will not i am not fan of the mod heavy side of gameplay. atm i have just kerbal alarm clock and chatterer (wich sadly broke)

so il add engineer later on. hope the edit in tech wont dmg my career save file.

but here is what is on the table

unknown.png

nvm the low liquid fuel msg i still have like 100 liquid fuel in both my launch boosters after they decouple i am basicly full.

the two half tanks have been added both only adding themselfes and a docking port to the weight.

first maneuvre node says 1700 delta v. dunno the other ones their delta v requirements

the red one is not a maneuvre node. it just inicates that after 2 orbits i will encounter moho.

have quicksaved.

and well il just hope it works. probably should. second maneuvre node should not have too much delta v requirements

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14 hours ago, jevry said:

this is what i have already shot into space

 

unknown.png

so what should i do?

would i make it? the odds in my favour?

or should i just redirect the mission to another planet?

 

The big issue I see so far is youve ejected yourself into the wrong solar orbit when leaving Kerbin.  You left in a prograde direction to Kerbin's orbit around the sun.   This would be great if you were heading outwards toward Duna and beyond.  Unfortunately, you want to go in the other direction.   Leave Kerbin so you are headed retrograde to its solar orbit and your departure burn will have helped instead of hurt you.  

 

You can certainly add more fuel tanks (go bigger than you're showing) on those docking ports, and that wold give you a better chance.  If I were you, and I had the funds, I would send that current ship to the outer solar system and make another to send to Moho with oddles of dV.

 

Edit: you posted as I wrote my reply.  Good luck!!

Edited by klesh
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unknown.png

am i?

pretty sure my burn goes retrograde, not perfectly retrograde i admit, but it goes retrograde

 

edit: oh, ohhhhhhhhhhh. i am sorry. the rpobe you see is a compeletely other mission

those are the positions of the planets, my ship is still in kerbin orbit

Edited by jevry
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1 minute ago, klesh said:

Okay, that looks better.  I was mistaking the orbit line (grey) for that relay as being for your ship.  Your ship is still in orbit around Kerbin in that last shot, yeah?

yep, just edited my comment. but yopu probs didn't see that. but yes. sorry. i understand the confusion though :D

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Right on,   Youre not in as bad shape as I thought!   You never know, some cats (no pun intended) just blast off interplanetary only to find out they went the wrong way.    Youre looking good, chief!

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2 minutes ago, klesh said:

You never know, some cats (no pun intended)

i originally wanted an alien dude as my aurora 4x has like 500 something pictures of alien dudes for the races (including dalek and r2d2)

but the picture was the wrong size, just like all the other 500 :( this one was the only that fitted.

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well i just got a way to get there in about 2 kerbal years saving like 900 dv.... worth it. even if it is a bit unrealistic to do so. whatevs

Edited by jevry
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Oh, that's the other good thing about aiming for the periapsis and not the planet ... lots of leisure to make a braking burn to set up your encounter, so the NEXT time around you need to do less braking.

By the way, you might be able to do a fairly nice Eve slingshot on the way back if you care to, save some delta-v and make your reentry MUCH gentler.

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welp i landed it. note to self. moho not worth the science.will reload a quicksave to actually get the in space science. will send a probehub kerbin-eve-duna next save as my first/second interplanetary mission. way more science and more efficient

and doesnt sacrifice a kerbal for the coming 5-10 years of the game

(not even enough for a nuclear engine 320 science total)

moho is mean.

 

aand i don't have the skill yet to just slingshot around every planet to get to my destination more efficient, thats a whole lot of work i did not sign up for

i know the basics and have seen people do it for example on youtube. but no it's alot of work. waiting for planets to line up and stuff. and knowing when.

maybe some time in the far future with some mods tho

Edited by jevry
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5 hours ago, klesh said:

Pm to me, I fix for you. :)

thanks for the offer btw but i am fine with this one. so i will reject it.

 

i need to stop hanging around the ksp community i get weirded out by all the positivity. no other place you get so much of it.

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19 hours ago, jevry said:

so il add engineer later on. hope the edit in tech wont dmg my career save file.

Some words about KER:

The Mod adds just 2 parts. But you dont need to add them to your vessel if you set KER to partless. Dont worry - if you havent added these parts to a flying vessel all savegames are save after removing KER, you just lose the displays.

moholander2b6yxqfdics.jpg

I ve done a quick rebuild of your lander. Maybe yours is a bit heavier but dV should be around 3000m/s too.

Body is set to Moho - you can see that you have enough TWR to land and takeof again. (I know you ve allready landed - congrats btw. - picture is just for demonstration)

Atmosphere is off - you only need it on for starts and use at other bodies with atmo.

In flight you get additional infos on top of the screen:

landerflightp84z6u3asx.jpg

Note the difference: 130m above sealevel, 58m above terrain - very helpfull for landings, even more when landing on the dark side :wink:

You can also observe the value of your apo without switching to map and back.

Display of remaining dV and actual TWR is excellent for starts and landings.

(lander is 20m above terrain, speed is 2,0m/s? just adjust your thrust to a TWR 0,99 - 1,01 - lean back and watch)

there are much much more things KER can display: distance, inclination, speed relative to target... biome you are flying above...

Again: If you use KER partless you are allways able to remove it without losing your saves :wink:

 

 

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Moho orbital period is short, so you may think you can go ther any time. But unlike Eve or Duna where all transfert windows are nearly alike, some moho transfer windows can be a (fuel) pain...

You must wait for a proper transfer windows and don't simply use the next one.The ideal window is when you align you target to rendezvous at Moho PE (so kerbin is near Moho AP.

You may think "but how do I match Moho being at PE while KE is near AP when I escape". Answer : you don't !

You simply leave Kerbin when you're near AP, so you'll reach Moho PE even if Moho isn't at PE when you reach it. That way you totally avoid doing a mid course plan change.

Then, at Moho PE, you simply burn to catch Moho at PE on next orbit. This is the same operation you do when you rendezvous.

This is the cheapest way to go to Moho.

Refinement : you can, on you escape burn match Moho plane to get an easier encounter later. Or you can even lift of with proper Moho plane. That very cheap but needs few tries to get it right as the game don't give you any help on that...

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