I Want To Go To Pol

[The Jedi Master]

I thought that since I'm coming up on my official one thousandth post (why, no I don't have a life ), I would try to visit a world that has perked my curiosity for a long while. Pol is easy to land on, has pretty colors, and (this is what really has me curious) it's incredibly neglected, and thus is shrouded in mystery. So, I want to give the little neglected moon a visit. The problem? I suck at building anything larger than a Mun lander, and I even struggle a bit with that. I usually use ships downloaded from the Spacecraft Exchange. Also, interplanetary encounters: hard.

So, my question: How would I go about building a Jool capable craft, flying out to Pol, landing and coming home again? Thanks in advance!

[Tex_NL]

Doing it 'Apollo style' is probably your best option; a big, heavy drive section carrying a small, lightweight lander. Leave the drive section in orbit and rendezvous once your ready to go home.

[Johnno]

My advice is to do a backwards design process, not the craft itself but the process. Start by figuring out, what do you need to get home from Pol. Capsule, fuel, RCS, electricity, engine.

Next figure out what you need for taking off from Pol, and landing because let's face it you won't need much. So a singlestage lander would be easiest.

So, you have your lander and your return craft, next up interplanetary stage. Check the mass of your lander and return craft, put a mockup mass of that above your interplanetary stage, add fuel/engines until you have enough delta-v to get you to Pol with an acceptable burntime.

Dock everything up in orbit and off you go. Personally I usually put together return&lander to be launched together, then interplanetary stage on its own, dock the two and ready to go.

If you want to do a single interplanetary burn then you'll need plenty of thrust (heap of nuclear engines), if you want to do 'periapsis kicks' ie multiple burns to raise your AP before leaving Kerbin's SOI then you can use just a few engines, but it'll take longer / more complex.

[JiWint]

Man,visit Gilly first,more fun right there.

You'll need only a jetpack to land and back to orbit on gilly!

[Motokid600]

Gilly is Duna's moon, yes? That's on my list as well. So your saying i don't even need a lander for Gilly? I can Eva a kerbal from an orbiting CM, land then take off and rendevouz? ( I hate spelling that word I know I got it wrong lmao )

[Johnno]

Gilly is Eve's moon, Duna's is Ike.

An 'extreme EVA', which is land from orbit and get back up into orbit after being on the surface with just your Kerbal's EVA rocketpack is possible on Minmus, Gilly, Pol and potentially Bop depending on how efficient your landing/takeoff is.

On Dres and Ike you can at least take off from the surface and make it into the orbit with just the EVA rocketpack, alternatively landing from orbit should be possible.

[magnemoe]

Two problems with Pol if you make it to Jool, one is that its small and a bit hard to get an intercept with. Not sure if its economical to do an braking in an high Jool orbit over Jool aerobrake. An Laythe aerobrake who put you in an Jool orbit close to Laythe might be cheapest but its an pretty advanced operation. If not I would calculate 1500-2000 m/s in addition to the 2000 for Jool.

Second is landing, it far less gravity than Minmus so landing is cheap however its very uneven, so you want an very wide and low lander.

Fun place, not as stupid low gravity as Gilly but not much more, also nice for kethane mining so you might want an detector and plant some flags.

[Moar Boosters]

I did Pol as my first long-range mission.

It's a pretty good target imo. Getting capture with jool is pretty easy because it's SOI is huge, and then I just played around with the maneuver node to setup a hohmann transfer to pol.

I wouldn't bother doing it apollo style, that overcomplicates things. All it does is save you fuel used for the actual landing and takeoff, and that's a very insignificant part of the journey considering how low Pol's gravity is. The terrain there is pretty nasty, but because the gravity is so low I was able to hover around and move sideways to find a landing spot without using much fuel.

My ship had a couple of nuclear engines and an asparagus system of drop-tanks which prevented me carrying around too much weight in empty fuel tanks.

[capi3101]

Gilly so far has been the only moon in the Kerbol system that I've had to thrust toward while trying to land...only takes 70 m/s of delta-V to land and launch again, easily within the abilities of a Kerbal space suit. Walking around on Gilly is...problematic.

As for Pol, Johnno's given you the best advice so far - plan the mission backwards. Only other thing I could suggest (and this is just me shooting my mouth off here; I've sent exactly jack to the region near Jool) would be to stick a refueling tanker in Jool orbit as a separate mission. Your mission profile then becomes 1) launch, 2) transfer to Jool, 3) rendezvous with refueling craft to refuel, 4) transfer to Pol, 5) send down lander, do business and come back up, 6) transfer back to Jool, 7) rendezvous with the refueling craft to refuel, 8) transfer back to Kerbin. That's an extraordinarily rough sketch and there may be merit in putting the refueling tanker over Pol as well (to avoid having to transfer back to Jool before heading home).

[MrPopcup]

Well, that's a really good target to get to!

Ummm.. from my experience I'd say that Pol is the easiest place to go in the Jool system ( in Air-less moons + low gravity ) but hard to intercept, it's inclined orbit and low velocity makes it hard to intercept, but gravity, on the other hand is low, so you should take off with little golden LV-N engine, make it to orbit, rendezvous with your return vehicle and head back to kerbin. so here's the deal.

I can send a whole space station ( Command module + solar panels with cubic structures and 4 docking ports, one storage module and kethane scanner ) to laythe in one launch and NO docking is required, so it's up to you, I personally can send up-to 20 ton vehicle to Jool system, the problem is getting it where you want it to be, I use aerobraking to get in Laythe SOI, that's a cheap way instead of wasting a lot of fuel ( 120000m is the ideal aerobraking to get in laythe SOI for who doesn't know.. )

So say you want to aero-brake and get in ORBIT around jool, not intercept or get in SOI of pol, is 140000m maybe? Idk maybe less,

so this:

1. TRY to make your lander+return vehicle below 8 tons, if you've done that, you're safely home.

2. Use nuclear engines in your return vehicle.

3. Make a 350 ton rocket ( which is my average rocket mass, it can get you to jool. )

4. the most important thing is you must be self-confident or you Just won't make it..

5. try to Aero-brake in jool's atmosphere.

6. remember to quick save before every single step you THINK that something else will happen, that way you won't waste another 10 minutes..

7. put your rendezvous vehicle in orbit, and try to land on the highest peak you see in map. ( a fart can get you above 5000 meters.. )

and I guess that's it, remember to be creative, have many tests, test your lander on minmus, because why not!

[SofusRud]

I recommend a stopover by Aerobraking at Laythe. Its actually not that hard, just fish around near Laythe's orbit with your manouver node until you get and then fine tune it on the way in. Depending on how fast you're going you wanna drop down to 18-25 km. then you can use the phase angle calculator to find the angle Laythe has to be in relation to Pol. You can find that here: http://ksp.olex.biz/

[magnemoe]

I did Pol as my first long-range mission.

It's a pretty good target imo. Getting capture with jool is pretty easy because it's SOI is huge, and then I just played around with the maneuver node to setup a hohmann transfer to pol.

I wouldn't bother doing it apollo style, that overcomplicates things. All it does is save you fuel used for the actual landing and takeoff, and that's a very insignificant part of the journey considering how low Pol's gravity is. The terrain there is pretty nasty, but because the gravity is so low I was able to hover around and move sideways to find a landing spot without using much fuel.

My ship had a couple of nuclear engines and an asparagus system of drop-tanks which prevented me carrying around too much weight in empty fuel tanks.

Your only real issue is that your mothership has to be designed to be landed. think 1500 m/s to get back.

However an actual lander would be easier to land, you could use the rover seats/ pod and eva back, no need to dock. an 45 liter tank and an 48-S7 could land almost anything on it, put an 2x2 plate on top, probe and as many rover seats you need in addition to an pod to refill rcs. Forget rovers.

[Rarity]

Since you've already got plenty of help as far as getting there, make sure to visit the poles and see if Pol has any moholes or other strange polar phenomena. Post pics if you find anything!

[Moar Boosters]

When I first went there I hadn't even attempted rendezvous maneuvers, so sending a lander would have been a lost kerbal.

This was my ship. Looking at it now, it's rubbish. Way too much RCS fuel and reaction wheels, those crappy radial engines are unnecessary and the rover didn't work.

But it got them down to the surface and back home, so I guess it was good enough! I found a floating rock, but I think they're pretty common.

Edited August 30, 2013 by Moar Boosters

[Geschosskopf]

There are a bunch of ways to get to Pol but here's what I prefer to do. When my goal is to get to a moon immediately upon entry into the system (as opposed to starting from orbit around the main planet), what I do is aerobrake at the main planet in such a way that I get captured into an elliptical orbit whose apoapsis is out in the general vicinity of the target moon (and as close to the same orbital plane as possible). I set this up shortly after entering the main planet's SOI by tweaking my periapsis at it, when this hardly takes any fuel. Anyway, after the aerobraking, I coast out to my new apoapsis and burn to circularize out there, which again is pretty cheap on fuel.

So now my ship is orbiting the main planet as if it was one of its moons. Then it's just a matter of a short wait for the proper phasing angle to make a transfer burn from my ship's orbit to the moon's orbit. You're looking for about the same angles you'd use if on Kerbin to launch for Duna or Eve, or setting up a rendezvous for docking, depending on whether your ship's inside or outside the target moon's orbit and by how much. This usually doesn't take much fuel, either. Anyway, now you're on an intercept course with the target moon and after that it's just a matter of getting captured there.

The main complication of getting to Pol is that if you want to use Jool itself to your advantage, you have to cross the orbits of all the other moons twice, once going in and then again on the way back out. Thus, depending on the luck of the draw, you could get encounters with 1 or more of the other moons on either side of the aerobraking, which might help or hurt. So, that might entail some more fiddling with your trajectory. Just note that your predicted path only takes gravity into account, not aerobraking and the velocity change that entails. So, before you actually do the aerobraking, understand that none of the encounters shown afterwards will really happen because you'll be going slower when you get there. But OTOH, what looks at first like a clear path out from Jool could also end up with extraneous encounters after aerobraking, so you have to be on your toes .

All good fun. But if you've got the fuel, you might instead want to incline your approach to Jool so you go over/under all the other moons by enough to avoid all encounters. But then you have to make another plane change after Jool to get back on Pol's plain.