Do you find the Jool system hard to navigate?

[Kelderek]

Is it just me or is the area around Jool a pain to navigate for everyone? It feels so cluttered with all the moons that seem to have large enough SOIs and small enough orbits that it can be really difficult to move around without encountering something that gets in the way of wherever you're trying to go. Most of my trouble is in getting back to Kerbin, or trying to get to/from the outer moons without encountering the inner ones.

On my last trip to the Jool system, I had to skip through 3 separate Kerbin transfer windows until I could find one that didn't get screwed up by one of Jool's moons. That just felt really excessive to me.

Does anyone have any tips to make this easier to deal with? Does ship design play any part in this (like longer or slower burn times)?

Edited February 2, 2015 by Kelderek

[EdFred]

You shouldn't have to skip transfer windows at all. Once en-route to the Jool system, make small dV changes with radial or -grade burns (or both), and you can adjust your timing into the system. I have never had to skip a transfer window into the system. Once you have your encounter on your trajectory, place a node about half way to Jool, and adjust it a couple of dV with radial and pro/retrograde burns and you can miss the moons. I do this routinely. Also Focus View on Jool to see what the result of your dV change is. When I did my Jool 5 Challenge, when I was about 1/2 way there, I "exploded" my craft into 5 sub ships, and even though all were pretty much on the same trajectory, the tweaks I made to each craft had them arriving up to 4 days apart at Jool's SOI. In +/-4 days, you can easily miss Tylo, Vall, or Laythe.

Edited February 2, 2015 by EdFred

[Slam_Jones]

My main issue with the Jool system is getting repeat moon encounters that throw my ship out of the system.

Never tried to explore any moons besides Laythe... they seemed too much a hassle to get to.

[EdFred]

My main issue with the Jool system is getting repeat moon encounters that throw my ship out of the system.

Never tried to explore any moons besides Laythe... they seemed too much a hassle to get to.

Adjust your orbit so it is parked between the orbits of the 3 large moons. There is plenty of room in the Jool system.

[Randazzo]

Is it just me or is the area around Jool a pain to navigate for everyone? It feels so cluttered with all the moons that seem to have large enough SOIs and small enough orbits that it can be really difficult to move around without encountering something that gets in the way of wherever you're trying to go. Most of my trouble is in getting back to Kerbin, or trying to get to/from the outer moons without encountering the inner ones.

On my last trip to the Jool system, I had to skip through 3 separate Kerbin transfer windows until I could find one that didn't get screwed up by one of Jool's moons. That just felt really excessive to me.

Does anyone have any tips to make this easier to deal with? Does ship design play any part in this (like longer or slower burn times)?

Unless you're on an extremely tight fuel budget, you can always make small adjustments en-route to avoid those moons. Once you're in the system you'll have to have a roughly circular orbit between any moons orbit to make absolutely certain you don't get slingshot out of the system. If your orbit crosses over the orbit of another moon (Laythe, Vall) you're very likely to eventually get a capture and slingshot on one of them, unless you're inclined far enough away to avoid them.

[Kelderek]

Perhaps I wasn't as clear. I have no trouble getting to Jool, making the transfer from Kerbin and then aerobraking and gaining a stable orbit close to Jool. My problems tend to be leaving Jool to either return to Kerbin or to try to reach the outer moons like Bop and Pol. Maybe I've been lucky arriving and unlucky leaving, but I often find it troublesome. The 3 Kerbin transfer windows I mentioned was for leaving Jool to get back home. Each time I tried it I ended up with a moon in the way that wasn't there when I initially made the maneuver node (i.e. the node looked like it would get me out just fine, but by the time my burn was done I was headed for an encounter that screwed up the whole thing).

[Vanamonde]

How about approaching Jool at a bit of an inclination so that you pass above or below the plane of the moons' orbits?

As for myself, I just make the transfer, and when I get there, see what opportunities for useful slingshots the geometry might have given me.

[pellinor]

The Jool system can be tricky to navigate but I find it incredibly cheap because of all those gravity assists. I usually park in an eccentric orbit of one of the inner moons. Brake just enough to get captured, then the exit burn is also cheap (there are some restrictions on exit, as the exit burn should be near the periapsis). Use Tylo to get to the outer moons, also use Tylo to throw the ship back to Kerbin.

Edit: for the exit burn, I actively look for a gravity assist. So I warp until shortly before the transfer window, then make an escape node from the parking moon (usually laythe), such that it crosses Tylo's orbit. Then I shift and fiddle with this node until it leads into a useful encounter. If it doesn't work out or Vall gets in the Way, improvise some way to stay near the inner moons and catch the next gravity assist. It's a quite spontaneous way of planning, but with a bit of practice it works out surprisingly often.

Edited February 2, 2015 by pellinor

[EdFred]

Perhaps I wasn't as clear. I have no trouble getting to Jool, making the transfer from Kerbin and then aerobraking and gaining a stable orbit close to Jool. My problems tend to be leaving Jool to either return to Kerbin or to try to reach the outer moons like Bop and Pol. Maybe I've been lucky arriving and unlucky leaving, but I often find it troublesome. The 3 Kerbin transfer windows I mentioned was for leaving Jool to get back home. Each time I tried it I ended up with a moon in the way that wasn't there when I initially made the maneuver node (i.e. the node looked like it would get me out just fine, but by the time my burn was done I was headed for an encounter that screwed up the whole thing).

Park yourself outside of Tylo. I did this exact thing yesterday.

[Kelderek]

Ok, thanks for the responses. It's been frustrating at times for me. I'm sure it's designed this way to make encounters easier so you can get to the moons, and also perhaps to keep the DV requirements more reasonable. I just wish it was easier to have a clear path in and out of the system.

[tsotha]

How about approaching Jool at a bit of an inclination so that you pass above or below the plane of the moons' orbits?

As for myself, I just make the transfer, and when I get there, see what opportunities for useful slingshots the geometry might have given me.

That's what I do. I don't think I've ever missed a transfer window, though I have wasted small amounts of dV when I wasn't in the mood to mess with it.

If you really need to minimize fuel consumption, playing pinball at Jool can do wonders.

[Laie]

The Joolian Pinball Machine. I know that feeling of moons getting in the way and tossing you around.

The only solution I found so far is to use the encounters as best I can. Placing a maneuver node and clicking the little plus sign lets me see what kind of encounter I will get in one, two, many orbits. It usually only takes only very little delta-V to turn an unwanted encounter into a useful gravity assist; it won't get you to the orbit you want, but it will get you a good deal closer. And the next encounter is bound to happen really soon.

The last two times I tried that it took me three encounters and about 600m/s to get from a very low orbit to one safely outside of Tylo; half of that to circularize. If I had done that under my own power, it would have been more than 2500m/s.

When planning the return trip, time and transfer windows are nowhere as essential as they were in getting there. If you find that your maneuver will make you brush up against Tylo, just check what things look like if you wait one more orbit, or two. Chances are that it will still be pretty much the same maneuver.

[Kelderek]

Ahhh, well the whole concept of the gravity assist is something I haven't tried to learn yet. Up to this point I just fly places and avoid hitting things, building my ships according to the DV maps I've found. So I guess I have a new challenge to work on: learning all about gravity assists and how to use them to my advantage and not be sacred to fly close to other objects that may be in my path.

[AlexinTokyo]

Have you tried increasing the number of conic sections the game displays (the CONIC_PATCH_LIMIT in the settings.cfg file)?

Increasing this number will allow you to see your projected path further into the future (past more SoI boundaries), so this might allow you to better figure out how to get out of the system between the moons (or at least let you know where you're going to end up ).

[Laie]

Ahhh, well the whole concept of the gravity assist is something I haven't tried to learn yet.

Can't say that I'm especially skilled. But Jool is a great environment to learn by doing. Just put down a node at your AP/PE or wherever, and play a little with pro-/retrograde. Give or take 20m/s, applied half an orbit before the encounter, has a huge effect on the resulting trajectory. Don't expect it to take you exactly where you want to go, though... but you have a lot of influence over whether you apoapsis goes up or down, and/or how eccentric your new orbit around Jool is going to be.

Have you tried increasing the number of conic sections the game displays (the CONIC_PATCH_LIMIT in the settings.cfg file)?

In a pinch, you can also put down a maneuver node in the last patch you see. It doesn't need to do anything -- but if there's a node, the game will display how the story continues. I actually prefer this, as being able to see far into the future can become very confusing; and most of the time, I don't need to look as far ahead.

[AlexinTokyo]

TBH, I use PreciseNode, so the limit can be controlled dynamically in game. Dropping a node is a nice stock workaround that I had't thought of, though.

[Kelderek]

I think I might take a well-fueled ship out to Jool using hyperedit to just screw around for a bit slingshotting around the moons to get some practice.

For gravity assists, is there any mod that helps to show "combo" launch windows? For example, on the next Kerbin-to-Duna window, you can also combo that to swing around to Jool - or something like that? Am I thinking of gravity assist in the right way here? I know that NASA almost always uses at least the moon and sometimes other planets to help build up speed for long range probes. That's what I think of when you talk about gravity assists. In those cases your launch window would depend on the location of multiple objects, not just your destination target.

[AlexinTokyo]

Everything you need to know about gravity assists but didn't know you needed to know about gravity assists.

Including how to use alexmoon's transfer window planner to plan them.

[Kelderek]

Wow, thanks for that link, I'll be sure to pore through all of that info.

[Red Iron Crown]

I have found this delta-V map very helpful when puttering around the Jool system:

[Sigma88]

I'm preparing to launch a ScanSat mission to the joolian system to scan the moons.

I'm thinking of putting together a set of 8 satellites: 2 relays with Antennas for comunication with kerbin (remote tech) and 6 scannig satellites (1 for each moon + 1 for jool)

I plan to do everything in polar orbits, does anyone have suggestions to give? thanks in advance

[Vahal]

I don't think scanning Jool itself would worth the effort, so you can save mass and funds.

One advise, don't forget RTG!

[AlexinTokyo]

I'd agree with Vahal that scanning Jool is pretty pointless. There are no biomes, and there's no surface to record altimetry data about. That said, you may be able to get the 'Analyse Data' science from there; not sure.

Also, remember that the SAR scanner for hi-resolution altimetry and the multispectral scanner for biomes and anomalies have different altitude requirements, so if you want both you may need to plan two satellites per body.

[Sigma88]

I'd agree with Vahal that scanning Jool is pretty pointless. There are no biomes, and there's no surface to record altimetry data about. That said, you may be able to get the 'Analyse Data' science from there; not sure.

Also, remember that the SAR scanner for hi-resolution altimetry and the multispectral scanner for biomes and anomalies have different altitude requirements, so if you want both you may need to plan two satellites per body.

I don't think scanning Jool itself would worth the effort, so you can save mass and funds.

One advise, don't forget RTG!

Thanks for the tips

I know about jool but I thought maybe in the future they will add some feature and then I'll have the satellite already there, plus this way I can store inside the fairings a square of 2x2 satellites with another 2x2 on top which makes it easier to design. Also I can always make the excuse that kerbals don't really know the biome scanner won't work on jool

Even better it gives me a third Comunication device around jool which could be useful if a moon is between a scansat and the relaysat to kerbin

As for the altitude requirements I plan to keep just 1 sat with both radars active at the best compromise altitude, and when one of the 2 radars is done I shift the orbit to match the optimal of the other

Regarding RTG, I'll use one from near future electrics wich has 7 years lifetime, cause I don't really like the infinite RTG (still I'm never going to play 7 years ingame so I guess that's the same thing, but it feels less cheaty ).

My biggest worry at this moment is being able to go from a polar orbit around jool to a polar around a moon. I hope the satellites have enough fuel to make the plane change required to get the encounter

-edit-

on a side note, I could do what NASA plans to do and send satellites with solar panels up there

but a couple of gigantor would produce only 1.27 charge/s (roughly) at that distance, so I decided to go with the generator anyway

Edited February 4, 2015 by Sigma88

[cerberusti]

I find it one of the best in terms of navigation potential. If you have an unwanted encounter when you enter the SOI just tap the engine or rcs and it will likely go away, it takes very little energy to make a significant change at the Jool SOI boundary.

My laythe plane also manages to make a nearly free return trip thanks to tylo more often than not.