Ideas and tips for a Joolian tour craft

[Monkeh]

I have been inspired by all the awesomeness around me on this forum to try to stretch myself a bit within KSP. So far I've made simple rockets that have got me to most of the celestial bodies. I have never given much thought to return or anything more complex.

Last night I decided I wanted to do a tour of the Joolian system. I want to get to Jool and visit as many of it's moon's as I can before returning home. I started designing a lander and a 'return homer', which seem to have some potential and I can attach them to each other in a stack. They can dock with each other or the other part of the craft. I have no idea whether they have enough delta 'v' for what I want to do but it's a start.

I was wondering if anyone who has done anything similar had any pointers or tips on how to achieve this tricky little task I have set for myself. I still need to design the interplanetary stage and the booster stage as well to get me into orbit. That part I should be able to manage I think, it's more the lander and orbiter that seems to be the tricky part.

So yeah, any 'grandish' tour tips or pointers would be awesome. Thank you.

[Johnno]

I've only done a Laythe + Vall trip, other than single destination trips in the system. I know Tylo is a tough nut, haven't done that yet. For delta-v readings I'd recommend Engineer Redux, or doing the math by hand. You can find what you need on the wiki cheat sheet.

For Laythe you'll likely want a separate lander since it has atmosphere, and if you're going to do Tylo you need a really beefy lander (but no chutes). Bop, Pol and Vall don't need much in ways of lander, the latter having slightly more than Mün in gravity.

I'd recommend a reusable lander for Vall, Bop and Pol, that you simply dock and refuel at the mothership. To save weight you could have a detatchable command section on the lander, that you then attach to a Laythe/Tylo descent/ascent stage. Depending on how fancy you want to get you could even use the same one with a bit of design prowess, giving it drop tanks/boosters that you take down on Laythe empty with the core stack being able to lift it to orbit there, dropping parachutes off after getting up from Laythe and then filling up the tanks for Tylo. Or you could have dedicated landers for each location.

Hope some of that gives you useful ideas.

[Monkeh]

Yeah. Cheers man. I was considering adding a couple of jets for the Laythe landing and take off. Do they work with Laythe's atmosphere?

Anyway, it sems I won't be doing it any time soon as I managed to delete all my steam games late last night. All my sub assemblies. All my saved craft. All things.

Got to start from scratch again. Head down.

If you check my last screenshot on the link in my sig below you can see how the lander and returner were shaping up. I was qite happy with them as far as they went. Was gonna change the lander to nukes and add jets for Laythe.

Back to then drawing board then spose. Using your ideas should help. Nice one.

Edited September 4, 2013 by Monkeh
Because typing on a phone can be tricksy...

[Motokid600]

Yes absolutely use jets for your Laythe ascent stage. They won't get you as high as they do on Kerbin, but once you drop the jets its only a quick rocket burst to reach orbit.

[Monkeh]

Awesome. Thank you. That should make life a bit easier. So there is oxygen on Laythe. The thick plottens...

[Geschosskopf]

...Last night I decided I wanted to do a tour of the Joolian system. I want to get to Jool and visit as many of it's moon's as I can before returning home. I started designing a lander and a 'return homer', which seem to have some potential and I can attach them to each other in a stack. They can dock with each other or the other part of the craft. I have no idea whether they have enough delta 'v' for what I want to do but it's a start.

If you have KSPX, then you have the 3-high large-diameter fuel tank and the big nuke engine. A transfer tug made of these 2 parts plus a probe core, a Clamp-O-Tron Sr., and some RCS for the necessary docking has enough delta-V to push a payload weighing 30-ish tons or less pretty much anywhere, especially if you're going to a place like Jool where you can aerobrake at 2 different planets to reduce the burns needed for capture. It won't get you home but an identical tug can also push a tank with 30 tons of fuel to the same destination to solve that problem, or you can get into Kethane to refuel yourself at the destination.

I was wondering if anyone who has done anything similar had any pointers or tips on how to achieve this tricky little task I have set for myself. I still need to design the interplanetary stage and the booster stage as well to get me into orbit. That part I should be able to manage I think, it's more the lander and orbiter that seems to be the tricky part.

So yeah, any 'grandish' tour tips or pointers would be awesome. Thank you.

Well, design a lifter that can toss about 30 tons into LKO and you're set. Here's a pic of my standard lifter lifting a standard transfer tug as described above:

The ascent stage is non-asparagus. The core is 2 of the biggest tanks in KW Rocketry tanks with the biggest KW Rocketry 4-barrel engine under them, assisted by 4 "Thor" SRBs, which I THINK are in KSPX, along with the tank and engine for the tug. The tug weighs a bit more than 30 tons so this beast (about 550 tons on the Launchpad) can't QUITE get it to orbit without the tug doing the last bit of the circularization burn. However, the tug's a nuke so has beaucoup delta-V and this little bit, plus whatever it burns rendezvousing with whatever payload it's supposed to push, still leave plenty to go just about anywhere. The lifter has an RCS tank and uses RCS thrusters on the tips of tail fins combined with those on the payload to rotate once out of the atmosphere to face prograde.

So, that's getting there. As to what to send there, you definitely want planes to fly around on Laythe and bragging rights for Tylo will require a specialized lander. Any lander that will work on Moho will also on Vall (as well as Dres and Eeloo should you go that way while you're in the vicinity). Pol is your best bet for Kethane exploitation to fuel moving around within the Jool system and eventually leaving it, Bop being a bit too inclined to be economical that way.

[Guest]

Any lander that will work on Moho will also on Vall (as well as Dres and Eeloo should you go that way while you're in the vicinity).

Any lander that works on Moho will work everywhere but Tylo, Laythe, and Eve (you could overbuild it for Duna with chutes and possibly have it work on Kerbin, and it won't land on Kerbol or Jool ofc, but anyway...).

When figuring your trip's delta-V budget be sure to include transfers to the moons from wherever you plan to start in the Joolian system. This budget must be met by either your lander or the main vehicle, or you could use a Joolian transfer vehicle to ferry around the lander, or whatever; the point being that your delta-V budget is going to be much more than simply Kerbin -> Jool -> Kerbin.

[TheSaint]

I designed mission that landed on all five Joolian moons and docked back at my station in LKO with about 3,000 m/s to spare. I had one vehicle that carried the crew (the Crew Vehicle, or CV). I had one lander with chutes and about 3,000 m/s of dv for Laythe and Vall, and then I had a two-stage lander for Tylo. The landers transfered to Jool on two pared-down versions of the crew vehicle that doubled as refueling tankers. So the CV and the Laythe lander aerobraked first around Jool and then into Laythe, while the Tylo lander aerobraked around Jool and then went straight to Tylo. The CV docked with the Laythe lander/transfer stage around Laythe, refueled from the transfer stage, and then Jeb and Bob took the lander down and back. Then the CV took the lander to Vall and performed that landing. That lander was abandoned at Vall while the CV moved on to Tylo, refueled again from the Tylo lander's transfer stage, and then they landed on Tylo. After that the CV took the second stage of the Tylo lander and used it to land on Bop and Pol. Then the CV returned to Kerbin.

I've started a new save since then, but I think that I still have the craft files somewhere, I can upload them tonight if you're interested. The only mod part I used was the large NERVA from the KSPX part set.

[-Velocity-]

You're doing exactly what I was PLANNING on doing. I'll try to post pics later, but my original plan was to assemble a massive carrier spacecraft/tanker, and haul enough gear to Jool to make a landing and return off the surface of every moon, then return home, taking EVERYTHING back with me.

It took me a month or two to develop the individual spacecraft. These were what I came up with:

Low gravity nuclear rover- utilizes two NTR engines (NTR engines ARE in fact the BEST lander engine in low gravity environments, where the poor TWR of the nuclear engines does not matter nearly as much). It combines a lander and rover into a single craft. It is capable of landing and returning from the surface of every body except probably Kerbin, Tylo, Eve, Laythe, and Jool of course.

Tylo Lander- uses some KW rocketry light and efficient engines to create a high TWR (1.8 TWR when fully fueled; TWR > 5 when near empty) lander with > 6000 delta V. I think it was 6200 but I can't remember exactly. It is capable of SSTO operation on Kerbin and Laythe, and can actually land and return from the surface of Laythe if modified with parachutes (however, very few flat spots exist for it to land on on Laythe). LACKS RCS, it is entirely dependent on the tug spacecraft (see below) to ferry it around.

Small VTOL space plane-uses some of the VTOL jet engines from (B9?), it's SSTO on Kerbin and of course Laythe. Be careful not to abuse the VTOL engines, they are very unrealistic (they can operate at like 40km+ altitude, and you can use nothing but the VTOL jet engines to get you up to Kerbin escape velocity), so unless you like to basically cheat, don't put too many of them on your space plane.

Large Tug - simply a large NTR tug to ferry around the various craft to the different bodies in the Jool system.

Finally, all this stuff was to be hauled with a massive 1000+ ton carrier ship, basically a bunch of fuel tanks with docking ports, nuclear engines, and habitation modules attached to it.

WHAT PREVENTED my master plan from taking place was incredible lag. I can create all the individual spacecraft, but I cannot mate them all up to a single carrier ship or the game basically stops running. Also, the very complex ships are EXTREMELY vulnerable to Kraken attack. This is what happened to my first attempt to send a carrier ship with a lot of spacecraft attached- it just randomly started exploding!:

So I'm in the process of sending multiple carrier ships. I made my carrier ships very easy to assemble in orbit (1500 ton vessels, assembly takes two launches, fueling takes 1-2 additional launches, then however many launches are required to put up any vessels the carrier ships will take with them). Anyway, that saves me time.

I ended up having to make a huge heavy lift rocket capable of lifting 800+ ton segments of the carrier ships into orbit so that I could quickly and easily build the carrier ships.

This is an early version of a carrier ship, carrying two of the nuclear rovers, two of the Tylo landers (modified with parachutes), and two of the large tugs. I sent it to Duna (the Tylo landers are a little ridiculously overpowered for Duna, but whatever ).

The newest carrier ships I am making now are approximately 1525 tons (liquid fuel capacity is ~1200 tons, equivalent to about 37 or 38 Jumbo 64 fuel tanks), nearly twice the mass of the carrier ship in the above screenshoot. They have a delta V of around 13,000 m/s (it takes like 3000 m/s delta V to get from HKO to HJO, assuming you use aerocapture). But, the bigger carrier ships I am building now actually have the same or smaller part counts, thanks to that wonderful Ubio welding mod. Anyway, there is nothing really clever about them, they are just giant gas bags with engines, a bunch of docking ports, some smoke and lights, and some habitation modules.

SPEAKING OF AEROCAPTURE!!!! BE CAREFUL AROUND JOOL! Due to bugs, it will often cause your ship lose parts when you depart its atmosphere after an areocapture/areobrake maneuver. What I did to counteract it was, after the bug damaged my ship, I would restore my ship to the state it was before the aerobrake using manual editing of the save file!

Anyway, I guess an interesting challenge I could pursue next would be to try out the deadly re-entry mod... I'd probably have to put some huge heat shields on the carrier ships, and probably some giant fins/wings to keep them going straight in atmospheres... assuming fins/wings don't burn off in deadly re-entry?

Edited September 4, 2013 by |Velocity|

[-Velocity-]

I designed mission that landed on all five Joolian moons and docked back at my station in LKO with about 3,000 m/s to spare. I had one vehicle that carried the crew (the Crew Vehicle, or CV). I had one lander with chutes and about 3,000 m/s of dv for Laythe and Vall, and then I had a two-stage lander for Tylo. The landers transfered to Jool on two pared-down versions of the crew vehicle that doubled as refueling tankers. So the CV and the Laythe lander aerobraked first around Jool and then into Laythe, while the Tylo lander aerobraked around Jool and then went straight to Tylo. The CV docked with the Laythe lander/transfer stage around Laythe, refueled from the transfer stage, and then Jeb and Bob took the lander down and back. Then the CV took the lander to Vall and performed that landing. That lander was abandoned at Vall while the CV moved on to Tylo, refueled again from the Tylo lander's transfer stage, and then they landed on Tylo. After that the CV took the second stage of the Tylo lander and used it to land on Bop and Pol. Then the CV returned to Kerbin.

I've started a new save since then, but I think that I still have the craft files somewhere, I can upload them tonight if you're interested. The only mod part I used was the large NERVA from the KSPX part set.

Sounds like a more clever plan than mine- I was just trying to brute force it all with a giant freaking spaceship- though, I had a more difficult set of conditions, as I was required to bring everything back with me. The only thing I can leave behind at Jool is rocket exhaust

A minimalist mission that only requires that the Kerbal crew return, like what it sounds like you did, would be a fun challenge too!

[TheSaint]

Sounds like a more clever plan than mine- I was just trying to brute force it all with a giant freaking spaceship- though, I had a more difficult set of conditions, as I was required to bring everything back with me. The only thing I can leave behind at Jool is rocket exhaust

A minimalist mission that only requires that the Kerbal crew return, like what it sounds like you did, would be a fun challenge too!

Yeah, it would be hard to bring everything back, that's a lot of dead weight on the return trip. It's hard enough just trying to send everything in one stack. That was the first mission profile I tried, and by the time I had pared it down enough so that lag, wobble, and the Kraken were not issues I didn't have enough dV to accomplish the mission. That was how I wound up with three different vehicles. Although I've learned a lot since I did that mission, and I think I could get away with smaller transfer stages now (the core of the original vehicles was four Jumbo tanks strapped together).

[SRV Ron]

This design all stock puts up a good size payload that can reach Moho. The key to all large asparagus designs is placements of struts for stability. It is easy to do a grand tour of Jool's moons by coming in to Pol and then slingshot inward all the way to Laythe.

Start out simple, then add capability as needed. You can also launch multiple missions 1/2 hour apart to the same system to achieve a goal of landing on all the moons and dropping a suicide probe on Jool.

[Temstar]

Back in 0.17 I did a manned landing and return to (then available, Pol wasn't around yet) all four moons of Jool in one go. Wrote up a huge mission report with loads of pictures too including an extensive explanation the logic behind the mission plan, but it all got eaten by the forum purge and all I'm left with is this picture:

Basically, to visit the four moons I use one large mothership and three landers, once assembled and fully fuelled in Low Kerbin Orbit the mothership burns its engines to send the whole fleet to Jool. Upon arrive at Jool events happened in this order:

1. Upon entering Jool SOI, the mothership adjusts its orbit for Jool aerocapture pass

2. After first pass through Jool's upper atmosphere the ship is captured into an elliptical orbit with apapsis around Tylo orbit. Due to a spot of luck and Tylo's huge SOI to semi-axis ratio the mothership is due to enter Tylo SOI on the first pass. At this point the Tylo lander (the big one connected to the nose docking port) undocks from the mothership and manoeuvres into position for Tylo orbit insertion burn, while the mothership manoeuvres away so it dodges Tylo SOI for another pass through Jools atmosphere

3. Tylo lander enters Tylo orbit and performs deorbit burn to land on its surface

4. Mothership minus one lander makes a second aerobraking pass through Jool's atmosphere and end up with apapsis around Laythe orbit. My luck wasn't that good so I didn't get encounter on first orbit. At apapsis mothership fires engine to raise the periapsis out of Jool's atmosphere

5. Several orbits later mothership gets a Laythe encounter and adjusts orbit for aerocapture pass through Laythe's atmosphere. After several pass it settles down into a 80km Low Laythe Orbit

6. Laythe lander (the one on the port docking arm with the parachutes) undocks from the mothership and makes a deorbit burn to land on Laythe

7. When the transfer window comes up, the Bop lader (the one on the starboard docking arm) undocks from the mothership and perform a moon-to-moon transfer to Bop for landing

8. After having explored Laythe, the Laythe lander ejects the atmosphere landing kit and takes off back into LLO to dock with the mothership and refuels. Having refuelled it then makes a moon-to-moon transfer to Vall for landing

9. After refuelling the Laythe lander, mothership makes a trans-Jool injection back to Jool, performs a few aerobraking pass again to settle down into Low Jool Orbit

10. The three landers take off from Bop, Tylo and Vall and all perform trans-Jool injection back to Jool, aerobrake using the atmosphere and then dock back with the mothership

11. With the fleet reassembled mothership fires its engines for transfer home back to Kerbin

When planning a mission of this kind there are a few obvious choices:

1. You're going to want to use aerocapture/aerobraking as much as possible. So you're going to want to first use Jool to slow down and get into some kind of elliptical Jool orbit, disgorge as many lander as you can so they go off on their own (saving fuel that would otherwise be used for moon-to-moon transfer or injection burn by reusing delta-V from interplanetary transfer). Generally this means at the minimum the Tylo lander since Tylo encounter is so common.

2. Once you're slowed down a bit you probably want to head to Laythe. Going from elliptical Jool orbit to Laythe orbit is almost free since you get to aerocapture again at Laythe. Parking the mothership at Laythe instead of Jool allows you to use the mothership tanks to refuel the Laythe lander, thus making it very easy to design this particular lander for double landing. Moon-to-moon transfer from LLO is also less expensive in terms of delta-V compared to trans-moon-injection from LJO.

3. For Bop and Pol, the landing requirement is very similar as both are low gravity worlds. You can get away with a very small lander for those worlds. On the other hand you need a lot of delta-V going out to them due to their wide and inclined orbit, doubly so if you are tempted to attempt both landing with the same small lander. This then calls for a powerful nuclear tug stage with a lot of delta-V for moving that lander around. Logically you want to design it so the these two parts are two separate crafts that can be assembled together. as required. Take my Gilly lander for inspiration:

4. Tylo lander design will be critical to the mission since it's going to be by far the biggest lander. If you like me and you consider it too "gamey" to have a command chair only lander for the whole Tylo lander you could still save weight by breaking down the lander into three pieces:

• orbital module that will remain in Tylo orbit for the crew to come back, contains habitation and is only responsible for bringing the crew back to the mothership after taking off from Tylo
  
• powerful descent stage with habitation for the crew to live in while they're on the surface
  
• tiny ascent stage using command chairs that will bring the crew back
  

Rational being since the crew is only going to be in the ascent stage for a few hours at best it doesn't really need to be a pressurised spacecraft

Edited September 5, 2013 by Temstar

[sojourner]

I've just started building for my Jool Mission. I decided to go with reusable interplanetary ships and use multiple trips to build up capability. So, here's the first ship I've built so far, the Discovery (yeah, I couldn't resist), ready to make it's first expedition to the Jool system with a Station core as payload. The station core is pretty much everything in front of the cupola in these images.

Subsequent missions will add a craft for transferring between the orbits of various moons, landers, and refueling facilities at the station.

[-Velocity-]

Yea, this is my latest "carrier-tanker" ship for sending to Jool. The idea is that it carries enough spare fuel for dozens of landing operations. I have an earlier (and smaller) version of this around Laythe right now.

It consists of two separately launched segments that are connected by 4 simultaneously docked Clampatron Sr. ports. If I go any heavier though, I'll probably need to go to 6 ports.

I know the crew capacity says 29, but for realism sake, I usually only put 6-8 Kerbals in it, the rest of the room in my mind represents living space and supplies.

Edited September 5, 2013 by |Velocity|

[Monkeh]

Wow, nice one guys, I'll have a good read through all this when I get home from work.

Thank you all.

[Monkeh]

Right then, after a minor hiatus when I deleted my entire steam folder trying to install Total War Rome 2, (slightly broken game, not worth playing yet imho), and then finding the game crashing every second or third launch and putting me off playing, I am back trying to fulfill this mission objective of mine. I honestly think I may have bitten off more than I can chew here, but I shall not be deterred. At least I worked out why it was crashing all the time, (bad mod install, damn you engineer redux!), and fixed it so I can play without having to reload the game every 5 minutes...YAY.

So I thought maybe a double lander transporter thing might be useful. I shall need some other design for Laythe and Vall I feel as I doubt they'll be much good in highish gravity, but it's a start.

The rovers I made for them are really nice, they can drive up steep slopes easily and had some fun at the KSC riding round those humps like a wheel of death motorbike! They can also pull doughnuts they're so stable.

So this is the base for the mission I think, I'll need a second launch to get the Laythe and Vall landings, so maybe I also need to assemble a station around Jool...yeah, this is some challenge for a noob like me, but I'm not going to give up. Trying to think my way through all this is an awesome challenge. I'll keep you updated...not that anyone cares, but it gives me something to do in work when I'm bored.

Edited September 10, 2013 by Monkeh