(OLD) The Ultimate Jool-5 Challenge:land Kerbals on all moons and return in one big mission

[SSSPutnik]

Decided nukes are useless for landing on Tylo, not enough TWR. Unsure how others managed it, especially from an 8km orbit without smashing into a mountain at 1000ms.

[Kasuha]

Decided nukes are useless for landing on Tylo, not enough TWR. Unsure how others managed it, especially from an 8km orbit without smashing into a mountain at 1000ms.

Nukes are definitely not useless for Tylo landing, it's just matter of using the right design. But I agree it's easier to build the lander using other engines.

Landing on Tylo from 8 km orbit is easy if you use

. Edited January 30, 2014 by Kasuha

[SSSPutnik]

That vid starts with horizontal velocity of only 500ms.

I don't see how you can start at 8 as about 6-7 you run the risk of hitting a mountain?

I guess if you picked a nice level area... But seems to me hell of a lot easier with rockets....

Dropping from orbital velocity to 1000ms means you've travelled about a third of the circumference almost.

Open to tips here. I really want to land a two man capsule.

Edited January 30, 2014 by SSSPutnik

[Mesklin]

Nukes are definitely not useless for Tylo landing, it's just matter of using the right design. But I agree it's easier to build the lander using other engines.

Landing on Tylo from 8 km orbit is easy if you use

.

I agreed with it, for nukes you should make lander as light as possible and use horizontal landing as described in video. But for Tylo, IMHO, only horizontal landing is optimal, vertical descend with constant speed is too costly on Tylo. And agreed with chemical engines and big TWR (>1.5 on start) landing on Tylo much more comfortable and easy.

[SSSPutnik]

I don't get the horizontal landing though, after I drop about 3-4 km, you get WHOOP WHOOP, Pull up, terrain. And bam.... (Tried it a few times). If it was flat...

[Mesklin]

Key words for it is training: try horizontal landing with high TWR craft first, you can save yourself more easy in case of sudden approach of surface. In any case you will take fuel economy for horizontal landing and for high TWR craft. And do not make vertical speed to big (maximum 20-30 m/s for Tylo for low TWR craft), plus watch surface ahead of craft, if you see mountains, try to make positive vertical speed to avoid collision. In my last Jool-5 mission at the end of landing I was very close to sudden disassembling, I fled on hight about 200 m with horizontal speed ~500 m/s on the top of small hill (vertical speed was ~+40 m/s at this moment). It was cool, but Bill was not very happy .

[Kasuha]

I don't get the horizontal landing though, after I drop about 3-4 km, you get WHOOP WHOOP, Pull up, terrain. And bam.... (Tried it a few times). If it was flat...

The point is, you don't burn retrograde. You burn above retrograde to keep your vertical velocity low and increase the angle as your horizontal speed (and centrifugal force) decreases. That way your height doesn't change much while you clear your horizontal speed. And when your horizontal speed is low enough, you land "normally".

[SSSPutnik]

So, you're basically hovering, what sort of deltav does that need? I guess overall Deltav is reduced due to your already low altitude. I get it now. Obvious now you mention it.

[Kasuha]

So, you're basically hovering, what sort of deltav does that need? I guess overall Deltav is reduced due to your already low altitude. I get it now. Obvious now you mention it.

You're hovering, but not much. The angle is usually rather steep. When you get to 45 degrees you're practically done (your horizontal speed is below 100 m/s) and at that angle still only 30% of your thrust is "wasted" as 70% still goes to clearing your horizontal speed. But it depends on your TWR. The lower it is, the more you need to spend on hovering. The higher, the less.

[Vaebn]

Nope, mine ended up parked at end of mission too.

I play a lot that way too. If you use 3DS, don't suppose you could make a crew cab with internal cryosleep capsule that can be manned then gotten out of?

You mean, if I want one, or do you want one? Haven't really poked with modding in KSP at all but I could take a look at it.

Do you mean something that is going to be barely bigger than a command-seat, with a structure over it, to basically excuse chairlanders? This sounds quite easy.

Or do you mean something you can see in the IVA view? This sounds quite a bit harder. Even if you could see a different Kerbal inside the same thing, like in the hitch-hiker module, I have no idea how you'd tell the game to "freeze" the animations. So at most it would look (if you could look at it), like a Kerbal peaking out of a window.

[Space Viking]

For the third time I've decided redoing this challenge on Jebediah's level. This time I will try to keep documentations better structured along with information on delta-V used during the mission.

- My game version is 0.23

- No mods is going to be used during the mission. I did however use MechJeb as a helping tool during the design phase.

- It will be a single launch mission.

- No refueling.

- There will be a Hitch-hiker's Storage installed on the space ship.

- There's an additional orbital Jool satellite along with a kamikaze probe. Each lander module's descent stage is also a scientific probe that will remain on the surface.

The MK 1-2 Command Pod itself will now be a modular spacecraft that can be attached to each lander module. So this time each landing will feature three kerbals instead of one.

Also – despite the supposed budget cuts it's pretty funny how my version of the mission has afforded over 400 tons worth of initial payload. If that's cheap enough for them, then I can't even barely imagine Vun Braun's "The Jool Project" must have been like.

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Nevertheless, the asparagus staged booster's simultaneous thrust of 32 Mainsails and 9 Skippers was designed to be atleast reasonably efficient.

[Jasonden]

Nukes are definitely not useless for Tylo landing, it's just matter of using the right design.

Or the right approach. I just landed on Tylo entirely with nukes, and starting TWR of only 1.2 (up to 1.7 or so by touchdown). Started in a 16x64km orbit, began burning at apoapsis as kept braking almost all the way down. Wasn't *too* bad on dV -- not significantly worse than usual Tylo anyway...

[SSSPutnik]

Craft file?

[Kasuha]

Or the right approach. I just landed on Tylo entirely with nukes, and starting TWR of only 1.2 (up to 1.7 or so by touchdown). Started in a 16x64km orbit, began burning at apoapsis as kept braking almost all the way down. Wasn't *too* bad on dV -- not significantly worse than usual Tylo anyway...

I would definitely recommend starting the burn at periapsis. Even with "hovering" you spend less fuel for that than for landing from higher point. Some time ago when I got some really weak lander for Tylo I did exactly that and it allowed me to return to orbit with remaining fuel. Doing so from its initial 50 km orbit was with no chances.

[zeppelinmage]

Set aside some time tonight to get working on this challenge. Finally beginning my 42-minute ejection burn from Kerbin.

[SSSPutnik]

Looks good! Good luck. Nice stubby design.

[zeppelinmage]

Thanks.

Still burning 2 hours later, btw. lol. Had to F9 once, and then had to do two burns as I couldn't get far enough from periapsis to get a good burn time without impacting Kerbin.

Lessons learned (so far):

* Moar SAS

* 85km is way too close for such long burns

* Moar monoprop

* 6x LV-N is the bare minimum. (I can't believe I even considered 3x!)

Edited February 1, 2014 by zeppelinmage

[zeppelinmage]

Also... laaaaaaaag...

I started an 18-minute burn... half an hour ago. And it still says I have 12 minutes left. Gah!

[SSSPutnik]

Yeah, long burns like that, you need to be at about 90km or higher.

Also, due to the long burn, low thrust, it's better to do shorter burns over multiple orbits, slowly increasing periapsis each time. It seems to use more fuel otherwise too as much of burn isn't done from near apoapsis.

Suggest you use more SAS than mono. You should only really carry mono for landers and emergencies.

[zeppelinmage]

You should only really carry mono for landers and emergencies.

That was the intention; I only loaded mono on my landers. But because my single SAS module isn't strong enough, I was forced to use mono to move the ship around. I have 12 units left, and I'm not even out of Kerbin SOI yet.

[SSSPutnik]

You should be able to use SAS even if it is slow.. Or use the engines on low power to assist, they have a small gimbal...

[zeppelinmage]

Yeah, I figured out what my problem was... the SAS modules (probe cores) on the radially-mounted landers were countering the action from the main module. I disabled them, and the ship moves now. Slowly, but it moves.

[SSSPutnik]

Yes, gotta watch SAS units, I had them on my dump tanks, was causing wobble till I turned them off, they were dumped pretty quick anyway.

[jacobgong]

500 tone Jeb level with most science run. Currently 500m/s short from returning home, gotta launch a 10t rescue pack to get the back.

[SSSPutnik]

Using LLL engines?