Going to Laythe

[Jebediah Kerman Jr.]

I need help with going to Laythe.

Can anyone help me?

Edited November 19, 2018 by Jebediah Kerman Jr.

[bewing]

Sure we can, but you're going to have to be more specific than that.

So, what happens when you try? Is this a problem with finding the window, doing the transfer burn, doing the midcourse correction, gravity assists, aerobraking, or a problem with your craft?

 

[Jebediah Kerman Jr.]

I got everything down but the craft design. About three weeks ago I sent Valentina to Pol. My rocket was quite overkill, being able to come back to Kerbin with no aerobraking. I could make a capture burn at Kerbin Pe. This might be the basis for a one-Kerbal manned mission to the seas of Laythe. However, I have been using my Brutus class VTOL SSTO rockets to build a four-module craft in LKO.

Modules:

#1) Command module with space for three Kerbals, and 8 MK1 liquid fuel fuselages

#2) 8 more liquid fuel fuselages

#3) Three Nerv atomic rocket motors and a single Rockomax X200-8 fuel tank with oxidizer drained

#4) Lander (still being designed)

The two main problems I have include:

I cannot for the life of me figure out how to build a Laythe lander.

I don't know if the ship I'm constructing will be able to reach Laythe with a heavy lander attached.

I also don't know if my lander should be a seaplane, a spaceplane, or just a generic land lander.

The spaceplane/seaplane design would have a higher range for more science, but those wings would be dead weight on the way to Laythe, reducing ΔV.

What do you think? Should I first send an orbit-only mission like Apollo 8? I'm pretty sure the mothership has enough ΔV for an orbital mission.

If I should send the orbiter/lander combo, can anyone help me with the lander design?

[bewing]

Several points:

I prefer to always design for a single kerbal scientist + experiments as payload. Increasing the kerbal count has no benefits except for artificially increasing the difficulty level.

Laythe is almost entirely water, so I find a pure LF seaplane SSTO is the most useful there. If you're willing to clip, I'd go for a single nuke/single panther design (with my single kerbal/MK1 format).

A Laythe spaceplane is too different from a Kerbin spaceplane to expect the thing to SSTO from Kerbin's surface. I find it much better to put the Laythe plane on top of a kickback or two, in order to get it to orbit. Then refuel, then send it to Laythe. Refuel it again, land it. Fly around a bit. Fly it back to orbit, refuel it again, and send it back to Kerbin.

The jet engines and wings are not enough deadweight to make a significant difference to your flight plan. The wings mean you need almost zero fuel and no parachutes to go from your Laythe parking orbit to "landed". So the wings completely pay for themselves.

19 hours ago, Jebediah Kerman Jr. said:

I don't know if the ship I'm constructing will be able to reach Laythe with a heavy lander attached.

Anything that can launch from the surface of Kerbin to orbit can go anywhere in the system except Moho, if you refuel it in orbit.

 

Edited November 20, 2018 by bewing

[Guest]

Ooh Laythe, my favourite body in the entire system.

Go with a plane, the place is built for them -- they fly there better than on Kerbin. I have to differ with @bewing a little here: I' recommend you just make a regular Kerbin SSTO, fly it up to orbit, refuel. It will fly to Laythe under its own fuel. No need for nukes, just RAPIERs as usual. Whether you make it a seaplane or regular lane is up to you. (Or, why not make it amphibious? You might even find that your regular plane is able to also function as a seaplane with no changes -- happened to me.) 

I always do my missions in stages -- first go to orbit, establish a comm network, and survey the body to find a suitable site for a base, if necessary send down a few probes to finalise the base site. Then send down the base core -- drill + ISRU. Then the rest of the base. Then play with my new toys. 

If you just want to do a round trip, you'll probably want to have a separate, minimalistic return capsule -- no point hauling those heavy engines and wings and what have you all the way back from Jool. (Although I did that once, because I wanted to -- had to refuel at my Duna base on the way back though.)

Other tips --

• Consider establishing a permanent presence. Whatever you send out there, stays out there, only kerbals and science come back. If you were able to build a craft that can do a round-trip with no Kerbin aerobraking, you will have no problems hauling up the extra weight of a plane, and it's a one-time expense only. Set up a surface base with an ISRU and you'll be able to operate in the entire Jolian system, and beyond.
• Gravity pinball FTW. You can get into Laythe orbit from a Hohmann transfer from Kerbin with a couple of hundred m/s expense only. Gravity brake off Tylo, then aerobrake off Laythe. (In theory you can get similar savings on the way back, but when I attempted it, it was beyond my capabilities as an orbital mechanic -- I could get ejected out of the Jolian system really cheaply really fast, but I was headed anywhere except where I wanted to).

 

[AeroGav]

I'd take a bit from @Brikoleur and @bewing

I'd launch like an airplane from Kerbin,  refuel in Kerbin SOI,  but i would put nukes on the thing,  in fact i'd make it oxidizer-free because if you're building around low drag mark 1 parts you can very easily get to orbit from Laythe with Panthers and nukes only.   Nuke only works best with a nuke TWR of 0.3 to 0.6 to 1 - this works fine so long as you can build an airplane that actually flies like one, with more lift than drag.  Too many Kerbal airplanes look like airplanes but are really rockets, they have more drag than lift and only fly because KSP jet engines are overpowered and give you TWR of 2 to 1 or better.

The seaplane aspect makes things harder, you need a good TWR to break free of the surface or you need to get lucky with hydrofoil design - perhaps you're best off with Panthers as your jet engines for this reason (highest twr at sea level and low speed).    If you're going with the refuelling approach,  use an inline clamp o tron instead of a shielded docking port (much less drag).   On the other hand, all that docking and refuelling is going to be a PITA,  especially in the Laythe system.   You could refuel in Laythe orbit,  doing so on the surface is really hard and annoying (ever tried ground docking two vehicles that are being  influenced by gravity, terrain and landing gear legs ? very hit or miss)

So you could just put a small IRSU on the airplane,  4 RTGs to power it, one small drill,  one small deployable radiator , the smallest ore tank, and bring an engineer with you (should come in under 1.5t for that stuff,  put the drill and ore tank and RTGs inside the 1.25m fairing on your nose)

 

If this contraption lacks the umph to get to Minmus from Kerbin, consider fitting droppable booster engines on pods under the wings like this thing 

https://kerbalx.com/AeroGav/Kranker
or this 

Spoiler

 

I also wrote a guide on Panther NERV ssto for career mode,

though as you're not stuck to tier 7 techs i'd swap all the Modular wing parts for Big S wings and Big S Stakes,  this will enable you to get rid of most of the cylindrical tanks ( big s wings have better capacity to drag ratio than cylindrical tanks, should always be used where possible on a spaceplane)