Laythe mission questions.

[ArmchairPhysicist]

At the moment I'm building a mega class rocket to put a K&K based space center on laythe. I've never been to laythe before and have only visited the hook system once. Is there anything strange about laythe that I should know? 

I know it has an atmosphere, but how thick is it? 

Whats the gravity like?

etc etc

[Snark]

Moving to Gameplay Questions.

39 minutes ago, ArmchairPhysicist said:

Is there anything strange about laythe that I should know? 

I know it has an atmosphere, but how thick is it? 

Whats the gravity like?

Laythe is a pretty close analog to Kerbin.  The wiki page will answer a lot of your questions, but to summarize:

• Surface gravity is 80% of Kerbin's.
• It's slightly smaller than Kerbin, 500 km radius (compared with Kerbin's 600).
• The air has oxygen, so you can fly jet engines there.
• The air is slightly thinner than Kerbin's.  60% of Kerbin's sea-level pressure, 50 km high.

So you can fly planes there pretty much like on Kerbin.  Need slightly more wing for landing/takeoff, but only slightly.  Significantly easier to escape from, and reentry heating is a bit kinder.

And it's water, water everywhere. 

[ArmchairPhysicist]

It's a good thing my ship was fully self sufficient (besides the blueprints needed from HQ) because this laythe colony just splashed down hard. The lander snapped in half, broke my science stuff and gave me a lot of paperwork. This just turned into a survival movie. 22 kerbals stranded on a water world with no way home. 

Gotta try to build them a boat to get to the nearest island, great.

[nascarlaser1]

2 minutes ago, ArmchairPhysicist said:

It's a good thing my ship was fully self sufficient (besides the blueprints needed from HQ) because this laythe colony just splashed down hard. The lander snapped in half, broke my science stuff and gave me a lot of paperwork. This just turned into a survival movie. 22 kerbals stranded on a water world with no way home. 

Gotta try to build them a boat to get to the nearest island, great.

If you can build a seaplane you could land the seaplane nearby, load em up and then just fly back to the island or even to a return ship if the plane is capable of orbit and has a docking port on it.

[ArmchairPhysicist]

I just did a little save reverting.

[Greenfire32]

14 minutes ago, ArmchairPhysicist said:

It's a good thing my ship was fully self sufficient (besides the blueprints needed from HQ) because this laythe colony just splashed down hard. The lander snapped in half, broke my science stuff and gave me a lot of paperwork. This just turned into a survival movie. 22 kerbals stranded on a water world with no way home. 

Gotta try to build them a boat to get to the nearest island, great.

The suspense!

6 minutes ago, ArmchairPhysicist said:

I just did a little save reverting.

dang it....

[ArmchairPhysicist]

One of these days I'll have a career mode with permadeath. But not today

[Bill Phil]

56 minutes ago, Snark said:

Moving to Gameplay Questions.

Laythe is a pretty close analog to Kerbin.  The wiki page will answer a lot of your questions, but to summarize:

• Surface gravity is 80% of Kerbin's.
• It's slightly smaller than Kerbin, 500 km radius (compared with Kerbin's 600).
• The air has oxygen, so you can fly jet engines there.
• The air is slightly thinner than Kerbin's.  60% of Kerbin's sea-level pressure, 50 km high.

So you can fly planes there pretty much like on Kerbin.  Need slightly more wing for landing/takeoff, but only slightly.  Significantly easier to escape from, and reentry heating is a bit kinder.

This.

Getting there isn't all that hard. You have a lot of options. Aerocapture with Jool, gravity assist with Tylo or even Laythe. Aerocapture with Laythe... Trouble with Laythe is the lack of land. There is some, but a lot of it is sloped. And landing there isn't always easy, but if you can use jets it should be much less of an issue.

1 hour ago, Snark said:

And it's water, water everywhere. 

And not a drop to drink?

[Snark]

2 minutes ago, Bill Phil said:

assist with Tylo or even Laythe

^ This.  A properly executed reverse gravity assist with one of these heavy moons can shave quite a bit off the dV requirements; basically, you get a free capture to the Jool system.

3 minutes ago, Bill Phil said:

Aerocapture with Laythe

^ This, much preferable to using Jool itself (at least, it is for me).  First, you hit atmosphere going a whole lot slower with Laythe than Jool, for a couple of reasons:  you're not diving so deep into Jool's massive gravity well, and also Laythe is orbiting Jool in the same direction you are, which shaves off some more speed.  Second, an aerocapture to Jool has an inconveniently low Pe, requiring either fuel expenditure or a high-speed aerocapture to Laythe to follow.

5 minutes ago, Bill Phil said:

And not a drop to drink?

Nor any drop to drink.  Get yer quotes right. 

[Ripper2900]

Laythe's atmosphere is smaller than Kerbin's, but it is only thinner in the low parts! Above a couple of thousand meters, it's actually thicker! And it gets thicker much faster than Kerbin's, when you enter from space. 

Jet engine flight is thus possible much higher than on kerbin, and aerobraking is easier/quicker, dependant on how you look at it... 

You do need bigger wings or more parachutes for the final descent though. 

Good luck. 

[Wanderfound]

General tips: it's very Kerbin-ish, but a bit smaller. So the gravity is less and the atmosphere is thinner. This means that you need to set your aerobraking altitudes a fair bit lower than you would on Kerbin, and the thin air raises aircraft stall speeds and lowers parachute effectiveness. A sea-level landing on Laythe is like a high-altitude landing on Kerbin.

If you're going to Laythe, it really is worth it to take a seaplane. It's the best way to get around out there.

To do that, you've got two options. Either a short range seaplane with a rocket to push it to Laythe (as shown above) or a big self-sufficient Nuke/ISRU-equipped  jobbie that can do it all in one (as seen below).

Edited July 19, 2017 by Wanderfound

[bigcalm]

Laythe sea-level air pressure is about the same as Kerbin at 3000m.  So if you want to test a plane or parachute system before you go, go and land on a mountain at Kerbin and see if you survive.

Laythe is almost all sea, with a few small islands.  Landing without wings or aerodynamics on your vessel(s) on actual land is going to be tricky and you may well end up in the drink if you're not careful.  The parts of Laythe that are land tend to be pretty darned hilly.  Again, go and land on a mountain at Kerbin - hilly terrain is what you'll get on Laythe - and practice makes perfect.

SSTO planes will work better on Laythe than on Kerbin.  Essentially, if you can build an SSTO plane that works for Kerbin, it'll easily work for Laythe.  However, do note the requirement for being able to land safely and successfully at 3000m altitude on Kerbin.

I am currently sending a USI base to Laythe, but I've made all the separate bits a winged vessel that can fly in an oxygenated atmosphere and survive re-entry into Kerbin's atmosphere (ignoring interplanetary pushers that will get thrown away).  Including a EPL runway that will allow me to build more stuff when I'm there, I think the vessels I'm sending are some of the craziest I've ever designed, but they're all well tested and should make it.

 

 

[OhioBob]

On ‎7‎/‎17‎/‎2017 at 5:25 PM, ArmchairPhysicist said:

... this laythe colony just splashed down hard. The lander snapped in half ...

That's unfortunate.  Terminal velocity is higher on Laythe than Kerbin, so you have to take this into account in your designs.  Generally speaking, you need about 30% more parachute on Laythe to have the same impact velocity that you have on Kerbin.  (Because air density varies with temperature, the actual percentage depends on when and where you land.)  So if you have a design that works on Kerbin, add about 30% more parachute and you should be good.  For example, if experiments show you can land safely on Kerbin with three parachutes, use four.