Difference between revisions of "Laythe"

Revision as of 22:42, 3 May 2015

Laythe
Laythe as seen from orbit.
Moon of Jool
Orbital Characteristics
Semi-major axis		27 184 000 m [Note 1]
Apoapsis		27 184 000 m [Note 1]
Periapsis		27 184 000 m [Note 1]
Orbital eccentricity		0
Orbital inclination		0 °
Argument of periapsis		0 °
Longitude of the ascending node		0 °
Mean anomaly		3.14 rad (at 0s UT)
Sidereal orbital period		52 981 s
		2 d 2 h 43 m 0.9 s
Synodic orbital period		53 007.7 s
Orbital velocity		3 224 m/s
Longest time eclipsed		3 754 s
Physical Characteristics
Equatorial radius		500 000 m
Equatorial circumference		3 141 593 m
Surface area		3.1415927×1012 m2
Mass		2.9397311×1022 kg
Standard gravitational parameter		1.9620000×1012 m3/s2
Density		56 144.728 kg/m3
Surface gravity		7.85 m/s2 (0.8 g)
Escape velocity		2 801.43 m/s
Sidereal rotation period		52 980.879 s
		2 d 2 h 43 m 0.9 s
Sidereal rotational velocity		59.297 m/s
Synchronous orbit		4 686.32 km
Sphere of influence		3 723 645.8 m [Note 1]
Atmospheric Characteristics
Atmosphere present		Yes
Atmospheric pressure		60.7950 kPa
		0.6 atm
Atmospheric height		50 000 m
		6.0×10-7 atm
Temperaturemin		-74.15 °C 199 K
Temperaturemax		3.85 °C 277 K
Oxygen present		Yes
Scientific multiplier
Surface		14
Splashed		12
Lower atmosphere		11
Upper atmosphere		10
Near space		9
Outer space		8
Recovery		8
↑ 1.0 1.1 1.2 1.3 The distances are given from the body's center, not from the surface (unlike ingame)

Laythe is the first of the five natural satellites of Jool. Although mostly covered in seas, Laythe has numerous rocky, sandy islands. Laythe is tidally locked to Jool. Synchronous orbits around Laythe are not possible, as they would lie outside of its SOI, at a radius of 5,186,399 meters. A circular archipelago prominent in surface maps of the moon suggests that Laythe suffered a massive impact in its distant past.

Achieving a stable orbit around Laythe from sea level requires a delta-V of ≈2800 m/s.

Laythe has no real-world analogue. In the real-world Jupiter system, the moons Ganymede, Europa and Io form a group with an orbital resonance just like KSP's Tylo, Vall and Laythe. But while Tylo and Vall have a certain resemblance to their real-life counterparts, Laythe is very unlike the volcanic, atmosphere-less, dry Io. Instead, the presence of a liquid ocean - plus a dense atmosphere - makes Laythe more similar to the Saturnian moon, Titan. Laythe also seems very similar to what happened to Europa in 2010: Odyssey Two.

Although Laythe has liquid water on its surface, the temperature there is below zero degrees Celsius. This means that Laythe's oceans must contain another compound, most likely ionic, such as salt. Surface samples indicate that much salt is present on Laythe's surface. Unlike that of Kerbin, the air cannot be breathed by Kerbals (according to EVA reports). It is therefore possible that there are also high concentrations of salt in the air, as well as on the surface, assuming that the salt is sodium chloride. The apparent toxicity of Laythe's atmosphere, despite being similar in composition to Kerbin's, may also be a reference to the film Avatar - the moon Pandora is very similar to Earth, but its atmosphere is too toxic for humans to inhale, and the moon also orbits a gas giant, like Laythe.

According to former developer NovaSilisko, Laythe was planned to have volcanic, probably cryovolcanic, activity and high radiation levels in later versions, making it a much more hostile moon than in 0.23.^[1][2]

In-game Description

Biomes

Laythe has 4 biomes. Laythe exists of a huge ocean, called The Sagen Sea, with some small Dunes and Shores biomes. It also has a Poles biome. There is also a rumour of a biome called "Cresent Bay", but as of 0.90, until proven otherwise, it's not reachable.

Biome list

Laythe In-game biome map as of 1.2

Poles Shores Dunes The Sagen Sea

Atmosphere

Laythe's atmosphere begins at 50,000 meters and is 40% thinner than Kerbin's. It is the only moon in the game which has an atmosphere.

Like all other atmospheres in the game, Laythe's atmosphere fades exponentially with increasing altitude (with a scale height of 4000 m). In general, the atmospheric pressure on Laythe at an altitude expressed in meters is:^[3]

${\displaystyle p_{l}=0.8\ e^{-altitude/4000}}$

With proper aerobraking near Laythe and Jool, reaching Laythe may require the least delta-V of all of Jool's moons. When approaching Jool on a Hohmann transfer orbit from Kerbin, aerobraking with a Jool periapsis of 119.5 km will put your apoapsis roughly near Laythe's orbit.

Another way is to approach Laythe directly, utilizing proper timing and making orbital adjustments on the way to Jool. Laythe's orbital period makes it an easy target to time and will have required less delta-v on arrival (only 2000 m/s). As such, aerobraking on Laythe is less extreme than on Jool.

Landing on higher points of Laythe's surface has to be done with the help of retro-burns, as parachutes alone will not suffice to sufficiently lower a craft's velocity for landing.

Jet engines work in Laythe's atmosphere due to the presence of oxygen. However, the air-intake efficiency is lower there.

Most of Laythe's surface is ocean. There are many craters on its surface, and some of the largest features it has may be related to impacts. Other features on the surface, such as small canyons, may have been carved out by flowing water that either came up through the surface or fell as rain when the planet was warmer.

Science

Laythe is the most science-rich body in the Joolean moon system. Even though Tylo has a slightly higher science multiplier for both surface and orbit, Laythe's atmosphere and oceans allow a lot more experiments to be performed, which means the total science output is higher.

Reference Frames

Gallery

• 

  A large user-created probe in low orbit around Laythe.

• 

  A probe on the surface of Laythe.

• 

  A topographic map of Laythe made with ISA MapSat.

• 

  A grayscale bump map normalized at sea level.

• 

  A color map of Laythe

• 

  Vall as seen on Laythe

• 

  Tylo as seen on Laythe

• 

  Bop as seen on Laythe

• 

  Laythe transfer plan

• 

  A topographic height map of Laythe as at Version 0.18.2 made with the ISA MapSat plugin

• 

  Laythe's northern ice cap, with the Sun, Vall, and Tylo.

• 

  User-created jet flying in Laythe's atmosphere.

• 

  User-created jet space plane on re-entry to Laythe.

• 

  A direct approach to Laythe.

• 

  A spaceplane escaping from Laythe.

• 

  A spaceplane flying into the sunset high above Laythe.

• 

  A modular, mobile base being set up at Laythe

Changes

1.0

• Atmosphere reduced

0.90

• Added biomes

0.17

• Initial Release

Notes

1. ↑ Forumpost from NovaSilisko
2. ↑ Post from NovaSilisko
3. ↑ A LV-N Atomic Rocket Motor has a specific impulse of 220 in 1 atm, 800 in vacuum, and the following at various Laythe altitudes:

   altitude (m)	600	1464	1800	2238	2698	3296	4104	16435
   specific impulse	400.7	478.2	504.2	534.8	563.7	596.5	633.7	792.4

v t e Kerbol System Kerbol Moho Eve Kerbin Duna Dres Jool Eeloo (The Sun)   Gilly Mun Minmus Ike   Laythe Vall Tylo Bop Pol