Difference between revisions of "Gilly"

Revision as of 21:32, 2 September 2015

Gilly
Gilly as seen from orbit.
Moon of Eve
Orbital Characteristics
Semi-major axis		31 500 000 m [Note 1]
Apoapsis		48 825 000 m [Note 1]
Periapsis		14 175 000 m [Note 1]
Orbital eccentricity		0.55
Orbital inclination		12 °
Argument of periapsis		10 °
Longitude of the ascending node		80 °
Mean anomaly		0.9 rad (at 0s UT)
Sidereal orbital period		388 587 s
		17 d 5 h 56 m 27.4 s
Synodic orbital period		417 243.4 s
Orbital velocity		274 - 945 m/s
Longest time eclipsed		5 102 s
Physical Characteristics
Equatorial radius		13 000 m
Equatorial circumference		81 681 m
Surface area		2.1237166×109 m2
Mass		1.2420363×1017 kg
Standard gravitational parameter		8 289 449.8 m3/s2
Density		13 496.328 kg/m3
Surface gravity		0.049 m/s2 (0.005 g)
Escape velocity		35.71 m/s
Sidereal rotation period		28 255.000 s
		1 d 1 h 50 m 55 s
Sidereal rotational velocity		2.8909 m/s
Synchronous orbit		42.14 km
Sphere of influence		126 123.27 m [Note 1]
Atmospheric Characteristics
Atmosphere present		No
Scientific multiplier
Surface		9
Splashed		N/A
Near space		8
Outer space		6
Recovery		6
↑ 1.0 1.1 1.2 1.3 The distances are given from the body's center, not from the surface (unlike ingame)

Gilly is a tiny asteroid, the only natural satellite of Eve, and the smallest celestial body in the Kerbol system.

In-game Description

Topography

A topographic map of Gilly.

Gilly's color might come from a high content of solid carbon. When terrain scatters are enabled in the settings menu, small rocks show up on the surface.

Biomes

With only 3 biomes Gilly has the fewest number of biomes in the Kerbol System.

Biome list

Gilly biome map as of 0.90.0

Gilly In-game biome map as of 1.2

Lowlands Midlands Highlands

Gravity

Gilly has the least gravity of all bodies in the Kerbol system at only 0.5% of Kerbin's surface gravity, which is half that of Jool's moon Pol. It is very impractical to walk on Gilly; each step will launch a Kerbal several meters into the air. A Kerbal can jump over 1000 meters on this moon and will usually take around 200 seconds to return to the surface. This makes jetpacks a necessity to move around the moon practically.

The low gravity also makes it very difficult to get into an encounter since it makes the sphere of influence so minuscule. An unplanned encounter with Gilly is unlikely when approaching Eve, even if the craft's trajectory is near the plane of Gilly's orbit. Gilly's mass is very small relative to Eve's mass, resulting in a very small sphere of influence compared to the semi-major axis of its orbit. In fact, no other moon in the game has a smaller mass ratio.

Gilly's gravity makes it ideal for very low fuel interplanetary missions; however, its eccentric and inclined orbit may make encounters more difficult and fuel-costly.

Landing

Landing on Gilly is challenging due to its very low mass, steep slopes, and highly eccentric orbit, making it very easy to overthrust engines or send a spacecraft tumbling. Gilly's odd shape and fast rotation give the surface near the peaks an apparent velocity near 5 m/s. Some players advise to keep the prograde on the navball tilted a little bit sideways to counter the Coriolis effect if you are landing close to the equator. To prevent tumbling upon landing, the final velocity trim may need to be performed by eye. It is advised to be adept in manually using RCS thrusters and to have SAS active on the lander.

Gilly was once even more dangerous to land on due to a clipping bug with the collision mesh. This problem was fixed in version 0.17.1.

Escaping Gilly is much easier — the EVA jetpack can easily put a lone Kerbal into orbit or set him on an escape trajectory. In fact, it's possible to deploy a Kerbal from a spacecraft in orbit around Gilly, send him down to the surface, and land him without using any other fuel source. Albeit with some difficulty due to the lack of a navball, the Kerbal can even return to orbit, rendezvous with the spacecraft, and still have just a bit less than 50% pack fuel left.

Reference Frames

Gilly/RefFrames

Gallery

• 

  An unsuccessful touchdown attempt in 0.17. Note the landing legs clipping through terrain.

• 

  Topographical image of Gilly.

• 

  A successful EVA landing.

• 

  A topographic height map of Gilly as of Version 0.18.2. Made with the ISA MapSat plugin.

• 

  A successful probe landing. Small rocks are visible on the surface in the background.

• 

  A successful scientific, electrically powered probe landed on Gilly. The probe's small mass combined with Gilly's low gravity makes ionic engines feasible, as shown here.

• 

  Successful EVA landing with a fuel check to show usage.

• 

  Return to Gilly orbit and the spacecraft via EVA.

• 

  A successful, if rushed, rendezvous with the orbiting spacecraft with just an EVA pack and some luck.

• 

  If done right, one could probably land, take off, and rendezvous with an orbiting spacecraft with over 3 units of EVApropellant.

Changes

0.90

• Added biomes

0.17.1

• Fixed terrain collision detection issues.

0.17

• Initial Release

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