The desert moon, also referred to as "31U00W," is the main location visited by Taylor in the game Lifeline. It is also featured in the sneak peak for Lifeline: Silent Night.
Its official name is 31U00W, and it is located in the Tau Ceti system. It is sarcastically dubbed "Jeff" by Viridian Wing Commander Melanie Chior in the Lifeline:Silent Night sneak peak.
31U00W houses The Green, on its surface and below the crust. Is it uncertain how long they have been there, or if they evolved on the moon itself.
31U00W is made entirely of deserts and is dotted with many canyons and craters.
Its atmosphere is breathable by humans and consists of mainly nitrogen with enough oxygen to be comfortable for the normal person to breath. Its climate seems relatively temperate during the days, but at night the temperature can plummet to the point that Taylor can die from hypothermia if left open to the elements at night.
In the section visited by Taylor in the duration of Lifeline, there are no major geological features except for The Peak and the large crater. The section also contains many spaceship wrecks caused by The Peak and The Green Lifeforms.
It seems understandable to assume there are no other beings living on the moon apart from The Green the Lifeforms and the occasional human survivor.
If Taylor escapes or dies after The Peak climax, the landscape of the moon will become cracked and huge fissures will have opened up due to the Lifeforms bursting out of the ground. The ground also becomes less stable, causing earthquakes and the continuing aftershocks from the massive seismic activity featured in the climax.
31U00W is first introduced in the beginning of the game alongside Taylor, as the central location of the game. Taylor becomes stranded on the moon when the Varia crashes onto its surface. Taylor spends their time trekking across the moon's surface and exploring the various spaceship wrecks on its surface. As the game progresses Taylor can succumb to the elements of the moon or from being ill prepared for the length of journey across its surface.
At the climax of the game Taylor visits the moon's most distinguishing feature, The Peak. At this point, the land will become cracked and
Throughout the game the moon houses the Green Lifeforms. They live mainly underneath the surface of the moon, focused under The Peak. Is is unspecified whether 31U00W is the birthplace of the Lifeforms or rather a temporary residence.
Taylor can die from hypothermia due to elements or from unpreparedness for the long trek across the vast deserts.