Isis

Isis is the primary moon of Osiris - a large ringed 'gas giant' planet. Isis
is 4,635km in diameter, with a rocky surface composed mainly of silicates and
some large areas of ice at the poles.

The surface gravity of Isis is 0.8g due to a very dense iron core, the origin
of which is currently still a matter of debate. This gravity is enough to
support a very light atmosphere of 70% carbon dioxide, 20% methane and 9%
ammonia, with traces of oxygen, hydrogen and helium. This atmosphere is most
certainly not breathable.

The first person to set foot on Isis was John Sernam, fifty years ago. Since
then, robot construction methods have fabricated a space terminus[0] and
biodome[1] that are inhabitable by humans.