what is Cislunar?

Answer 1

You may remember from your schooldays Julius Caesar's historical account of his military campaigns in Gaul, De Bello Gallico and its famous first line "All Gaul is divided into three parts"

Two of those parts were cis-Alpine Gaul and trans-Alpine Gaul, From Rome's point of view everything the Italian side of the Alps was cis-Alpine, and everything beyond the Alps trans-Alpine.

So the prefix cis- means "everything up to but not including" and the prefix trans- means "everything beyond but not including".

Trans- is used more frequently and is more familiar as a result. e.g. Trans-Uranic elements: the unstable radioactive elements beyond Uranium, starting with Neptunium, element no 93.

Answer 2

Cislunar space (alternatively, cis-lunar space) is the volume within the Moon's orbit, or a sphere formed by rotating that orbit. Volumes within that such as low earth orbit (LEO) are distinguished by other names. Practically, cislunar space is a useful label for "the volume between geostationary orbit and the moon's orbit".

Beyond cislunar space lies translunar space.

Cis-lunar is Latin for "on this side of the moon" but also "not beyond the moon". Therefore, one might regard the Lagrange points L4 and L5, the stable regions of the Moon's Trojan points, as cislunar, but in practice they are so interesting as to be likely to be talked about in their own

Answer 3

From the Wikipedia...

Cislunar space (alternatively, cis-lunar space) is the volume within the Moon's orbit, or a sphere formed by rotating that orbit.

Answer 4

situated between the earth and the moon

Answer 5

a sitellite of saturn