Naming of moons to as "Proserpina". More recently, especially in science-fictional contexts, the Moon has been called by the Latin name "Luna", presumably on the analogy of the Latin names of the planets, or by association with the adjectival form "lunar". In technical terminology, the word-stems "seleno-" (from Greek "selēnē" "moon") and "cynthi-" (from "Cynthia", an epithet of the goddess Artemis) are sometimes used to refer to the Moon, as in "selenography, selenology," and "pericynthion." The moons of Mars (Phobos and Deimos) were named by Asaph Hall in 1878, soon after he discovered them. They are named after the sons of the god
Lithobraking launched, including penetrators on the two Phobos probe landers targeted for Mars' moon Phobos and ones for Mars itself on Mars 96 and Deep Space 2, but so far none have succeeded. The cancelled LUNAR-A probe would have carried penetrators to the Moon. Lithobraking as a method for de-orbiting a spacecraft has not been used due to the extremely high orbital velocities of most bodies (e.g. for the Moon it is over 7000 km/h). However, some small moons and asteroids have very low gravity and it could conceivably be used there (e.g. Phobos has an "escape velocity" of 40 km/h.)