Phobos (mythology) of Cypselus on the shield of Agamemnon. American astronomer Asaph Hall named a satellite of the planet Mars, "Phobos", which he discovered along with the second Mars satellite, "Deimos", in 1877. Phobos is the larger of the two satellites. The word "phobia" derives from "phobos", (Φόβος), meaning fear. The two brothers Deimos and Phobos were particularly worshipped in the city state of "Sparta" as they were the sons of Ares, the god of war. Phobos in Greek literally means "fear" (). Spartan soldiers would idolize Phobos, because he symbolized discipline, and consistency of the armed forces. Because Phobos and Deimos
Mars Global Surveyor shoot pictures of other orbiting bodies, such as other spacecraft and the moons of Mars. In 1998 it imaged what was later called the Phobos monolith, found in MOC Image 55103. After analyzing hundreds of high-resolution pictures of the Martian surface taken by the orbiting Mars Surveyor spacecraft, a team of researchers found that weathering and winds on the planet create landforms, especially sand dunes, remarkably similar to those in some deserts on Earth. Results from the "Mars Global Surveyor" primary mission (1996–2001) were published in the Journal of Geophysical Research by M. Malin and K. Edgett. Some of these