In this picture, the Phobos Shuttle to Arcadia City is on final approach. Beneath it is a series of "rocky islands"--the debris from an ancient meteorite impact. Compared to space shuttles of our present age, this shuttle is huge. Six decks and a present day shuttle would not completely fill the space in one of the larger engine nacelles. Phobos Port is the entryway to Mars for colonists. Thousands are arriving every Martian month and Phobos Port is their Ellis Island. From the Port, shuttles arrive from and depart to every major Martian city. Three hundred new settlers and their belongings are being ferried to Arcadia City. In a few minutes, their long journey from Earth to Mars will come to an end. Phobos (Panic/Fear) was picked for the Port because it is the closest of Mars's two moons. It is so close to the planet that Phobos skims around Mars, completing its orbit in 7.66 hours--that is more than three orbits each Martian day. Phobos is so close to the Martian surface that if the new colonists were headed for Marineris Center, near the equator, Phobos 22.22 km. diameter would look at full moon about one-third the size of Earth's full moon. However, since they will be settling on the Arcadia Planitia plain, which is next door to the northern Polar regions, a full-moon Phobos will look much smaller in the sky because it is literally farther away from the viewer than it would be at the equator. From either pole, Phobos remains permanently hidden just over the horizon. Because Phobos is rotating much faster than Mars itself, its orbit continues to shrink. Eventually, Phobos will reach the Roach Limit and break up into a thin ring of debris circling Mars. That event, however, is still tens of thousands of years in the future. Phobos's sister moon, Deimos (Terror/Dread) is much farther out from the Martian surface and it moves so slowly (30.35 hours for a single rotation) that its orbit is slowly growing larger as it moves away from the planet's surface. Between Deimos-rise and Demos-set, Mars will have completed one rotation and part of another. Another interesting difference between the Martian moons is that speedy Phobos rises in the west and, due to the slower rotation of Mars, 11 hours later sets in the east, while pokey Deimos rises in the east and takes 2.7 days to set in the west and the same amount of time to rise back in the east. The 30 hour rotation period of Deimos causes Deimos to constantly fall behind the faster rotation of Mars. In other words, the spot on Mars where the viewer is located is moving faster than Deimos and slower than Phobos. So in a very real sense, the viewer is moving faster than Deimos. Whew! Here are a couple of fun sites for you all to check out in regard to the motions of Phobos and Deimos: Actual movie taken by NASA's Spirit robot on Mars: http://en.wikipedia.org/wiki/Image:Phobos_%26_Deimos_full.gif Diagram of Martian Moons in their orbits around Mars by SKY & Telescope: http://www.skyandtelescope.com/observing/objects/javascript/mars_moons Have fun! Jeremy CREDITS: Bryce 6.0, NASA's MRO. Shuttlecraft: by Billy.