The Space Shuttle was a partially reusable low Earth orbital spacecraft system that was operated from 1981 to 2011 by the U. S. National Aeronautics and Space Administration (NASA) as part of the Space Shuttle program. Its official program name was Space Transportation System (STS), taken from a 1969 plan for a system of reusable spacecraft of which it was the only item funded for development. The first of four orbital test flights occurred in 1981, leading to operational flights beginning in 1982. In addition to the prototype whose completion was cancelled, five complete Shuttle systems were built and used on a total of 135 missions from 1981 to 2011, launched from the Kennedy Space Center (KSC) in Florida. Operational missions launched numerous satellites, interplanetary probes, and the Hubble Space Telescope (HST); conducted science experiments in orbit; and participated in construction and servicing of the International Space Station. The Shuttle fleet’s total mission time was 1322 days, 19 hours, 21 minutes and 23 seconds.
Each of the little Space eggs resides within its own ring arc--which is a fragmentary ring of Saturn. One hypothesis states that glittering ice crystals swarming around in the ring arc might be floating down to the surface of Methone, filling in its impact craters or other rough topography. This is something that is thought to have occurred on two other small, icy moons of Saturn--Atlas and Pan. Icy stuff swarming around in Saturn's rings apparently piled up around each moonlet's equator. The astronomers then conducted an analysis called a Bouger correction in order to subtract the gravitational effect of topological features, such as valleys and mountains, from the total gravity field. What is then left is the gravity field hidden beneath the lunar surface, existing within its crust. Earth's Moon is the largest and brightest object suspended in the darkness of the starry night sky. It is both lovely and enchanting, and it has, since ancient times, inspired curiosity and wonder in human beings who gaze up at the mysterious sky after the Sun has set. As such, Earth's Moon has long served as the inspiration for imaginative, wild and marvelous tales--it is the stuff of mythology and folklore. The "Man in the Moon" refers to several fantastic images of a human face that certain traditions see outlined in the gleaming disk of the full Moon. In November 2013, astronomers using data from the lunar-orbiting twins composing NASA's Gravity Recovery and Interior Laboratory (GRAIL) mission, announced that they have been acquiring new and fascinating insight into how this bewitching "face," etched on our Moon's disk, received its captivating and enchanting good looks!