Juno Launch - Introduction to countdown coverage

George Diller/Launch Commentator: This is Atlas Launch Control at T-2 hours and holding. We're in a planned built-in hold at this time on the launch of the Juno spacecraft aboard an Atlas V rocket. We are now two hours, 32 minutes, 32 seconds away from the liftoff of the Atlas V. Liftoff is from Launch Complex 41 at Cape Canaveral. The Juno spacecraft will provide the most detailed observations to date of Jupiter, the solar system's largest planet. Additionally, as Jupiter was most likely the first planet to form, Juno's findings will shed light on the history and evolution of the entire solar system. The launch window today extends from 11:34 a.m. to 12:43 p.m. EDT, a duration of 69 minutes. Following a five-year cruise to Jupiter, which will include a gravity assist Earth flyby, Juno will enter into a polar orbit around the planet, completing 33 orbits during its science phase before being commanded to enter Jupiter's atmosphere to complete the mission. Juno will orbit the planet every 11 days, coming as close as 3,100 miles to Jupiter's cloud tops while measuring magnetic and gravity fields, atmospheric composition, and performing infrared, ultraviolet and visible light photography. The Juno spacecraft is unique in several ways. It's the first solar-powered spacecraft to perform operations this far from the sun. To accomplish this, Juno is equipped with three very large solar arrays, which, when extended, bring the spacecraft to a total diameter of 66 feet. To combat its exposure to radiation during its year-long orbit of Jupiter, most of Juno's electronics have been housed inside a titanium vault in the center of the spacecraft. Juno will be spin stabilized throughout its mission in order to maximize the scientific observations. We've had a weather forecast from our Launch Weather Officer Clay Flinn and forecast is essentially unchanged from what we've been watching all week. There is just a 30 percent chance of not meeting the launch weather criteria. There will be a chance for some isolated showers, winds will be out of the southeast at around 12 knots, visibility of 7 to 10 miles, winds generally from the southeast, and a temperature of approximately 86 degrees.