SUBMITTED BY ARTHUR N1ORC - AMSAT A/C #31468

*Atlantis Set for Launch Today, Tanking Begins *

/ Sept. 9, 5:10 a.m. EDT (0910 UTC)/ At Launch Pad 39B, the loading of Space Shuttle Atlantis' orange external tank with about 528,000 gallons of liquid oxygen and hydrogen began on time at 1:15 a.m. EDT today. The "topping off" of propellants into the tank will continue until liftoff. All systems onboard the space shuttle, including the four engine cut-off (ECO) sensors, are functioning normally and are ready for launch at 11:15 a.m. EDT.(1515 UTC)

Throughout the morning, the STS-115 astronauts will prepare for launch in the Operations and Checkout Building's crew quarters before taking the 20-minute ride to the launch pad later this morning aboard the Astrovan.

Yesterday the launch was postponed when launch controllers detected a problem with one of the ECO sensors inside the liquid hydrogen section of the space shuttle's orange external tank. The sensor system is one of several that protect the shuttle's main engines by triggering their shut down if fuel runs unexpectedly low. + See ECO Sensor Description http://www.nasa.gov/images/content/157006main_122488main_ECO_sensors.jpg

The Mission Management Team decided to wait another 24 hours before launching to give the engineers more time to study the sensor data.

Follow our live coverage today! + NASA's Launch Blog http://www.nasa.gov/mission_pages/shuttle/launch/sts-115/launch-vlcc.html + NASA TV http://www.nasa.gov/multimedia/nasatv/index.html

*Atlantis' Crew and Mission * The STS-115 crew consists of Commander Brent W. Jett Jr., Pilot Christopher J. Ferguson and Mission Specialists Heidemarie M. Stefanyshyn-Piper, Joseph R. Tanner, Daniel C. Burbank and Steven G. MacLean, who represents the Canadian Space Agency. + Learn more about the crew http://www.nasa.gov/mission_pages/shuttle/shuttlemissions/sts115/index.html

With this mission, NASA is ready to get back to building the International Space Station, marking the first time in almost four years that a space station component has been added to the orbiting outpost. That also means the shuttle program is coming up on some of the most challenging space missions ever. + Learn more about the mission http://www.nasa.gov/mission_pages/shuttle/shuttlemissions/sts115/mission_overview.html

During their three spacewalks, crew members of Atlantis will install the P3/P4 integrated truss and a second set of solar arrays on the space station, doubling the station’s current ability to generate power from sunlight and adding 17.5 tons to its mass. + Learn more about the truss http://www.nasa.gov/mission_pages/station/behindscenes/truss_segment.html