Arianespace has given the green light for the launch tomorrow of its dual payload the EUTELSAT 21B and Star One C3 satellites. It is the sixth launch of the year for the heavy lift Ariane 5. The launch window opens up at 4:05 p.m. ET (9:05 GMT) and closes at 5:51 p.m. ET (10:51 GMT) and will be webcast on Arianespace TV.