First static test of the booster for the Ares I rocket, set to send man back to the moon and eventually to mars. The week before this video was taken another test was attempted, but a problem was found and the test was scrubbed with 20 seconds left on the clock, that's why the crowd cheers with 19 seconds left on the clock. Notice how long it takes for the sound to reach the crowd, that's how far away we were.
