Scientific American: “The relief was as deep as the stakes were high. At 7:20 A.M. (ET), the rocket carrying the largest, most ambitious space telescope in history cleared the launchpad in French Guiana, and the members of mission control at the Space Telescope Science Institute in Baltimore roared their elation.”
“The suspense was not quite over. Half an hour postlaunch, the telescope still needed to decouple from its host rocket, after which had to deploy solar panels to partly power its journey. Only after that first deployment proved successful, said a NASA spokesperson in a statement to Scientific American, would ‘we know we have a mission.’ When the announcement of a successful rocket separation and solar-array deployment finally came, it was almost drowned out by cheers.”