Atlantis and four astronauts thundered into orbit on Nasa's last space shuttle voyage, writing the final chapter in a 30-year story of dazzling triumphs, shattering tragedy and, ultimately, unfulfilled expectations.
After days of gloomy forecasts full of rain and heavy cloud cover, the spaceship lifted off Friday - just two and a half minutes late - and embarked on the 135th shuttle mission. The crowd of spectators was estimated at nearly one million.
"Let's light this fire one more time," Commander Christopher Ferguson said just before taking flight.
The shuttle was visible for 42 seconds before disappearing into the clouds.
It will be at least three years - possibly five or more - before astronauts are launched again from US soil, and so this final journey of the shuttle era packed in crowds and roused emotions on a scale not seen since the Apollo moon shots. Nasa has set a long-term goal of flying to an asteroid and eventually Mars.
"Take a deep breath. Enjoy a little time here with your families again. But we've got a lot of work to do. We've got another programme that we've got to get under way," Nasa administrator Charles Bolden told the launch control team after Atlantis reached orbit. He added: "We know what we're doing. We know how to get there. We've just got to convince everybody else that we know what we're doing."
Atlantis' crew will deliver a year's worth of critical supplies to the International Space Station and return with as much rubbish as possible. The spaceship is scheduled to come home on July 20 after 12 days in orbit.
In a statement, President Barack Obama saluted Nasa's workforce, saying, "You helped our country lead the space age, and you continue to inspire us each day.
"Today's launch may mark the final flight of the space shuttle," he added, "but it propels us into the next era of our never-ending adventure to push the very frontiers of exploration and discovery in space."
The four experienced astronauts rode Atlantis from the same launch pad used more than a generation ago by the Apollo moon-mission astronauts. Nasa waived its own weather rules in the final minutes of the countdown to allow the launch to go forward. In the end, though, the lift-off was delayed not by the weather but by the need to verify that the launch pad support equipment was retracted all the way.