Space shuttle Discovery and seven astronauts blazed into orbit on a spectacular midnight flight to the international space station, transporting a treadmill named after a TV comedian, mice and thousands of pounds of more solemn supplies.
Discovery lit up the sky for miles around as it thundered away on Nasa's third launch attempt.
Lightning flashed far in the distance, and the ascending shuttle resembled a bright star until it blinked out of sight five minutes after liftoff.
The space station was soaring more than 220 miles above the Indian Ocean, southwest of Tasmania, when Discovery took off. The shuttle will reach the orbiting outpost tomorrow night.
"It looks like third time really is the charm," launch director Pete Nickolenko told commander Rick Sturckow. "We wish you and your team good luck and Godspeed."
Tuesday's launch attempt was called off by thunderstorms and Wednesday's by fuel valve trouble.
Everything came together in Nasa's favour at the third try; even the valve and its indicator switch behaved, allowing the shuttle to blast off seconds before midnight at Cape Canaveral.
Discovery's most prominent payload is Nasa's new $5m (€3.48m) treadmill, which is named after Comedy Central's Stephen Colbert.
In all, the space shuttle will deliver about 17,000 pounds of gear to the space station.
The experiments include six mice that will remain at the orbiting complex until the following shuttle visit in November.
Part of a bone loss study, the mice will be the first mammals - other than humans - to spend a prolonged period at the space station.
"Let's go step up the science on the international space station," Mr Sturckow radioed right before liftoff.
Three spacewalks will be performed during the 13-day shuttle flight, to install a new ammonia tank, part of the space station's cooling system, and replace other equipment and retrieve outdoor experiments.
The station also will get a new resident, Nicole Stott. She will replace an astronaut who moved in during the 13-day shuttle flight last month.
That spaceman will return to Earth aboard Discovery, as will Buzz Lightyear. The action figure toy has been in orbit for more than a year, courtesy of Walt Disney World.
Only seven shuttle flights remain, including this one.