The US space shuttle Atlantis has launched from Florida on what is expected to be its final outing.
The orbiter soared into blue skies above the Kennedy Space Center, leaving the pad at 1420 local time (1820 GMT).
Its 12-day mission will take it to the International Space Station (ISS) where it will deliver a Russian module.
Only two further flights remain after this one, by Discovery and Endeavour. Nasa is trying to get these missions concluded before the end of the year.
The orbiter fleet will then be retired to museums.
Big crowds had gathered on the roads leading to the Nasa facility and on the beaches of Florida's Space Coast, all eager to catch the spectacular ascent of a shuttle one more time.
Mike Leinbach, Nasa's shuttle launch director, gave the final go for launch.
"On behalf of all the manufacturing, processing, flight and launch teams that have worked on Atlantis since March of 1980, I'd like to wish you all good luck, God speed; and have a little fun up there," he told the crew.
Commander Ken Ham radioed back: "If you don't mind we'll take her out of the barn and make a few more laps around the planet."
The crew's mission badge shows Atlantis flying into a sunset.
The ship climbed to orbit without apparent problem, shutting down its main engines eight-and-a-half minutes after leaving Kennedy and having reached an altitude of some 220km (120 nautical miles).
The crew will use a sensor system on the end of a robotic arm to check the integrity of the vehicle's exterior surfaces on day two of the mission. Docking with the ISS should occur on day three.
US President Barack Obama has announced a new exploration policy that he says would take humans beyond the International Space Station (ISS), beyond even the Moon, to asteroids and to Mars.
The shuttles, which have been working in space since 1981, cannot fulfil that role.
Nasa is being asked to pass the business of taxiing astronauts to and from the ISS to private companies and to concentrate its efforts on developing the vehicles that can reach more distant targets.
Veteran astronaut Jerry Ross who made five of his seven spaceflights on Atlantis - more than anyone else - said it was a shame to see the programme come to an end but that he recognised the orbiters had probably had their day.
"The shuttles seem to be flying about as well as they've ever flown. We're flying longer missions and having fewer problems on orbit than we've ever had on the vehicles," he told reporters in a pre-flight briefing.
"Like I said, you're gonna get a lot of different opinions on what's going on. My own private, personal opinion is that the shuttle has run its course. It's time to press on with something different."
Atlantis's final mission is its 32nd since entering service in 1985.
Notable achievements in its career have included launching interplanetary probes from orbit and leading the Shuttle-Mir programme which saw the ship visit the Russian Mir space station more times than any other ship in the fleet.
The current mission has Atlantis carrying a 7m-long (23ft) docking and storage module known as Rassvet (Russian for "dawn") for installation on the ISS.
The shuttle's cargo bay also contains a large rack structure holding six new batteries for the orbiting platform, as well as a spare communications Ku-band antenna, and a tool tray for the station's Dextre robot system.
These items will be placed on the outside of the platform during three spacewalks.
The trickiest moment of the mission is likely to come on flight day five when the Rassvet module is attached to the underside of the station. Russian modules are normally flown into their berthing positions, not lifted into place by a robotic arm.
The Atlantis crew have to be sure they apply sufficient pressure with the arm to engage the docking mechanism on Rassvet.
The British-born US astronaut Piers Sellers will be directing robotic operations.
"We're going to be pretending to dock this like a Soyuz or Progress spacecraft," he said.
"We're going to use the arm and very carefully approach the docking cone, and we're going to fool Rassvet into thinking it's docking itself. That's how it's going to activate all its latches and hooks."
After it returns from the ISS, Atlantis will not go straight to a museum. It will instead be prepared as a standby shuttle ready to go rescue the astronauts on November's Endeavour flight should they get into trouble.
Nasa has not excluded the possibility that it could yet fly out this standby shuttle to take additional spares and supplies to the space station.
The next shuttle mission - what should be the second to last - will see Discovery deliver a container full of supplies and spares to the ISS. Nasa is working towards a September lift-off.