UPDATED at 5:20 a.m. EDT with comments from NASA Administrator Charles Bolden and White House science adviser John Holdren.

WASHINGTON — Space Exploration Technologies Corp. (SpaceX) on May 22 successfully launched an unmanned Dragon capsule on a demonstration mission to the international space station (ISS).

The SpaceX Falcon 9 rocket carrying Dragon lifted off from Cape Canaveral Air Force Station, Fla., at 3:44 a.m. EDT. Eleven minutes later, Dragon was in orbit, solar arrays deployed.

“Falcon flew perfectly!! Dragon in orbit, comm locked and solar arrays active!! Feels like a giant weight just came off my back,” SpaceX founder and chief executive Elon Musk said via Twitter.

Docking with the ISS is scheduled to occur May 25 at 11:05 a.m., assuming Dragon passes a series of confidence-building tests planned for the capsule’s first three days of on-orbit operations.

The pre-dawn liftoff followed a May 19 launch attempt that was aborted at the last second when the Falcon 9’s flight computer detected high pressure in one of the rocket’s nine main-stage engines. SpaceX engineers traced the problem to a faulty check valve, which was subsequently replaced.

“Today was the first of a number of milestones in this mission. What a spectacular start,” NASA Administrator Charles Bolden told reporters a little over an hour after the May 22 liftoff, which he described as “a picture-perfect launch.” His remarks were carried live on NASA TV.

SpaceX, meanwhile, issued the following mission timeline:

May 23: Dragon orbits Earth as it travels toward the ISS.

May 24: Dragon’s sensors and flight systems are subject to a series of complicated tests to determine if the vehicle is ready to berth with the space station; these tests include maneuvers and systems checks that see the vehicle come within 2.4 kilometers of the station.

May 25: NASA decides if Dragon is allowed to attempt to berth with the station.  If so, Dragon approaches; it is captured by station’s robotic arm and attached to the station.  This requires extreme precision as both Dragon and station orbit the Earth every 90 minutes.

May 26 – 31: Astronauts open Dragon’s hatch, unload supplies and fill Dragon with return cargo.

May 31: Dragon is detached from the station and returns to Earth, landing in the Pacific, hundreds of kilometers west of Southern California.

If all goes according to plan, SpaceX will be poised to begin making regular cargo deliveries to the ISS under a $1.6 billion NASA contract awarded in 2008.

SpaceX has received more than $300 million from the U.S. space agency to date under a 2006 Commercial Orbital Transportation Services (COTS) agreement with NASA to develop the capability to fly cargo to the ISS.  SpaceX’s first COTS demo occured in December 2010 — more than two years later than originally planned — when a Dragon capsule completed two orbits before splashing down in the Pacific Ocean. 

Before dawn on May 22, President Barack Obama’s top science adviser —  John P. Holdren, director of  the White House Office of Science and Technology Policy — issued a statement congratulating SpaceX and NASA on the successful launch.

“Every launch into space is a thrilling event, but this one is especially exciting because it represents the potential of a new era in American spaceflight,” Holdren said in the statement. “Partnering with U.S. companies such as SpaceX to provide cargo and eventually crew service to the International Space Station is a cornerstone of the President’s plan for maintaining America’s leadership in space. This expanded role for the private sector will free up more of NASA’s resources to do what NASA does best — tackle the most demanding technological challenges in space, including those of human space flight beyond low Earth orbit.”