A Falcon 9 rocket carrying the SpaceX Dragon spacecraft stands ready for launch from complex 40 at the Cape Canaveral Air Force Station in Cape Canaveral, Fla. on Monday, Jan. 5, 2015. The mission will... (Associated Press) 
 
 FILE - In this May 29, 2014 file photo, Elon Musk, CEO and CTO of SpaceX, introduces the SpaceX Dragon V2 spaceship at the SpaceX headquarters in Hawthorne, Calif. Minutes after a planned launch from... (Associated Press) 
 
 The unmanned Falcon rocket was supposed to blast off before sunrise Tuesday. But the countdown was halted with just one minute remaining. The soonest SpaceX can try again is Friday. No reason was immediately given for the launch abort. 
 
 The Dragon capsule aboard the rocket contains more than 5,000 pounds of supplies and experiments ordered up by NASA. That's the primary objective for SpaceX. But the California-based company was to attempt an even more extraordinary feat once the Dragon is on its way: flying the booster rocket to a platform in the Atlantic. No one has ever pulled off such a touchdown. 
 
 SpaceX's billionaire founder Elon Musk says recovering and reusing rockets could speed up launches and drive down costs. ||||| SpaceX called off its early morning rocket launch to the International Space Station, citing a last minute malfunction. 
 
 NASA said the SpaceX team had detected an “actuator drift,” causing the launch to be scrubbed. The next possible launch time is Friday at 2:09 a.m. Pacific time. 
 
 The launch by Elon Musk's SpaceX could ultimately be most notable for what happens as it returns to Earth. 
 
 Besides delivering 5,000 pounds of food, equipment and experiments to the space station, SpaceX engineers are planning to attempt what has never been done. Instead of letting the rocket's towering first stage disintegrate upon reentry to the atmosphere, they plan to land it on a barge floating in the ocean. 
 
 The rocket was originally scheduled for liftoff at 3:20 a.m. Pacific time Tuesday from Cape Canaveral, Fla. It's the first such mission since Oct. 28, when a supply ship that another company, Orbital Sciences, was operating for NASA exploded just seconds after leaving the launchpad. 
 
 Typically, the rocket's first stage, which includes the engines needed to blast it to space, is allowed to fall back to Earth after separating from its payload. After burning up in the atmosphere, it lands in pieces in the ocean or remote places. 
 
 But Musk wants to land the 14-story first stage, which includes nine engines, and reuse it on a future flight. 
 
 If successful, the feat could transform space travel by sharply lowering the cost. 
 
 "To say it would be revolutionary is absolutely true," said Charles Lurio, a Boston-based space analyst who publishes the Lurio Report. "It could be a race toward the bottom in terms of cost." 
 
 The space shuttle was reusable, Lurio said, but it was extraordinarily expensive to rebuild and refurbish once it was back on Earth. 
 
 Already, SpaceX has shaken up the satellite-launching business by having some of the lowest launch costs in the world. 
 
 "Reusability is really, I think, the critical breakthrough needed in rocketry to take things to the next level," Musk explained this fall at a public event at MIT. 
 
 But the landing won't be easy. The Hawthorne-based company compares it to "trying to balance a rubber broomstick on your hand in the middle of a wind storm." 
 
 To start, engineers must slow the rocket, traveling at nearly 3,600 miles per hour, to zero. They already proved they could do that in two previous launches, when they slowed the first stage so that it briefly hovered over the water, before toppling over. 
 
 With this launch, the rocket will be equipped with landing legs as well as deployable steering fins that will help engineers guide it to the barge, which will be floating in the Atlantic some 200 miles east of Jacksonville, Fla. 
 
 Musk calls the football field-sized barge the "autonomous spaceport drone ship." It is not anchored, but equipped with thrusters that help it stay in place. 
 
 The company said last month its odds of success are "50% at best." 
 
 The flight would be the sixth time that SpaceX has reached the space station. It is the fifth trip covered by a $1.6-billion deal that SpaceX has with NASA to shuttle cargo back and forth from the space station. 
 
 The launch was first planned for Dec. 19, but SpaceX delayed the flight after an engine was shut down prematurely during a pre-launch test. The engine test was later completed without problem, the company said. 
 
 melody.petersen@latimes.com 
 
 Twitter: @melodypetersen
– With just one minute to go before SpaceX's 6:20am ET launch of a Falcon 9 rocket in what would be a rather remarkable test of reusing rocket components, the space agency called off the mission at Cape Canaveral. The Los Angeles Times reports that a problem with the "actuator drift" was the culprit; in a more technical tweet, NASA writes, "At 1:21 before launch, a thrust vector control actuator for the Falcon 9's 2nd stage failed to perform as expected. @SpaceX is evaluating." The AP reports that Elon Musk himself had given the likelihood of successfully parking a rocket booster on a barge in the Atlantic a 50-50 chance of success. The launch is now postponed til 5:09am ET Friday at the earliest. The Dragon capsule aboard the rocket is to carry 5,000 pounds of supplies to the International Space Station, and after the initial separation, the rocket booster's engine is supposed to fire it around to an unmanned barge equipped with GPS sensors some 200 miles east of Jacksonville, Fla. The goal is to vertically land the rocket there. Click for more on the planned feat.