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. (Read more SpaceX stories.)