"A last-minute problem with a single actuator forced a postponement of SpaceX's attempt to launch a Falcon 9 launch vehicle carrying cargo to the International Space Station on Tuesday," writes veteran space journalist Alan Boyle at NBC:
The landing experiment would have involved bringing the first stage of the two-stage rocket down onto a floating platform in the Atlantic Ocean, about 200 miles off the coast of Florida. Such a feat has never been done before. A successful maneuver would have marked a significant step toward making rockets more reusable and driving down the cost of spaceflight.
Need to investigate the upper stage Z actuator. Was behaving strangely. Next launch attempt on Friday at 5am.
— Elon Musk (@elonmusk) January 6, 2015
The next opportunity for a launch will be 5:09 AM ET this Friday. NASA TV coverage begins at 4:15 AM ET. Forecasters predict a 70% chance of acceptable weather conditions.
Related: SpaceX founder Elon Musk did a Reddit AMA yesterday, and it's good reading.
Drone spaceport ship heads to its hold position in the Atlantic to prepare for a rocket landing pic.twitter.com/kXYHGVKTfE
— Elon Musk (@elonmusk) January 5, 2015