There's an 80 percent chance of acceptable weather for a 4:47 a.m. ET blastoff, according to Air Force forecasters.
It's SpaceX's second try at launching its fifth International Space Station resupply mission under a $1.6 billion NASA contract.
A first attempt Tuesday morning was scrubbed due to concerns about a motor in the system that controls steering of the rocket's upper-stage engine nozzle.
NASA said SpaceX replaced the component.f the mission launches Saturday, the unmanned Dragon and more than 5,000 pounds of food, supplies and science experiments would be expected to arrive at the station Monday morning.
If there's no launch, the next possible attempt would be at 3:36 a.m. Tuesday, when forecasts now show a 60 percent chance of favorable weather.
Adding to the drama of the launch will be SpaceX's attempt to land the Falcon 9's first stage on an ocean platform, the most challenging experiment yet in the company's efforts to develop a reusable rocket.
