SpaceX will launch its first recycled rocket for NASA on Friday.
The unmanned Falcon rocket originally flew in June. The Dragon capsule made a space station shipment in 2015.
This is the first launch in more than a year from this Florida pad, the scene of a rocket explosion in 2016. Late Tuesday, SpaceX pushed back the launch for the second day in a row, saying it needs to rid the second-stage fuel system of unwanted particles. Liftoff had been scheduled for Tuesday, then Wednesday and now Friday.
As before, SpaceX will attempt to land the first-stage booster back at Cape Canaveral after liftoff. SpaceX chief Elon Musk is pushing to lower launch costs by reusing the most expensive rocket parts.
The Dragon holds nearly 5,000 pounds of supplies, including a barley experiment for Budweiser.