Thick clouds and rain over the Florida coast early Saturday forced the California-based SpaceX to postpone the launch of its Dragon cargo carrier to deliver food and supplies to the International Space Station.
Another attempt is planned for early Sunday at 1:52 am (0552 GMT) from Cape Canaveral, Florida, when the weather forecast is 40 percent favorable for launch.
The journey by SpaceX's unmanned Dragon cargo capsule would be the fifth for SpaceX, and the fourth in a series of SpaceX's contracted supply missions with NASA.
The supply ship is carrying 5,000 pounds (2,300 kilograms) of supplies, food and equipment for the six-member crew at the orbiting outpost.
SpaceX in 2010 became the first private company to send a spacecraft to the ISS.
The company is run by Internet mogul Elon Musk, who accumulated his fortune by co-founding PayPal and also runs Tesla Motors.
SpaceX this week was awarded a $2 billion contract from NASA to continue developing its Dragon V2 vehicle with the goal of sending people to the space station as early as 2017.
Boeing won a larger NASA contract, more than $4 billion, for the development of its CST-10 crew vehicle.