A planned SpaceX launch Saturday was scrubbed 13 seconds before it was expected to lift off. The move came after CEO Elon Musk on Friday night took to Twitter to announce that it “looks like we are go for launch.”

The new window for the mission, which will send cargo and hundreds of science experiments to the International Space Station, will open at 9:38 a.m. Sunday.

The voyage will eventually mark a return to launch activity for Launch Complex 39.

That was the site of a rocket that carried the first U.S. astronauts to the moon. It was also the site of the last manned mission to leave U.S. soil in 2011.

SpaceX officials released the following statement after the scrub:

“Standing down to take a closer look at an engine actuator on the second stage. 9:38am ET (Sunday) is our next earliest launch opportunity.” 

The launch’s scrub of the unmanned Falcon 9 rocket threw off well-laid plans for some who had gathered at Kennedy Space Center for a public viewing.

“It’s disappointing,” said Robbie Haney of Grayslake, Ill., who is in Central Florida visiting friends in Tampa Bay and attended the viewing with her husband Ken.

They made a specific trip to KSC to check out their first-ever launch.

Ken Haney said increased activity from private companies has been fun to watch.

“It always brings tears to your eyes to see what we are doing and what we send into space,” said Haney, 66.

The launch was set to be the first from Florida for SpaceX since a rocket exploded at Launch Complex 40 on Sept. 1.

That accident forced the company to accelerate a plan to refurbish Launch Complex 39 and get it ready for this mission to deliver goods within the Dragon Spacecraft capsule.

Gulf War U.S. Navy veteran Todd Ellison of Denver, Colo., is in the area visiting friends in West Palm Beach.

He said he has been following Musk’s work and was excited to see activity return to Launch Complex 39A.

“It’s iconic,” he said. “I love what Elon Musk has been doing. This is the best of America.”

When the rocket does soar, SpaceX will attempt to land the first-stage booster on a landing pad south of its launch pad.

When that happens, Central Florida residents could hear something like an explosion as the rocket returns to the atmosphere.

The last time that happened, a sonic boom rattled windows and touched off concern from area residents.

In a wide-ranging news conference on Friday, SpaceX chief operating officer Gwynne Shotwell said the historic nature of Saturday’s launch had her anticipating it more than any other launch she has seen as a SpaceX employee during the last 14 years.

The payload includes hundreds of science experiments, including some related to autonomous vehicles, lighting and biological tissue regeneration.

For Connie Tetro of Long Island, N.Y., those experiments are a side attraction to a return to a pad that has hosted some of the more memorable U.S. space flights.

“When I was younger, I used to watch all of the flights,” she said. “This is history. It brings back emotions from childhood.”

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