PHOENIX — The world will have to wait a few more days to watch a private U.S. company send two astronauts to the International Space Station for the first time.

The SpaceX launch was called off about 15 minutes before Wednesday’s liftoff time because of bad weather over Kennedy Space Center in Florida.

The next attempt was set for Saturday.

SpaceX founder Elon Musk still has much to prove compared to NASA, one Arizona professor says.

“Is the agile and fast-moving private space launch safe enough?” Elliott Bryner, director of Embry Riddle University’s Propulsion Laboratory and Rocket Test Complex in Prescott, told KTAR News 92.3 FM on Tuesday.

If successful, Bryner says Musk could use this to launch civilians into outer space commercially.

“Search the internet, and you’ll a lot of stuff about these gigantic spacecrafts that he’s planning on building to go to Mars that’ll hold hundreds of people,” he said.

The SpaceX Dragon Crew Capsule has a touch screen to do much of the astronauts’ work, whereas the space shuttle and Apollo capsule utilized a plethora of dials, buttons, switches and knobs, Bryner said.

He added the mission excites the university for rocketry development and engineering.

“Our students are able to get their hands on this real rocket technology and test out engines that you might see on a real commercial vehicle,” he said.

The capsule’s launch will be the first from the U.S. in nine years, when NASA ended the space shuttle program.

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