SpaceX Scrubs Cargo Launch from Apollo-Era Pad Due to Engine Issue

CAPE CANAVERAL, Fla. — SpaceX's first liftoff from a historic NASA pad will have to wait for another day.

The company's robotic Dragon cargo capsule was supposed to lift off this morning (Feb. 18) from Launch Complex 39A at NASA's Kennedy Space Center, the onetime stepping-off point for Apollo moon missions and space shuttle flights. But, just 13 seconds before the planned 10:01 a.m. EST (1501 GMT) liftoff, SpaceX called it off to look into an issue with the second stage of its Falcon 9 rocket.

"Standing down to take a closer look at positioning of the second stage engine nozzle. 9:38 am ET [1438 GMT] tomorrow is next earliest launch opportunity," SpaceX representatives said via Twitter just after the scrub. [In Photos: NASA's Historic Launch Pad 39A, from Apollo to Shuttle to SpaceX]

You can watch tomorrow's liftoff try live here at Space.com, courtesy of NASA TV. There's a 70 percent chance of good weather for the launch, according to mission officials.

"All systems go, except the movement trace of an upper stage engine steering hydraulic piston was slightly odd. Standing down to investigate," SpaceX founder and CEO Elon Musk tweeted. "If this is the only issue, flight would be fine, but need to make sure that it isn't symptomatic of a more significant upstream root cause."

Dragon is loaded with almost 5,500 lbs. (2500 kilograms) of supplies for the astronauts aboard the International Space Station (ISS), including a particularly large suite of science experiments, NASA officials have said. The spacecraft is scheduled to stay at the station for 29 days before heading back down to Earth with nearly 5,000 lbs. (2,500 kg) aboard.

SpaceX also detected a small leak in the two-stage Falcon 9's upper stage yesterday (Feb. 17) but worked through that issue to prep the rocket for liftoff today.

The resupply launch, when it happens, will kick off SpaceX's 10th cargo mission to the ISS for NASA. Eight of the nine missions to date have been successful, with the lone failure coming in June 2015, when a Falcon 9 broke apart less than 3 minutes after liftoff.

SpaceX will also attempt to land the first stage of the Falcon 9 shortly after launch, as part of the company's effort to develop reusable rockets. SpaceX has achieved seven successful such landings to date.

Launch Complex 39A hasn't seen a liftoff since the July 2011 launch of the space shuttle Atlantis on the shuttle program's final mission. SpaceX signed a 20-year lease to use the pad in April 2014.

Email Sarah Lewin at slewin@space.com or follow her @SarahExplains. Follow us @Spacedotcom, Facebook and Google+. Original article on Space.com.