The SpaceX launch meant to test the process of landing the company's 14-story-tall Falcon 9 rocket on an "autonomous spaceport drone ship" in the ocean has been delayed until January 6th, according to Reuters. SpaceX spokesperson John Taylor named a problem with the routine pre-launch test firing of the rocket's engine as the reason.
According to the article, the engine was lit but did not run the full duration of the test. "The data suggests we could push forward without a second attempt, but out of an abundance of caution, we are opting to execute a second static fire test prior to launch," Taylor told Reuters.
Aside from testing the rocket retrieval process, the mission was also supposed to send cargo to the International Space Station. It's the first resupply mission for the ISS since Orbital Science's Antares rocket exploded six seconds after liftoff back in October. SpaceX also lost a rocket of its own earlier this year, when a test version of the Falcon 9 exploded in mid-air at a facility in Texas.