4:30pm update: Bad weather prevailed. Due to lightning in the vicinity of Kennedy Space Center, which is not permitted within 30 minutes of liftoff, SpaceX scrubbed Thursday’s launch attempt. The next launch attempt will come at 5:07pm ET on Saturday.

Original post: Weather conditions are not great at Kennedy Space Center—with clouds and scattered thunderstorms—but SpaceX is going to try launching a Dragon spacecraft from Florida to the International Space Station on Thursday evening. The instantaneous launch window opens at 5:55pm ET (10:55pm BST).

The launch is significant because it marks SpaceX’s first attempt to re-fly a Dragon spacecraft. This particular Dragon first flew to the International Space Station in September 2014 when it delivered nearly 2.5 tons of cargo. That was SpaceX’s fourth supply mission to the orbiting laboratory. Thursday’s is the company’s 11th. The spacecraft has undergone significant refurbishment and has a new heat shield.