UPDATE: SpaceX has postponed its Falcon 9 launch. In a tweet, the company said its teams are "reviewing the data and next available launch date."
SpaceX is slated to launch a Falcon 9 rocket today from Cape Canaveral, Fla. The launch window opens at 6:46 p.m. Eastern time. The payload is SES-9, a 5,300-kilogram (5.8-ton) communications satellite destined for geostationary orbit.
The first rule of launches is that they don’t always go off as planned: Technical issues and weather can lead to decisions to wait for better conditions.
SpaceX will once again try to perfect the landing of the rocket’s first stage on a drone ship, which would be a milestone for Elon Musk’s company. In December, SpaceX successfully stuck a landing on land—but landing on a bobbing barge floating in the ocean has proved more challenging.
Watch it live here: