Updated post: Shortly after midnight, local time, SpaceX's Falcon 9 rocket lifted off from Cape Canaveral. It then flew a nominal mission and deployed the SES-12 into a geostationary transfer orbit. The company's 11th mission of 2018 is successfully in the books.

Original story: SpaceX will go for its 11th successful launch of the year early on Monday, with a mission to send a communications satellite into geostationary transfer orbit. The launch from Cape Canaveral, Florida, has a four-hour window that opens at 12:29am ET (04:29 UTC). The weather appears favorable, with a 70-percent chance of "go" conditions.

This flight will use the Falcon 9 first stage rocket that first launched the US Air Force’s X-37B Orbital Test Vehicle on its fifth mission last September. (This spacecraft, OTV-5, remains in orbit about 300km above the Earth's surface. The Air Force has not said what this mini, uncrewed space shuttle is doing.)

SpaceX will not attempt to recover the first stage—the rocket will instead fall into the ocean. The company intends to fly a handful more of its used Block 4 versions of the Falcon 9 rocket before fully transitioning to the Block 5 version later this summer or early fall. The Block 5 variant of the rocket, optimized for reusability, has flown a single time, on May 11.

Engineers and technicians with SpaceX are presently assessing the health and resiliency of that booster to ensure that these Block 5 variants can be flown multiple times without significant refurbishment. “We are going to be very rigorous in taking this rocket apart and confirming our design assumptions to be confident that it is indeed able to be reused without taking it apart,” Musk said last month. “Ironically, we need to take it apart to confirm it does not need to be taken apart.”

Monday's launch attempt will try to send the 5.4-ton SES-12 communications satellite to a high transfer orbit. This satellite will provide video, data, and other communications services across the Asia-Pacific region and the Middle East. According to the mission's press kit, the Falcon 9 rocket's second stage will deploy the satellite 32 minutes and 14 seconds after liftoff.

If you're up late Sunday night or early Monday morning, the webcast below should begin about 15 minutes before the anticipated launch time.