Watch SpaceX push the Falcon 9 rocket to its limits (updated)

SpaceX launches are seldom boring, but its next mission will be notable precisely for what isn't happening. Elon Musk's outfit is poised to launch the Inmarsat-5 F4 broadband satellite on May 15th at 7:20PM ET, and the payload is both so heavy (13,448lbs) and going into such a high orbit (22,000 miles) that the Falcon 9 rocket won't have enough propellant left to land. That's right -- although SpaceX had hoped to make a habit of reusing rockets, this vehicle won't be returning safely to terra firma. This weight shouldn't be an issue once Falcon Heavy is available, but the larger rocket won't be ready to fly for a while.

Not that SpaceX will necessarily mind. This is its first launch involving Inmarsat, so losing a rocket may be worthwhile if it helps secure a long-term customer. And of course, it's particularly important for Inmarsat itself -- the satellite will help fill out its Global Xpress internet service for commercial aircraft and ships. If you have a faster connection the next time you're flying overseas, you might chalk it up to this mission.

Just don't base your schedule around this blast-off. SpaceX periodically has to scrub launches due to weather or last-minute glitches, and it has a backup scheduled for a similar time on May 16th if things go awry. Although conditions are looking good so far, there's always the chance of a surprise delay.

Update: Success! SpaceX's Falcon 9 launch carrying a payload of Inmarsat satellites launched from the company's LC-39A complex at Kennedy in Florida on Monday. It has completed its first stage separation and initiated its second stage burn to reach its intended orbit.