Update: Just before the video feed cut out from the autonomous drone ship, it appeared that the first stage of the Falcon 9 rocket made a hard landing at sea. About 20 minutes later, a SpaceX engineer confirmed that "unfortunately, it appears as though we lost the vehicle." A bit later, Elon Musk added further clarity with a delightful bit of rocket jargon, tweeting that the "booster rocket had a RUD on droneship." Which is to say a rapid, unscheduled disassembly.

This offers a good reminder that first stage landings, especially those for missions to geostationary transfer orbit, remain experimental. A company spokesman said SpaceX did glean valuable data from the descent that will improve future recovery attempts, and the rocket did fulfill its primary purpose of delivering two satellites to space.

SpaceX's next flight is likely a resupply mission to the International Space Station, tentatively scheduled for July 16. This mission offers a more benign flight profile for a landing at sea. It might also be possible to return this rocket all the way to the company's ground-based landing site along the Florida coast.

Original story: SpaceX has had a very nice run of success since April 8: it's launched three Falcon 9 rockets and landed all three of them on an autonomous drone ship in the Atlantic Ocean. Critically, the last two of these rockets have delivered payloads to geostationary transfer orbit, more than 35,000km above the surface of the Earth. The higher energies required to reach this more challenging orbit has made the sea-based landings of the Falcon 9 rocket's first stage considerably more difficult.

On Wednesday, the rocket company will go for a hat trick by landing its third rocket after a geostationary transfer orbit payload delivery. With a 45-minute launch window opening at 10:29am ET (3:29pm BST), the Falcon 9 rocket will attempt to send two commercial communications satellites into high orbit. The satellites, EUTELSAT 117 West B and ABS-2A, are operated respectively by Eutelsat and ABS.

"As with other GTO missions, the first-stage will be subject to extreme velocities and re-entry heating, making a successful landing difficult," SpaceX noted in a news release. The landing attempt will come about eight to 10 minutes after launch.

The recovery is an important aspect of the mission, but Wednesday's launch attempt will also bring SpaceX closer to its goal of launching every other week during the second half of 2016. The company has a crowded launch manifest, and critics have accused the company of not having the capability to meet all of the promises it has made to customers. However, a successful mission Wednesday would make for four Falcon 9 launches since April 8, with an average of a little more than three weeks between flights. This would be the company's best ever performance in terms of launch rate.

Weather for this morning's launch looks favorable, and the webcast below should begin about 20 minutes before the launch window opens.