SpaceX to try rocket landing during satellite launch but success "not expected"

U.S. space firm SpaceX will try again to land the first stage of its Falcon 9 rocket on a droneship in the Atlantic Ocean on Wednesday during the evening launch of a European commercial communications satellite, but it did not expect a high probability of success.

A 90-minute window for the liftoff will open at 6:46 p.m. EST (2346 GMT) at Cape Canaveral Air Force Station, Florida, with a backup launch window opening at about the same time on Thursday.

The main mission is to launch a commercial communications satellite called SES-9, which will deliver television and high-speed broadband services to the Asia-Pacific region, to a Geostationary Transfer Orbit (GTO) for the Luxembourg-based SES, a satellite operator.

If everything goes as planned, the Falcon 9's first stage will separate about 2.5 minutes after launch and then perform a series of engine burns for an experimental landing on the "Of Course I Still Love You" droneship, which was stationed in the Atlantic Ocean off the Florida coast.

SpaceX has tried and failed to land the first stage on an ocean droneship three times before -- in January 2015, April 2015, and just last month. The California-based firm did achieve a successful soft landing in December last year, but on a grounded landing pad.

This time, the SES-9's high Earth orbit, about 36,000 kilometers above our planet, will require the rocket to fly faster than usual, which makes it more difficult to stick the landing after stage separation.

"Given this mission's unique GTO profile, a successful landing is not expected," SpaceX said in a statement.

All of these landing attempts are part of SpaceX's effort to produce a fully and rapidly reusable rocket, which it said will dramatically reduce the cost of space transport.

Traditionally, rockets are designed for a single use only, burning up or crashing into the ocean after liftoff. Endite