Washington: US aerospace company, SpaceX successfully landed the first stage of its Falcon 9 rocket on a droneship in the Atlantic Ocean after launching a commercial communications satellite into orbit for a Thai firm. "Falcon 9 first stage has landed," the California-based company said on Twitter, minutes after the satellite launch at 5.39 p.m. from Cape Canaveral Air Force Station in Florida. The success means that SpaceX has now landed three Falcon 9 first stages in a row on a boat in just two months, Xinhua news agency reported. The main objective of the mission was to deliver a commercial communications satellite called THAICOM 8 to a supersynchronous transfer orbit, which was used to move a satellite into a geostationary orbit about 36,000 km over the equator. The 3,000-kg satellite, owned by Thailand's Thaicom, will provide communications coverage for South Asia and Southeast Asia and has an operational design life of 15 years. Given this mission's high-orbit destination, SpaceX said before launch that a successful landing is "challenging" because the first stage of the rocket would be subject to extreme velocities and re-entry heating. Prior to the three successful droneship touchdowns, SpaceX's four such attempts failed. 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 lift-off.