The liftoff was initially planned for Jan. 9 but was postponed twice to Jan. 17 and then to Jan. 18.
The 70-meter (230-foot) Falcon 9 rocket, with a diameter of 3.7 meters and weight of roughly 550 tons, has a payload capacity of 22,000 kilograms (over 24 tons) in low Earth orbit, 8,300 kg in geostationary transfer orbit and 4,000 kg on Mars.