The spacecraft’s payload this time is mundane and useful: Arabsat-6A, a Saudi Arabian communications satellite which will relay television, internet and mobile phone signals to the Middle East, Africa and Europe.

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Why is Falcon Heavy different from other SpaceX rockets?

The company’s workhorse is the Falcon 9 rocket, which first launched in 2010. The first stage of the Heavy essentially consists of three Falcon 9 first stages bound together. The second stages of the two rockets are identical.

The additional thrust allows the Heavy to propel 140,000 pounds to low-Earth orbit, nearly three times what the Falcon 9 can lift.

How does this Falcon Heavy differ from the first one?

On the test flight, the two side boosters were older versions reused from earlier flights. (SpaceX’s best innovation to date is landing the booster stage of its rockets and launching it again; traditionally, rockets have been one-use throwaways, with the booster stages dropped into the ocean.)