The first Falcon Heavy rocket being prepared for launch at SpaceX's Kennedy Space Center hangar on December 20, 2017.
Another potential use for the Falcon Heavy is NASA's human exploration program, which has a renewed focus on the Moon. Humans require a lot of heavy equipment to stay alive in deep space, which is why it took the mammoth Saturn V to launch the Apollo missions to the Moon. This is why NASA is building the Space Launch System, which will be even more powerful than the Falcon Heavy. But SLS is expensive, and its critics have long pointed to the Falcon Heavy as a cheaper alternative.

The Heavy can't match SLS in terms of sending mass to lunar orbit. In cargo mode with its advanced upper stage, SLS can blast about 41 metric tons toward the Moon. The numbers on how much mass Falcon Heavy can send to lunar space vary from source to source, but since SpaceX says it can send 16.8 metric tons to Mars, we can assume it can do at least a little better than that for the Moon.

The main U.S. laboratory module aboard the ISS, Destiny, weighs 14.5 metric tons, so SpaceX could, in theory, launch a Destiny-sized module to lunar orbit. NASA's current plan calls for a small space station in lunar orbit called the Deep Space Gateway, with modules weighing around 10 metric tons, so that's also doable for the Falcon Heavy. However, NASA plans on launching each Deep Space Gateway module with an Orion crew capsule. Orion has an on-orbit mass of about 26.5 metric tons, making it too heavy for even a single Falcon Heavy lunar flight. So in order for SpaceX to participate, NASA's current plans would have to change. That's certainly possible, but examining how it would work from both an operational and political standpoint would take a whole other article.