The third is a small experimental satellite for the Air Force, coordinated by Spaceflight Industries, who also organised the Israeli moon lander.
Spaceflight Industries acts as a broker for satellite operators that need to get into space, finding extra room on rockets already launching.
Falcon 9 will drop off the lander at about 60,000km.
It will then spend the next two months stretching its elongated orbit to make it all the way to the moon and achieve lunar orbit.