SpaceX sent a packed rocket of 60 satellites into space on Thursday evening, in a key first mission toward building the company's own high-speed internet network.

The launch was "the heaviest payload a Falcon 9 [rocket] has ever launched, or Falcon Heavy, for that matter," SpaceX CEO Elon Musk told reporters before the mission. All in all, the rocket lifted more than 37,000 pounds of mass, he said.

Called "Starlink," the satellites represent the company's ambitious plan to build an interconnected satellite network to beam high-speed internet to anywhere on the planet. It's how Musk believes SpaceX will be able to generate enough revenue to realize its even more ambitious goals of sending astronauts to Mars, and to establish the first human colony on the Red Planet.