And Musk's focus on Mars as the next destination for humanity after low Earth orbit should come as no surprise; the billionaire has long had the Red Planet in his sights. In a December X post, for example, he dismissed the moon as "a distraction," saying that "we're going straight to Mars."

As chairman of the US Senate Committee on Commerce, Science, & Transportation, Cruz effectively has control over Isaacman's confirmation process. He was also just re-elected to a six-year term, so theoretically Cruz is less susceptible to political pressure from the Trump White House.