Jared Isaacman has been nominated to lead NASA during a critical phase of space exploration by President-elect Donald Trump.Isaacman is a billionaire entrepreneur and experienced private astronaut with close ties to SpaceX and Elon Musk.If confirmed by the Senate, he will succeed Bill Nelson as NASA administrator, overseeing missions to the moon and Mars.Isaacman's nomination raises questions about the future of NASA's spaceflight capabilities and the influence of his relationship with SpaceX.