Christopher Sembroski is an American data engineer, Air Force veteran, and commercial astronaut, currently living in Gig Harbor, Washington, United States. He flew to orbit on Inspiration4, a private spaceflight funded by billionaire Jared Isaacman.

A commercial astronaut is a person who has commanded, piloted, or served as an active crew member of a privately funded spacecraft. This is distinct from an otherwise non-government astronaut, for example Charlie Walker, who flies while representing a non-government corporation but with funding or training or both coming from government sources.