Sian Hayley "Leo" Proctor is an American commercial astronaut, geology professor, artist, author, and science communicator. She became the first female commercial spaceship pilot on the all-civilian Inspiration4 orbital spaceflight, 15 September 2021. As pilot of the Inspiration4's SpaceX Crew Dragon space capsule, Proctor became the first African-American woman to pilot a spacecraft. She was also the education outreach officer for the first Hawaii Space Exploration Analog and Simulation (HI-SEAS) Mission.

Inspiration4 was a 2021 human spaceflight operated by SpaceX on behalf of Shift4 Payments CEO Jared Isaacman. The mission launched the Crew Dragon Resilience on 16 September 2021 at 00:02:56 UTC from Kennedy Space Center's Launch Complex 39A atop a Falcon 9 launch vehicle. It placed the Dragon capsule into low Earth orbit with mission termination on 18 September 2021 at 23:06:49 UTC when Resilience splashed down in the Atlantic Ocean.