Sian Hayley "Leo" Proctor (28 March 1970, Hagåtña, Guam) is an American commercial astronaut, geology professor, artist, author, and science communicator.

She became the first female commercial spaceship pilot and the first artist selected to go to be an astronaut on the all-civilian Inspiration4 orbital spaceflight, 15 September 2021.

Her father was a Sperry Corporation UNIVAC engineer working for NASA at the Guam Remote Ground Terminal during the Apollo era.

After the Moon landings, Proctor's family moved to Minnesota and later to various Northeastern states while her father changed jobs.

[15] Proctor went to space as a commercial astronaut and pilot of the Crew Dragon orbital spaceflight mission Inspiration4, which launched on 15 September 2021.

[25][26][27][28] She was joined by Jared Isaacman, Hayley Arceneaux, and Chris Sembroski, for the first all-civilian human spaceflight mission.

[34] Proctor acted as education outreach officer for the NASA-funded Hawaii Space Exploration Analog and Simulation (HI-SEAS) mission.

As part of this program, she spent a month in Barrow, Alaska learning historical ecology for risk management and investigating the impact of climate change on the coastline and community.

[40] Proctor returned to San Pedro, Chile in 2017 to engage in STEM education outreach activities with the local high school and surrounding community.

In her case, during three weeks she conducted pollock research in the Bering Sea on the fisheries vessel Oscar Dyson and detailed her experience for the blog of NOAA.