Jennifer Anne "Jenni" MacKinnon Sidey (born 3 August 1988) is a Canadian astronaut, engineer, and academic. She was selected by the Canadian Space Agency (CSA) as one of the two members of the 2017 CSA Group alongside Joshua Kutryk. In 2023, CSA assigned her to be Jeremy Hansen's backup for the Artemis II lunar flyby mission. As of the 2023 CSA Artemis announcement, she goes by her married name, Jenni Gibbons.

Jennifer Anne MacKinnon Sidey was born on 3 August 1988 in Calgary, Alberta.^[1][2] She graduated from McGill University with a Bachelor of Engineering with honours degree in mechanical engineering. While she was at McGill, she carried out research in collaboration with the Canadian Space Agency (CSA) and the National Research Council Flight Research Laboratory on flame propagation in microgravity.^[2]

She subsequently went on to complete a PhD in engineering at Jesus College, Cambridge in 2015, where she focused on combustion (The process of burning something) under the supervision of Professor Nondas Mastorakos.^[1]

Prior to joining the Canadian Space Agency (CSA), Gibbons was a lecturer in internal combustion engines at the Department of Engineering of the University of Cambridge. The focus of her research was turbulent flame physics and pollutant reduction in combustion systems.^[3] She also taught undergraduate and graduate students in the Energy, Fluid Mechanics and Turbomachinery Division on topics ranging from conventional and alternative energy production to introductory thermodynamics and flame physics. In 2016, she was awarded the Institution of Engineering and Technology's Young Woman Engineer of the Year Award, as well as a Royal Academy of Engineering Young Engineer of the Year Award.

Gibbons was selected by the Canadian Space Agency (CSA) to undergo training as an astronaut part of the 2017 CSA Group, the fourth Canadian astronaut recruitment campaign.^[4] Gibbons and Joshua Kutryk were selected among a large field of qualified candidates.^[5] Gibbons was the third female candidate chosen by the Canadian Space Agency after Roberta Bondar and Julie Payette, and when selected at age 28, was the youngest astronaut candidate ever selected by the Canadian Space Agency.^[6]

In July 2017, Gibbons relocated to Houston, Texas, to complete the two-year NASA Astronaut Candidate Training Program at the Johnson Space Center. She was training alongside the 2017 NASA astronaut class.

On 22 November 2023, during a public ceremony at CSA headquarters, Gibbons was assigned as Jeremy Hansen's backup for the Artemis II mission slated to fly no earlier than September 2025.^[7][8][9]