Tracy Caldwell Dyson

Did You Know?

• Caldwell Dyson celebrated her 38th birthday on day 7 of STS-118.
• During Expedition 23/24, she was one of four women together in space for the first and only time, alongside Stephanie Wilson, Dorothy Metcalf-Lindenburger, and Naoko Yamazaki.
• She performed all three contingency spacewalks in August 2010 to replace a failed coolant pump on the ISS.

Early life and education

Caldwell Dyson, the younger of two daughters, was born in Arcadia, California. During the early 1980s, her family relocated to Beaumont, California, where her father worked as an electrician and she completed junior high and high school. Outside of work, she enjoys running, weight training, hiking, softball, basketball, and working on cars. She attended California State University, Fullerton, where she was a sprinter and long jumper on the track and field team.

As an undergraduate, she created electronics and hardware for a laser-ionization, time-of-flight mass spectrometer used to study gas-phase chemistry in the atmosphere. She also monitored labs for hazardous chemicals and radioactive materials, calibrated instruments, and helped manage chemical and radioactive waste while working as a lab assistant in the university’s safety office. During and after college, she worked as an electrician and inside wireman for her father’s electrical contracting company, handling commercial and light industrial construction projects.

At the University of California, Davis, she taught general chemistry labs and started graduate research, studying how metal surfaces react at the molecular level using electron spectroscopy, laser desorption, and Fourier transform mass spectrometry. She also built parts for a variable-temperature, ultra-high vacuum scanning tunneling microscope. In 1997, she earned the Camille and Henry Dreyfus Postdoctoral Fellowship in Environmental Science at the University of California, Irvine, where she examined the reactivity and kinetics of atmospheric systems with atmospheric pressure ionization mass spectrometry, Fourier transform infrared and ultraviolet absorption spectroscopies, and developed chemical ionization techniques for identifying trace compounds. Her research has appeared in numerous scientific journals and technical conference presentations.

Career

Caldwell Dyson was selected by NASA in June 1998 and began training two months later in August 1998. Her astronaut candidate training included orientation briefings and tours, scientific and technical briefings, instruction in Shuttle and International Space Station systems, physiological training, ground school for T-38 flight training, and water and wilderness survival techniques. Completion qualified her as a mission specialist. In 1999 she was assigned to the Astronaut Office ISS Operations Branch as a Russian Crusader, participating in testing and integration of Russian hardware and software for the ISS.

In 2000 she became prime crew support astronaut for ISS Expedition 5, representing the crew on technical and operational issues during training and the on-orbit phase. In 2003 she moved to the Astronaut Shuttle Operations Branch, working on flight software verification in the Shuttle Avionics Integration Laboratory and supporting launch and landing operations at Kennedy Space Center, Florida. She also served as Lead CAPCOM for Expedition 11. Between her second and third flights she continued as CAPCOM for both shuttle and station operations, including lead CAPCOM for various ISS missions and development of the CAPCOM cadre for Boeing Starliner Mission Operations.

She was ground IV for US EVA 32, performed by Scott Kelly and Kjell Lindgren. Caldwell Dyson initiated and led projects to improve training and operations aboard the ISS, notably developing the EVA Qualification training flow (EVQ) for astronaut candidates. After her third trip to space she served as ground IV for US EVA 95, performed by Jessica Meir and Christopher Williams in March 2026, and worked as CAPCOM for the Artemis II mission during three separate shifts.

In summer 2026 she participated in the European Space Agency's CAVES training program with NASA astronaut Ben Bailey and astronauts John McFall, Ayu Yoneda, and Rosemary Coogan.

Other activities

Caldwell Dyson is a private pilot and conversational in American Sign Language and Russian. She is the lead vocalist for the all-astronaut band Max Q. In 2011 she served as guest judge on a space-themed episode of the Food Network show Cupcake Wars and appeared on Episode 3 of MasterChef Junior Season 4. She advised Jessica Chastain when the actress prepared to portray an astronaut and mission commander in the 2015 movie The Martian. She is a member of Sigma Xi Research Society and the American Chemical Society.