Tracy Dyson is an American chemist and NASA astronaut, and she is married to Navy pilot George Dyson. She was born Tracy Ellen Caldwell on August 14, 1969 in Arcadia, California. She moved to Beaumont, California during her childhood, and graduated from Beaumont High School in 1987. She then went on to California State University, Fullerton where, as an undergraduate researcher, she designed and built electronics and hardware, including a time-of-flight mass spectrometer for studying gas phases in the atmosphere. She also worked as a lab assistant, monitoring laboratories while using hazardous chemicals and radioactive materials. In 1993, Dyson graduated with a Bachelor of Science degree from CSUF. She then continued her education at the University of California, Davis, where she taught chemistry while doing her graduate research, which focused on molecular reactivity and kinetics of metal surfaces. In 1997, Dyson received her Ph.D. in Physical Chemistry from UC Davis. During her college years, she received many awards and honors, such as Pro Femina Research Consortium Graduate Research Award, American Vacuum Society Graduate Research Award, and the Camille and Henry Dreyfus Postdoctoral Fellowship in Environmental Science.
In 1998, Dyson was selected by NASA, and she reported for training that same year. Her Astronaut Candidate Training included orientation briefings and tours, numerous scientific and technical briefings, intensive instruction in Shuttle and International Space Station systems, physiological training, T-38 flight training, and water and wilderness survival techniques. In 1999, Dyson was assigned to the Astronaut Office ISS Operations Branch as a Russian Crusader, participating in the testing and integration of Russian hardware and software products developed for ISS. The following year, she was assigned prime Crew Support Astronaut for the ISS Expedition 5 crew. During ISS Expeditions 4 through 6, Caldwell also served as an ISS spacecraft communicator inside Mission Control. In 2003, she was reassigned to the Astronaut Shuttle Operations Branch and began working with flight software verification in the Shuttle Avionics Integration Laboratory and launch and landing operations at Kennedy Space Center, Florida. Dyson also served as Lead CAPCOM for Expedition 11.
Dyson’s first mission to space was STS-118 aboard shuttle Endeavour. The mission launched on August 8, 2007, and once in space the crew effectively added another truss segment, which is a new gyroscope and external spare parts platform, to the International Space Station. In addition, four spacewalks were performed by three crew members. The mission was completed in 12 days, 17 hours, 55 minutes and 34 seconds. Finally, during the flight of STS-118, Dyson celebrated her 38th birthday in space. On April 2, 2010, Dyson was launched into space from Baikonur spaceport aboard a Russian Soyuz capsule. Two days later, she joined the Expedition 23 crew aboard ISS. She returned to Earth with the Soyuz TMA-18 landing unit on September 25, 2010.