John B. Charles led a distinguished 35-year career at the NASA Johnson Space Center before retiring as associate director of Exploration Research Planning and chief scientist of the NASA Human Research Program in 2018.
Dr. Charles was the mission scientist for two space shuttle flights, responsible for coordinating all of the NASA-sponsored biomedical, biological and microgravity science investigations for these missions.
As chief scientist of the Human Research Program, Dr. Charles focused on the One-Year Mission and the Twins Study. The One-Year Mission began in March 2015, and followed astronaut Scott Kelly and Russian Cosmonaut Mikhail Kornienko who spent one year on the International Space Station (ISS). The Twins Study examined twin astronauts Scott and Mark Kelly for differences between the two after a year on Earth (Mark) and a year in space (Scott). Results were published in Science Magazine on April 12, 2019.