Christopher John "Chris" Cassidy is a NASA astronaut and United States Navy SEAL. Chris Cassidy achieved the rank of Captain in the U.S. Navy. He was the Chief of the Astronaut Office at NASA from July 2015 until June 2017. Cassidy attended York High School, in York, Maine. He then graduated from the Naval Academy Preparatory School in Newport, Rhode Island, in 1989. He received a Bachelor of Science degree in Mathematics from the United States Naval Academy in 1993 and a Master of Science degree in Ocean Engineering from MIT in 2000. While in the Navy, Cassidy passed BUD/S and became a Navy SEAL. While a SEAL he served several tours of duty supporting the fight in the War on Terror. His first spaceflight was on Space Shuttle mission STS-127, and his second was as a flight engineer for Expedition 35/36, launched aboard Soyuz TMA-08M. He was in space between July 15–31, 2009 and March 28 – September 10, 2013. Cassidy has worked as a CAPCOM for both International Space Station and Space Shuttle missions in the past. Cassidy announced his retirement from both the Navy and NASA Astronaut Corps on May 28, 2021.