 Cassidy volunteered for and completed a week-long, charity kayak paddle from Norfolk, Virginia to Washington, D.C. to raise money and awareness for the Special Operations Warrior Foundation.Cassidy was selected as an astronaut candidate by NASA in May 2004.In February 2006 he completed Astronaut Candidate Training, which included scientific and technical briefings, intensive instruction in Space Shuttle and International Space Station systems, physiological training, T-38 Talon flight training, and water and wilderness survival training.