Abstract : This document provides general guidance for operators of manned commercial aerospace flights (suborbital and orbital) in the medical assessment of prospective passengers. This guidance is designed to identify those individuals who have medical conditions that may result in an inflight medical emergency or inflight death, or may compromise in any other way the health and safety of any occupants (crew members and passengers) onboard a commercial aerospace vehicle. Space flight exposes individuals to an environment that is far more hazardous than what is experienced by passengers who fly onboard current airline transports. With orbital and suborbital flights, pre-existing medical conditions can be aggravated or exacerbated by exposure to environmental and operational stressors such as acceleration, microgravity, and solar/cosmic radiation, among others.