Extravehicular activity development and verification testing at NASA's Neutral Buoyancy Laboratory

As an initial step in the preparation for future Extravehicular Activities (EVAs), astronauts perform neutral buoyancy testing to develop and verify EVA hardware and operations. Neutral buoyancy evaluations at the National Aeronautics and Space Administration (NASA) Johnson Space Center (JSC) Sonny Carter Neutral Buoyancy Laboratory (NBL) to date, have primarily trained and evaluated assembly and maintenance tasks associated with elements of the International Space Station (ISS), space shuttle, and Hubble Space Telescope. With the retirement of the shuttle, completion of ISS assembly, and introduction of commercial operators for human transportation to space, evaluations at the NBL will take on a new focus. Crew training will be more skills based rather than training for a specific EVA. Development test objectives are selected for their criticality, lack of previous testing, or design changes that justify retesting. Assembly tasks and Orbital Replacement Unit (ORU) maintenance tasks investigated are performed using procedures developed by the flight hardware providers and the Mission Operations Directorate (MOD) EVA flight controllers. This paper describes the requirements and process for performing a neutral buoyancy test, including typical hardware and support equipment requirements, personnel and administrative resource requirements, examples of ISS systems and operations that are evaluated, and typical operational objectives that are evaluated. Implications for future EVA missions well beyond earth orbit are also explored.