English: NASA astronaut Peggy Whitson (left) and ESA (European Space Agency) astronaut Thomas Pesquet are photographed inside the Bigelow Expandable Activity Module, or BEAM. BEAM is an experimental expandable module attached to the station. Expandable habitats could greatly decrease the amount of transport volume for future space missions. These "expandables" weigh less and take up less room than traditional rigid metal habitats on a rocket while allowing additional space for living and working. They also provide protection from solar and cosmic radiation, space debris, and other contaminants. Crews traveling to the moon, Mars, asteroids, or other destinations could potentially use them as habitable structures.