Expanding exercise capabilities in orbit
Exercise is a vital part of daily life in orbit. Without the constant pull of gravity that normally stimulates muscles, astronauts quickly experience physiological deconditioning that can affect their health, performance and safety on the International Space Station. Daily exercise sessions of approximately 90 minutes on devices such as the T2 treadmill, the CEVIS bike or the ARED weight‑lifting machine are the most effective countermeasures currently available.
Although these machines are effective, they also have limitations. To expand the Station's exercise capabilities and prepare for the needs of future exploration missions, ESA commissioned the development of E4D, developed by the Danish Aerospace Company, alongside NASA's Vibration Isolation System.

