A submerged space station
The European Astronaut Centre (EAC), established in 1990, is the base for the European Space Agency's (ESA) astronaut corps. One of its most significant training areas is the Neutral Buoyancy Facility (NBF). This is a swimming pool; it's a 10-meter-deep tank containing 3.7 million liters of water, heated to a constant 28°C for comfort during long training sessions. The pool's total dimensions are 22 meters long by 17 meters wide. Inside this vast tank rests a 1:1 scale mockup of the International Space Station's (ISS) Columbus module, a European-built laboratory.
By carefully weighting astronauts in their training suits, instructors can make them neutrally buoyant. This state closely mimics the weightlessness experienced during an Extra-Vehicular Activity (EVA), commonly known as a spacewalk. It allows astronauts to practice maneuvering around the exterior of the station, handling tools, and performing complex repair or installation tasks. Every ESA astronaut begins their path to space here, with a 12-month basic training program that includes SCUBA diving in the NBF as a first step towards full EVA preparation. This underwater training is a part of preparing for the physical and spatial challenges of working in orbit.
Beyond buoyancy
The NBF is a centerpiece, the EAC campus, which it shares with the German Aerospace Center (DLR), provides comprehensive preparation for spaceflight. Astronauts receive academic instruction in subjects from spaceflight engineering and orbital mechanics to human physiology and astronomy. They also learn Russian, a required language for ISS operations, and undergo survival training for various emergency landing scenarios.
Adjacent to the EAC is the :envihab medical research facility, a 3,500-square-meter building dedicated to studying the effects of extreme environments on the human body. Its name combines "environment" and "habitat". Researchers use its modules, including a short-arm human centrifuge and a pressure chamber that can simulate altitudes up to 5,500 meters, to investigate issues like muscle atrophy and cardiovascular changes in microgravity. This research helps develop countermeasures to keep astronauts healthy during long-duration missions and also has applications for Earth-bound medicine, particularly in relation to aging and sedentary lifestyles. After returning from space, ESA astronauts use :envihab for their rehabilitation.