The Fénix capsules were designed by the Chilean Navy, in collaboration with the United States space agency NASA. They have a diameter of 54 centimetres (21 in), and have eight wheels located on the top and the bottom, with a damping system for mobility in the pipeline. The Fénix capsules have a harness to hold the occupant, an oxygen supply, and a microphone with speakers, which were used to connect the miners with the rescuers at the surface during the rescue.
Officially, three prototypes of the capsule were created. The Fénix 1 had a larger diameter than the other two capsules and was used in tests in the shaft created by the T-130 drill, where it descended to a depth of 610 metres (2,000 ft). Fénix 2 was operated with an Austrian pulley system and was used throughout the rescue of the miners. Fénix 3 was held in reserve and not used. 2010 Copiapó mining accident.