Personal Rescue Enclosure
The personal rescue enclosure (PRE) or "rescue ball" was developed[when?] as a solution for transporting astronauts from one Space Shuttle to another in case of an emergency. The device was produced as a prototype but never flew on any missions.
The ball was 36 inches (86 cm) in diameter and had a volume of 0.33 cubic meters. The structure comprised three fabric layers and incorporated a window and a zipper to allow the astronaut to enter and exit the ball. The ball enabled one crew member to curl up inside and don an oxygen mask and hold a carbon dioxide scrubber/oxygen supply device with one hour worth of oxygen. The ball would have been connected by an umbilical to the shuttle to supply air until the airlock depressurized. The rescue ball containing the crew member would have been carried to the rescue shuttle by a space suited astronaut.