Personal Egress Air Packs

: "PEAP is also an acronym for Protected Extensible Authentication Protocol".

Personal Egress Air Packs, or PEAPs, are devices onboard a Space Shuttle which provide crew members approximately six minutes of breathable air in the case of a mishap while the vehicle is still located on the ground. PEAPs do not provide pressurized air, meaning that they are only intended to be used should the air inside the shuttle cabin become unbreathable by way of noxious gases.

The devices gained notoriety due to the "Challenger" disaster. After the recovery of the vehicle cockpit, it was discovered that three of the crew PEAPs were activated, including those of mission specialist Ellison Onizuka, mission specialist Judith Resnik, and pilot Michael J. Smith. The location of Smith's activation switch, on the back side of his seat, means that either Resnik or Onizuka could have activated it for him. This is the only evidence available from the disaster which shows that at least two of the crewmembers (Onizuka and Resnik) were alive after the cockpit separated from the vehicle. However, if the cabin had lost pressure, the packs alone would not have sustained the crew during the two-minute descent. [http://www.hq.nasa.gov/office/pao/History/kerwin.html]

After the "Challenger" disaster, the PEAPs were removed as they were deemed unnecessary. The partial-pressure launch-entry suits replaced the PEAPs, which were subsequently followed by the "ACES" full-pressure suits, which include self-contained oxygen tanks.