This view of the damaged Apollo 13 Service
Module (SM) was photographed from the Command Module (CM) just
after the CM/SM separation prior to Earth re-entry. As seen here,
an entire panel on the SM was blown away by the apparent explosion
of oxygen tank number two located in Sector 4 of the SM. Two
of the three fuel cells are visible just forward (above) the
heavily damaged area. Three fuel cells, two oxygen tanks, and
two hydrogen tanks are located in Sector 4. The damaged area
is located above the S-band high gain antenna. Nearest the camera
is the Service Propulsion System (SPS) engine and nozzle. The
damage to the SM caused the Apollo 13 crewmen to use the Lunar
Module (LM) as a "lifeboat". The LM was jettisoned
just prior to Earth reentry by the Command Module.