YDS READING PASSAGES / TEST 4 34. Soru

-12. THE MISSION OF APOLLO 13

Apollo 13 was an American space mission, part of the Apollo program. It was intended to be the third mission to land on the Moon. An oxygen tank in the Service Module exploded while the spacecraft was on its way to the Moon requiring the mission to be aborted: the Moon landing was cancelled and only a single pass around the Moon was made. Considerable ingenuity under extreme pressure was required from both the crew and the ground controllers to figure out how to jury-rig the craft for the crew's safe return, with much of the world watching the drama on television. Reentry in the Earth's atmosphere required the unusual step of undocking the lunar module, which had been retained for the flight back to Earth, in addition to the separation of the damaged service module. The lunar module had remained attached to the spacecraft to provide emergency propulsion and life support. The crew returned unharmed on the Earth. In the wake of the near-disaster, NASA appointed a review board under the leadership of Edgar M. Cortright, director of Langley Research Center, to investigate the Apollo 13 accident. After some three months of study, the cause of the explosion was traced to two inadequate thermostatic switches in an oxygen-tank heater assembly. Dysfunction of the switches under load caused overheating that led to an insulation fire, and the subsequent blast tore a side panel from the service module and disabled the fuel cells. Other defects in manufacture and in testing procedures were also found. Further Apollo flights were delayed until 1971 so that modifications could be made to prevent similar incidents. Jim Lovell, who was one of the crew members, wrote a book about the mission, Lost Moon, which was later turned into a successful movie, Apollo 13, starring Tom Hanks.

According to the passage, the plan to return the Apollo 13's crew safely to the Earth ------ .