Roughly 56 hours into its mission, Apollo 13 suffered an explosion when an oxygen tank ruptured, crippling the command module's power and life support. Astronauts Jim Lovell, Jack Swigert, and Fred Haise, along with NASA's Houston ground team, improvised a survival plan using the lunar module Aquarius as a lifeboat for the four-day return to Earth, turning a moon mission into one of spaceflight's most celebrated rescue stories.
'Houston, we've had a problem,' Jack Swigert radioed at 9:08 PM Houston time, moments after a violent bang shook the spacecraft. An electrical fault had ignited insulation inside oxygen tank two, which ruptured and damaged tank one as well, venting the command module's oxygen and power into space. Commander Jim Lovell watched, appalled, as a gas plume streamed from his ship 200,000 miles from home.
With the lunar landing scrapped, mission control faced an unprecedented engineering puzzle: keep three men alive using a lunar module designed to sustain two people for two days, now needed for four days and three men. Engineers on the ground worked around the clock, devising a way to jury-rig the command module's square carbon dioxide scrubbers to fit the lunar module's round receptacles using plastic bags, cardboard, and duct tape—a fix later mythologized in the phrase 'square peg in a round hole.'
Temperatures in the crippled spacecraft dropped near freezing, condensation coated the walls, and the crew subsisted on minimal water and food to conserve resources. On April 17, the command module Odyssey splashed down safely in the South Pacific. NASA later called the mission a 'successful failure'—no moon landing, but a masterclass in crisis engineering that some regard as the agency's finest hour.
Key people: Jim Lovell, Jack Swigert, Fred Haise