Apollo 13 — What Happened?
, Apollo 13 — What Happened What Went Wrong, and How the Crew Survived.
On 11 April 1970, Apollo 13 lifted off from Kennedy Space Center carrying astronauts Jim Lovell, Jack Swigert and Fred Haise towards what was intended to be NASA’s third crewed lunar landing.
Two days later, approximately 200,000 miles from Earth, an oxygen tank in the spacecraft’s service module exploded.
The mission changed instantly.
The Moon landing was abandoned and Apollo 13 became something entirely different: a desperate attempt to bring three astronauts safely home from deep space in a spacecraft that had suffered a catastrophic systems failure.
The words transmitted by Jack Swigert — followed shortly afterwards by Jim Lovell — became some of the most famous associated with human spaceflight:
“Houston, we’ve had a problem.”
What followed was one of the most remarkable rescue operations in the history of exploration.
What Was Apollo 13?
Apollo 13 was NASA’s seventh crewed mission in the Apollo programme and was intended to become the third mission to land astronauts on the Moon.
The spacecraft consisted principally of three sections:
- the Command Module Odyssey, which housed the astronauts during launch and the eventual return to Earth;
- the Service Module, containing oxygen, electrical power and other essential systems;
- the Lunar Module Aquarius, originally intended to carry Lovell and Haise down to the lunar surface.
The planned landing site was the Fra Mauro highlands.
The crew consisted of Commander James A. Lovell Jr, Command Module Pilot John L. “Jack” Swigert Jr, and Lunar Module Pilot Fred W. Haise Jr.
None of them would reach the lunar surface.
Instead, their survival would depend upon using the spacecraft in ways for which it had never originally been intended.
What Went Wrong?
Approximately 56 hours after launch, mission controllers asked the crew to stir the spacecraft’s cryogenic oxygen tanks.
Soon afterwards, oxygen tank number two exploded.
The explosion damaged the service module and caused oxygen to begin escaping rapidly into space.
Apollo’s fuel cells required oxygen to generate electrical power. As the oxygen supply disappeared, the command module began losing its principal source of electricity and water.
The crew initially did not know the full extent of what had happened.
Mission Control began seeing abnormal readings.
Swigert transmitted:
“Okay, Houston, we’ve had a problem here.”
When Houston asked for the message to be repeated, Lovell responded with the phrase that would become famous around the world.
The situation rapidly became critical.
Apollo 13 was losing oxygen.
Electrical power was disappearing.
And the spacecraft was hundreds of thousands of miles from Earth.
The Oxygen Tank Explosion
The immediate cause of the accident was the failure of an oxygen tank inside the service module.
The origins of that failure stretched back before launch.
The tank had previously been damaged during handling and subsequently underwent procedures that exposed internal components to temperatures far higher than they had been designed to withstand.
Electrical insulation inside the tank was damaged.
During the flight, when the tank’s internal fans were activated, damaged wiring allowed an electrical spark to ignite insulation material in the oxygen-rich environment.
Pressure rose rapidly.
The tank ruptured.
The resulting explosion also damaged neighbouring spacecraft systems.
It was not merely the failure of one component. The explosion effectively crippled the systems upon which the command module depended for continued operation.
The Moon Landing Is Abandoned
NASA quickly realised that landing on the Moon was no longer possible.
The priority became survival.
The astronauts shut down most of the Command Module Odyssey to preserve its remaining batteries for re-entry.
They then moved into the Lunar Module Aquarius.
Aquarius had been designed to support two astronauts for approximately two days while they travelled to and from the lunar surface.
It would now have to keep three men alive for nearly four days.
The lunar module became a lifeboat.
Going Around the Moon
Apollo 13 could not simply turn around and fly directly back to Earth.
Mission planners chose a trajectory that would take the spacecraft around the far side of the Moon and use lunar gravity to help send it back towards Earth.
The crew therefore continued towards the Moon even though they would never land upon it.
Apollo 13 passed behind the Moon and reached a distance from Earth greater than any human beings had previously travelled.
Yet there was little opportunity to appreciate the achievement.
Every remaining resource was precious.
Power had to be rationed.
Water consumption was severely restricted.
The spacecraft became increasingly cold.
And another danger was building inside Aquarius.
The Carbon Dioxide Crisis
The lunar module’s life-support system had been designed for two astronauts.
With three men breathing inside the confined spacecraft, carbon dioxide levels began rising.
The crew possessed additional lithium hydroxide canisters from the command module which could remove carbon dioxide from the air.
There was one major problem.
The command module used square canisters.
The lunar module system required round fittings.
Engineers on Earth therefore had to devise a method of fitting a square cartridge into a round opening using only materials available aboard the spacecraft.
Using plastic bags, cardboard, tape and other readily available items, Mission Control developed an improvised adaptor.
The astronauts built it.
Carbon dioxide levels began falling.
The solution became one of the defining examples of improvised engineering under extreme pressure.
Course Corrections
Reaching Earth safely required extraordinary navigational precision.
Apollo 13’s damaged condition meant many of its normal guidance systems could not be relied upon in the usual manner.
The crew performed engine burns using the lunar module’s descent engine to adjust their trajectory.
At one stage, Jim Lovell used Earth visible through the spacecraft window as a visual reference while the crew manually controlled a burn.
A small error could have caused Apollo 13 to miss the narrow corridor required for atmospheric re-entry.
Mission Control and the crew repeatedly recalculated their position, speed and trajectory.
Each correction brought them closer to home.
Cold, Exhaustion and Dehydration
The astronauts faced conditions far removed from those imagined for a lunar mission.
Electrical systems were switched off wherever possible.
Temperatures inside the spacecraft fell dramatically.
Moisture condensed on surfaces.
The crew reduced their water intake because supplies were limited.
Fred Haise became ill during the return journey.
Sleep was difficult.
Food was unappealing in the increasingly cold cabin.
Yet the crew still had to perform complicated procedures precisely, often while tired, cold and dehydrated.
On Earth, meanwhile, teams of engineers and flight controllers worked continuously to solve one problem after another.
Preparing Odyssey for Re-entry
The Command Module Odyssey had remained largely powered down since shortly after the explosion.
It was the only part of Apollo 13 capable of surviving atmospheric re-entry.
Before returning to Earth, the astronauts therefore had to bring Odyssey back to life.
Normal start-up procedures assumed a functioning spacecraft with ample electrical power.
Apollo 13 had neither.
Engineers developed a completely new power-up sequence designed to use the absolute minimum amount of electricity.
The procedure was tested in simulators on Earth before being transmitted to the crew.
Odyssey successfully powered up.
Aquarius, which had kept the astronauts alive, was then separated and allowed to burn up in Earth’s atmosphere.
The Damaged Service Module
Before discarding the service module, the crew finally saw the damage caused by the explosion.
An entire external panel had been blown away.
Internal components were exposed to space.
The sight demonstrated just how serious the accident had been.
Lovell later described the damage as extensive.
Until that moment, neither the astronauts nor Mission Control had been able to see precisely what the explosion had done.
Re-entry
On 17 April 1970, Apollo 13 approached Earth.
The service module was discarded.
The lunar module was released.
Only Odyssey remained.
During atmospheric re-entry, communications between spacecraft and Mission Control were expected to disappear temporarily because of ionised gases surrounding the capsule.
Apollo 13’s blackout lasted longer than anticipated.
For several agonising moments, Mission Control heard nothing.
Then radio contact returned.
The spacecraft’s parachutes deployed.
Apollo 13 descended into the Pacific Ocean.
Jim Lovell, Jack Swigert and Fred Haise were alive.
Why Did Apollo 13 Survive?
There was no single reason.
Apollo 13 survived because numerous systems, decisions and people worked together under extraordinary circumstances.
The spacecraft contained redundancy that allowed alternative systems to be used.
The Lunar Module Aquarius happened to provide an independent source of oxygen, power and propulsion.
NASA’s engineers were able to reproduce problems on Earth and develop solutions using equipment available to the astronauts.
Mission controllers constantly reassessed the situation.
And the astronauts themselves remained disciplined enough to carry out complicated instructions under enormous pressure.
Apollo 13 therefore became both an engineering failure and an extraordinary demonstration of engineering resilience.
Was Apollo 13 a Failure?
The intended mission failed.
Apollo 13 did not land on the Moon.
Its planned scientific objectives were not achieved.
Yet NASA famously described the mission as a successful failure.
An accident that might easily have killed three astronauts instead became one of the greatest demonstrations of crisis management, teamwork and improvisation in the history of space exploration.
The investigation also resulted in significant changes to Apollo spacecraft design and operating procedures.
Future missions benefited directly from lessons learned during Apollo 13.
The Legacy of Apollo 13
Apollo 13 remains one of the defining stories of the space age.
Its significance is not simply that three astronauts survived.
It demonstrated what can happen when highly trained people refuse to accept that a catastrophic situation is beyond recovery.
Astronauts in space, engineers in laboratories, simulator crews, contractors, mathematicians and flight controllers collectively turned a crippled spacecraft into a survivable vehicle.
Apollo 13 never reached the lunar surface.
But its journey home became arguably more famous than many missions that did.
Frequently Asked Questions
When was Apollo 13 launched?
Apollo 13 launched from Kennedy Space Center in Florida on 11 April 1970.
Who were the Apollo 13 astronauts?
The crew were Jim Lovell, Jack Swigert and Fred Haise.
Did Apollo 13 land on the Moon?
No. The planned lunar landing was abandoned after an oxygen tank exploded in the spacecraft’s service module.
What caused the Apollo 13 accident?
An oxygen tank ruptured after damaged electrical insulation contributed to a fire and rapid pressure increase inside the tank.
What did “Houston, we have a problem” actually mean?
The wording generally remembered today differs slightly from the original transmission. Jack Swigert initially reported, “Houston, we’ve had a problem here,” and Jim Lovell shortly afterwards repeated that they had had a problem.
How did the astronauts survive?
The crew used the Lunar Module Aquarius as an emergency lifeboat while engineers and Mission Control developed procedures to conserve power, remove carbon dioxide, correct the spacecraft’s trajectory and safely reactivate the command module.
When did Apollo 13 return to Earth?
Apollo 13 splashed down safely in the Pacific Ocean on 17 April 1970.
Were any of the astronauts killed?
No. All three astronauts survived.
Read More https://www.amazon.com/dp/B0H6K98JB7
Apollo 13 belongs to a wider history of disasters and near-disasters in which engineering, human judgement, organisational decisions and emergency response determined the outcome.
Explore more Investigations & History articles on Billy’s Book Club, examining major disasters, aviation and maritime accidents, Cold War events, intelligence operations and other moments when ordinary decisions produced extraordinary consequences.
About the Author
Bill Stewart is an award winning author and former seafarer whose career included service in the Royal Navy and Merchant Navy, followed by work in marine auditing and accident investigation.
His nonfiction writing examines major disasters, unexplained events, intelligence operations and historical investigations, with particular emphasis on separating documented evidence from speculation.
His books and Investigation Pages form part of the growing nonfiction archive at Billy’s Book Club — Books Worth Talking About.