Apollo 13: The Complete Mission in Real-Time 3D
April 15, 1970
Experience the Apollo 13 mission of April 15, 1970: follow the spacecraft's real Earth-to-Moon trajectory and back, in a real-time 3D reconstruction.
April 11, 1970, Kennedy Space Center.
Apollo 13 is leaving for the third Moon landing, bound for the Fra Mauro hills.
Aboard: Jim Lovell, Jack Swigert and Fred Haise. It is Lovell's fourth flight.
Swigert replaces Ken Mattingly, exposed to German measles three days before launch.
The capsule is called Odyssey. The lunar module, the LM, is called Aquarius.
The goal: rocks thrown out by the giant impact that dug the Sea of Rains.
Liftoff. The five F-1 engines push with 3,400 tonnes of force.
The first stage burns 2,100 tonnes of kerosene and oxygen in two and a half minutes.
Lovell, the commander, is to land the LM on the Moon with Haise, the LM pilot.
Swigert, the capsule's pilot, is to wait for them alone in lunar orbit.
First stage separation. The second stage's five J-2 engines light.
5 min 30 s: the second stage's centre engine goes into pogo, a violent shaking.
Thrust and fuel flow feed each other, sixteen times a second.
A sensor sees the engine's pressure collapse and shuts it down, two minutes early.
The rocket's computer compensates: the other four engines burn 34 seconds longer.
The shut-down engine's fuel stays in the tanks, and the other four burn it.
The third stage also burns 9 seconds longer, out of its reserves.
In orbit at 185 km, 44 seconds later than planned.
One and a half orbits to check out the spacecraft before leaving for the Moon.
The third stage reignites for six minutes: from 28,000 to 39,000 km/h.
Onto a free return: left alone, the spacecraft would loop round the Moon and come home.
Swigert pulls the capsule and service module away from the third stage and turns around.
He docks with the LM, stowed on top of the stage.
The spacecraft pulls the LM out of its housing. The empty third stage goes its own way.
The stage is sent to crash into the Moon, a first, for Apollo 12's seismometer.
The spacecraft rolls three times an hour to spread the Sun's heat.
30 h 40 into the flight: the main engine fires for 3.5 seconds.
The spacecraft leaves the free return to aim better at the landing site.
Without another correction, this path would no longer bring the crew home.
Haise floats into the LM to inspect it in front of the television camera.
55 hours in: the crew wraps up a live broadcast that no network carried.
Two oxygen tanks feed the fuel cells that make electricity and water.
Houston asks Swigert to stir those tanks, a routine job.
Fans inside mix the oxygen so the gauges read true.
A dull bang. The spacecraft shudders, an alarm sounds.
Lovell first thinks Haise is joking, he often bangs a valve.
Swigert: "Okay, Houston, we've had a problem here."
Lovell adds: an undervolt on main bus B, one of the two electrical circuits.
The gauges read nonsense. On the ground, they first suspect the sensors.
Flight director Gene Kranz: "Let's solve the problem, but let's not make it worse by guessing."
Two of the three fuel cells are dead.
The spacecraft moves on its own. Its thrusters fire to hold its attitude.
Lovell, at the window: "We are venting something out into space."
It is oxygen. Tank 2 is empty, and tank 1 is leaking.
Nobody knows yet what exploded, or why.
The jet pushes the spacecraft like a thruster that cannot be shut off.
Lovell flies by hand, but some of the thrusters no longer respond.
He must avoid gimbal lock, which would lose the spacecraft its orientation.
The last tank's pressure drops before their eyes, minute after minute.
Houston has two fuel cells shut to try to stop the leak.
A closed cell cannot be reopened: without them, no landing is possible.
The leak goes on. The Moon is lost: now it is about survival.
On the ground, two options: turn around right away, or swing round the Moon.
Turning around would need the main engine, perhaps damaged, and dropping the LM.
Houston chooses to swing round the Moon, with the LM as a lifeboat.
The capsule keeps its batteries and entry oxygen, sealed off for the end of the trip.
Lovell and Haise power up the LM in a hurry, before the capsule goes dark.
Lovell copies the capsule's platform alignment over to the LM's by hand.
58 h 40: the capsule goes dark. The three men crowd into the LM.
Lovell, unaware his microphone is live:
"This is going to be the last Moon mission for a long time."
They float from one module to the other through the tunnel, without spacesuits.
Using the LM as a lifeboat was studied before the flight, on paper.
Apollo 9 has already pushed a docked spacecraft with an LM's engine.
But nobody planned to shut the capsule down for four days, or to restart it after.
The rest is invented on the ground, hour by hour, and read up to the crew.
The LM is built for two men for two days. It must carry three, for four.
On the ground, they recount everything: oxygen, water, power. Water will run out first.
It also cools the electronics. Each man limits himself to 20 cl a day.
The LM runs at a minimum: radio, fans, guidance computer, nothing else.
The plan: swing round the Moon, and come home on the LM's descent engine.
The main engine, next to the blast, can't be trusted. The LM pushes the whole stack.
61 h 29: the LM's descent engine fires for 34 seconds.
The spacecraft is back on a free return: left alone, it will come back to Earth.
The Soviet Union offers its ships to help with the recovery.
The capsule is dark: nothing warms it now. Its heat radiates away into space.
It is 3 °C inside, barely warmer in the LM, where the electronics give off heat.
Moisture condenses everywhere: walls and panels drip with water.
Against the cold, Lovell and Haise pull on the boots meant for walking on the Moon.
Swigert has none. He spends the trip home with wet, frozen feet.
Behind the Moon, no radio contact for 25 minutes.
254 km above the far side, they are 400,171 km from Earth.
No one has ever been this far.
Haise and Swigert see the far side for the first time and photograph it nonstop.
Lovell saw it on Apollo 8: "If we don't get home, you won't get them developed."
The third stage hits the Moon at 9,000 km/h, 140 km from Apollo 12's seismometer.
The impact equals 11 tonnes of TNT. The Moon rings for more than three hours.
Two hours after the pass, the LM's engine fires for 4 min 24 s: this is PC+2.
Debris round the spacecraft hides the stars. The alignment is checked on the Sun.
Splashdown moves nine hours earlier, from the Indian Ocean to the Pacific.
No one sleeps more than a few hours, in the cold and the noise of the pumps.
Houston bans dumping urine overboard: every dump would nudge the trajectory.
Every breath gives off carbon dioxide. In high doses, it poisons.
To remove it, the air flows through lithium hydroxide canisters that trap it.
The LM's, meant for two men and two days, are saturating. The level rises.
The capsule has spare canisters, but they are square: they do not fit the LM.
The LM's socket is round. Two spacecraft, two contractors, two shapes.
On the ground, a team rigs an adapter: manual covers, bags, duct tape.
Houston reads up the assembly step by step. The carbon dioxide comes down.
105 hours in: the LM's engine steepens an entry angle that is too shallow.
The computer is off. They line up by hand on Earth's day-night line.
Haise, dehydrated, has a urinary infection. He shivers with fever.
On the ground, Ken Mattingly and the engineers write the procedure to restart the capsule.
It must fit in what little power the entry batteries have left.
The LM recharges one of the capsule's batteries through the cable between the modules.
A last correction on the LM's thrusters, five hours before entry.
The service module is cast off. For the first time, the crew sees the damage.
Lovell: "There's one whole side of that spacecraft missing!" The panel is gone.
Haise photographs the open bay, for the investigation.
The capsule is powered up on its batteries. Condensed water runs over the wiring.
The circuits hold.
The LM is released. Houston: "Farewell, Aquarius, and we thank you."
It will burn up in the atmosphere, over the South Pacific.
The capsule enters the atmosphere at 40,000 km/h, at an angle of just over 6 degrees.
The radio blackout lasts six minutes, longer than expected. Then Swigert answers: "Okay, Joe."
Three 25-metre parachutes slow the capsule to 35 km/h.
April 17, splashdown southeast of Samoa, 6 km from the carrier Iwo Jima.
The three men have lost 14 kg between them.
The inquiry goes back to 1968: tank 2, dropped 5 cm at the factory, kept a damaged tube.
In 1970, to empty it on the ground, it is heated for eight hours at 65 volts.
Its thermostats, rated for 28 volts, weld shut. The wire insulation bakes.
In flight, the stir starts the fans: a bare wire sparks.
The insulation catches fire in pure oxygen. The pressure rises, the tank bursts.
The LM's plutonium fuel rests at the bottom of the Tonga Trench.
Apollo 13's distance record will stand for 56 years, until Artemis II.
For Apollo 14, the oxygen tanks are redesigned, with no fans inside.
The wires left inside are sheathed in stainless steel.
A third tank is added, isolated in another bay of the service module.
The service module gets a backup battery, the capsule a store of water.
Ten months later, Apollo 14 lands at Fra Mauro.
NASA calls it a "successful failure": no goal reached, three men alive.