Getting back to Earth

While the astronauts suffered in the cramped conditions aboard an LM designed to accommodate just two men for two days, Houston ground controllers led by Gene Kranz (see p.100) feverishly calculated their path back to safety. Conditions on Aquarius soon became cold and damp, but more problematically the chemical filters designed to

CRISIS TALKS

Apollo 13 Lunar Module Pilot Fred Haise talks with the Mission Operations Control Room at Houston during the crew's final television transmission, shortly before they boarded the LM. Gene Kranz is in the foreground with his back to the camera, wearing a distinctive white waistcoat.

"Flight control will never lose an American in space. You've got to believe ... that this crew is coming home."

Gene Kranz, briefing mission controllers at Houston

lifeboat aquarius

The Apollo 13 crew, now aboard the Command Module, took this snapshot of their trusty LM as it drifted away from them shortly after separation on the final approach to Earth.

lifeboat aquarius

The Apollo 13 crew, now aboard the Command Module, took this snapshot of their trusty LM as it drifted away from them shortly after separation on the final approach to Earth.

remove toxic carbon dioxide from the air were near exhaustion. Using simulators at Houston, Mattingly (who had not, after all, fallen ill) and the others found a way to convert the incompatible filters from the CSM for use on the LM, using only materials the astronauts had to hand. With no access to the CSM engines, the crew had to improvise their course-correction burns, calculating their precise position and trajectory by the stars and using the descent engine on the LM as a retrorocket for the entire spacecraft. A passage behind the Moon put the spacecraft on a return course for Earth, and the crew were able to re-enter the Command Module on 17 April as they approached Earth.

Fortunately, the Command Module separated without problems and, as millions of television viewers around the world held their breath, the crew splashed down safely in the Pacific Ocean.

explosion damage

After abandoning the Service Module, the crew were able to see how the explosion had blown out one side of the module. The fault was eventually traced to poorly insulated wiring.

explosion damage

After abandoning the Service Module, the crew were able to see how the explosion had blown out one side of the module. The fault was eventually traced to poorly insulated wiring.

TECHNOLOGY

around the moon to safety

The mission controllers at Houston soon worked out that the only way of bringing the Apollo 13 astronauts back to Earth was through a daring manual engine burn. This would put them into a free return trajectory - an orbit that would use the Moon's gravity like a slingshot, effectively catching the spacecraft, swinging it around the far side, and throwing it back towards the Earth without the need for a long engine burn. Nevertheless, some thrust was needed to adjust Apollo 13's approach to the Moon, and because there was no way of knowing how badly the CSM engine might be damaged, the burn used the LM's descent engine instead. Approaching Earth, the Service Module was, unusually, jettisoned with the Command Module still attached to the LM. This gave the astronauts a chance to photograph the damage.

1 Apollo 13 enters translunar orbit

4 second LM engine burn to accelerate return

1 Apollo 13 enters translunar orbit

4 second LM engine burn to accelerate return

6 prior to reentry, crew enter Command Module and jettison LM

2 oxygen tank ruptures in Service Module

3 descent engine bum

6 prior to reentry, crew enter Command Module and jettison LM

2 oxygen tank ruptures in Service Module

3 descent engine bum

EXPERIENCE

an explosion in space

Two days and eight hours into their mission, and more than 320,000km (199,000 miles) from Earth, the crew of Apollo 13 were thrown into crisis as an explosion left them with a crippled Service Module and a deteriorating oxygen and power supply. Their immediate response was crucial to their chances of survival.

On the evening of 13 April 1970, the crew of Apollo 13 broadcast a guided tour of their spacecraft back to Earth. Five minutes after transmission ended, they were still scattered through the spacecraft. Command Module Pilot Jack Swigert was in the CM, Lunar Module Pilot Fred Haise in the LM (specially opened for the tour), and Commander Jim Lovell in the tunnel between the two, helping

Haise to close up the LM. Jack Lousma, on shift as Capcom at Houston, relayed a few routine requests - NASA wanted them to photograph Comet Bennett, and the engineers wanted some data on the high-gain antenna. Swigert reeled off the data from the instrument panels in front of him. The next request was to stir the tanks of low-temperature cryogenic oxygen - a routine procedure that prevented impurities in the liquid from settling to the bottom of the tank. As Swigert activated the stirring motor, a loud bang was heard throughout the spacecraft. Lovell looked accusingly at Haise - during the TV show he had startled them by triggering a repressurization valve that made a similar noise. But Haise's expression was deadly serious. The communications transcript records the moment:

Capcom: 13, we've got one more item for you, when you get a chance. We'd like you to stir up your cryo tanks. In addition, I have shaft and trunnion ...

for looking at the Comet Bennett, if you need it.

JS: Okay, Houston, we've had a problem here.

Capcom: This is Houston. Say again, please.

Jim Lovell: Houston, we've had a problem. We've had a main B bus undervolt.

Capcom: Roger. Main B undervolt. Capcom: Okay, stand by, 13. We're looking at it.

Fred Haise: Okay. Right now, Houston, the voltage is - is looking good. And we had a pretty large bang associated with the Caution and Warning there. And if I recall, main B was the one that had had an amp spike on it once before.

The "main bus undervolt" that flashed in the CM meant that one of the Service Module's power circuits was rapidly draining. As the crew struggled to reconcile the readings of their own instruments with the telemetry received on the ground, they realized that one of their two oxygen tanks was empty, and two of their three fuel cells were running flat. While staff at Houston frantically tried to work out what was happening, Lovell concentrated on stabilizing the spacecraft as it bucked from side to side. Peering out of the tiny CM windows, he spotted something that dashed his hopes of landing on the Moon - a jet of gas issuing from the side of the Service Module.

forth, and as soon as we get all that information, we'll pass it up to you. We also have the 14 backup crew over in the simulators looking at dock burns and also trying to see what kind of alignment procedure they can come up with for looking at stars out the window. So if you ever are able to see any stars out there and

IMPROVISED LIFE-SAVER

As carbon dioxide built up in the LM, Mission Control told the astronauts how to build o "mailbox" device thot would allow them to use chemical scrubbers from the Command Module in the incompatible LM system.

IMMORTALIZED ON CELLULOID

Ron Howard's acclaimed 1995 film, Apollo 13 stuck closely to the actual sequence of events and helped to reignite popular interest in the Apollo missions.

think you can do an alignment ... why [not] let us know?"

Jack Lousma, Apollo 13 Capcom

WORKING TOGETHER

Staff from all four Mission Control shifts collaborated to get the astronauts home. Pictures from the spacecraft were soon cut for power reasons, ond the team had to rely on voice communications only. This made it even more difficult to relay instructions for building the "mailbox" filter that would keep the crew's air breathable.

IMMORTALIZED ON CELLULOID

Ron Howard's acclaimed 1995 film, Apollo 13 stuck closely to the actual sequence of events and helped to reignite popular interest in the Apollo missions.

Worse was to come, as the crew realized that pressure in the second oxygen tank was now also slowly dropping. The problem now became clear - the explosion had created a major rupture in the fuel cell system, into which they were still pumping precious oxygen. Not wanting to risk anything that might worsen the condition of the Service Module, Houston now sent Lovell and Haise back to the LM in an attempt to draw power from it. However, this idea was rapidly abandoned in favour of a lifeboat procedure - transferring the crew and their consumables to the LM Aquarius and powering down the CSM completely in order to swing around the Moon and back to Earth. Within three hours of the explosion, the crew of Apollo 13 were aboard Aquarius and ready for the long trip around the Moon and back to safety.

LUCKY ESCAPE

Alan Shepard, who might hove commanded Apollo 13 but for his ear problem, listens in to the unfolding drama at Mission Control.

"Okay, Aquarius ... down here we're getting regrouped trying to work on your control modes and ... taking a look at consumables as opposed to flight plan, and so

"It looks to me, looking out the hatch, that we are venting something. We are venting something into the - out into the space"

Jim Lovell in the aftermath of the accident

IMPROVISED LIFE-SAVER

As carbon dioxide built up in the LM, Mission Control told the astronauts how to build o "mailbox" device thot would allow them to use chemical scrubbers from the Command Module in the incompatible LM system.

return to earth

(Left) Odyssey splashed down in the Pacific Ocean at 12:07pm Houston time on 17 April. The sight of its return was greeted with jubilation in a Mission Control packed with NASA personnel including (in the front row, from left) Apollo 13 Flight Directors Ceroid Griffin, Gene Kranz, and Glynn Lunney.

safe and sound

Navy divers were first to the scene, helping the crew aboard a life raft (top), while, back at Mission Control, Gene Kranz allowed himself a well-deserved cigar (middle). Within on hour of splashdown (from left) Haise, Swigert, and Lovell were being welcomed aboard the USS Iwo Jima (bottom).

WWMi

W/fmmi

2 September 1970

NASA abandons plans for Apollos 15 and 19 in the face of budget cuts.

24 November 1970

Robert Gilruth reports that all recommendations of the Apollo 13 Review Board have been implemented.

31 January 1971

Apollo 14 blasts off. After some trouble docking with the LM, it makes a successful burn to put it on course for the Moon.

4 February 1971

Apollo 14 enters into lunar orbit.

5 February 1971

The LM Antores lands in the Fra Mauro area of the Moon. Alan Shepard and Ed Mitchell make their first moonwalk.

6 February 1971

The astronauts make a second moonwalk, and later take off from the lunar surface to reunite with the CSM for their return to Earth.

Apollo 14

After the near-disaster of Apollo 13, NASA's next mission was vital to restoring its own confidence, and the prestige of the US space programme. Fortunately, it was a resounding success.

9 February 1971

The Apollo 14 Command Module splashes down in the Pacific Ocean.

teeing off

As he returned from the second moonwolk, Shepard surprised everyone by producing a couple of smuggled golf balls and a club fashioned from various lunar tools. The first golf stroke on the Moon was a slice, but the second sent the ball for several hundred metres - the low gravity probably helped, since Shepard could use only one hand.

tense moments

Screens in the Mission Operations Control Room at Houston show the view from Kitty Hawk during its repeated attempts to dock with An tares in Earth orbit. The top of the LM can be made out, still inside the S-IVB upper stage.

By the time Apollo 14 launched, on 31 January 1971, NASA had been away from the Moon for more than a year. During the hiatus, two more missions - the original Apollos 15 and 19 - had been lost to budget cuts, but Apollo 13's landing site at Fra Mauro, on the edge of the Oceanus Procellarum, was still a scientific priority, and so Apollo 14 was directed there instead. Leading the crew was a true veteran of the space programme. Alan Shepard, grounded since his historic Freedom 7 flight, had undergone painful surgery to correct his ear problem, and Deke Slayton saw to it that his old Mercury Seven colleague would go to the Moon. Shepard's crewmates - Stuart Roosa and Edgar Mitchell - were both rookies.

Although launch and departure from Earth orbit went well, Apollo 14 hit a significant snag on its way to the Moon. As Shepard attempted to join the CSM Kitty Hawk to the Lunar Module Antores, the docking mechanism persistently failed to engage. Fortunately, it took on the sixth try. More problems dogged the LM's final descent, and Shepard's first words on the surface seemed doubly appropriate: "... it's been a long way, but we're here."

Shepard and Mitchell remained on the Moon for 33 hours, during which they made two long moonwalks. After collecting their contingency sample of rock, they set up the ALSEP and other experiments that would remain on the surface. The astronauts also investigated the lunar regolith using a device that fired "thumper" charges into the ground. The way these were detected by the ALSEP seismometers revealed properties of the ground in the area.

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