Apollo 13: A Successful Failure
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NASA Marshall Space Flight Center (NASA-MSFC)
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The launch of Apollo 13
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On April 11, 1970, Apollo 13 was launched from Pad 39A at Cape Kennedy (now Cape Canaveral), Florida. It was intended to be the third Apollo mission to carry astronauts to the surface of the moon, but an explosion damaged the spacecraft. The astronauts were forced to cancel their planned lunar landing and had to work very hard to return to Earth. This month marks the thirty-fifth anniversary of the Apollo 13 mission.
In the 1960s, U.S. President John F. Kennedy announced that he wanted the United States to attempt to land a man on the Moon and return him safely to Earth. In response, National Aeronautics and Space Administration (NASA) scientists began to plan a series of missions named Apollo. On July 20, 1969, Apollo 11 became the first spacecraft to land on the Moon, and astronaut Neil Armstrong became the first person to walk on its surface.
The Apollo astronauts had to train for a long time before they could fly to the moon. They had to know each part of the flight plan and the spacecraft very well. Each Apollo mission had two crews: the prime (main) crew and the backup crew. James A. Lovell, Fred W. Haise, Jr., and Ken Mattingly were the prime-crew astronauts for Apollo 13. John W. Young, John L. Swigert, and Charles M. Duke were the backup crew.
Three days before Apollo 13 was due to be launched, National Aeronautics and Space Administration (NASA) officials decided to replace Ken Mattingly with John L. Swigert. Mattingly had been exposed to German measles (rubella), and NASA doctors were afraid that he would get sick while he was in space. Lovell, Haise, and Swigert trained together for the three days before the launch to make sure that the new team was ready.
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NASA Marshall Space Flight Center (NASA-MSFC)
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The Apollo 13 astronauts Fred Haise (left), John Swigert (center), and James Lovell (right) during a press conference.
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On April 11, 1970, at 2:13 p.m., Apollo 13 was launched. The Saturn 5 rocket was used to lift the spacecraft off the ground. One of the engines of the Saturn 5 rocket shut itself off two minutes before it was supposed to, but the astronauts used the remaining four engines for a little longer. This put them on a path towards the Moon.
At 5:19 p.m., the astronauts separated the lunar module (LM) named Aquarius from the remaining section of the Saturn 5 rocket. John Swigert then turned the command module (CM) named Odyssey around and rejoined it with Aquarius. For the first two days, the flight went very well.
On April 13, the three astronauts made a television broadcast. They taped the CM and LM, and showed people how they lived and worked while in space. When the broadcast was finished, Mission Control asked the astronauts to stir their oxygen tanks. The oxygen was for the astronauts to breathe, but was also needed to run the spacecraft. Nobody knew that the second oxygen tank had been damaged before it was installed in Apollo 13. When the tanks were stirred, the damaged tank exploded.
All three astronauts felt and heard a bang. John Swigert saw a warning light and told Mission Control; "We’ve had a problem here." James Lovell then said to Mission Control "Houston, we’ve had a problem" and explained that they had a main B bus undervolt. This meant that the spacecraft did not have enough electricity. More warning lights flashed on, telling the astronauts that two of their three fuel cells were dead. The fuel cells were the main source of electricity aboard the spacecraft.
At first, the astronauts were very disappointed. Mission rules said that all three fuel cells must work before astronauts could attempt to land on the Moon. Because only one fuel cell was working, the astronauts would have to cancel the landing and return home.
James Lovell then noticed that there was no oxygen in tank 2, and that the level of oxygen in tank 1 was falling. From Odyssey’s window, he could see a gas being leaked out into space, and realized that they were losing their oxygen supply very quickly. The astronauts knew that they were in danger of losing their lives. Not only were they 200,000 miles (321,800 kilometers) from Earth, but the engine in the service module was damaged in the explosion, so they did not have enough power for a direct abort (an immediate return to Earth.)
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NASA Marshall Space Flight Center (NASA-MSFC)
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The damaged Apollo 13 service module. An entire panel of the module was completely destroyed by the explosion.
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Both the crew and Mission Control realized that the astronauts could not use Odyssey any longer. The CM was almost out of oxygen, and its batteries had to be saved for re-entry (returning to Earth.) The astronauts would have to move to Aquarius and use it as a lifeboat. James Lovell and Fred Haise moved to the LM, and began to power it up. John Swigert stayed in the CM, and began to turn it off. He used the remaining oxygen to recharge the CM’s batteries. He then joined Lovell and Haise in the LM.
Mission Control decided that the fastest way to return the astronauts to Earth was to move the spacecraft to a free-return trajectory. This meant that when the astronauts reached the moon, its gravity would pull them into orbit, and would help to send them home rather than into space. The astronauts fired the LM engine to put them on the correct path.
Aquarius had to keep the three astronauts alive for four days. It was designed to keep two astronauts alive for two days. The LM had enough oxygen, but not enough water and power. They rationed (limited the use of) water so that there would be enough to cool Aquarius. After a second engine burn, the astronauts had to turn off almost everything in Aquarius in order to save power. It became very cold, and the astronauts found it very difficult to sleep. In fact, it became so cold that some of the astronauts’ food froze!
Because there were three astronauts in Aquarius, the level of carbon dioxide (CO2) in the air soon began to build up to a dangerous level. All animals (including humans) breathe in oxygen and breathe out carbon dioxide. Too much carbon dioxide in the air can make people feel very sick and can eventually cause suffocation (dying from a lack of oxygen). A chemical called lithium hydroxide removes CO2 from the air and traps it.
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JSC/NASA
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John Swigert holding the air filter that the astronauts had made.
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The LM had some lithium hydroxide canisters, but not enough to support three people. There were spare canisters in Odyssey, but they were a different shape to those in Aquarius. NASA scientists had foreseen this problem, and had designed an air filter using one of the CM’s canisters, a flight-plan cover, a sock, a plastic bag, tape, and a spacesuit hose—all materials that were aboard Apollo 13. Mission Control instructed James Lovell and John Swigert on the correct way to assemble the filter. It worked, and the CO2 in the air dropped to a safe level.
The astronauts had to fire the engine once more before they could return to Earth. The angle of entry had to be correct. If it was too shallow, they would skip across Earth’s atmosphere and return to space. If it was too steep, they would burn up on re-entry. They did not have enough power to use their computer to guide them. Instead, they aligned the spacecraft using Earth as a guide.
As the astronauts began to near Earth, Mission Control sent instructions on how to power up the CM. They could not use the LM for re-entry, because it did not have a good heat shield. Four hours before Apollo 13 entered Earth’s atmosphere, the service module was released. The astronauts could see that one side of the module was missing, and that the oxygen tanks and fuel cells had all been badly damaged.
Once Odyssey was ready, the astronauts left Aquarius and closed the hatch. The LM was set adrift in space. The astronauts were sad to leave it, as it had saved their lives. One NASA scientist said "Farewell Aquarius, and we thank you" as they left the LM behind.
On April 17, 1970 at 1:07 p.m., Apollo 13 landed in the Pacific Ocean near Samoa. It landed four miles away from the ship the USS Iwo Jima, which was to pick them up. The ship sent a helicopter to the landing site and divers jumped from it. They helped the astronauts out of the spacecraft and they were airlifted to the USS Iwo Jima. From there, they were brought to Honolulu in Hawaii. President Richard Nixon was there to greet them as well as the astronauts’ friends and families.
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NASA
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The crew of Apollo 13 aboard the USS Iwo Jima.
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Although the Apollo 13 astronauts did not get to land on the moon, the mission was called a successful failure. It drew the attention of millions of people and is one of the most famous near-disaster stories in the history of human spaceflight.
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Writing Prompt
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Do you think that Apollo 13 was a successful failure? Why or why not?
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Other Web Sites
Apollo 13 -
Apollo Expeditions to the Moon: Apollo 13 -
Apollo 13 Mission -
Space Exploration -