Apollo 13 (April 1117, 1970) was the seventh crewed mission in the
Apollo space program and the third meant to
land on the Moon. The craft was launched from
Kennedy Space Center
The John F. Kennedy Space Center (KSC, originally known as the NASA Launch Operations Center), located on Merritt Island, Florida, is one of the National Aeronautics and Space Administration's (NASA) ten field centers. Since December 1968 ...
on April 11, 1970, but the lunar landing was aborted after an oxygen tank in the
service module
A service module (also known as an equipment module or instrument compartment) is a component of a crewed space capsule containing a variety of support systems used for spacecraft operations. Usually located in the uninhabited area of the spacec ...
(SM) failed two days into the mission. The crew instead looped around the Moon and returned safely to Earth on April 17. The mission was commanded by
Jim Lovell
James Arthur Lovell Jr. (; born March 25, 1928) is an American retired astronaut, naval aviator, test pilot and mechanical engineer. In 1968, as command module pilot of Apollo 8, he became, with Frank Borman and William Anders, one of th ...
, with
Jack Swigert as
command module (CM) pilot and
Fred Haise
Fred Wallace Haise Jr. ( ; born November 14, 1933) is an American former NASA astronaut, engineer, fighter pilot with the U.S. Marine Corps and U.S. Air Force, and a test pilot. He is one of only 24 people to have flown to the Moon, having f ...
as
Lunar Module (LM) pilot. Swigert was a late replacement for
Ken Mattingly
Thomas Kenneth Mattingly II (born March 17, 1936) is an American former aviator, aeronautical engineer, test pilot, rear admiral in the United States Navy and astronaut who flew on the Apollo 16, STS-4 and STS-51-C missions.
Mattingly had b ...
, who was grounded after exposure to
rubella.
A routine stir of an oxygen tank ignited damaged wire insulation inside it, causing an explosion that vented the contents of both of the SM's oxygen tanks to space. Without oxygen, needed for breathing and for generating electric power, the SM's propulsion and life support systems could not operate. The CM's systems had to be shut down to conserve its remaining resources for reentry, forcing the crew to transfer to the LM as a lifeboat. With the lunar landing canceled, mission controllers worked to bring the crew home alive.
Although the LM was designed to support two men on the lunar surface for two days,
Mission Control in Houston improvised new procedures so it could support three men for four days. The crew experienced great hardship, caused by limited power, a chilly and wet cabin and a shortage of
potable water. There was a critical need to adapt the CM's cartridges for the
carbon dioxide scrubber
A carbon dioxide scrubber is a piece of equipment that absorbs carbon dioxide (CO2). It is used to treat exhaust gases from industrial plants or from exhaled air in life support systems such as rebreathers or in spacecraft, submersible craft or ...
system to work in the LM; the crew and mission controllers were successful in improvising a solution. The astronauts' peril briefly renewed public interest in the Apollo program; tens of millions watched the splashdown in the
South Pacific Ocean
South is one of the cardinal directions or compass points. The direction is the opposite of north and is perpendicular to both east and west.
Etymology
The word ''south'' comes from Old English ''sūþ'', from earlier Proto-Germanic ''*sunþaz ...
on television.
An investigative review board found fault with preflight testing of the oxygen tank and
Teflon
Polytetrafluoroethylene (PTFE) is a synthetic fluoropolymer of tetrafluoroethylene that has numerous applications. It is one of the best-known and widely applied PFAS. The commonly known brand name of PTFE-based composition is Teflon by Chemo ...
being placed inside it. The board recommended changes, including minimizing the use of potentially combustible items inside the tank; this was done for
Apollo 14. The story of Apollo 13 has been dramatized several times, most notably in the 1995 film ''
Apollo 13'' – based on ''
Lost Moon
''Lost Moon: The Perilous Voyage of Apollo 13'' (published in paperback as ''Apollo 13''), is a 1994 non-fiction book by astronaut Jim Lovell and journalist Jeffrey Kluger, about the failed April 1970 Apollo 13 lunar landing mission which Lovell c ...
'', the 1994 memoir co-authored by Lovell – and an episode of the 1998 miniseries ''
From the Earth to the Moon
''From the Earth to the Moon: A Direct Route in 97 Hours, 20 Minutes'' (french: De la Terre à la Lune, trajet direct en 97 heures 20 minutes) is an 1865 novel by Jules Verne. It tells the story of the Baltimore Gun Club, a post-American Civil W ...
''.
Background
In 1961, U.S. President
John F. Kennedy
John Fitzgerald Kennedy (May 29, 1917 – November 22, 1963), often referred to by his initials JFK and the nickname Jack, was an American politician who served as the 35th president of the United States from 1961 until his assassination ...
challenged his nation to land an astronaut on the
Moon
The Moon is Earth's only natural satellite. It is the fifth largest satellite in the Solar System and the largest and most massive relative to its parent planet, with a diameter about one-quarter that of Earth (comparable to the width of ...
by the end of the decade, with a safe return to Earth.
NASA
The National Aeronautics and Space Administration (NASA ) is an independent agencies of the United States government, independent agency of the US federal government responsible for the civil List of government space agencies, space program ...
worked towards this goal incrementally, sending astronauts into space during
Project Mercury
Project Mercury was the first human spaceflight program of the United States, running from 1958 through 1963. An early highlight of the Space Race, its goal was to put a man into Earth orbit and return him safely, ideally before the Soviet Un ...
and
Project Gemini, leading up to the
Apollo program. The goal was achieved with
Apollo 11
Apollo 11 (July 16–24, 1969) was the American spaceflight that first landed humans on the Moon. Commander Neil Armstrong and lunar module pilot Buzz Aldrin landed the Apollo Lunar Module ''Eagle'' on July 20, 1969, at 20:17 UTC, ...
, which landed on the Moon on July 20, 1969.
Neil Armstrong and
Buzz Aldrin
Buzz Aldrin (; born Edwin Eugene Aldrin Jr.; January 20, 1930) is an American former astronaut, engineer and fighter pilot. He made three spacewalks as pilot of the 1966 Gemini 12 mission. As the Lunar Module ''Eagle'' pilot on the 1969 A ...
walked on the lunar surface while
Michael Collins Michael Collins or Mike Collins most commonly refers to:
* Michael Collins (Irish leader) (1890–1922), Irish revolutionary leader, soldier, and politician
* Michael Collins (astronaut) (1930–2021), American astronaut, member of Apollo 11 and Ge ...
orbited the Moon in
Command Module ''Columbia''. The mission returned to Earth on July 24, 1969, fulfilling Kennedy's challenge.
NASA had contracted for fifteen
Saturn V
Saturn V is a retired American super heavy-lift launch vehicle developed by NASA under the Apollo program for human exploration of the Moon. The rocket was human-rated, with three stages, and powered with liquid fuel. It was flown from 1967 ...
rockets to achieve the goal; at the time no one knew how many missions this would require. Since success was obtained in 1969 with the sixth SaturnV on Apollo 11, nine rockets remained available for a hoped-for
total of ten landings. After the excitement of Apollo 11, the general public grew apathetic towards the space program and Congress continued to cut NASA's budget;
Apollo 20 was canceled. Despite the successful lunar landing, the missions were considered so risky that astronauts could not afford life insurance to provide for their families if they died in space.
![1970 Mission Control Apollo 13](https://upload.wikimedia.org/wikipedia/commons/d/d0/1970_Mission_Control_Apollo_13.jpg)
Even before the first U.S. astronaut entered space in 1961, planning for a centralized facility to communicate with the spacecraft and monitor its performance had begun, for the most part the brainchild of
Christopher C. Kraft Jr., who became NASA's first
flight director
Flight controllers are personnel who aid space flight by working in such Mission Control Centers as NASA's Mission Control Center or ESA's European Space Operations Centre. Flight controllers work at computer consoles and use telemetry to mon ...
. During
John Glenn's Mercury ''
Friendship 7
Mercury-Atlas 6 (MA-6) was the first crewed American orbital spaceflight, which took place on February 20, 1962. Piloted by astronaut John Glenn and operated by NASA as part of Project Mercury, it was the fifth human spaceflight, preceded by Sovi ...
'' flight in February 1962 (the first crewed orbital flight by the U.S.), one of Kraft's decisions was overruled by NASA managers. He was vindicated by post-mission analysis and implemented a rule that, during the mission, the flight director's word was absolute
– to overrule him, NASA would have to fire him on the spot.
Flight directors during Apollo had a one-sentence job description, "The flight director may take any actions necessary for crew safety and mission success."
In 1965, Houston's
Mission Control Center opened, in part designed by Kraft and now named for him.
In Mission Control, each flight controller, in addition to monitoring
telemetry
Telemetry is the in situ collection of measurements or other data at remote points and their automatic transmission to receiving equipment (telecommunication) for monitoring. The word is derived from the Greek roots ''tele'', "remote", an ...
from the spacecraft, was in communication via voice loop to specialists in a Staff Support Room (or "back room"), who focused on specific spacecraft systems.
Apollo 13 was to be the second
H mission, meant to demonstrate precision lunar landings and explore specific sites on the Moon. With Kennedy's goal accomplished by Apollo 11, and
Apollo 12 demonstrating that the astronauts could perform a precision landing, mission planners were able to focus on more than just landing safely and having astronauts minimally trained in geology gather lunar samples to take home to Earth. There was a greater role for science on Apollo 13, especially for geology, something emphasized by the mission's motto, ''Ex luna, scientia'' (From the Moon, knowledge).
Astronauts and key Mission Control personnel
![Apollo 13 Crew before launch - S70-34767](https://upload.wikimedia.org/wikipedia/commons/0/06/Apollo_13_Crew_before_launch_-_S70-34767.jpg)
Apollo 13's mission commander,
Jim Lovell
James Arthur Lovell Jr. (; born March 25, 1928) is an American retired astronaut, naval aviator, test pilot and mechanical engineer. In 1968, as command module pilot of Apollo 8, he became, with Frank Borman and William Anders, one of th ...
, was 42 years old at the time of the spaceflight. He was a graduate of the
United States Naval Academy
The United States Naval Academy (US Naval Academy, USNA, or Navy) is a federal service academy in Annapolis, Maryland. It was established on 10 October 1845 during the tenure of George Bancroft as Secretary of the Navy. The Naval Academy ...
and had been a naval aviator and
test pilot
A test pilot is an aircraft pilot with additional training to fly and evaluate experimental, newly produced and modified aircraft with specific maneuvers, known as flight test techniques.Stinton, Darrol. ''Flying Qualities and Flight Testin ...
before being selected for the
second group of astronauts in 1962; he flew with
Frank Borman
Frank Frederick Borman II (born March 14, 1928) is a retired United States Air Force (USAF) colonel (United States), colonel, aeronautical engineer, test pilot, businessman, and NASA astronaut. He was the commander of Apollo 8, the first missio ...
in
Gemini 7 in 1965 and Buzz Aldrin in
Gemini 12 the following year before flying in
Apollo 8 in 1968, the first spacecraft to orbit the Moon. At the time of Apollo 13, Lovell was the NASA astronaut with the most time in space, with 572 hours over the three missions.
Jack Swigert, the command module pilot (CMP), was 38 years old and held a
B.S.
A Bachelor of Science (BS, BSc, SB, or ScB; from the Latin ') is a bachelor's degree awarded for programs that generally last three to five years.
The first university to admit a student to the degree of Bachelor of Science was the University ...
in mechanical engineering and an
M.S.
A Master of Science ( la, Magisterii Scientiae; abbreviated MS, M.S., MSc, M.Sc., SM, S.M., ScM or Sc.M.) is a master's degree in the field of science awarded by universities in many countries or a person holding such a degree. In contrast to ...
in aerospace science; he had served in the Air Force and in state
Air National Guards and was an engineering test pilot before being selected for the
fifth group of astronauts in 1966.
Fred Haise
Fred Wallace Haise Jr. ( ; born November 14, 1933) is an American former NASA astronaut, engineer, fighter pilot with the U.S. Marine Corps and U.S. Air Force, and a test pilot. He is one of only 24 people to have flown to the Moon, having f ...
, the lunar module pilot (LMP), was 35 years old. He held a B.S. in aeronautical engineering, had been a
Marine Corps
Marines, or naval infantry, are typically a military force trained to operate in littoral zones in support of naval operations. Historically, tasks undertaken by marines have included helping maintain discipline and order aboard the ship (refl ...
fighter pilot, and was a civilian research pilot for NASA when he was selected as a Group5 astronaut.
According to the standard Apollo crew rotation, the prime crew for Apollo 13 would have been the backup crew for
Apollo 10
Apollo 10 (May 18–26, 1969) was a human spaceflight, the fourth crewed mission in the United States Apollo program, and the second (after Apollo8) to orbit the Moon. NASA described it as a "dress rehearsal" for the first Moon landing, and ...
, with Mercury and Gemini veteran
Gordon Cooper
Leroy Gordon "Gordo" Cooper Jr. (March 6, 1927 – October 4, 2004) was an American aerospace engineer, test pilot, United States Air Force pilot, and the youngest of the seven original astronauts in Project Mercury, the first human spa ...
in command,
Donn F. Eisele
Donn Fulton Eisele (June 23, 1930 – December 1, 1987) (Colonel USAF) was a United States Air Force officer, test pilot, and later a NASA astronaut. He occupied the command module pilot seat during the flight of Apollo 7 in 1968. After ...
as CMP and
Edgar Mitchell as LMP.
Deke Slayton
Donald Kent "Deke" Slayton (March 1, 1924 – June 13, 1993) was a United States Air Force pilot, aeronautical engineer, and test pilot who was selected as one of the original NASA Mercury Seven astronauts. He went on to become NASA's fir ...
, NASA's Director of Flight Crew Operations, never intended to rotate Cooper and Eisele to a prime crew assignment, as both were out of favorCooper for his lax attitude towards training, and Eisele for incidents aboard
Apollo7 and an extramarital affair. He assigned them to the backup crew because no other veteran astronauts were available. Slayton's original choices for Apollo 13 were
Alan Shepard
Alan Bartlett Shepard Jr. (November 18, 1923 – July 21, 1998) was an American astronaut, naval aviator, test pilot, and businessman. In 1961, he became the second person and the first American to travel into space and, in 1971, he beca ...
as commander,
Stuart Roosa
Stuart Allen Roosa (August 16, 1933 – December 12, 1994) was an American aeronautical engineer, smokejumper, United States Air Force pilot, test pilot, and NASA astronaut, who was the Command Module Pilot for the Apollo 14 mission. The missi ...
as CMP, and Mitchell as LMP. However, management felt Shepard needed more training time, as he had only recently resumed active status after surgery for an
inner ear disorder and had not flown since 1961. Thus, Lovell's crew (himself, Haise and
Ken Mattingly
Thomas Kenneth Mattingly II (born March 17, 1936) is an American former aviator, aeronautical engineer, test pilot, rear admiral in the United States Navy and astronaut who flew on the Apollo 16, STS-4 and STS-51-C missions.
Mattingly had b ...
), having all backed up Apollo 11 and being slated for
Apollo 14, was swapped with Shepard's.
Swigert was originally CMP of Apollo 13's backup crew, with
John Young John Young may refer to:
Academics
* John Young (professor of Greek) (died 1820), Scottish professor of Greek at the University of Glasgow
* John C. Young (college president) (1803–1857), American educator, pastor, and president of Centre Col ...
as commander and
Charles Duke
Charles Moss Duke Jr. (born October 3, 1935) is an American former astronaut, United States Air Force (USAF) officer and test pilot. As Lunar Module pilot of Apollo 16 in 1972, he became the tenth and youngest person to walk on the Moon, at ...
as lunar module pilot.
Seven days before launch, Duke contracted
rubella from a friend of his son.
This exposed both the prime and backup crews, who trained together. Of the five, only Mattingly was not immune through prior exposure. Normally, if any member of the prime crew had to be grounded, the remaining crew would be replaced as well, and the backup crew substituted, but Duke's illness ruled this out, so two days before launch, Mattingly was replaced by Swigert.
Mattingly never developed rubella and later flew on
Apollo 16.
For Apollo, a third crew of astronauts, known as the support crew, was designated in addition to the prime and backup crews used on projects Mercury and Gemini. Slayton created the support crews because
James McDivitt
James Alton McDivitt (June 10, 1929 – October 13, 2022) was an American test pilot, United States Air Force (USAF) pilot, aeronautical engineer, and NASA astronaut in the Gemini and Apollo programs. He joined the USAF in 1951 and flew 1 ...
, who would command
Apollo 9
Apollo 9 (March 313, 1969) was the third human spaceflight in NASA's Apollo program. Flown in low Earth orbit, it was the second crewed Apollo mission that the United States launched via a Saturn V rocket, and was the first flight of the ful ...
, believed that, with preparation going on in facilities across the US, meetings that needed a member of the flight crew would be missed. Support crew members were to assist as directed by the mission commander. Usually low in seniority, they assembled the mission's rules,
flight plan, and checklists, and kept them updated; for Apollo 13, they were
Vance D. Brand,
Jack Lousma
Jack Robert Lousma (born February 29, 1936) is an American astronaut, aeronautical engineer, retired United States Marine Corps officer, former naval aviator, NASA astronaut, and politician. He was a member of the second crew, Skylab-3, on ...
and either
William Pogue
William Reid Pogue (January 23, 1930 – March 3, 2014) was an American astronaut and pilot who served in the United States Air Force (USAF) as a fighter pilot and test pilot, and reached the rank of colonel. He was also a teacher, public spea ...
or
Joseph Kerwin.
For Apollo 13, flight directors were
Gene Kranz
Eugene Francis "Gene" Kranz (born August 17, 1933) is an American aerospace engineer who served as NASA's second Chief Flight Director, directing missions of the Mercury, Gemini and Apollo programs, including the first lunar landing mission, Ap ...
, White team (the lead flight director);
Glynn Lunney
Glynn Stephen Lunney (November 27, 1936 – March 19, 2021) was an American NASA engineer. An employee of NASA since its creation in 1958, Lunney was a flight director during the Gemini and Apollo programs, and was on duty during historic even ...
, Black team;
Milton Windler, Maroon team and
Gerry Griffin
Gerald D. Griffin (born December 25, 1934) is an American aeronautical engineer and former NASA official, who served as a flight director during the Apollo program and director of Johnson Space Center, succeeding Chris Kraft in 1982.
When Gr ...
, Gold team. The
CAPCOMs (the person in Mission Control, during the Apollo program an astronaut, who was responsible for voice communications with the crew) for Apollo 13 were Kerwin, Brand, Lousma, Young and Mattingly.
Mission insignia and call signs
![Apollo 13 Flown Silver Robbins Medallion (SN-354)](https://upload.wikimedia.org/wikipedia/commons/c/c8/Apollo_13_Flown_Silver_Robbins_Medallion_%28SN-354%29.jpg)
The Apollo 13 mission insignia depicts the Greek god of the Sun,
Apollo
Apollo, grc, Ἀπόλλωνος, Apóllōnos, label=genitive , ; , grc-dor, Ἀπέλλων, Apéllōn, ; grc, Ἀπείλων, Apeílōn, label= Arcadocypriot Greek, ; grc-aeo, Ἄπλουν, Áploun, la, Apollō, la, Apollinis, label ...
, with three horses pulling his chariot across the face of the Moon, and the Earth seen in the distance. This is meant to symbolize the Apollo flights bringing the light of knowledge to all people. The mission motto, ''Ex luna, scientia'' ("From the Moon, knowledge"), appears. In choosing it, Lovell adapted the motto of his alma mater, the Naval Academy, ''Ex scientia, tridens'' ("From knowledge, sea power").
On the patch, the mission number appeared in
Roman numerals as Apollo XIII. It did not have to be modified after Swigert replaced Mattingly, as it is one of only two Apollo mission insigniathe other being Apollo 11not to include the names of the crew. It was designed by artist
Lumen Martin Winter
Lumen Martin Winter (December 12, 1908 – April 5, 1982) was an American public artist whose skills in sculpture, paintings, and works on paper, were widely known during his lifetime. His ability to master a wide range of media – including oil ...
, who based it on a mural he had painted for the
St. Regis Hotel in New York City. The mural was later purchased by actor
Tom Hanks
Thomas Jeffrey Hanks (born July 9, 1956) is an American actor and filmmaker. Known for both his comedic and dramatic roles, he is one of the most popular and recognizable film stars worldwide, and is regarded as an American cultural icon. Ha ...
, who portrayed Lovell in the movie ''
Apollo 13'', and is now in the
Captain James A. Lovell Federal Health Care Center
The Captain James A. Lovell Federal Health Care Center (FHCC), opened on October 1, 2010, and is the United States' first federal health care center that partners the United States Department of Veterans Affairs and the Department of Defense into ...
in Illinois.
The mission's motto was in Lovell's mind when he chose the call sign ''Aquarius'' for the lunar module, taken from
Aquarius
Aquarius may refer to:
Astrology
* Aquarius (astrology), an astrological sign
* Age of Aquarius, a time period in the cycle of astrological ages
Astronomy
* Aquarius (constellation)
* Aquarius in Chinese astronomy
Arts and entertainme ...
, the bringer of water. Some in the media erroneously reported that the call sign was taken from
a song by that name from the musical ''
Hair''. The command module's call sign, ''Odyssey'', was chosen not only for its
Homeric association but to refer to the recent movie, ''
2001: A Space Odyssey'', based on
a short story by
science fiction
Science fiction (sometimes shortened to Sci-Fi or SF) is a genre of speculative fiction which typically deals with imaginative and futuristic concepts such as advanced science and technology, space exploration, time travel, parallel uni ...
author
Arthur C. Clarke. In his book, Lovell indicated he chose the name ''Odyssey'' because he liked the word and its definition: a long voyage with many changes of fortune.
Space vehicle
![Apollo 13 CSM (Ap13-69-H-1791)](https://upload.wikimedia.org/wikipedia/commons/d/d8/Apollo_13_CSM_%28Ap13-69-H-1791%29.jpg)
The Saturn V rocket used to carry Apollo 13 to the Moon was numbered SA-508, and was almost identical to those used on Apollo8 through 12. Including the spacecraft, the rocket weighed in at . The
S-IC first stage's engines were rated to generate less total thrust than Apollo 12's, though they remained within specifications.
To keep its
liquid hydrogen
Liquid hydrogen (LH2 or LH2) is the liquid state of the element hydrogen. Hydrogen is found naturally in the molecular H2 form.
To exist as a liquid, H2 must be cooled below its critical point of 33 K. However, for it to be in a fully l ...
propellent cold, the
S-II second stage's cryogenic tanks were insulated; on earlier Apollo missions this came in the form of panels that were affixed, but beginning with Apollo 13, insulation was sprayed onto the exterior of the tanks.
Extra propellant was carried as a test, since future
J missions to the Moon would require more propellant for their heavier payloads. This made the vehicle the heaviest yet flown by NASA, and Apollo 13 was visibly slower to clear the launch tower than earlier missions.
The Apollo 13 spacecraft consisted of Command Module 109 and Service Module 109 (together CSM-109), called ''Odyssey'', and Lunar Module7 (LM-7), called ''Aquarius''. Also considered part of the spacecraft was the
launch escape system
A launch escape system (LES) or launch abort system (LAS) is a crew-safety system connected to a space capsule that can be used to quickly separate the capsule from its launch vehicle in case of an emergency requiring the abort of the launch, suc ...
, which would propel the command module (CM) to safety in the event of a problem during liftoff, and the Spacecraft–LM Adapter, numbered as SLA-16, which housed the lunar module (LM) during the first hours of the mission.
The LM stages, CM and service module (SM) were received at
Kennedy Space Center
The John F. Kennedy Space Center (KSC, originally known as the NASA Launch Operations Center), located on Merritt Island, Florida, is one of the National Aeronautics and Space Administration's (NASA) ten field centers. Since December 1968 ...
(KSC) in June 1969; the portions of the Saturn V were received in June and July. Thereafter, testing and assembly proceeded, culminating with the rollout of the launch vehicle, with the spacecraft atop it, on December 15, 1969. Apollo 13 was originally scheduled for launch on March 12, 1970; in January of that year, NASA announced the mission would be postponed until April 11, both to allow more time for planning and to spread the Apollo missions over a longer period of time.
The plan was to have two Apollo flights per year and was in response to budgetary constraints that had recently seen the cancellation of Apollo 20.
Training and preparation
![Lovell deploying the flag](https://upload.wikimedia.org/wikipedia/commons/5/5f/Lovell_deploying_the_flag.jpg)
The Apollo 13 prime crew undertook over 1,000 hours of mission-specific training, more than five hours for every hour of the mission's ten-day planned duration. Each member of the prime crew spent over 400 hours in simulators of the CM and (for Lovell and Haise) of the LM at KSC and at Houston, some of which involved the flight controllers at Mission Control. Flight controllers participated in many simulations of problems with the spacecraft in flight, which taught them how to react in an emergency.
Specialized simulators at other locations were also used by the crew members.
The astronauts of Apollo 11 had minimal time for geology training, with only six months between crew assignment and launch; higher priorities took much of their time. Apollo 12 saw more such training, including practice in the field, using a CAPCOM and a simulated backroom of scientists, to whom the astronauts had to describe what they saw. Scientist-astronaut
Harrison Schmitt
Harrison Hagan Schmitt (born July 3, 1935) is an American geologist, retired NASA astronaut, university professor, former U.S. senator from New Mexico, and the most recent living person—and only person without a background in military aviation ...
saw that there was limited enthusiasm for geology field trips. Believing an inspirational teacher was needed, Schmitt arranged for Lovell and Haise to meet his old professor,
Caltech
The California Institute of Technology (branded as Caltech or CIT)The university itself only spells its short form as "Caltech"; the institution considers other spellings such a"Cal Tech" and "CalTech" incorrect. The institute is also occasional ...
's
Lee Silver
Lee M. Silver (born 1952) is an American biologist. He is a professor at Princeton University in the Department of molecular biology of the Woodrow Wilson School of Public and International Affairs. He also has joint appointments in the Program i ...
. The two astronauts, and backups Young and Duke, went on a field trip with Silver at their own time and expense. At the end of their week together, Lovell made Silver their geology mentor, who would be extensively involved in the geology planning for Apollo 13.
Farouk El-Baz
Farouk El-Baz ( arz, فاروق الباز, ''Pronunciation'': ) (born January 2, 1938) is an Egyptian American space scientist and geologist, who worked with NASA in the scientific exploration of the Moon and the planning of the Apollo program. ...
oversaw the training of Mattingly and his backup, Swigert, which involved describing and photographing simulated lunar landmarks from airplanes. El-Baz had all three prime crew astronauts describe geologic features they saw during their flights between Houston and KSC; Mattingly's enthusiasm caused other astronauts, such as Apollo 14's CMP, Roosa, to seek out El-Baz as a teacher.
Concerned about how close Apollo 11's LM, ''Eagle'', had come to running out of propellant during its lunar descent, mission planners decided that beginning with Apollo 13, the CSM would bring the LM to the low orbit from which the landing attempt would commence. This was a change from Apollo 11 and 12, on which the LM made the burn to bring it to the lower orbit. The change was part of an effort to increase the amount of hover time available to the astronauts as the missions headed into rougher terrain.
The plan was to devote the first of the two four-hour lunar surface
extravehicular activities
Extravehicular activity (EVA) is any activity done by an astronaut in outer space outside a spacecraft. In the absence of a breathable Earthlike atmosphere, the astronaut is completely reliant on a space suit for environmental support. EVA inc ...
(EVAs) to setting up the
Apollo Lunar Surface Experiments Package (ALSEP) group of scientific instruments; during the second, Lovell and Haise would investigate
Cone crater, near the planned landing site. The two astronauts wore their spacesuits for some 20 walk-throughs of EVA procedures, including sample gathering and use of tools and other equipment. They flew in the "
Vomit Comet
A reduced-gravity aircraft is a type of fixed-wing aircraft that provides brief near-weightless environments for training astronauts, conducting research and making gravity-free movie shots.
Versions of such airplanes were operated by the NAS ...
" in simulated microgravity or lunar gravity, including practice in donning and doffing spacesuits. To prepare for the descent to the Moon's surface, Lovell flew the
Lunar Landing Training Vehicle
The Bell Aerosystems Lunar Landing Research Vehicle (LLRV, nicknamed the Flying Bedstead) was a Project Apollo era program to build a simulator for the Moon landings. The LLRVs were used by the FRC, now known as the NASA Armstrong Flight Resear ...
(LLTV). Despite four of the five LLTVs and similar Lunar Landing Research Vehicles having crashed during the Apollo program, mission commanders considered flying them invaluable experience.
Experiments and scientific objectives
![Lovell and Haise geology training (S70-20253)](https://upload.wikimedia.org/wikipedia/commons/1/1a/Lovell_and_Haise_geology_training_%28S70-20253%29.jpg)
Apollo 13's designated landing site was near
Fra Mauro crater; the
Fra Mauro formation was believed to contain much material spattered by the impact that had filled the
Imbrium basin
Mare Imbrium (Latin ''imbrium'', the "Sea of Showers" or "Sea of Rains", "Sea of Tears") is a vast lunar mare, lava plain within the Imbrium Basin on the Moon and is one of the larger craters in the Solar System. The Imbrium Basin formed fro ...
early in the Moon's history. Dating it would provide information not only about the Moon, but about the Earth's early history. Such material was likely to be available at Cone crater, a site where an impact was believed to have drilled deep into the lunar
regolith
Regolith () is a blanket of unconsolidated, loose, heterogeneous superficial deposits covering solid rock. It includes dust, broken rocks, and other related materials and is present on Earth, the Moon, Mars, some asteroids, and other terrestr ...
.
Apollo 11 had left a
seismometer
A seismometer is an instrument that responds to ground noises and shaking such as caused by earthquakes, volcanic eruptions, and explosions. They are usually combined with a timing device and a recording device to form a seismograph. The outpu ...
on the Moon, but the solar-powered unit did not survive its first two-week-long lunar night. The Apollo 12 astronauts
also left one as part of its ALSEP, which was nuclear-powered. Apollo 13 also carried a seismometer (known as the Passive Seismic Experiment, or PSE), similar to Apollo 12's, as part of its ALSEP, to be left on the Moon by the astronauts. That seismometer was to be calibrated by the impact, after jettison, of the ascent stage of Apollo 13's LM, an object of known mass and velocity impacting at a known location.
Other ALSEP experiments on Apollo 13 included a Heat Flow Experiment (HFE), which would involve drilling two holes deep. This was Haise's responsibility; he was also to drill a third hole of that depth for a core sample. A Charged Particle Lunar Environment Experiment (CPLEE) measured the protons and electrons of solar origin reaching the Moon. The package also included a Lunar Atmosphere Detector (LAD) and a Dust Detector, to measure the accumulation of debris. The Heat Flow Experiment and the CPLEE were flown for the first time on Apollo 13; the other experiments had been flown before.
![Haise RTG (Ap13-70-H-103)](https://upload.wikimedia.org/wikipedia/commons/b/b3/Haise_RTG_%28Ap13-70-H-103%29.jpg)
To power the ALSEP, the
SNAP-27 radioisotope thermoelectric generator (RTG) was flown. Developed by the
U.S. Atomic Energy Commission
The United States Atomic Energy Commission (AEC) was an agency of the United States government established after World War II by U.S. Congress to foster and control the peacetime development of atomic science and technology. President ...
, SNAP-27 was first flown on Apollo 12. The fuel capsule contained about of
plutonium oxide. The cask placed around the capsule for transport to the Moon was built with heat shields of graphite and of beryllium, and with structural parts of titanium and of
Inconel
Inconel is a registered trademark of Special Metals Corporation for a family of austenitic nickel-chromium-based superalloys.
Inconel alloys are oxidation-corrosion-resistant materials well suited for service in extreme environments subjected ...
materials. Thus, it was built to withstand the heat of reentry into the Earth's atmosphere rather than pollute the air with plutonium in the event of an aborted mission.
A United States flag was also taken, to be erected on the Moon's surface. For Apollo 11 and 12, the flag had been placed in a heat-resistant tube on the front landing leg; it was moved for Apollo 13 to the Modularized Equipment Stowage Assembly (MESA) in the LM descent stage.
The structure to fly the flag on the airless Moon was improved from Apollo 12's.
For the first time, red stripes were placed on the helmet, arms and legs of the commander's
A7L spacesuit. This was done as, after Apollo 11, those reviewing the images taken had trouble distinguishing Armstrong from Aldrin, but the change was approved too late for Apollo 12.
New drink bags that attached inside the helmets and were to be sipped from as the astronauts walked on the Moon were demonstrated by Haise during Apollo 13's final television broadcast before the accident.
Apollo 13's primary mission objectives were to: "Perform selenological inspection, survey, and sampling of materials in a preselected region of the Fra Mauro Formation. Deploy and activate an Apollo Lunar Surface Experiments Package. Develop man's capability to work in the lunar environment. Obtain photographs of candidate exploration sites." The astronauts were also to accomplish other photographic objectives, including of the
Gegenschein
Gegenschein (; ; ) or counterglow is a faintly bright spot in the night sky centered at the antisolar point. The backscatter of sunlight by interplanetary dust causes this optical phenomenon.
Explanation
Like zodiacal light, gegenschein is ...
from lunar orbit, and of the Moon itself on the journey back to Earth. Some of this photography was to be performed by Swigert as Lovell and Haise walked on the Moon. Swigert was also to take photographs of the
Lagrangian points of the Earth-Moon system. Apollo 13 had twelve cameras on board, including those for television and moving pictures. The crew was also to downlink
bistatic radar
Bistatic radar is a radar system comprising a transmitter and receiver that are separated by a distance comparable to the expected target distance. Conversely, a conventional radar in which the transmitter and receiver are co-located is called ...
observations of the Moon. None of these was attempted because of the accident.
Flight of Apollo 13
Launch and translunar injection
![Apolo-1](https://upload.wikimedia.org/wikipedia/commons/9/9a/Apolo-1._CSM%26LM_diagram.svg)
The mission was launched at the planned time, 2:13:00 pm
EST (19:13:00 UTC) on April 11. An anomaly occurred when the second-stage, center (inboard) engine shut down about two minutes early.
This was caused by severe
pogo oscillation
Pogo oscillation is a self-excited vibration in liquid-propellant rocket engines caused by combustion instability. The unstable combustion results in variations of engine thrust, causing variations of acceleration on the vehicle's flexible structu ...
s. Starting with Apollo 10, the vehicle's guidance system was designed to shut the engine down in response to chamber pressure excursions. Pogo oscillations had occurred on
Titan rockets (used during the
Gemini program) and on previous Apollo missions, but on Apollo 13 they were amplified by an interaction with turbopump
cavitation.
A fix to prevent pogo was ready for the mission, but schedule pressure did not permit the hardware's integration into the Apollo 13 vehicle. A post-flight investigation revealed the engine was one cycle away from catastrophic failure. The four outboard engines and the
S-IVB
The S-IVB (pronounced "S-four-B") was the third stage on the Saturn V and second stage on the Saturn IB launch vehicles. Built by the Douglas Aircraft Company, it had one J-2 rocket engine. For lunar missions it was fired twice: first for Earth ...
third stage burned longer to compensate, and the vehicle achieved very close to the planned circular
parking orbit
A parking orbit is a temporary orbit used during the launch of a spacecraft. A launch vehicle boosts into the parking orbit, then coasts for a while, then fires again to enter the final desired trajectory. The alternative to a parking orbit is ''di ...
, followed by a translunar injection (TLI) about two hours later, setting the mission on course for the Moon.
After TLI, Swigert performed the separation and transposition maneuvers before docking the CSM ''Odyssey'' to the LM ''Aquarius'', and the spacecraft pulled away from the third stage.
Ground controllers then sent the third stage on a course to impact the Moon in range of the Apollo 12 seismometer, which it did just over three days into the mission.
The crew settled in for the three-day trip to Fra Mauro. At 30:40:50 into the mission, with the TV camera running, the crew performed a burn to place Apollo 13 on a hybrid trajectory. The departure from a
free-return trajectory
In orbital mechanics, a free-return trajectory is a trajectory of a spacecraft traveling away from a primary body (for example, the Earth) where gravity due to a secondary body (for example, the Moon) causes the spacecraft to return to the primar ...
meant that if no further burns were performed, Apollo 13 would miss Earth on its return trajectory, rather than intercept it, as with a free return.
A free return trajectory could only reach sites near the lunar equator; a hybrid trajectory, which could be started at any point after TLI, allowed sites with higher latitudes, such as Fra Mauro, to be reached.
Communications were enlivened when Swigert realized that in the last-minute rush, he had omitted to file his
federal income tax return (due April 15), and amid laughter from mission controllers, asked how he could get an extension. He was found to be entitled to a 60-day extension for being out of the country at the deadline.
Entry into the LM to test its systems had been scheduled for 58:00:00; when the crew awoke on the third day of the mission, they were informed it had been moved up three hours and was later moved up again by another hour. A television broadcast was scheduled for 55:00:00; Lovell, acting as emcee, showed the audience the interiors of ''Odyssey'' and ''Aquarius''.
The audience was limited since none of the television networks were carrying the broadcast, forcing Marilyn Lovell (Jim Lovell's wife) to go to the VIP room at Mission Control if she wanted to watch her husband and his crewmates.
Accident
Approximately six and a half minutes after the TV broadcastapproaching 56:00:00Apollo 13 was about from Earth.
Haise was completing the shutdown of the LM after testing its systems while Lovell stowed the TV camera.
Jack Lousma
Jack Robert Lousma (born February 29, 1936) is an American astronaut, aeronautical engineer, retired United States Marine Corps officer, former naval aviator, NASA astronaut, and politician. He was a member of the second crew, Skylab-3, on ...
, the
CAPCOM, sent minor instructions to Swigert, including changing the
attitude
Attitude may refer to:
Philosophy and psychology
* Attitude (psychology), an individual's predisposed state of mind regarding a value
* Metaphysics of presence
* Propositional attitude, a relational mental state connecting a person to a pro ...
of the craft to facilitate photography of
Comet Bennett.
The pressure sensor in one of the SM's oxygen tanks had earlier appeared to be malfunctioning, so
Sy Liebergot
Seymour "Sy" Abraham Liebergot (born February 15, 1936 in Camden, New Jersey) is a retired NASA flight controller, serving during the Apollo program. Liebergot was an EECOM controller and was responsible for the electrical and environmental s ...
(the
EECOM, in charge of monitoring the CSM's electrical system) requested that the stirring fans in the tanks be activated. Normally this was done once daily; a stir would
destratify the contents of the tanks, making the pressure readings more accurate.
The Flight Director, Kranz, had Liebergot wait a few minutes for the crew to settle down after the telecast, then Lousma relayed the request to Swigert, who activated the switches controlling the fans,
and after a few seconds turned them off again.
Ninety-five seconds after Swigert activated those switches, the astronauts heard a "pretty large bang", accompanied by fluctuations in electrical power and the firing of the attitude control thrusters. Communications and telemetry to Earth were lost for 1.8 seconds, until the system automatically corrected by switching the
high-gain S-band antenna, used for translunar communications, from narrow-beam to wide-beam mode. The accident happened at 55:54:53 (03:08 UTC on April 14, 10:08 PM EST, April 13). Swigert reported 26 seconds later,
"Okay, Houston, we've had a problem here," echoed at 55:55:42 by Lovell, "Houston, we've had a problem. We've had a Main B Bus undervolt."
William Fenner was the
guidance officer (GUIDO) who was the first to report a problem in the control room to Kranz.
Lovell's initial thought on hearing the noise was that Haise had activated the LM's cabin-repressurization valve, which also produced a bang (Haise enjoyed doing so to startle his crewmates), but Lovell could see that Haise had no idea what had happened. Swigert initially thought that a
meteoroid
A meteoroid () is a small rocky or metallic body in outer space.
Meteoroids are defined as objects significantly smaller than asteroids, ranging in size from grains to objects up to a meter wide. Objects smaller than this are classified as mi ...
might have struck the LM, but he and Lovell quickly realized there was no leak. The "Main Bus B undervolt" meant that there was insufficient
voltage
Voltage, also known as electric pressure, electric tension, or (electric) potential difference, is the difference in electric potential between two points. In a static electric field, it corresponds to the work needed per unit of charge to ...
produced by the SM's three
fuel cells (fueled by hydrogen and oxygen piped from their respective tanks) to the second of the SM's two electric power distribution systems. Almost everything in the CSM required power. Although the bus momentarily returned to normal status, soon both buses A and B were short on voltage. Haise checked the status of the fuel cells and found that two of them were dead. Mission rules forbade entering lunar orbit unless all fuel cells were operational.
In the minutes after the accident, there were several unusual readings, showing that tank2 was empty and tank1's pressure slowly falling, that the
computer on the spacecraft had reset and that the high-gain antenna was not working. Liebergot initially missed the worrying signs from tank2 following the stir, as he was focusing on tank1, believing that its reading would be a good guide to what was present in tank2; so did controllers supporting him in the "back room". When Kranz questioned Liebergot on this, he initially responded that there might be false readings due to an instrumentation problem; he was often teased about that in the years to come.
Lovell, looking out the window, reported "a gas of some sort" venting into space, making it clear that there was a serious problem.
Since the fuel cells needed oxygen to operate, when Oxygen Tank1 ran dry, the remaining fuel cell would shut down, meaning the CSM's only significant sources of power and oxygen would be the CM's batteries and its oxygen "surge tank". These would be needed for the final hours of the mission, but the remaining fuel cell, already starved for oxygen, was drawing from the surge tank. Kranz ordered the surge tank isolated, saving its oxygen, but this meant that the remaining fuel cell would die within two hours, as the oxygen in tank1 was consumed or leaked away. The volume surrounding the spacecraft was filled with myriad small bits of debris from the accident, complicating any efforts to use the stars for navigation. The mission's goal became simply getting the astronauts back to Earth alive.
Looping around the Moon
![Direct Abort Trajectory - Lunar Landing Symposium, MSC Jun66](https://upload.wikimedia.org/wikipedia/commons/9/93/Direct_Abort_Trajectory_-_Lunar_Landing_Symposium%2C_MSC_Jun66.jpg)
The lunar module had charged batteries and full oxygen tanks for use on the lunar surface, so Kranz directed that the astronauts power up the LM and use it as a "lifeboat"
a scenario anticipated but considered unlikely. Procedures for using the LM in this way had been developed by LM flight controllers after a training simulation for Apollo 10 in which the LM was needed for survival, but could not be powered up in time.
Had Apollo 13's accident occurred on the return voyage, with the LM already jettisoned, the astronauts would have died,
as they would have following an explosion in lunar orbit, including one while Lovell and Haise walked on the Moon.
A key decision was the choice of return path. A "direct abort" would use the SM's main engine (the
Service Propulsion System
The Apollo command and service module (CSM) was one of two principal components of the United States Apollo spacecraft, used for the Apollo program, which landed astronauts on the Moon between 1969 and 1972. The CSM functioned as a mother shi ...
or SPS) to return before reaching the Moon. However, the accident could have damaged the SPS, and the fuel cells would have to last at least another hour to meet its power requirements, so Kranz instead decided on a longer route: the spacecraft would swing around the Moon before heading back to Earth. Apollo 13 was on the hybrid trajectory which was to take it to Fra Mauro; it now needed to be brought back to a free return. The LM's
Descent Propulsion System (DPS), although not as powerful as the SPS, could do this, but new software for Mission Control's computers needed to be written by technicians as it had never been contemplated that the CSM/LM spacecraft would have to be maneuvered from the LM. As the CM was being shut down, Lovell copied down its guidance system's orientation information and performed hand calculations to transfer it to the LM's guidance system, which had been turned off; at his request Mission Control checked his figures.
At 61:29:43.49 the DPS burn of 34.23 seconds took Apollo 13 back to a free return trajectory.
![Mare Moscoviense AS13-60-8648](https://upload.wikimedia.org/wikipedia/commons/9/97/Mare_Moscoviense_AS13-60-8648.jpg)
The change would get Apollo 13 back to Earth in about four days' timethough with splashdown in the
Indian Ocean
The Indian Ocean is the third-largest of the world's five oceanic divisions, covering or ~19.8% of the water on Earth's surface. It is bounded by Asia to the north, Africa to the west and Australia to the east. To the south it is bounded by t ...
, where NASA had few recovery forces. Jerry Bostick and other
Flight Dynamics Officers (FIDOs) were anxious both to shorten the travel time and to move splashdown to the
Pacific Ocean
The Pacific Ocean is the largest and deepest of Earth's five oceanic divisions. It extends from the Arctic Ocean in the north to the Southern Ocean (or, depending on definition, to Antarctica) in the south, and is bounded by the contin ...
, where the main recovery forces were located. One option would shave 36 hours off the return time, but required jettisoning the SM; this would expose the CM's heat shield to space during the return journey, something for which it had not been designed. The FIDOs also proposed other solutions. After a meeting involving NASA officials and engineers, the senior individual present,
Manned Spaceflight Center
The Lyndon B. Johnson Space Center (JSC) is NASA's center for human spaceflight (originally named the Manned Spacecraft Center), where human spaceflight training, research, and flight control are conducted. It was renamed in honor of the late ...
director
Robert R. Gilruth
Robert Rowe Gilruth (October 8, 1913 – August 17, 2000) was an American aerospace engineer and an aviation/space pioneer who was the first director of NASA's Manned Spacecraft Center, later renamed the Lyndon B. Johnson Space Center.
He worked ...
, decided on a burn using the DPS, that would save 12 hours and land Apollo 13 in the Pacific. This "PC+2" burn would take place two hours after
pericynthion, the closest approach to the Moon.
At pericynthion, Apollo 13 set the record (per the ''Guinness Book of World Records''), which still stands, for the highest absolute altitude attained by a crewed spacecraft: from Earth at 7:21 pm EST, April 14 (00:21:00 UTC April 15).
While preparing for the burn the crew was told that the S-IVB had impacted the Moon as planned, leading Lovell to quip, "Well, at least something worked on this flight."
Kranz's White team of mission controllers, who had spent most of their time supporting other teams and developing the procedures urgently needed to get the astronauts home, took their consoles for the PC+2 procedure. Normally, the accuracy of such a burn could be assured by checking the alignment Lovell had transferred to the LM's computer against the position of one of the stars astronauts used for navigation, but the light glinting off the many pieces of debris accompanying the spacecraft made that impractical. The astronauts used the one star available whose position could not be obscured – the Sun. Houston also informed them that the Moon would be centered in the commander's window of the LM as they made the burn, which was almost perfectless than 0.3 meters (1 foot) per second off.
The burn, at 79:27:38.95, lasted four minutes and 23 seconds. The crew then shut down most LM systems to conserve consumables.
Return to Earth
![Apollo13 apparatus](https://upload.wikimedia.org/wikipedia/commons/6/63/Apollo13_apparatus.jpg)
The LM carried enough oxygen, but that still left the problem of
removing carbon dioxide, which was absorbed by canisters of
lithium hydroxide
Lithium hydroxide is an inorganic compound with the formula LiOH. It can exist as anhydrous or hydrated, and both forms are white hygroscopic solids. They are soluble in water and slightly soluble in ethanol. Both are available commercially. While ...
pellets.
The LM's stock of canisters, meant to accommodate two astronauts for 45 hours on the Moon, was not enough to support three astronauts for the return journey to Earth. The CM had enough canisters, but they were of a different shape and size to the LM's, hence unable to be used in the LM's equipment. Engineers on the ground devised a way to bridge the gap, using plastic, covers ripped from procedures manuals, duct tape, and other items. NASA engineers referred to the improvised device as "the mailbox". The procedure for building the device was read to the crew by CAPCOM
Joseph Kerwin over the course of an hour, and it was built by Swigert and Haise; carbon dioxide levels began dropping immediately. Lovell later described this improvisation as "a fine example of cooperation between ground and space".
![Apollo 13 Hasselblad image from film magazine 62-JJ (cropped)](https://upload.wikimedia.org/wikipedia/commons/4/40/Apollo_13_Hasselblad_image_from_film_magazine_62-JJ_%28cropped%29.jpg)
The CSM's electricity came from fuel cells that produced water as a byproduct, but the LM was powered by
silver-zinc batteries
A silver zinc battery is a secondary cell that utilizes silver(I,III) oxide and zinc.
Overview
Silver zinc cells share most of the characteristics of the silver-oxide battery, and in addition, is able to deliver one of the highest specific ener ...
which did not, so both electrical power and water (needed for equipment cooling as well as drinking) would be critical. LM power consumption was reduced to the lowest level possible; Swigert was able to fill some drinking bags with water from the CM's water tap,
but even assuming rationing of personal consumption, Haise initially calculated they would run out of water for cooling about five hours before reentry. This seemed acceptable because the systems of Apollo 11's LM, once jettisoned in lunar orbit, had continued to operate for seven to eight hours even with the water cut off. In the end, Apollo 13 returned to Earth with of water remaining. The crew's ration was 0.2 liters (6.8 fl oz) of water per person per day; the three astronauts lost a total of among them, and Haise developed a
urinary tract infection
A urinary tract infection (UTI) is an infection that affects part of the urinary tract. When it affects the lower urinary tract it is known as a bladder infection (cystitis) and when it affects the upper urinary tract it is known as a kidne ...
.
This infection was probably caused by the reduced water intake, but microgravity and effects of cosmic radiation might have impaired his immune system's reaction to the pathogen.
Inside the darkened spacecraft, the temperature dropped as low as . Lovell considered having the crew don their spacesuits, but decided this would be too hot. Instead, Lovell and Haise wore their lunar EVA boots and Swigert put on an extra coverall. All three astronauts were cold, especially Swigert, who had got his feet wet while filling the water bags and had no lunar overshoes (since he had not been scheduled to walk on the Moon). As they had been told not to discharge their urine to space to avoid disturbing the trajectory, they had to store it in bags. Water condensed on the walls, though any condensation that may have been behind equipment panels caused no problems, partly because of the extensive electrical insulation improvements instituted after the
Apollo 1
Apollo 1, initially designated AS-204, was intended to be the first crewed mission of the Apollo program, the American undertaking to land the first man on the Moon. It was planned to launch on February 21, 1967, as the first low Earth orbita ...
fire. Despite all this, the crew voiced few complaints.
Flight controller
John Aaron
John W. Aaron (born 1943) is a former NASA engineer and was a flight controller during the Apollo program. He is widely credited with saving the Apollo 12 mission when it was struck by lightning soon after launch, and also played an important rol ...
, along with Mattingly and several engineers and designers, devised a procedure for powering up the command module from full shutdownsomething never intended to be done in flight, much less under Apollo 13's severe power and time constraints. The astronauts implemented the procedure without apparent difficulty: Kranz later credited all three astronauts having been test pilots, accustomed to having to work in critical situations with their lives on the line, for their survival.
Recognizing that the cold conditions combined with insufficient rest would hinder the time critical startup of the command module prior to reentry, at 133 hours into flight Mission Control gave Lovell the okay to fully power up the LM to raise the cabin temperature, which included restarting the LM's guidance computer. Having the LM's computer running enabled Lovell to perform a navigational sighting and calibrate the LM's IMU. With the lunar module's computer aware of its location and orientation, the command module's computer was later calibrated in a reverse of the normal procedures used to set up the LM, shaving steps from the restart process and increasing the accuracy of the
PGNCS-controlled reentry.
Reentry and splashdown
Despite the accuracy of the transearth injection, the spacecraft slowly drifted off course, necessitating a correction. As the LM's guidance system had been shut down following the PC+2 burn, the crew was told to use the line between night and day on the Earth to guide them, a technique used on NASA's Earth-orbit missions but never on the way back from the Moon.
This DPS burn, at 105:18:42 for 14 seconds, brought the projected entry flight path angle back within safe limits. Nevertheless, yet another burn was needed at 137:40:13, using the LM's
reaction control system
A reaction control system (RCS) is a spacecraft system that uses thrusters to provide attitude control and translation. Alternatively, reaction wheels are used for attitude control. Use of diverted engine thrust to provide stable attitude cont ...
(RCS) thrusters, for 21.5 seconds. The SM was jettisoned less than half an hour later, allowing the crew to see the damage for the first time, and photograph it. They reported that an entire panel was missing from the SM's exterior, the fuel cells above the oxygen tank shelf were tilted, that the high-gain antenna was damaged, and there was a considerable amount of debris elsewhere. Haise could see possible damage to the SM's engine bell, validating Kranz's decision not to use the SPS.
![Apollo13 splashdown](https://upload.wikimedia.org/wikipedia/commons/7/71/Apollo13_splashdown.jpg)
The last problem to be solved was how to separate the lunar module a safe distance away from the command module just before reentry. The normal procedure, in lunar orbit, was to release the LM and then use the service module's RCS to pull the CSM away, but by this point, the SM had already been released.
Grumman
The Grumman Aircraft Engineering Corporation, later Grumman Aerospace Corporation, was a 20th century American producer of military and civilian aircraft. Founded on December 6, 1929, by Leroy Grumman and his business partners, it merged in 1994 ...
, manufacturer of the LM, assigned a team of
University of Toronto
The University of Toronto (UToronto or U of T) is a public university, public research university in Toronto, Ontario, Canada, located on the grounds that surround Queen's Park (Toronto), Queen's Park. It was founded by royal charter in 1827 ...
engineers, led by senior scientist
Bernard Etkin, to solve the problem of how much air pressure to use to push the modules apart. The astronauts applied the solution, which was successful.
The LM reentered Earth's atmosphere and was destroyed, the remaining pieces falling in the deep ocean.
Apollo 13's final midcourse correction had addressed the concerns of the Atomic Energy Commission, which wanted the cask containing the plutonium oxide intended for the SNAP-27 RTG to land in a safe place. The impact point was over the
Tonga Trench in the Pacific, one of its deepest points, and the cask sank to the bottom. Later helicopter surveys found no radioactive leakage.
Ionization of the air around the command module during reentry would typically cause a four-minute communications blackout. Apollo 13's shallow reentry path lengthened this to six minutes, longer than had been expected; controllers feared that the CM's heat shield had failed. ''Odyssey'' regained radio contact and splashed down safely in the South Pacific Ocean, , southeast of
American Samoa
American Samoa ( sm, Amerika Sāmoa, ; also ' or ') is an unincorporated territory of the United States located in the South Pacific Ocean, southeast of the island country of Samoa. Its location is centered on . It is east of the Internationa ...
and from the recovery ship,
USS ''Iwo Jima''. Although fatigued, the crew was in good condition except for Haise, who had developed a serious urinary tract infection because of insufficient water intake. The crew stayed overnight on the ship and flew to
Pago Pago
Pago Pago ( ; Samoan: )Harris, Ann G. and Esther Tuttle (2004). ''Geology of National Parks''. Kendall Hunt. Page 604. . is the territorial capital of American Samoa. It is in Maoputasi County on Tutuila, which is American Samoa's main island. ...
,
American Samoa
American Samoa ( sm, Amerika Sāmoa, ; also ' or ') is an unincorporated territory of the United States located in the South Pacific Ocean, southeast of the island country of Samoa. Its location is centered on . It is east of the Internationa ...
, the next day. They flew to Hawaii, where President
Richard Nixon
Richard Milhous Nixon (January 9, 1913April 22, 1994) was the 37th president of the United States, serving from 1969 to 1974. A member of the Republican Party, he previously served as a representative and senator from California and was ...
awarded them the
Presidential Medal of Freedom
The Presidential Medal of Freedom is the highest civilian award of the United States, along with the Congressional Gold Medal. It is an award bestowed by the president of the United States to recognize people who have made "an especially merit ...
, the highest civilian honor. They stayed overnight, and then were flown back to Houston.
En route to Honolulu, President Nixon stopped at Houston to award the Presidential Medal of Freedom to the Apollo 13 Mission Operations Team.
He originally planned to give the award to NASA administrator
Thomas O. Paine
Thomas Otten Paine (November 9, 1921 – May 4, 1992) was an American engineer, scientist and advocate of space exploration, and was the third Administrator of NASA, serving from March 21, 1969, to September 15, 1970.
During his administratio ...
, but Paine recommended the mission operations team.
Public and media reaction
![Jim Lovell newspaper](https://upload.wikimedia.org/wikipedia/commons/b/b6/Jim_Lovell_newspaper.jpg)
Worldwide interest in the Apollo program was reawakened by the incident; television coverage was seen by millions. Four Soviet ships headed toward the landing area to assist if needed, and other nations offered assistance should the craft have to splash down elsewhere. President Nixon canceled appointments, phoned the astronauts' families, and drove to NASA's
Goddard Space Flight Center in
Greenbelt, Maryland
Greenbelt is a city in Prince George's County, Maryland, United States, and a suburb of Washington, D.C. At the 2020 census, the population was 24,921.
Greenbelt is the first and the largest of the three experimental and controversial New D ...
, where Apollo's tracking and communications were coordinated.
The rescue received more public attention than any spaceflight to that point, other than the first Moon landing on Apollo 11. There were worldwide headlines, and people surrounded television sets to get the latest developments, offered by networks who interrupted their regular programming for bulletins.
Pope Paul VI
Pope Paul VI ( la, Paulus VI; it, Paolo VI; born Giovanni Battista Enrico Antonio Maria Montini, ; 26 September 18976 August 1978) was head of the Catholic Church and sovereign of the Vatican City State from 21 June 1963 to his death in Augus ...
led a congregation of 10,000 people in praying for the astronauts' safe return; ten times that number offered prayers at a religious festival in India. The
United States Senate
The United States Senate is the upper chamber of the United States Congress, with the House of Representatives being the lower chamber. Together they compose the national bicameral legislature of the United States.
The composition and pow ...
on April 14 passed a resolution urging businesses to pause at 9:00pm local time that evening to allow for employee prayer.
An estimated 40million Americans watched Apollo13's splashdown, carried live on all three networks, with another 30million watching some portion of the six and one-half hour telecast. Even more outside the U.S. watched.
Jack Gould
John Ludlow Gould (February 5, 1914 – May 24, 1993) was an American journalist and critic, who wrote commentary about television.
Early life and education
Gould was born in New York City into a socially prominent family and attended the Loomi ...
of ''
The New York Times
''The New York Times'' (''the Times'', ''NYT'', or the Gray Lady) is a daily newspaper based in New York City with a worldwide readership reported in 2020 to comprise a declining 840,000 paid print subscribers, and a growing 6 million paid d ...
'' stated that Apollo13, "which came so close to tragic disaster, in all probability united the world in mutual concern more fully than another successful landing on the Moon would have".
Investigation and response
Review board
![Apollo13 tank2](https://upload.wikimedia.org/wikipedia/commons/5/5c/Apollo13_tank2.jpg)
Immediately upon the crew's return, NASA Administrator Paine and Deputy Administrator
George Low
George Michael Low (born Georg Michael Löw, June 10, 1926 – July 17, 1984) was an administrator at NASA and the 14th president of Rensselaer Polytechnic Institute. Low was one of the senior NASA officials who made numerous decisions as m ...
appointed a review boardchaired by NASA
Langley Research Center Director
Edgar M. Cortright and including Neil Armstrong and six othersto investigate the accident.
The board's final report, sent to Paine on June 15,
found that the failure began in the service module's number2 oxygen tank. Damaged
Teflon
Polytetrafluoroethylene (PTFE) is a synthetic fluoropolymer of tetrafluoroethylene that has numerous applications. It is one of the best-known and widely applied PFAS. The commonly known brand name of PTFE-based composition is Teflon by Chemo ...
insulation on the wires to the stirring fan inside Oxygen Tank2 allowed the wires to
short circuit
A short circuit (sometimes abbreviated to short or s/c) is an electrical circuit that allows a current to travel along an unintended path with no or very low electrical impedance. This results in an excessive current flowing through the circui ...
and ignite this insulation. The resulting fire increased the pressure inside the tank until the tank dome failed, filling the fuel cell bay (SM Sector4) with rapidly expanding gaseous oxygen and combustion products. The pressure rise was sufficient to pop the rivets holding the aluminum exterior panel covering Sector4 and blow it out, exposing the sector to space and snuffing out the fire. The detached panel hit the nearby high-gain antenna, disabling the narrow-beam communication mode and interrupting communication with Earth for 1.8 seconds while the system automatically switched to the backup wide-beam mode. The sectors of the SM were not airtight from each other, and had there been time for the entire SM to become as pressurized as Sector4, the force on the CM's heat shield would have separated the two modules. The report questioned the use of Teflon and other materials shown to be flammable in supercritical oxygen, such as aluminum, within the tank. The board found no evidence pointing to any other theory of the accident.
Mechanical shock forced the oxygen valves closed on the number1 and number3 fuel cells, putting them out of commission. The sudden failure of Oxygen Tank2 compromised Oxygen Tank1, causing its contents to leak out, possibly through a damaged line or valve, over the next 130 minutes, entirely depleting the SM's oxygen supply. With both SM oxygen tanks emptying, and with other damage to the SM, the mission had to be aborted. The board praised the response to the emergency: "The imperfection in Apollo 13 constituted a near disaster, averted only by outstanding performance on the part of the crew and the ground control team which supported them."
Oxygen Tank 2 was manufactured by the
Beech Aircraft Company of Boulder, Colorado, as subcontractor to
North American Rockwell
North American Aviation (NAA) was a major American aerospace manufacturer that designed and built several notable aircraft and spacecraft. Its products included: the T-6 Texan trainer, the P-51 Mustang fighter, the B-25 Mitchell bomber, the F- ...
(NAR) of Downey, California, prime contractor for the CSM. It contained two thermostatic switches, originally designed for the command module's 28-volt DC power, but which could fail if subjected to the 65 volts used during ground testing at KSC. Under the original 1962 specifications, the switches would be rated for 28 volts, but revised specifications issued in 1965 called for 65 volts to allow for quicker tank pressurization at KSC. Nonetheless, the switches Beech used were not rated for 65 volts.
At NAR's facility, Oxygen Tank 2 had been originally installed in an oxygen shelf placed in the
Apollo 10
Apollo 10 (May 18–26, 1969) was a human spaceflight, the fourth crewed mission in the United States Apollo program, and the second (after Apollo8) to orbit the Moon. NASA described it as a "dress rehearsal" for the first Moon landing, and ...
service module, SM-106, but which was removed to fix a potential
electromagnetic interference problem and another shelf substituted. During removal, the shelf was accidentally dropped at least , because a retaining bolt had not been removed. The probability of damage from this was low, but it is possible that the fill line assembly was loose and made worse by the fall. After some retesting (which did not include filling the tank with liquid oxygen), in November 1968 the shelf was re-installed in SM-109, intended for Apollo 13, which was shipped to KSC in June 1969.
The
Countdown Demonstration Test took place with SM-109 in its place near the top of the Saturn V and began on March 16, 1970. During the test, the cryogenic tanks were filled, but Oxygen Tank 2 could not be emptied through the normal drain line, and a report was written documenting the problem. After discussion among NASA and the contractors, attempts to empty the tank resumed on March 27. When it would not empty normally, the heaters in the tank were turned on to boil off the oxygen. The thermostatic switches were designed to prevent the heaters from raising the temperature higher than , but they failed under the 65-volt power supply applied. Temperatures on the heater tube within the tank may have reached , most likely damaging the Teflon insulation. The temperature gauge was not designed to read higher than , so the technician monitoring the procedure detected nothing unusual. This heating had been approved by Lovell and Mattingly of the prime crew, as well as by NASA managers and engineers. Replacement of the tank would have delayed the mission by at least a month.
The tank was filled with liquid oxygen again before launch; once electric power was connected, it was in a hazardous condition. The board found that Swigert's activation of the Oxygen Tank2 fan at the request of Mission Control caused an
electric arc
An electric arc, or arc discharge, is an electrical breakdown of a gas that produces a prolonged electrical discharge. The current through a normally nonconductive medium such as air produces a plasma; the plasma may produce visible light. An ...
that set the tank on fire.
The board conducted a test of an oxygen tank rigged with hot-wire ignitors that caused a rapid rise in temperature within the tank, after which it failed, producing telemetry similar to that seen with the Apollo 13 Oxygen Tank 2. Tests with panels similar to the one that was seen to be missing on SM Sector4 caused separation of the panel in the test apparatus.
Changes in response
![Apollo 14 redesigned oxygen tank (S71-16745)](https://upload.wikimedia.org/wikipedia/commons/4/42/Apollo_14_redesigned_oxygen_tank_%28S71-16745%29.jpg)
For
Apollo 14 and subsequent missions, the oxygen tank was redesigned, the thermostats being upgraded to handle the proper voltage. The heaters were retained since they were necessary to maintain oxygen pressure. The stirring fans, with their unsealed motors, were removed, which meant the oxygen quantity gauge was no longer accurate. This required adding a third tank so that no tank would go below half full. The third tank was placed in Bay1 of the SM, on the side opposite the other two, and was given an isolation valve that could isolate it from the fuel cells and from the other two oxygen tanks in an emergency and allow it to feed the CM's environmental system only. The quantity probe was upgraded from aluminum to stainless steel.
All electrical wiring in Bay4 was sheathed in stainless steel. The fuel cell oxygen supply valves were redesigned to isolate the Teflon-coated wiring from the oxygen. The spacecraft and Mission Control monitoring systems were modified to give more immediate and visible warnings of anomalies. An emergency supply of of water was stored in the CM, and an emergency battery, identical to those that powered the LM's descent stage, was placed in the SM. The LM was modified to make transfer of power from the LM to the CM easier.
Aftermath
![President Richard Nixon speaks before awarding the Apollo 13 astronauts the Presidential Medal of Freedom](https://upload.wikimedia.org/wikipedia/commons/1/18/President_Richard_Nixon_speaks_before_awarding_the_Apollo_13_astronauts_the_Presidential_Medal_of_Freedom.jpg)
On February 5, 1971,
Apollo 14's LM, ''Antares'', landed on the Moon with astronauts
Alan Shepard
Alan Bartlett Shepard Jr. (November 18, 1923 – July 21, 1998) was an American astronaut, naval aviator, test pilot, and businessman. In 1961, he became the second person and the first American to travel into space and, in 1971, he beca ...
and
Edgar Mitchell aboard, near Fra Mauro, the site Apollo 13 had been intended to explore. Haise served as CAPCOM during the descent to the Moon, and during the second EVA, during which Shepard and Mitchell explored near Cone crater.
None of the Apollo 13 astronauts flew in space again. Lovell retired from NASA and the Navy in 1973, entering the private sector.
Swigert was to have flown on the 1975
Apollo–Soyuz Test Project
Apollo–Soyuz was the first crewed international space mission, carried out jointly by the United States and the Soviet Union in July 1975. Millions of people around the world watched on television as a United States Apollo spacecraft docked ...
(the first joint mission with the Soviet Union) but was removed as part of the fallout from the
Apollo 15 postal covers incident
The Apollo 15 postal covers incident, a 1972 NASA scandal, involved the astronauts of Apollo 15, who carried about 400 unauthorized postal covers into space and to the Moon's surface on the Lunar Module ''Falcon''. Some of the envelopes were ...
. He took a leave of absence from NASA in 1973 and left the agency to enter politics, being elected to the House of Representatives in 1982, but died of cancer before he could be sworn in. Haise was slated to have been the commander of the canceled
Apollo 19 mission, and flew the
Space Shuttle
The Space Shuttle is a retired, partially reusable low Earth orbital spacecraft system operated from 1981 to 2011 by the U.S. National Aeronautics and Space Administration (NASA) as part of the Space Shuttle program. Its official program ...
Approach and Landing Tests before retiring from NASA in 1979.
Several experiments were completed during Apollo 13, even though the mission did not land on the Moon.
One involved the launch vehicle's
S-IVB
The S-IVB (pronounced "S-four-B") was the third stage on the Saturn V and second stage on the Saturn IB launch vehicles. Built by the Douglas Aircraft Company, it had one J-2 rocket engine. For lunar missions it was fired twice: first for Earth ...
(the Saturn V's third stage), which on prior missions had been sent into solar orbit once detached. The seismometer left by Apollo 12 had detected frequent impacts of small objects onto the Moon, but larger impacts would yield more information about the Moon's crust, so it was decided that, beginning with Apollo 13, the S-IVB would be crashed into the Moon. The impact occurred at 77:56:40 into the mission and produced enough energy that the gain on the seismometer, from the impact, had to be reduced. An experiment to measure the amount of atmospheric electrical phenomena during the ascent to orbitadded after Apollo 12 was struck by lightningreturned data indicating a heightened risk during marginal weather. A series of photographs of Earth, taken to test whether cloud height could be determined from
synchronous satellites, achieved the desired results.
As a joke, Grumman issued an invoice to North American Rockwell, prime contractor for the CSM, for "towing" the CSM most of the way to the Moon and back. Line items included 400001 miles at $1 each (plus $4 for the first mile); $536.05 for battery charging; oxygen; and four nights at $8 per night for an "additional guest in room" (Swigert). After a 20% "commercial discount", and a 2% discount for timely payment, the final total was $312,421.24. North American declined payment, noting that it had ferried three previous Grumman LMs to the Moon without compensation.
![Apollo13 CommandModule Kansas](https://upload.wikimedia.org/wikipedia/commons/b/ba/Apollo13_CommandModule_Kansas.JPG)
The CM was disassembled for testing and parts remained in storage for years; some were used for a trainer for the
Skylab Rescue Mission. That trainer was subsequently displayed at the
Kentucky Science Center
The Kentucky Science Center, previously known as the Louisville Museum of Natural History & Science and then Louisville Science Center, is Kentucky's largest science museum. Located in Louisville, Kentucky, on "Museum Row" in the West Main Dist ...
. Max Ary of the
Cosmosphere
Cosmosphere is a space museum and STEM education center in Hutchinson, Kansas, United States. It was previously known as the Kansas Cosmosphere. The museum houses over 13,000 spaceflight artifacts—the largest combined collection of US and ...
made it a project to restore ''Odyssey''; it is on display there, in
Hutchinson, Kansas
Hutchinson is the largest city and county seat in Reno County, Kansas, United States, and located on the Arkansas River. It has been home to salt mines since 1887, thus its nickname of "Salt City", but locals call it "Hutch". As of the 2020 ...
.
Apollo 13 was called a "successful failure" by Lovell.
Mike Massimino
Michael James Massimino (born August 19, 1962) is an American professor of mechanical engineering at Columbia University and a former NASA astronaut. He is the senior advisor of space programs at the Intrepid Sea, Air & Space Museum.
Early ...
, a
Space Shuttle
The Space Shuttle is a retired, partially reusable low Earth orbital spacecraft system operated from 1981 to 2011 by the U.S. National Aeronautics and Space Administration (NASA) as part of the Space Shuttle program. Its official program ...
astronaut, stated that Apollo 13 "showed teamwork, camaraderie and what NASA was really made of".
The response to the accident has been repeatedly called "NASA's finest hour";
it is still viewed that way.
Author
Colin Burgess wrote, "the life-or-death flight of Apollo 13 dramatically evinced the colossal risks inherent in manned spaceflight. Then, with the crew safely back on Earth, public apathy set in once again."
William R. Compton, in his book about the Apollo Program, said of Apollo 13, "Only a heroic effort of real-time improvisation by mission operations teams saved the crew." Rick Houston and
Milt Heflin, in their history of Mission Control, stated, "Apollo 13 proved mission control could bring those space voyagers back home again when their lives were on the line." Former NASA chief historian
Roger D. Launius
Roger D. Launius (born May 15, 1954) is an American historian and author of Lithuanian descent, a former chief historian of NASA. He retired in 2016 as Associate Director for Collections and Curatorial Affairs for the Smithsonian National Air ...
wrote, "More than any other incident in the history of spaceflight, recovery from this accident solidified the world's belief in NASA's capabilities". Nevertheless, the accident convinced some officials, such as Manned Spaceflight Center director Gilruth, that if NASA kept sending astronauts on Apollo missions, some would inevitably be killed, and they called for as quick an end as possible to the program. Nixon's advisers recommended canceling the remaining lunar missions, saying that a disaster in space would cost him political capital. Budget cuts made such a decision easier, and during the pause after Apollo 13, two missions were canceled, meaning that the program ended with
Apollo 17 in December 1972.
Popular culture, media and 50th anniversary
![Universal Studios Hollywood 2012 58](https://upload.wikimedia.org/wikipedia/commons/5/56/Universal_Studios_Hollywood_2012_58.jpg)
The 1974 movie ''
Houston, We've Got a Problem'', while set around the Apollo 13 incident, is a fictional drama about the crises faced by ground personnel when the emergency disrupts their work schedules and places further stress on their lives. Lovell publicly complained about the movie, saying it was "fictitious and in poor taste".
"Houston... We've Got a Problem" was the title of an episode of the
BBC #REDIRECT BBC #REDIRECT BBC
Here i going to introduce about the best teacher of my life b BALAJI sir. He is the precious gift that I got befor 2yrs . How has helped and thought all the concept and made my success in the 10th board exam. ...
...
documentary series ''A Life At Stake'', broadcast in March 1978. This was an accurate, if simplified, reconstruction of the events. In 1994, during the
, PBS released a 90-minute documentary titled ''Apollo 13: To the Edge and Back''.
Following the flight, the crew planned to write a book, but they all left NASA without starting it. After Lovell retired in 1991, he was approached by journalist
about writing a non-fiction account of the mission. Swigert died in 1982 and Haise was no longer interested in such a project. The resultant book, ''
'', was published in 1994.
The next year, in 1995, a film adaptation of the book, ''
as Marilyn Lovell. James Lovell, Kranz, and other principals have stated that this film depicted the events of the mission with reasonable accuracy, given that some
was taken. For example, the film changes the tense of Lovell's famous follow-up to Swigert's original words from, "Houston, we've had a problem" to "
".
", uttered by Harris as Kranz in the film; the phrase became so closely associated with Kranz that he used it for the title of his 2000 autobiography.
The film won two of the nine Academy Awards it was nominated for, Best Film Editing and Best Sound.
In the 1998 miniseries ''
'', co-produced by Hanks and Howard, the mission is dramatized in the episode "We Interrupt This Program". Rather than showing the incident from the crew's perspective as in the ''Apollo 13'' feature film, it is instead presented from an Earth-bound perspective of television reporters competing for coverage of the event.
In 2020, the
began airing ''13 Minutes to the Moon'', radio programs which draw on NASA audio from the mission, as well as archival and recent interviews with participants. Episodes began airing for Season 2 starting on March 8, 2020, with episode 1, "Time bomb: Apollo 13", explaining the launch and the explosion. Episode 2 details Mission Control's denial and disbelief of the accident, with other episodes covering other aspects of the mission. The seventh and final episode was delayed due to the
. In "Delay to Episode 7", the BBC explained that the presenter of the series, medical doctor
, had been called into service.
In advance of the 50th anniversary of the mission in 2020, an
site for the mission went online, allowing viewers to follow along as the mission unfolds, view photographs and video, and listen to audio of conversations between Houston and the astronauts as well as between mission controllers. Due to the COVID-19 pandemic, NASA did not hold any in-person events during April 2020 for the flight's 50th anniversary, but premiered a new documentary, ''Apollo 13: Home Safe'' on April 10, 2020. A number of events were rescheduled for later in 2020.
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