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[April 22, 1970] “Houston, We’ve had a Problem Here!” (Apollo-13 emergency in space)

April 22, 2025 Kaye Dee Leave a comment

[New to the Journey? Read this for a brief introduction!]

by Kaye Dee

We all breathed a sigh of relief when the astronauts of Apollo-13 returned to Earth safely a few days ago, after the Apollo programmes’ first (and hopefully last) inflight emergency, but superstitious people are claiming that Apollo-13 was unlucky because of a prevalence of “13s”! After all, the mission was launched at 13:13 Houston time (but somewhere in the world there will always be a place where the time is 13: something!) and the explosion that caused its inflight emergency occurred on 13 April (but only in certain timezones – it was already 14 April in Australia and most of the world east of the United States).

Don’t tell me the Apollo-13 crew were “unlucky”; in fact, they were immensely lucky that when something did go wrong they were a team with the right skills for the situation. As seasoned test pilots, the crew were experienced at working in critical situations with their lives on the line, and their professional skills as astronauts were matched by the “tough and competent” (to quote Flight Director Mr. Gene Kranz) Mission Control teams, backed by highly trained engineers and scientists – all determined to “return them safely to the Earth”, just as President Kennedy committed NASA to do when he set the goal of a manned lunar landing by 1970!

Timeline of major mission events during Apollo-13

Crew Switcheroo
The prime crew for Apollo-13 changed multiple times, the last alteration occurring just days before launch! Instead of rotating the Apollo-10 back-up crew to become the prime crew for Apollo-13 – the normal procedure – Director of Flight Crew Operations, Mr. Deke Slayton, designated astronauts Alan Shepard (Commander), Stuart Roosa (Command Module Pilot) and Edgar Mitchell (Lunar Module Pilot) as the Apollo-13 prime crew. However, although he was the first American in space, Captain Shepard had only recently returned to flight status after a lengthy medical issue. It was felt that he needed more training time, so in August 1969, his crew was swapped with the prime crew for Apollo-14.

The prime crew for Apollo 13 then became US Navy Captain James Lovell, as Commander, civilian Mr. Fred Haise as Lunar Module Pilot (LMP) and USAF Lt. Col. Ken Mattingly as Command Module Pilot (CMP).

Official crew portrait for Apollo-13. L.-R. Jim Lovell, Ken Mattingly and Fred Haise. They are shown with ancient scientific and navigation instruments hinting at the classical elements in the mission patch and callsigns

Unfortunately, just a week before launch back-up LMP Charles Duke contracted German measles (rubella) from a child and accidentally exposed both the prime and back-up crews to the disease. CMP Mattingly was found to have no immunity, and the astronauts’ medical team had serious concerns that he could become too sick to perform adequately during the flight if he began to experience symptoms of the disease.

Normally, NASA policy would dictate that the back-up crew step into the mission. However, since back-up LMP Duke also had the measles, this wasn’t feasible. Just three days before launch, the difficult decision was made to replace Lt. Col. Mattingly with Mr. Jack Swigert, the fortunately-immune back-up CMP. This made the final crew for Apollo-13 Lovell, Haise and Swigert. Astronaut Mattingly will be re-assigned to a later Apollo mission, probably Apollo 16.

The last minute Apollo-13 crew portrait, following the swap of Ken Mattingly to Jack Swigert

Who’s Who?
Although he announced his intention to retire from NASA prior to Apollo-13, 42-year-old Mission Commander James “Jim” Lovell is the world's most experienced astronaut, the record holder for the most time in space, with 572 hours aboard Gemini-7, Gemini-12 and Apollo-8!

Members of the fifth astronaut group, selected in 1966, Captain Lovell’s crewmates may have both been space rookies, but fortuitously they each had specialisations that provided vital knowledge and experience during the in-flight emergency.

Mr. Fred Haise, the Lunar Module pilot (LMP), is a 36-year-old aeronautical engineer, who was both a Marine Corps and Air National Guard fighter pilot. A civilian research pilot for NASA before his selection as an astronaut, Mr. Haise previously served as back-up LMP for Apollo-8 and 11. He is a specialist on the Lunar Module (LM), having spent fourteen months at the Grumman factory where the spacecraft are built.

Mr. John “Jack” Swigert, the Command Module Pilot (CMP), is 38 years old, with degrees in mechanical engineering and aerospace science. He has served in the US Air Force and in state Air National Guards and was an engineering test pilot immediately prior to his astronaut selection. A specialist in malfunctions of the Command and Lunar Modules, Mr. Swigert “practically wrote the book on spacecraft malfunctions.”

Knowledge from the Moon
It’s probably fortunate that, like Apollo-11, Captain Lovell’s original crew made the decision that the Apollo-13 mission patch would not carry their names: when the last minute crew swap occurred, no changes were required to the design. Instead of names, the Apollo-13 patch carries the motto “Ex Luna, Scientia”, Latin for “From the Moon, knowledge”. This references Apollo-13’s intended role as the second ‘H’-class mission, designed to demonstrate precision landing capability so that the crew could explore a specific site on the Moon. As a Navy officer, Captain Lovell derived the motto from that of the US Naval Academy, “Ex scientia, tridens ("From knowledge, sea power").

A powerful image of the Sun rising behind the horses of the god Apollo’s chariot forms the centrepiece of the design. As Apollo is the god of both the Sun and knowledge, this plays upon both the project name and the mission motto. Against the black background of space, the golden horses of Apollo prance over the Moon, their journey from the Earth (in the background) to the Moon depicted by a bright blue path. Artist Lumen Martin Winter, designer of the Apollo-13 mission patch, based the horses on a mural he previously painted for the St. Regis Hotel in New York City (below). Using Roman numerals for the mission number also complements the classical connections of the spacecraft names and callsigns.

Classical Callsigns
Captain Lovell drew upon classical mythology in selecting the Command Module callsign “Odyssey” – taken from Homer’s epic Greek poem. Since an “odyssey is “a long voyage with many changes of fortune”, it turned out to be an extremely appropriate choice indeed! The name was also a nod to the classic science fiction film "2001: a Space Odyssey".

For the Lunar Module, the crew selected the callsign “Aquarius”. Although the media have linked the callsign to the song in the musical “Hair”, it is actually meant to reference Aquarius, the cup-bearer of the Graeco-Roman gods, and bringer of water – the only water on the Moon being that carried there by the Apollo crew.

Medieval illustration of Aquarius watering the Earth

Preflight Preparations
Apollo-13’s launcher, AS-508, had some slight modifications compared to earlier Saturn-V vehicles, to prepare for the future J-class missions which will carry heavier payloads. New “spray-on insulation” was used for the liquid hydrogen propellent tanks in the S-II second stage. The rocket also carried additional fuel, as a test for future launches, making it the heaviest Saturn-V yet flown.

The intensive preparation for the Apollo-13 crew included over 1,000 hours of mission-specific training, with a much greater focus on geology, since the intended landing area in the hilly Fra Mauro formation (named for a 15th Century cartographer monk) is of significant geological interest. If rocks from this area could be dated, they might improve our understanding of the early geological history of both the Moon and the Earth. Scientist-astronaut Harrison Schmitt, himself a geologist, was heavily involved in the crew’s geological training.

Jim Lovell and Fred Haise during geology training in Hawaii

Due to the difficulty of distinguishing astronauts Armstrong and Aldrin from each other in Apollo-11 photographs, NASA introducec a means of differentiating crew members from each other on the Moon by adding red stripes on the helmet, arms and legs of the commander's spacesuit. This system will now be implemented on Apollo-14.

Experiments That Might Have Been
A major component of Apollo-13’s lunar surface activities would have been the installation of a new Apollo Lunar Surface Experiment Package (ALSEP), powered by a SNAP-27 radioisotope thermoelectric generator (RTG). This small nuclear generator contains 8.36lb of plutonium oxide. The fuel capsule is intended to withstand the heat of re-entry into the Earth's atmosphere in the event of an aborted mission, which means that Apollo-13’s RTG may have survived Aquarius’ re-entry on return to Earth, splashing down into a remote area of the southern Pacific Ocean.

Mission Commander Lovell practicing the deployment of an ALSEP instrument during training

Like Apollo-11 and 12, Apollo-13’s ALSEP included a seismometer (the Passive Seismic Experiment), which was to be calibrated by the impact of Aquarius’ ascent stage, a Lunar Atmosphere Detector (LAD) and a Dust Detector. New to the Apollo-13 instrument package was a Heat Flow Experiment (HFE), and a Charged Particle Lunar Environment Experiment (CPLEE), designed to measure solar protons and electrons reaching the Moon.

A Shakey Start
Originally scheduled for launch in March, Apollo-13 was delayed for a month while NASA re-considers how it will schedule the remaining Apollo missions out to Apollo-19, now that Apollo-20 has been axed due to President Nixon’s budget cuts.

The mission hit trouble right at the start: five and a half minutes after liftoff on Saturday 11 April (US time). The crew felt “a little vibration”, then the centre engine of the S-II stage shut down two minutes early. This required the remaining four engines to burn and additional 34 seconds longer, while the S-IVB third stage had to burn 9 seconds longer to put the spacecraft into orbit. But with the extra fuel on board for this flight, the engine failure fortunately didn’t cause any major problem.

A successful trans lunar injection burn placed Apollo-13 on course for the Moon, with the CSM and LM docking occurring 20 minutes’ later. Unlike previous lunar missions, after the LM was extracted from the S-IVB stage, the stage was not sent off into solar orbit, but targetted to impact the Moon so the vibrations could be detected by the Apollo-12 seismometer. This would later cause unexpected communications complications after the accident occurred.

Apollo-13's S-IVB stage heading towards the Moon

“We’re Bored to Tears”
With the spacecraft safely on its way to the Moon, the first phase of the flight was uneventful. Approaching 31 hours into the flight, the crew performed a burn to place Apollo 13 on a hybrid trajectory, enabling Aquarius to ultimately land at the Fra Mauro site. This change from the free-return trajectory used on earlier missions would cause later complications for returning the astronauts to Earth: on a free-return trajectory, no further engine burns were necessary to ultimately bring the spacecraft home, but a hybrid trajectory would miss Earth on its return leg, unless further burns were performed.

Apollo-13 White Team Flight Director Mr. Gene Kranz catching up on his paperwork in Mission Control during the calm before the storm

The day after launch, Mr. Swigert became worried by the realisation that, in the rush to replace Ken Mattingly, he had forgotten to file his Income Tax Return, and needed to apply for an extension! Fortunately for him, an amused Mission Control advised that “American citizens out of the country get a 60-day extension on filing; assume this applies to you.”

With Apollo-13’s telemetry showing that the spacecraft was “in real good shape”, on 13 April Capcom Joe Kerwin told the crew “We are bored to tears down here.”—a situation that was soon to change.

The Last Apollo-13 Show
Astronauts Lovell and Haise entered the LM to test its systems about an hour before a major television broadcast, scheduled for 55 hours into the mission.

With Commander Lovell acting as MC, the astronauts put on a lively show, exhibiting some of their gear such as space helmets, sleeping hammocks and newly-designed bags for drinking water inside their spacesuits. From Odyssey, Captain Lovell played tinkly lounge music using a small tape recorder, and he said it was an awesome thing to see the Moon accompanied by the theme to 2001.

Mission Control during the Apollo-13 broadcast. Astronaut Fred Haise can be seen on the big screen

Disappointingly, American television viewers had become, it seems, even more bored than Mission Control with now-“routine” missions to the Moon. None of the major US networks carried the broadcasts, although they were seen in Australia and, I believe, other countries. Marilyn Lovell and Mary Haise had to go to the Mission Control VIP viewing room to see their husbands’ half hour broadcast on television.

“Houston, We’ve had a Problem Here!”
Just nine minutes after the conclusion of the television broadcast, at 205,000 miles from Earth, an incident occurred that turned Apollo-13 from a routine mission into an emergency situation: one that the media and anxious communities in the US and around the world would intently follow as soon as the news broke!

At the request of Mission Control, Mr. Swigert stirred the cryogenic hydrogen and oxygen tanks that powered the fuel cells in the Service Module (SM). This action was followed by a “pretty large bang”, felt as a jolt through the spacecraft, accompanied by fluctuations in electrical power, attitude control thrusters firing automatically and a brief loss of communications and telemetry to Earth.

Diagram of the Service Module showing the location of the fuel cells and oxygen tanks that must have been damaged by the explosion, based on the available telemtry

CMP Swigert quickly reported "Okay, Houston, we've had a problem here," confirmed moments later by the Mission Commander, "Houston, we've had a problem. We've had a Main B Bus undervolt”. This meant that the SM’s three fuel cells were not providing sufficient voltage to the second of the Service Module’s two electrical power distribution systems

Captain Lovell momentarily thought that LMP Haise had activated Aquarius’ cabin-repressurisation valve (which Haise could have done as a joke, since its bang would startle his crewmates); CMP Swigert initially thought that a meteoroid might have struck the LM, though there was no atmospheric leakage. But voltage was dropping in both electrical buses, one oxygen tank was empty, and the other leaking, and two of the three fuel cells were failing!

Headline from Australian newspaper "The Sun" just a few hours after the accident. It references Lovell's description of gas venting from the Service Module

Looking out Odyssey’s hatch window, seeking a cause for the spacecraft thrusters to be firing erratically and affecting their course to the Moon, Captain Lovell saw “gas of some sort” venting into space. Some kind of physical rupture had definitely occurred: whatever had caused the problem, the situation was serious.

Mission Control Swings into Action
Although the Flight Controllers in Houston initially assumed that their bizarre anomalous readings from Apollo-13 had to be the result of instrumentation issues, it quickly became obvious, judging from the reports from the crew, that they were dealing with a genuine emergency.

The Mission Control White Team, led by Flight Director Gene Kranz, was on duty when the incident occurred and had to deal with the initial hours afterwards. With extensive Flight Director experience going back to the Mercury programme, and including critical phases of the Apollo-11 mission, Mr. Kranz played a crucial role in the rescue of the Apollo-13 crew.

Flight Director Gene Kranz (seated) and senior Flight Controllers during the tense period following the Apollo-13 accident

With telemetry data providing some insight into the condition of the spacecraft, and support from “backroom” teams of technical specialists, White Team worked to diagnose the problems and prioritise recovery and rescue actions.

The fuel cells needed oxygen to operate, but it was rapidly leaking away. Attempting to stem the leak, they shut down the two failing fuel cells. This immediately meant the loss of the lunar landing, as mission rules prohibited going into orbit around the Moon unless all three fuel cells were functioning. With oxygen still being lost, Mr. Kranz ordered the isolation of a small oxygen supply within the Odyssey, to retain it for use with the last remaining fuel cell, which would be needed for the final hours of the mission. The CM's batteries would be needed to power the craft during re-entry, so they were also shut down to conserve power.

Lifeboat Aquarius
Ninety-three minutes after the accident, oxygen pressure in the Command Module was dropping and Mission Control determined that the last fuel cell would soon fail as oxygen ran out, leaving the CM effectively dead. Aware of training simulations that had used the LM as a “lifeboat”, Mission Control ordered the crew to transfer to Aquarius.

Lovell, Haise and Swigert had themselves already realised that Aquarius would be needed as a lifeboat, and had commenced to power-up the Lunar Module, transferring necessary information to the LM’s guidance system. They bagged up as much water as possible from Odyssey’s supply (needed for equipment cooling as well as drinking), storing the water and food supplies in Aquarius.

The Apollo-13 crew's only view of their lifeboat Aquarius in space, drifting after it was cast loose shortly before re-entry

It was going to be a tight fit for three astronauts in a spacecraft meant for two, but the crew were fortunate that the emergency occurred when they had a fully-powered and supplied Lunar Module attached to the Odyssey. Had the explosion occurred after the lunar landing, with Aquarius jettisoned, the CM would not be able to provide enough life support to keep the astronauts alive until they returned to Earth.

Apollo-13 was being surrounded by a cloud of debris from the explosion. Communications were weak and erratic, due to probable antenna damage from debris, as well as interference from the S-IVB stage also on its way to the Moon. Its tracking beacon was operating on the same frequency as the Lunar Module, as it had not been anticipated that the LM and S-IVB stage would be communicating at the same time. (I’ll cover this situation in more detail in an article in May).

Flight Controllers conferring on how best to bring Apollo-13 safely home. Note the lack of data usually present on the big screens

“Returning Them Safely to the Earth”
Apollo-13’s new mission goal became the safe return of the crew to the Earth. Vital consumables (oxygen, electricity, and water) were assessed and rationing plans devised. Calculating the best way to get the spacecraft back to Earth before supplies were exhausted became a priority, with the mindset that “failure is not an option”.

Ultimately, the safest course of action was deemed to be putting Apollo-13 back on a free-return trajectory, firing the LM’s descent engine so that the spaceship would loop around the Moon and head back to Earth. Using the large Service Module engine was ruled out, since it was uncertain if it had been damaged by the explosion.

NASA’s “Return to Earth” trajectory specialist, Miss Poppy Northcutt, calculated a new course to carry Apollo-13 around the Moon and safely home. Anxious to assist in any way they could, other astronauts arrived at Mission Control, including Lt. Col. Mattingly, who still had not developed German measles! Some would spend time in the Apollo simulators, helping to work up needed procedures, such as powering up the Command Module for re-entry with limited electricity available.

NASA Contollers and astronauts gathered in Mission Control to assist the rescue of Apollo-13. Seated, left to right, Guidance Officer Raymond F. Teague; astronaut Edgar D. Mitchell, Apollo 14 prime crew lunar module pilot; and astronaut Alan B. Shepard Jr., Apollo 14 prime crew commander. Standing, left to right, are scientist-astronaut Anthony W. England; astronaut Joe H. Engle, Apollo 14 backup crew lunar module pilot; astronaut Eugene A. Cernan, Apollo 14 backup crew commander; astronaut Ronald E. Evans, Apollo 14 backup crew command module pilot; and M.P. Frank, a flight controller

Sixty one and a half hours after launch, Aquarius’ descent engine burn put Apollo-13 back on a free return trajectory. As it looped around the Moon, Apollo-13 captured the Guinness World Record for the farthest distance from Earth attained by a crewed spacecraft – 248,655 miles.

The Moon's far side photographed by the Apollo-13 crew. The shut down CM Odyssey can also be seen in the foreground of this view from Aquarius

I’m sure you recall the tension during those 25 minutes of radio blackout when Apollo-13 was behind the Moon. People around the world tuned into television and radio, or gathered in public spaces, eager for news, now engrossed in the gripping drama being played out in space. Would the astronauts survive? Religious leaders led congregations in prayer for their safe return.

On Their Way Home
Mission Control determined that a burn following trans-Earth injection would shave 12 hours off the flight time back to Earth and land Apollo-13 in the Pacific, where the main US recovery fleet was located. Thirteen nations (another number 13!), including the USSR, offered to provide rescue ships or aircraft for emergency recovery, should the spacecraft come down off course in the Pacific, Indian or Atlantic Oceans.

When this crucial burn took place, the debris cloud surrounding the spacecraft made it impossible to use stellar navigation to check the accuracy of the firing. However, the crew were able to use the positions of the Sun and Moon to confirm that the trajectory was on target. They were going home!

The astronauts then shut down most LM systems to conserve consumables, making for a miserable return flight: in Aquarius it was extremely cold (38 °F), dark and damp, with moisture condensing out on every surface, including the windows. The same issue occurred in Odyssey, raising concerns of short-circuits occurring when it was powered back up. Fortunately, lessons learned from the Apollo-1 fire prevented that from happening.

Mission Commander Lovell tries to sleep in the extreme cold and semi-darkness of the Lunar Module

The crew slept poorly, eating and drinking little (cold frankfurters and water for dinner, anyone?). They lost weight, with Mr. Haise developing a urinary tract infection, apparently from dehydration.

Putting a Square Peg in a Round Hole
A new problem arose during the return journey – with three astronauts in the LM, dangerous levels of carbon dioxide were building up in Aquarius. They were running out of lithium hydroxide canisters, designed to scrub it from the air, and the square canisters used in Odyssey were not compatible with the round openings in Aquarius!

Jack Swigert, with assistance from Jim Lovell (just out of frame) assembles the connections for the makeshift CO2 scrubbing device nicknamed "the mailbox", which is box shaped object beside Swigert

NASA engineers fortunately found a way to fit “a square peg in a round hole,” using only items available on the spacecraft. After the instructions for building the device were radioed up, Swigert and Haise constructed it and carbon dioxide levels began dropping immediately.

The Final Leg
Apollo-13 showed a tendency to drift slowly off course, and two more mid-course correction burns were needed to keep the spacecraft within the safe re-entry flight path. Just after 138 hours into the mission, the crew jettisoned the SM from the command module, allowing the astronauts to see and photograph the explosion area for the first time. They were shocked by the extent of the damage they saw and concerned that the explosion might have damaged the heatshield.

The astronauts' only view of the Service Module, showing the extent of the damage caused by the explosion, which blew out an entire side panel.

Moving back into Odyssey, the astronauts then reactivated its life support systems, while retaining Aquarius until about 70 minutes before entry. With no heatshield of its own, the LM could not safely re-enter, but as it drifted away, watched sadly by the crew, Capcom Kerwin offered an epitaph from Mission Control: “Farewell Aquarius, and we thank you”.

There's no place like home! Earth taken from Apollo-13 in the final stages of its return from the Moon

Home at Last!
At last, on April 17 (US time),142 hours after launch, Apollo-13 re-entered Earth’s atmosphere. Its shallow re-entry path lengthened the usual four-minute radio communications blackout to six minutes, causing Mission Control to briefly fear that the CM's heat shield had failed. But Odyssey had survived and splashed down safely in the South Pacific Ocean south-east of American Samoa, just four miles from the recovery ship, USS Iwo Jima: total flight time: 5 days, 22 hours, 54 minutes and 41 seconds. Mission Control erupted in cheers!

While the world rejoiced at their safe return, the exhausted Apollo-13 crew stayed overnight on the recovery ship, without undergoing quarantine since they did not land on the Moon.

Exhausted but elated, the Apollo-13 crew are formally welcomed aboard the recovery ship, USS Iwo Jima as returning heroes after their space ordeal

The astronauts flew to Pago Pago in American Samoa the next day, then on to Hawaii, where they were re-united with their wives and President Nixon awarded them the Presidential Medal of Freedom, the highest US civilian honour. The Presidential Medal of Freedom was also awarded to the Apollo-13 Mission Operations Team, for their efforts in ensuring the safe return of the Apollo-13 crew. After staying overnight in Hawaii, Capt. Lovell, Mr. Haise and Mr. Swigert have now returned to Houston to be re-united with their families.

Returning heroes after their space ordeal. the Apollo-13 crew stand proudly with President Nixon after being awarded the Presidential Medal of Freedom

At present, the cause of the explosion that crippled Apollo-13 is unknown, so I will leave the speculation until my follow-up article in May, talking more about Apollo-13’s epic journey. I’d like to end here with the words of President Nixon, during the Presidential Medal of Freedom presentation: “You did not reach the Moon, but you reached the hearts of millions of people on Earth by what you did.”

The astronauts only learned about the extent of the pubic reaction to their emergency after they returned to Earth!

[New to the Journey? Read this for a brief introduction!]

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Science / Space Race

[August 4, 1969] A Small Step and a Giant Leap (Apollo-11, Part 2)

August 4, 2024 Kaye Dee 4 Comments

by Kaye Dee

The crew of Apollo-11 has returned home in triumph, splashing down safely in the Pacific Ocean on 24 July US time, at the end of their historic mission. The New York Times Editorial of 20 July has called their epic adventure “more than a step in history; it is a step in evolution.” Those footprints (well, bootprints, like Col. Aldrin's above) on the Moon mark the beginning of humanity's giant leap from its home planet into the cosmos.

Despite their hero status, right now the crew of Apollo-11 are pariahs – in quarantine to ensure that they have not brought home any nasty surprises from the Moon in the form of unknown pathogens. But alongside the treasure trove of Moonrocks, what they have brought home is a stunning visual record of Mankind's "greatest adventure", and I have waited a little to prepare this article so that it could be illustrated with many of the images taken during the flight (which had not been developed and distributed until now). I hope you’ll agree that it has been worth the delay.

The Apollo-11 mission has been epic in every sense of the word – so much so, that my intended two-part article has evolved into a three-part story, the final chapter to come after the astronauts are released from their quarantine.

A Smooth Cruise
At the end of Part 1, we left the Apollo-11 crew on their coast to the Moon, which was largely routine and uneventful. Despite the intrinsically dangerous nature of the Apollo-11 mission, the flight was, overall, probably the most trouble-free Apollo mission to date. Certainly, the Operations Supervisor at the Honeysuckle Creek Manned Space Flight (MSFN) Tracking Station has described it as “a very smooth mission from our perspective”, and I understand that Mission Control in Houston thought the same, despite the stresses inherent in such a historically significant undertaking as the first Moon landing.

Coming to You in Living Colour
34 hours into the flight, Mr. Armstrong, Col. Aldrin and Col. Collins gave their first public television broadcast. Highlights of the 36-minute transmission (in colour for those countries with colour TV service) included views of the Earth, Lunar Module (LM) Pilot Aldrin demonstrating zero-g push-ups and “Chef” Collins dishing up a space food chicken stew.

Compare the resolution of this photo taken by the crew with the television image of a similar view of the Earth at around 10,000 nautical miles

Another television transmission took place 55 hours after launch, with a 96-minute colour broadcast. Shown live in the US, Japan, western Europe and much of South America, this show again included views of the Earth, now 201,300 miles away. Viewers could see the removal of the probe and drogue docking apparatus and the opening of the spacecraft tunnel hatch to the LM, with Command Module (CM) Pilot Collins making jokes about his non-union “stagehands” (Armstrong and Aldrin).

Col. Aldrin entered the LM first, followed by Mr. Armstrong, providing a tour around the vehicle that would land the first human beings on the Moon. Aldrin also described the Moonwalking gear waiting to be used.

Aldrin in the LM during its first checkout. His sunglasses were specially developed by Australian ophthalmologist Dr. John Colvin

Into Lunar Orbit
On mission day four, Col. Collins swung the Command Service Module (CSM) around, so that the crew could look at the rapidly approaching Moon, its crater-pocked surface now filling their windows. As the spacecraft entered the Moon’s shadow, Mr. Armstrong noted “Now we are able to see stars again and recognise constellations for the first time on the trip. The sky is full of stars, just like the nights on Earth. But all the way here, we’ve only been able to see stars occasionally… but not recognise any star patterns.”

An eerie view approaching the Moon in its shadow, with the solar corona and dimly Earthlit craters appearing around the lunar rim

Like Apollo-8 and 10, the CSM engine burn required to place Apollo-11 into lunar orbit had to occur behind the Moon, with the crew out of direct contact with the Earth. Shortly before they disappeared behind the Moon, while in contact with the MSFN station near Madrid, the astronauts described the lunar surface they could see through their windows, with Col. Collins likening its colour to “Plaster of Paris grey.”

After a Trans-Lunar Coast that lasted for 73 hours, 5 minutes and 35 seconds, a 5 minute 57.53 second burn placed Apollo-11 exactly where it should be – in a lunar orbit of 195 by 69 miles. When reporting to Mission Control on the Lunar Orbit Insertion burn, once contact was re-established, Col. Collins could only say “It was like… perfect.”

Around the Moon
Orbiting the Moon, in their Columbia, like the heroes of Jules Verne’s “Autour de la Lune” (Around the Moon) in their Columbiad, at 78 hours and 20 minutes into the mission Armstrong, Aldrin and Collins offered viewers back on Earth a 40-minute live colour television transmission that showed spectacular views of the lunar surface and the approach path to the LM Eagle’s planned landing site. As the spacecraft prepared to go behind the Moon again, Aldrin quipped, “And as the Moon sinks slowly in the west, Apollo-11 bids good day to you,” paraphrasing Lowell Thomas’ famous travelogue sign-off to fit the occasion.

As Apollo-11 approached the Sea of Tranquility for the first time, it was early dawn on the surface below, with long, black shadows stretching across the cratered Moonscape.

Just over two hours later, CMP Collins initiated a second engine burn of 16.88 seconds, to place the spacecraft into an elliptical orbit, ready for the LM to depart for the lunar surface. This burn was critical, because if it was even two seconds too long it could put Apollo-11 on a collision course with the other side of the Moon!

Checking out the LM
A little over 81 hours after launch, during their fourth orbit of the Moon, LMP Aldrin entered the LM, to power up and checkout the spacecraft systems. Then Commander Armstrong and Col. Aldrin called Mission Control in Houston for the first time from the lunar landing vehicle, using the “Eagle” callsign.

A view of the approach to the Apollo-11 landing site, captured during the LM checkout period. It has been annotated with formal and unofficial names to show the approach path

Once this communications test was completed, the astronauts began to prepare for a sleep period. Collins suggested that Armstrong and Aldrin take the most comfortable sleeping positions in the Command Module, so they would get a good rest before the landing attempt. He was undoubtedly concerned about the possibility of an error due to overtiredness, which could have catastrophic consequences for the mission and the crew. The possibility of having to return to Earth alone if disaster should strike the lunar module crew seems to have weighed on Col. Collins’ mind, as he mentioned his understandable apprehension in several interviews prior to the flight.

Just before the sleep period, the astronauts captured another glorious vision of the Earth hovering above the lunar surface that is certain to become as iconic as Apollo-8’s Earthrise image

The Big Day Arrives
On 20 July (21 July in the eastern hemisphere, including Australia), astronauts Armstrong and Aldrin donned their spacesuits in the CM equipment bay, before entering Eagle for their descent to the lunar surface. After sealing the hatch and completing the final checkout of the LM, they extended Eagle’s landing gear and prepared to separate from the CSM.

This manoeuvre took place behind the Moon, during the 13th orbit, so as to place Eagle on the correct descent trajectory to touch down at the ALS-2 landing site. The LM moved away from Columbia and pirouetted around so that Col. Collins could inspect the vehicle and ensure that Eagle was totally ready for its historic descent to the Moon. “The Eagle has wings,” Armstrong assured Mission Control, as he and Aldrin put the craft through its paces. A nine-second Reaction Control System engine burn by the CSM then separated the two spacecraft to a safe distance apart

Meanwhile, Back in Mission Control
In focussing on the astronauts, it’s easy to forget the flight controllers and their support teams monitoring, guiding and approving every stage of a manned space flight.

Flight Director Kranz (second from right) in the MOCR

For the critical lunar landing phase of Apollo-11, the Mission Operations Control Room (MOCR), better known as Mission Control in Houston, was staffed by the White Team of flight controllers, under Flight Director, Mr. Eugene Kranz, usually known as Gene. The space specialists now filling roles that did not even exist outside the pages of science fiction a decade ago, have an average age of just 26 years! Rookie astronaut Charles Duke served as CAPCOM, the direct contact with the astronauts.

CAPCOM Duke, with Apollo-8's Jim Lovell, the Apollo-11 backup commander, listening in

As the time for Apollo-11’s historic landing approached, every available audio outlet in Mission Control had a headset plugged into it, to listen to the spacecraft communications channel. Senior NASA officials and astronauts, including Alan Shepard and John Glenn, positioned themselves in the MOCR to be eyewitnesses to the fulfillment of President Kennedy’s bold challenge of 1961. The families of the crew were also present.

The Eagle Stoops to the Moon
The Descent Orbit Insertion (DOI) burn needed to land Eagle safely on the Moon, required a 30 second firing of the LM descent engine. All the telemetry data being received at Mission Control indicted that everything was going to plan, but the landing on the Moon’s surface was (aside from re-entry) the most dangerous part of the flight: within forty minutes, the Eagle and its crew would either “land, crash or abort”, determining the success of the mission.

At 102:33:05.01 GET (Ground Elapsed Time) Eagle fired its descent engine to commence the landing sequence. Unexpectedly, the burn placed the LM 4.6 miles further downrange than planned, resulting in the landing point being 4.6 miles beyond the designated ALS-2 site. It seems the cause of this discrepancy was some residual pressure in the tunnel connecting the CM and LM when the two craft undocked (the tunnel should have been in vacuum, but had not been fully decompressed). This pushed the spacecraft apart with more velocity than planned.

With the LM’s legs facing the flight path, the astronauts were essentially flying backwards and unable to see where they were going, although they could see landmarks passing by and knew where they were as they descended towards the Moon’s surface.

Problems Arise
As the LM’s altitude decreased, the on-board radar data was critical for evaluation and comparison with altitude data from the tracking stations on Earth. But a potential electrical problem with the radar was just one of an increasing number of problems that began to arise as the LM dropped towards the lunar surface. Communications difficulties with Mission Control meant that Col. Collins in Columbia had to relay some messages between Houston and Eagle.

Nevertheless, when Flight Director Kranz polled his team, they were all prepared to give the “Go!” for powered descent. Guidance Officer Steve Bales had the only reservations, noting that the spacecraft was moving a little faster than planned. As a result, Eagle was going to land further downrange than planned, in what was expected to be a rockier area.

Abort?
At 102:38:22 GET the astronauts received a 1202 alarm, which meant their computer was overloaded by irrelevant data from the rendezvous radar (which should have been switched off) and couldn’t do all the tasks in the time available. Would the landing have to be aborted?

The backroom boys supporting Mission Control. They realised the alarms were minor issues

With the lives of Commander Armstrong and Col. Aldrin – and the success of the entire mission – in their hands, Guidance Officer Bales and his support team fortunately recognised the issue immediately and were able to give assurance that the computer would perform, nevertheless, and landing could proceed. When a similar 1201 alarm sounded, with Eagle just 2,000 ft above the lunar surface, they once again gave a positive response for the landing to continue.

Heading for Touchdown
With four minutes until touchdown, communications between the LM and Earth finally strengthened and stablised. Another rollcall of the flight controllers gave the landing the “Go!” to proceed.

At 9,000 ft, the LM began to drop its legs to point down to the Moon’s surface. Mission Commander Armstrong was trained to land the LM, controlling the spacecraft’s flight while looking out the window at the landing site. Col. Aldrin’s role was to concentrate on the display panel and provide Armstrong with the information he needed as he guided the Eagle safely down to the lunar surface. At this point, the flight control team back on Earth could do no more for the landing: everything now depended on the skill and teamwork of Armstrong and Aldrin.

Commander Armstrong flying the LM to touchdown in a training simulation

As an experienced test pilot, Neil Armstrong chose to fly the final landing phase (about the last ¾ of a mile to the touch down spot from a thousand feet) manually, like flying a helicopter. This enabled him to exercise his judgement to fly beyond the intended landing position, when it became clear that “a gigantic crater and lots of very big rocks” made it a very unfavourable position to touch down.

Time is Running Out!
Extending his downrange flight, Mr. Armstrong searched for a more suitable landing site, but time and fuel were fast running out. At around 250 ft altitude, an amber light warned that only 5 per cent fuel remained – there were only 94 seconds left to land! Approaching 100 ft above the Moon’s surface, the downblast of the LM’s descent engine began to stir up the dust, making it difficult for Armstrong to gauge their velocity, or sight a safe place to land, by observing surface features.

View from the LM window about 30 seconds before touchdown, with the shadow of an LM leg and contact probe against the lunar surface

Finally, with just 10 seconds of fuel left, as Armstrong saw the shadow of the LM stretching in front of him, Col. Aldrin called “Contact light!”, indicating that one of Eagle’s landing leg probes had touched the lunar surface. So gently that the crew barely noticed it, the first manned spacecraft from Earth touched down on the surface of the Moon! It was 102:45:40 GET, 15:17CDT on 20 July in the United States. (For us on the east coast of Australia, it was 6.17am on a cold winter’s morning!)

“The Eagle has Landed!”
Inside the Eagle, Mr. Armstrong and Col. Aldrin apparently looked across at each other and silently shook their space-gloved hands, celebrating the success of their flight in reaching the Moon’s surface. But as historic as that safe landing was, the astronauts had to immediately prepare the LM for a sudden abort ascent in the event the landing had damaged the Eagle, or some other emergency arose.

Eagle's shadow on the Moon's surface following the landing. This view was taken after the Moonwalk and the astronaut's bootprints can be seen on the surface

“Houston, Tranquility Base here. The Eagle has landed!” Apollo-11 Commander Armstrong announced proudly to Mission Control and the world, as soon as he was sure that Eagle had touched down safely. Since the descent stage of the LM will remain on the Moon (and presumably be designated as a historic monument in the future), it was an appropriate gesture to identify its landing site as Tranquility Base – Earth’s first outpost on another world.

In Mission Control, the flight controllers briefly celebrated, before Flight Director Kranz called for a “Stay/No Stay” decision from his team just one minute after landing. There were abort points at three and twelve minutes after landing – after that, the astronauts would have to wait for Columbia to go around the Moon again. At each decision point, flight controllers approved Eagle to stay on the lunar surface.

The Loneliest Man
While Eagle’s crew on the Moon were in constant communication with Mission Control, CMP Collins was orbiting the Moon, relying on events being relayed to him so that he knew what was happening. After forty minutes of complete isolation behind the Moon on each orbit, he could talk and listen to the Earth for seventy minutes, through either the Goldstone or Tidbinbilla DSN stations. However, he only had about eight minutes in direct contact with Eagle each time his orbit passed over Tranquility Base. Fortunately, Columbia was in the contact zone when Eagle was landing, so that he could hear the verbal exchanges of the touchdown, but his general communication isolation from the Earth, and from his crewmates, earned Mike Collins the nickname “the Loneliest Man”.

Where Did They Land?
Each time he passed over the Sea of Tranquility, Collins scanned the lunar surface for signs of the LM, hoping to spot the spacecraft (he never did) and any landmarks that would assist in identifying Eagle’s actual landing site: since Commander Armstrong had taken the LM further downrange than planned in search of a safe landing site, its exact position on the lunar surface was uncertain.
Annotated NASA image showing Collins' attempts to sight the Eagle's landing site. Very close, but no cigar!

Using huge lunar maps and data from the spacecraft and tracking stations, the Mapping Sciences Laboratory in Houston had narrowed the landing site down to a 5-mile radius, but Eagle’s crew could not identify anything of significance from their position. It wasn’t until Apollo-11 was halfway back to Earth that a chance remark by Mr. Armstrong finally helped the mappers to pinpoint the location of the landing site!

Going for a (Moon) Walk
Apollo-11’s flight plan called for a four-hour rest period after touching down on the Moon. However, as everything had gone according to schedule, the astronauts were eager to take their first steps on the lunar surface before their rest period. Two hours after landing, Armstrong requested Mission Control’s approval to postpone the scheduled sleep period and go out on the lunar surface straight away.

Mission Control concurred, and Armstrong and Aldrin began to carefully don their lunar Extravehicular Activity (EVA) spacesuits. In the cramped space of the LM’s cabin, surrounded by vulnerable switches and instrument panels, this took considerably longer than the expected preparation time of about two hours. Every move in the donning process had to be meticulously carried out and checked, ultimately taking around 3½ hours for the crew to be fully suited up and ready for Mankind’s historic first steps onto the Moon.

Preparing for the Moonwalk Broadcast
Like me, I’m sure you will be surprised to learn that NASA originally intended to provide only radio coverage of Apollo-11’s history-making first steps on the Moon! It was not until early this year that the decision was finally made to include television coverage of the lunar EVA! However, as a contingency, Westinghouse (which produced the colour television camera used in the Apollo 10 and 11 Command Modules) had been contracted to develop a compact television camera that could be used on the lunar surface. This slow-scan black and white camera has a vertical resolution of 320 lines scanned at 10 frames per second, designed to work with the small transmission bandwidth available from the LM on the Moon, which was not sufficient for a standard TV signal.

The Westinghouse Apollo-11 Lunar Surface Camera was initially mounted in the Modular Equipment Stowage Assembly (MESA), in the LM Descent Stage, positioned so that it could see the astronauts descending the ladder to step onto the lunar surface. Because of its design, and the limited space available within the MESA, the camera had to be mounted upside down. This meant that the transmitted view of Mission Commander Armstrong coming down the ladder was upside down, and a special switch had to be activated at the reception station on Earth to invert the image to the right way up. This step was not necessary when the camera was removed from the MESA and set up on the Moon’s surface itself to cover the activities of the lunar EVA.

On the Apollo-11 flight plan, the lunar EVA was scheduled so that the television transmission would be received at the Goldstone DSN station, where the 210 ft “Mars” antenna would provide maximum reception capability of the relatively weak television signal. However, should the Moonwalk should occur when Goldstone was unable to receive the television signals, NASA contracted the 210 ft Parkes Radio Telescope in Australia to act as a back-up to receive the astronaut telemetry and television broadcast from the Moon. As events transpired, it was fortunate that this arrangement was in place! The "Mars" DSN antenna at Goldstone, so called because it was developed to support space probes to Mars

Live from the Moon (via Australia)!
When Neil Armstrong finally backed gingerly out of the narrow LM hatch in his bulky spacesuit, he pulled a small ring to activate the television camera in the MESA. At 109:22:00 GET, the first television from the surface of the Moon was received at Goldstone. In Australia, where the Moon was just rising into their field of view, Honeysuckle Creek MSFN station (which was tracking the LM) and the Parkes Radio Telescope could also see the television transmission.

The Honeysuckle Creek antenna, near Canberra, tracking Eagle on the Moon just as Armstrong stepped onto the surface

Although the picture quality received at Goldstone was good, the vision sent to Houston was extremely contrasty, due to incorrect settings on the scan converter that turned the slow-scan signal into one suitable for regular television broadcast. It was also initially upside down, as the camera operator forgot to flick the inversion switch. The images received at Honeysuckle Creek, though of lower resolution due to its smaller antenna, were clearer than Parkes, where the signal strength was very low. After a few moments switching between signals for the best picture, the broadcast controllers at Houston settled on the signals from Honeysuckle Creek for the initial global television transmission of Armstrong coming down the ladder and stepping onto the Moon’s surface.

About nine minutes later, when the Moon had risen high enough at Parkes to provide a much stronger signal, the quality of its images led the broadcast controllers to switch to the Parkes feed. This was used for the rest of the two-and-a-half-hour broadcast from the lunar surface.

The combined Australian and NASA team at Parkes were so dedicated to ensuring that the historic lunar television broadcast was made available to the world, that they kept the radio telescope in operation and stayed at their posts, even when a violent storm arose with windspeeds well in excess of the safe operating limit of the antenna.

“One Small Step for Man”
Moving carefully down the ladder on the leg of the LM, testing every phase of the descent to the surface, Mission Commander Neil Armstrong halted momentarily on the Eagle’s footpad to describe the lunar surface. At 109:24:15 GET, 21:56 CDT July 20 he then took Mankind’s first step onto another world, saying “That’s one small step for Man. One giant leap for Mankind”.

Armstrong about to take the First Step, as seen on the monitor at Honeysuckle Creek.

Armstrong had not shared with anyone what he planned to say as he stepped onto the Moon, and while his first words on the lunar surface will undoubtedly resound through history, they are, in fact, something of a non-sequitur. There’s already speculation that he may have slightly flubbed his intended line – understandable due to the stress and tension of the circumstances – and that he really meant to say “That’s one small step for a man (meaning himself). One giant leap for Mankind", which would be more logical (and indeed, later in the flight, Aldrin quoted Armstrong's utterance with the "a" included).

That First Step was watched around the world by an estimated 650 million viewers, potentially making it the most viewed television event in history (unless 700 million really did watch the Our World broadcast in 1967!). Millions more listened-in on the radio. There are estimates that 93% of televisions in the US were tuned the broadcast.

To watch the historic event, people gathered around television screens at home, or wherever they could find them. In Australia, where television ownership is still relatively low, crowds gathered around the shopfronts of any building displaying a television, like the bank shown below, since the Moonwalk occurred around lunchtime. School children spent the day in front of sets in the classroom or assembly hall. Seasoned newsmen around the world, like your famous Walter Cronkite, struggled to convey their emotions as the ancient dream of touching the Moon was realised in Armstrong's "small step".

On the Surface of the Moon
After ensuring that the Moon’s surface could bear his weight, Armstrong moved around a little, collecting a contingency sample of lunar soil – more correctly called regolith – and a couple of small rocks, in case he had to make a quick retreat to the LM. He also took a series of photographs. At least there would be something for the scientists if Eagle had to make an emergency departure! On the other side of the Moon at the time, Col. Collins was disappointed to miss the historic moment of Armstrong’s first step.

Sixteen minutes later, Col. Aldrin began backing cautiously out of Eagle’s hatch to join Armstrong, making a joke about not locking them out of the LM. On reaching the surface, an awestruck Aldrin described the vista before him as “magnificent desolation”.

As they inspected their spacecraft and their surroundings, both astronauts found their suits comfortable to walk around in, although they found it difficult to stand up again after bending down to pick up an object.

Ceremonial Activities
As a momentous historic event, the Moonwalk included several ceremonial activities, commencing with the unveiling of a small commemorative plaque, marking the place that humans first landed on the Moon, that was attached to between the third and fourth rungs of the LM ladder. At 109:52:19 GET, the two astronauts gathered around the Eagle’s ladder and ‘unveiled’ this plaque by removing its cover. Armstrong then read the inscription aloud for everyone back on Earth.

Armstrong reading the plaque, with Aldrin beside him. You can almost see the astronauts' faces!

After this moving moment, Mr. Armstrong and Col. Aldrin removed the television camera from the MESA and set it up on a stand, so that it could view their field of operations as they went about performing the real work of their mission.

Although not listed on their procedure checklist, the astronauts' next ceremonial task was setting up a US flag, just as the polar explorers of the past have done on reaching their goals. Since the United Nations’ Outer Space Treaty, established in 1967, prohibits any nation on Earth from claiming ownership of the Moon, the US Government has been very careful to state that the flag-planting is purely symbolic, recognising the United States as the first country to land on the Moon, but not representing territorial claim.

The astronauts found it difficult to insert the flagpole into the lunar surface and had trouble extending the arm designed to stretch out the flag to its full extent on the airless lunar surface. However, this worked to good effect, creating the impression that the flag was actually waving in a breeze.

Aldrin poses with the "waving" flag

When the astronauts planted the flag on the Moon's surface, an identical flag was raised in the MOCR.

As a symbolic act of international representation, a silicon disc about the size of a 50-cent piece was placed on the Moon's surface. It contains goodwill messages in the form of statements from leaders of 73 countries around the world, although the USSR and the People's Republic of China are not included.

A final symbolic event took place a little while later, at 110:16:30 GET, when President Richard Nixon made the first interplanetary phone call from the Oval Office in the White House directly to the astronauts on the Moon. Armstrong and Aldrin stood before the television camera to receive the call, so it could be telecast as a split-screen, showing both the astronauts and President Nixon in conversation. The President praised the astronauts for their historic achievement, adding “Because of what you have done, the heavens have become a part of Man’s world… For one priceless moment in the whole history of Man, all the people on this Earth are truly one.”

Down to Work
After the ceremonial activities, the real work of the Apollo-11 astronauts began. Aldrin conducted experiments to determine the extent of an astronaut’s mobility, attempting to run and hop like a kangaroo. He also took a core tube sample of the regolith, although he was not able to drive a core tube far into the surface.

Two more images destined to become iconic, I'm sure. Aldrin on the lunar surface, and a close-up of the impression his boot is making in the regolith!

Mr. Armstrong carried out geological observations and collected bulk samples of rock and regolith. He took a large number of photographs of the lunar surface, from close-ups of rock structures and regolith to panoramas and views of craters.

Because Armstrong was usually carrying the camera, the majority of Apollo-11 photographs of an astronaut on the lunar surface show Col. Aldrin. The picture above is one of the rare images – as distinct from television coverage or film – of Armstrong on the lunar surface.

Col. Aldrin set out the EASEP (Early Apollo Scientific Experiments Package), the first set of scientific instruments to be placed on the Moon. EASEP instruments include: a seismic detector to measure Moonquake activity, a laser reflector that can be targetted from Earth to precisely measure the distance between our planet and its satellite; a solar wind particle collector; and even a tiny detector to measure the characteristics of lunar dust. Tracking stations on Earth are now collecting data from these instruments to continually monitor conditions around the landing site, even though the astronauts have departed (bringing the solar wind collector sheet back with them to Earth for analysis).

Aldrin setting up the EASEP seismic detector

The solar wind particle collector

The lunar laser ranging experiment for making precise measurements of the distance between the Earth and the Moon

Back to the LM
After 2 hours 31 minutes and 40 seconds, Neil Armstrong and “Buzz” Aldrin concluded their activities on the surface of the Moon, loading back into the LM some 47lbs of lunar rocks and regolith. They had taken 339 images of the lunar surface and their activities, and walked a total of 1100 yds, travelling a maximum of 67 yds from the LM. The extent of the Apollo-11 lunar excursions could be contained within a football field, but from this small beginning future missions will expand the range of their activities, exploring further away from the LM.

Back aboard Eagle, the astronauts’ first chore was to pressurise the cabin and begin stowing the rock boxes and film magazines. To allow for the weight of the lunar samples, the astronauts’ lunar overboots, life support backpacks, spacecraft trash, and any other gear no longer required, were jettisoned onto the Moon’s surface (proving that humans can leave litter anywhere!).

Elated but exhausted, Armstrong and Aldrin then took time to rest and get some sleep, Col. Aldrin curled up in the limited floor space of the LM, while Armstrong rigged up a sleeping place on the cover of the ascent engine. Neither of them slept well, though future lunar crews will have proper hammocks, I'm told.

After more than 21½ hours on the Moon, Mr. Armstrong and Col. Aldrin prepared their ship for lift off, firing their ascent engine just one minute behind the flight plan scheduled time at 124:22:01 GET. The blast from the engine appears to have knocked over the flagpole planted by the astronauts, but that didn’t dampen the crew’s spirits as the ascent engine worked as expected and set them on a trajectory to rendezvous with Col. Colins in Columbia!

This article has been lengthy, but there has been so much to cover with such a historic mission. I'm going to pause at this triumphant moment in the story, and will continue with a final wrap-up later this month, when we will hopefully have even more information as the lunar samples are analysed and the Apollo-11 crew are released from isolation.