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

April 22, 2025 Kaye Dee 2 Comments

[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

[March 16, 1969] Flight of the Space Spider (Apollo 9)

March 16, 2024 Kaye Dee 1 Comment

by Kaye Dee

Riding on Apollo's Coat-tails
The Traveller recently referred to President Nixon’s 8-day European tour, but it would seem Mr. Nixon deliberately decided to pave the way by riding on the coat-tails of the general international applause accorded to the historic Apollo-8 mission. Shortly before he announced his own trip to Europe, the President personally dispatched Apollo-8 commander Colonel Frank Borman and his family on an eight-nation European goodwill tour. (The other Apollo-8 crewmembers, already in training as part of the Apollo-11 backup crew, were not available to participate in the tour.)

Departing on 2 February, Col. Borman, his wife Susan, and two sons undertook a 19-day tour, visiting the UK, France, Belgium, the Netherlands, West Germany (including West Berlin), Italy (including Vatican City), and Spain (like Australia, home to an Apollo Manned Space Flight Network station and a Deep Space Network facility): an itinerary very closely paralleling that later followed by President Nixon!

The Borman family meets the Royal Family and Col. Borman presents a picture of the Moon to the Pope during his goodwill tour of Europe

Col. Borman said that he was particularly gratified to make the journey because of a conviction that space efforts “can be a very positive force for creating better relations among the people of the world”.

A Long-Delayed Mission
But while Colonel Borman was embarking on his diplomatic mission, the crew of the long-delayed first test flight of the Lunar Module (LM) in Earth orbit were in the final stages of preparations for the Apollo-9 mission, which splashed down just a few days ago with all its objectives successfully completed. Intended to be Apollo-8, the mission was bumped later in the sequence due to a succession of technical delays in the development of the LM, the first manned spacecraft designed solely for operations in space.

Apollo-9’s main task was to qualify the LM for manned lunar flight, demonstrating that the craft could perform all the necessary manoeuvres required for a landing on the Moon. The flight was therefore intended to be very much a mission of “firsts” that would finally fully test-out the entire suite of hardware needed to accomplish a Moon landing mission. It would see the first flight of the complete Apollo Saturn vehicle – Saturn V launcher (AS-504 for this mission), Command Service Module (CSM-104) and Lunar Module (LM-3) – as well as the first docking and extraction of a LM from the Saturn S-IVB stage.

Putting the LM through its paces would involve the first flight tests of its upper and lower stages, with the first firings of their engines in space, and include the first rendezvous and docking between with the CSM and LM. The mission would also undertake the first spacewalk of the Apollo programme, to test the reliability of the Apollo A-7L space suit and the Portable Life Support System (PLSS) backpack, essential for lunar surface operations.

The Crew Who Waited
Original 1966 crew photo of Astronauts Scott, McDivitt and Schweickart. Their training for the flight that eventually became Apollo-9 commenced in January 1967, even before the Apollo-1 fire

Probably the best prepared mission crew to date, the Apollo-9 crew originally came together in January 1966, as the back-ups for Apollo-1, before being assigned as the first crew to fly the LM. Their 1,800 hours of mission-specific training was equivalent to about seven hours for every hour of their eventual flight!

With so much riding on a successful LM test flight, Apollo-9’s crew comprised two veteran Gemini astronauts and one rookie. Mission Commander Air Force Col. James McDivitt previously commanded the Gemini-IV mission, during which the first US EVA was conducted. Command Module Pilot Lt.-Col. David Scott, also with the US Air Force, was Pilot of Gemini-VIII, its flight cut short by the first US in-flight space emergency, but for which he undertook considerable EVA training.

Finally Go for launch! Astronauts McDivitt, Scott and Schweickart in their official Apollo-9 pre-flight crew portrait

The new kid on the block for Apollo-9 was LM Pilot Mr. Russell Schweickart, originally selected in the third group of astronauts in 1963. An experienced fighter pilot, serving with the U.S. Air Force and the Massachusetts Air National Guard between 1956 and 1963, Mr. Schweickart joined NASA as a civilian, from a position as a research scientist at the Experimental Astronomy Laboratory of the Massachusetts Institute of Technology (MIT). Mr. Schweickart is nicknamed “Rusty” for his red hair (but in Australia, with our sense of humour, we’d have called him “Bluey”!).

Introducing Gumdrop and Spider
Because Apollo-9 would have two spacecraft from the same mission operating independently for the first time (unlike the Gemini VI-VII rendezvous, in which the two spacecraft were separate missions with their own callsigns), they each required separate callsigns for easy communications identification. NASA Administrators therefore finally lifted the ban on spacecraft names, which has been in operation since the beginning of the Gemini programme, permitting the crew to select their own names for the CM and LM.

The Apollo-9 CSM and LM being prepared for launch at Kennedy Space Centre

The astronauts chose “Gumdrop” for the CM, based on the shape of the capsule, which resembles the popular sweet, and “Spider” for the LM, given the spider-like appearance of the lander, with its four spindly legs. Unfortunately, it seems that certain NASA officials were not happy with these choices, feeling they were not dignified enough, so I hope they will not place restrictions on the names that can be selected for future missions, or force the crews to revert to dull numerical callsigns.

Patching Up
North American Rockwell artist Allen Stevens seems to be quite a favourite with the Apollo astronauts as a mission patch designer. He has designed the patches for Apollo-1, 7 and Apollo-9, and seems to have had a strong influence on the design of the Apollo-8 patch.

Stevens’ Apollo-9 patch evolved from a design he originally developed when Apollo-9 was still anticipated to be Apollo-8. The relatively simple concept depicts all the vehicle elements of the Apollo mission – the Saturn V in launch configuration, with the CSM and the LM flying separately as they would do during orbital test manoeuvres. In the final version of the design they appear against a mottled blue background that could represent either the Earth’s oceans or orbital space. Rather than show the CSM and LM docked together in orbit, as we often see them in NASA illustrations, Stevens chose to depict them in their on orbit ‘station-keeping’ positions, with the CSAM and LM facing each other, although this does give the impression that the CM is attempting to dock with the front of the LM!

Completing the design, the names of the crew and mission circle just inside the red-bordered edge of the patch, with the “D” in McDivitt’s name also filled in red. This is a nod to Apollo-9 being originally designated as the “D” mission in the sequence of Apollo flights prior to the Moon landing.

A Busy Moonport
Due to the long delay with the LM, preparations for Apollo-9 initially overlapped those of Apollo-7 and 8. By February, while the astronauts were spending long hours in mission simulators preparing for their flight, Kennedy Space Centre (KSC) was a hive of activity with Apollo-9 in the final stages of pre-launch testing, and advance preparations for Apollo 10 and Apollo 11 also underway (Apollo 10 is currently due for launch in May and Apollo 11 in July).

In addition to Apollo-9’s launch preparations, the Apollo 10 spacecraft was moved from the Manned Spacecraft Operations Building (MSOB) to the Vehicle Assembly Building (VAB) for mating with its Saturn V launcher (above left); the first and second stages for the Apollo 11 Saturn V arrived, with the stacking of that launcher commencing in the VAB (above right); and the upper and lower stages of the Apollo 11 LM were also mated in the MSOB, in preparation for testing in the altitude chamber. NASA is really moving at a cracking pace to achieve a manned lunar landing this year!

An Unexpected Delay
The countdown for Apollo-9 commenced on 26 February, for a planned launch on the 28th. But fate stepped in to delay the crew’s trip to space just a bit longer! Ironically, despite their years of training for this mission, the astronauts pushed themselves so hard in their final weeks that, as launch day approached, they developed cold-like symptoms such as sore throats and nasal congestion.

Apollo-9's LM crew, McDivitt and Schweickart, training in the Lunar Module simualator

For NASA’s most complex manned mission to date, senior managers and flight surgeons wanted the crew to be in the best possible health for the 10-day flight. (They were probably also mindful of preventing a recurrence of the issues with the Apollo-7 crew, due to in-flight health problems). Consequently, the launch was rescheduled to 3 March to give the astronauts time to recover.

Finally on their Way!

Once KSC medical director Dr Charles Berry finally cleared the crew for launch, Apollo-9 left the pad exactly on time at 16:00GMT on 3 March. Hopefully the smooth launch impressed Vice President Spiro Agnew (on right in the picture below), who was present in the Launch Control Centre in his new role as Head of the National Space Council, especially as President Nixon has asked his science adviser, Dr Lee Dubridge, to report on possible cost reductions within the US space programme.

To maximize the chances of accomplishing them, in case any problems forced an early return to Earth, the most critical mission tasks were scheduled for the first five days of the flight. So once the Saturn rocket’s S-IVB third stage and the CSM were safely in orbit, things moved quickly. During the second orbit, CM Pilot Scott turned the CSM and successfully docked with the Lunar Module, nestled in the Spacecraft-Lunar Module Adapter of the S-IVB stage. The linked spacecraft were ejected from the S-IVB, which was then remotely controlled to simulate Trans-Lunar Injection and eventually be sent into a solar orbit.

Demonstrating that the “probe and drogue” CM-LM docking assembly worked properly is another crucial step towards enabling the future Moon landing. If this system didn’t work, a lunar landing would not be possible.

Once the probe is inserted in the drogue it retracts and pulls the two spacecraft together so that a series of twelve latches locks them tight.

Burning Along
Six hours into the mission, the next task was to establish that the docked CSM-LM could be manoeuvred using the Service Module’s Service Propulsion System (SPS) engine. A five-second burn placed the CSM in an orbit of 125 by 145 miles, to improve its orbital lifetime. This short firing demonstrated the CSM guidance and navigation system’s ability to control the burn and showed that the LM’s relatively light structure could withstand thrust, acceleration and vibration.

Following the first sleep period on an Apollo mission during which all three astronauts slept at the same time, Apollo-9’s second day focussed on putting the SPS engine, and the CSM, to the test, through a series of three burns. The first burn, lasting 110 seconds, raised Apollo 9’s orbit to 213 miles and tested the structural dynamics of the docked spacecraft under conditions simulating a lunar mission. This involved gimballing (swivelling) the SPS engine to determine whether the spacecraft’s guidance and navigation autopilot could dampen the induced oscillations. The CSM remained very stable, with the oscillations damped within just five seconds.

Apollo spacecraft diagram key. CSM (right) and LM (launch configuration) docked. I – Lunar module descent stage; II – Lunar module ascent stage; III – Command module; IV – Service module. 1 LM descent engine skirt; 2 LM landing gear; 3 LM ladder; 4 Egress platform ("porch"); 5 Forward hatch; 6 LM reaction control system quad; 7 S-band inflight antenna (2); 8 Rendezvous radar antenna; 9 S-band steerable antenna; 10 Command Module crew compartment; 11 Electrical power system radiators; 12 SM reaction control system quad; 13 Environmental control system radiator; 14 S-band steerable antenna

The second SPS burn lasted 280 seconds, changing the orbit to 126 by 313 miles, while the short third burn, just 28.2 seconds, changed the plane of the spacecraft’s orbit. These orbital changes were designed to position Apollo-9 for better ground tracking and lighting conditions during upcoming mission activities.

Space Sickness Strikes
Entering the LM and checking out its systems was scheduled for flight day three, but planned operations were initially disrupted when space sickness reared its head. Flight surgeons still know little about this condition, which seems to affect some astronauts but not others, and some more than others.

A view inside Command Module Gumdrop

Both Col. McDivitt and Mr. Schweickart were affected, with McDivitt apparently experiencing some mild nausea. Mr. Schweickart, however, vomited in the CM and again later in the LM. When Col. McDivitt contacted the flight surgeons from the LM to report the medical situation, they were less than happy that the earlier incident had not been initially reported, as they could have treated Schweickart’s symptoms sooner.

Opening Up the LM
Although the initial bout of space sickness delayed the start of operations to clear the docking tunnel and access the LM, the astronauts were able to continue with the day’s activities, and both Commander and LM Pilot used the docking tunnel to make the first ever transfer between manned spacecraft without needing to spacewalk. With Lt.-Col. Scott remaining in the CM, and hatches between the Gumdrop and Spider closed, the LM’s communications and life support systems demonstrated that they were operating independently from the CM. Schweickart also deployed Spider’s landing legs (which had been folded for launch) into the position they would assume for landing on the Moon, giving the LM the appearance of its namesake!

A Jumping Spider!
During the nine hours they inhabited Spider, still docked to the CSM, Col. McDivitt and Mr. Schweickart conducted a major test of the Lunar Module’s descent engine, firing it for 367 seconds to simulate the pattern of throttling planned for a descent to the lunar surface. For the final 59 seconds of the burn McDivitt controlled the throttling, varying the thrust from 10 to 40 percent and shutting it off manually, marking the first manual throttling of an engine in space.

This burn, which demonstrated that the LM descent engine could manoeuvre the combined LM-CSM stack, was followed by an additional SPS firing after the LM crew returned to the CM. Together, these burns placed Apollo 9 into an orbit of 142 by 149 miles, ahead of the rendezvous exercises to be performed on day five.

Red Rover (Doesn’t Quite) Cross Over
The step-by-step testing program for Apollo-9 earmarked the fourth day of the mission for a spacewalk to test the reliability of the Apollo EVA suit and the PLSS backpack, necessary because it would be impractical and dangerous for astronauts to move across the Moon’s surface trailing umbilical lines connected to the LM. As the only EVA scheduled before the Moon landing, it was the single opportunity to test the PLSS operationally in space.

Astronaut Schweickart training for his planned EVA

Using the call sign “Red Rover”, “Rusty” Schweickart was originally scheduled to perform a two-hour EVA to simulate a space rescue technique in the event that a CM-LM docking could not be made, crossing from Spider to Gumdrop. This would have involved him exiting the hatch on the LM and making his way along the outside of the spacecraft to the CM hatch, where Lt.-Col. Scott would be standing by to assist access to the CM. However, the LM Pilot’s bout of space sickness led Col. McDivitt to initially cancel the EVA, due to the flight surgeons’ concerns about the dangers of vomiting in a spacesuit. This also meant the cancellation of a planned TV broadcast of the spacewalk itself, which would have been another first.

Wearing Golden Slippers
But with Mr. Schweickart feeling somewhat better by day four, a modified short EVA was substituted to enable the EVA equipment test to be carried out. After McDivitt and Schweickart again transferred to Spider, Mr. Schweickert climbed out onto the LM porch for a 37.5-minute EVA, exclaiming “Hey, this is like spectacular” as he stood in the void. For much of this time, the astronaut’s feet were held in gold-coloured restraints, nicknamed the “Golden Slippers”, but he was also able to move around the LM’s exterior using handholds to retrieve some experiments.

At the same time, David Scott, wearing a bright red helmet, made a stand-up EVA in Gumdrop’s hatch and both astronauts photographed each. Scott, too, retrieved experiments from outside the CM. Mr. Schweickart has said that he found moving around easier than it had been in simulations and was confident that he could have completed the spacewalk to the CM had it gone ahead.

The Spider Takes Flight

The key event in Apollo -9’s programme was the undocking and rendezvous tests scheduled for the fifth day of the mission. These manoeuvres would simulate all the activities required for a successful lunar landing and return to lunar orbit. With McDivitt and Schweickart in Spider, and Scott remaining in Gumdrop, the two craft undocked to commence a complex set of manoeuvres and burns of both the LM descent and ascent engines. These tests also carried a new element of danger. The Lunar Module has no ability to return to Earth on its own, since it lacks a heatshield: if something went seriously wrong its crew could end up stranded in space with no way home.

After 45 minutes separated but station keeping, an initial 24.9-second LM descent engine burn placed Spider into a 137 by 167 mile orbit; a second 24.4-second firing circularized the orbit around 154 by 160 miles, approximately 12 miles higher than Gumdrop. Over the next four hours, McDivitt fired the LM’s descent engine at several throttle settings, before lowering Spider’s orbit to begin a two-hour ‘chase’ to catch-up with Gumdrop. The LM descent stage was then jettisoned, and the ascent stage engine fired for the first time, lowering the LM’s orbit still further and placing Spider 75 miles behind and 10 miles below Gumdrop for the rendezvous manoeuvre.

Although it is planned that in future Moon missions, the Command Module pilot will conduct the rendezvous with a returning LM, for Apollo-9 Spider carried out the rendezvous, to demonstrate that the manoeuvre could be performed by either craft. Apart from this difference, the approach and rendezvous hewed as closely as possible to the current plans for lunar missions. Mission Commander McDivitt flew the LM close to Gumdrop, manoeuvring Spider so that CM Pilot Scott could see each side of the vehicle and inspect it for any damage. As he photographed the ascent stage, Scott joked “You’re the biggest, friendliest, funniest looking Spider I’ve ever seen.”

McDivitt then docked to the CM, guided by Scott, as Sun glare was interfering with his vision. Once Spider’s crew returned to Gumdrop, the ascent stage was jettisoned and remotely commanded to fire its engine to fuel depletion, simulating an ascent stage’s climb from the lunar surface. With the approach and rendezvous operation complete, the only major LM system that had not been fully tested during Apollo-9 was the lunar landing radar.

A Bit Camera Shy
Unlike the previous two missions, Apollo 9’s packed programme restricted the television broadcasts made by the astronauts. Spider was equipped with a Westinghouse b/w Lunar Surface Lunar TV Camera, identical to the one taken to be carried to the Moon’s surface on the first landing, as another equipment trial. This low-light “slow scan” camera produced a 320 line, 10 frames per second non-interlaced picture.

Only two broadcasts were from Spider. The first, seven minutes’ long, occurred on day three and showed Mr. Schweickart and Col. McDivitt working in the confined space of the LM. The second broadcast occurred shortly after the end of the EVA on the fourth day, with Spider’s crew still wearing their spacesuits.

The quality of this 15-minute transmission was much better than the previous day, and the crew treated viewers to a scene of Col. McDivitt eating. The camera was then pointed out the LM’s top window to show Gumdrop, then through one of the forward windows to glimpse one of Spider’s attitude control thruster quads and a landing leg. Finally, the view switched back into the cabin to show the LM’s instrument panel and a radiation detector. Once the LM ascent stage was jettisoned, on day five, there were no further broadcasts as the CM did not carry a television camera.

Cruisin' in Orbit
Once the crowded test schedule of the first five days was complete, the second five days of Apollo-9’s flight, intended to test the endurance of the CSM for the total length of a Moon landing mission, were quiet and relaxed by comparison.

Col. McDivitt thanked the Mission Control team for their work during the hectic first half of the mission and jokingly mused: “Might give you the impression that it might work, huh?” The crew sang a belated “Happy Birthdays” to Christopher C. Kraft, Jr., Director of Flight Operations at the Manned Spacecraft Centre, and Apollo 9 crew secretary Charlotte Maltese.

There were additional SPS burns on days six and eight to change the spacecraft’s orbit, with no major activities scheduled for the ninth day, although the astronauts made observations of the Pegasus 3 satellite, passing within 1,000 miles and 700 miles of Apollo 9 during two successive orbits. They also observed the LM ascent stage from about 700 miles away.

Observing the Earth
The main activity of the second half of the Apollo-9’s flight was the mission’s only formal scientific investigation, a programme of multi-spectral terrain photography, using four Hasselblad 70 mm cameras pointed out the CM’s round hatch window. This allowed photographs to be taken in four specific wavelengths of the visible and near infrared spectrum simultaneously.

Multi-spectral images. The same view of San Diego and parts of California in four different wavelengths

This experiment was designed to determine whether multi-spectral photography can be effectively utilised for earth resources programmes such as agriculture, forestry, geology, oceanography, hydrology, and geography. The results will help to refine the instruments for the Earth Resources Technology Satellite (ERTS), due for launch in 1972, Landsat, and techniques for multi-spectral photography to be conducted aboard the Skylab space station in the early 1970s.

Altogether 127 complete four-frame sets of photographs were taken over California, Texas, other areas of the southern United States, Mexico, the Caribbean and the Cape Verde Islands. Astronauts also took more than 1,100 standard Earth observation photographs of targets around the world, using colour and colour infrared film and a handheld Hasselblad camera.

Apollo-9 astronauts' colour photograph of the North Carolina coast and a colour infra-red view of California's Salton Sea

Coming Home
Apollo -9 returned to Earth on 13 March (the 14th for us here in Australia), the tenth day of the mission. Re-entry was delayed by one revolution due to heavy seas in the primary recovery area, but Gumdrop splashed down safely in the Atlantic, within three miles of the recovery ship, the USS Guadalcanal, after a mission totalling 241 hours, 53 seconds – just 10 seconds longer than planned!

On board the recovery ship, the crew were treated to a share of a 350-pound cake baked in their honour. Now safely back in Houston for their flight debriefings, NASA’s attention – and the world’s – is already turning to Apollo-10, due to fly in May to test the LM around the Moon!

Ready for the Next Steps
While Apollo-9 might not have seemed as exciting a mission as Apollo-8’s epic lunar voyage, it was critical because it has simulated in Earth orbit, as far as possible, many of the conditions that the astronauts and their equipment will face when the lunar landing attempt is made. Beyond that first landing and its successors, there is the Apollo Applications Programme, and other developments such as the Skylab manned earth orbiting workshop. Everything that has been learned in space with Apollo-9 will be useful sooner or later in future space activities!

And you can bet we'll be covering each and every one of them here on the Journey…

Apollo-9 view of the Moon

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Science / Space Race

[January 24, 1968] On Track for the Moon (Apollo 5 and Surveyor 7]

January 24, 2023 Kaye Dee Leave a comment

by Kaye Dee

As we approach the first anniversary of the shocking loss of the crew of Apollo 1, the success of the recent Apollo 5 mission reminds us that the spirit of Grissom, White and Chaffee lives on as NASA continues developing and testing the technology to make a manned lunar landing a reality.

Apollo 1's Legacy
Although the fire that engulfed Apollo 1 and killed its crew destroyed its Command Module, the accident took place on the launchpad during a launch simulation, and fortunately the Saturn IB booster intended to loft that mission into orbit remained undamaged. Because that AS-204 vehicle was the last Saturn IB with full research and development instrumentation, NASA decided that this rocket would be re-assigned to Apollo 5, the much-delayed first test flight of the Lunar Module – the spacecraft essential for successfully landing astronauts on the Moon – while manned Apollo missions continue on hold.

From LEM to LM
The spacecraft we now call the Lunar Module (LM) became part of the Apollo programme in 1962, when NASA decided to adopt the technique of lunar orbit rendezvous (LOR) for its Moon landing missions. First proposed in 1919 by Ukrainian engineer and mathematician Yuri Kondratyuk, the LOR technique uses two spacecraft that travel together to the Moon and then separate in lunar orbit, with a lander carrying astronauts from orbit to the Moon’s surface. The LOR method allows the use of a smaller and lighter lander than the large, all-on-one spacecraft originally proposed for Apollo, and also provides for greater flexibility in landing site selection.

An early diagram comparing the size of a lunar landing vehicle using the Direct Ascent method of reaching the Moon and a LOR lunar excursion vehicle

The version of lunar orbit rendezvous suggested to NASA by engineer John C. Houbolt called for a landing vehicle consisting of two parts: a landing stage, that would accomplish the descent from orbit and remain on the Moon’s surface, and an ascent stage that would carry the astronauts back to the main spacecraft in orbit. This design gave us the Command Service Module as the Moon orbiting spacecraft, and what was originally called the Lunar Excursion Module (LEM, pronounced as a word, not as the individual letters) as the vehicle that would land astronauts on the Moon.

Dr. Houbolt illustrating the main spacecraft needed for his Lunar Orbit Rendezvous proposal for the Apollo programme

In June 1966, NASA changed the name to Lunar Module (LM), eliminating the word “excursion”. My friends at the WRE tell me that this was because there were concerns that using “excursion” might make it sound like the lunar missions were frivolous, and so reduce support for the Apollo programme! Despite the official name change, the astronauts, as well as staff at Grumman, still call it “the lem”, which certainly feels easier to say.

Delays…Delays…
However, the two-stage LEM/LM has proved much harder to develop and manufacture than the contractor Grumman originally anticipated, because of the complexity and level of reliability required of the hardware. Originally, NASA planned for the automated test flight of LM-1, the first Lunar Module, to occur in April 1967, but the delivery of the spacecraft was repeatedly delayed: the two stages of LM-1 did not arrive at Cape Kennedy until late June last year.

The separately-crated stages of LM-1 arriving at Kennedy Space Centre on board a Super Guppy cargo plane. The stages were mated to each other four days later

A team of 400 engineers and technicians then checked out the spacecraft to ensure that it met specifications. The discovery of leaks in the ascent stage propulsion system meant that the ascent and descent stages were demated and remated multiple times for repairs between August and October. LM-1 was finally mounted on its Saturn IB booster on 19 November and a launch date was set for the latter part of January 1968.

LM-1, encased in its SLA, being hoisted up for mounting on its launch vehicle

Lift Off at Last!

Although the launch was delayed for 10 hours when the countdown was held up by technical difficulties, Apollo 5 finally lifted off on 22 January 1968 (23 January for us here in Australia). The mission was designed to test the LM's descent and ascent propulsion systems, guidance and navigation systems, and the overall structural integrity of the craft. It also flight tested the Saturn V Instrument Unit.

Because they would not be needed during the Apollo 5 test flight, LM-1 had no landing legs, which helped to save weight. NASA also decided to replace the windows of LM-1 with aluminium plates as a precaution, after one of the windows broke during testing last December. Since the mission was of short duration, only some of LM-1’s systems were fully activated, and it only carried a partial load of consumables.

LM-1's "legless" configuration is clearly seen in this view of it during checkout at Kennedy Space Centre

The Apollo 5 flight did not include Command and Service Modules (CSM), or a launch escape tower, so pictures of the launch vehicle show it to look more like its predecessor AS-203 than AS-202, which tested the CSM. The Apollo 5 stack had an overall height of 180ft and weighed 1,299,434 lbs. The LM was contained within the Spacecraft Lunar Module Adapter (SLA), located just below the nose cap of the rocket. The SLA consists of four panels that open like petals once the nose cap is jettisoned in orbit, allowing the LM to separate from the launcher.

The Saturn IB worked perfectly, inserting the second stage and LM into an 88-by-120-nautical-mile orbit. After the nose cone was jettisoned, LM-1 coasted for 43 minutes 52 seconds, before separating from the SLA into a 90-by-120-nautical-mile orbit. NASA’s Carnarvon tracking station in Western Australia tracked the first six orbits of the mission, while the new Apollo tracking station at Honeysuckle Creek, near Canberra, followed LM-1’s first orbit.

Putting LM-1 Through its Paces
Since it had no astronaut crew, the LM-1 test flight had a mission programmer installed, which could control the craft remotely. The first planned 39-second descent-engine burn commenced after two orbits, only to be aborted by the Apollo Guidance Computer after just four seconds, as the spacecraft was not travelling at its expected velocity. Exactly why this occurred is now being investigated. Of course, if there had been a crew onboard, the astronauts would probably have been able to analyse the situation and decide whether the engine should be restarted.

Instead, Mission Control, under Flight Director Gene Kranz, decided to conduct the engine and "fire-in-the-hole" tests under manual control, as without these test firings the mission would be deemed a failure. The "fire in the hole" test verified that the ascent stage could fire while attached to the descent stage, a procedure that will be used to launch from the Moon’s surface, or in the event of an aborted lunar landing. It involves shutting down the descent stage, switching control and power to the ascent stage, and firing the ascent engine while the two stages are still mated.

Apollo 5 Flight Director Gene Kranz (right) with future Lunar Module crew Astronauts McDivitt (left) and Schweickart (centre) discussing LM-1's control issues

Both the ascent and descent engines were fired multiple times during the flight to demonstrate that they could be restarted after initial use. Eight hours into the mission, a problem with the guidance system did cause the ascent stage to spin out of control, but the vital engine test burns had been completed by then. LM-1 also demonstrated its ability to maintain a stable hover, and the guidance and navigation systems controlled the spacecraft's attitude and velocity as planned.

At the conclusion of the flight testing, the separated ascent and descent stages were left in a low orbit, with the anticipation that atmospheric drag would naturally cause their orbits to decay so that the craft would re-enter the atmosphere. The ascent stage re-entered and was destroyed on 24 January, but as I write the descent stage is still in orbit.

Another Step on the Road to the Moon
NASA considers that the LM performed well during its test flight, and have deemed Apollo 5 a success. One wonders now if the second unmanned test flight with LM-2, planned for later this year, will need to go ahead. NASA also plans to return astronauts to space with a test flight of the redesigned Command Module in September this year. Once that goal is accomplished, every part of the Apollo system will have been tested in spaceflight and it will finally be “Go!” for astronauts to shoot for the Moon. I can’t wait!

Lunar map showing the landing sites of all the successful Surveyor missions

So Long Surveyor!
As the Apollo programme powers forward, the last of NASA’s automated lunar exploration programmes is coming to an end, with Surveyor 7 now in operation on the Moon. The Surveyor project was developed with the goal of demonstrating the feasibility of soft landings on the Moon's surface, ensuring that it would be safe for Apollo crews to touch down in their Lunar Modules. The Surveyor landings have complemented the Lunar Orbiter programme (which drew to a close in the latter part of last year), which imaged the Moon from orbit, mapping the lunar surface and providing detailed photographs of many proposed Apollo landing sites.

Making It Safe for a LM Landing
Of the seven Surveyor missions, five achieved their objectives, returning valuable data and images from the lunar surface. Surveyor 1, launched on 30 May (US time) in 1966, was the first American spacecraft to soft land on the Moon (following the successful landing of the USSR’s Luna 9 on 31 January that year), returning 11,237 images of the lunar surface. Unfortunately, its successor, Surveyor 2, failed in September 1966, impacting onto the lunar surface when a malfunction of the guidance system caused an error in the mid-course correction as it travelled to the Moon.

Surveyor 1's panorama of the lunar surface, which captured its shadow, cast by the light of the Earth

Surveyor 3, which lifted off on 17 April 1967, was the first to conduct in-situ experiments on the lunar soil, using its extendable arm and scoop. The spacecraft also returned over 6,000 images, including the famous "Surveyors Footprint" shot, showing its footpad on the lunar surface. The probe had a lucky escape as it tried to land: a problem with its descent radar caused the descent engine to cut off late, resulting in the lander bouncing twice on the lunar surface before settling down to a final safe landing!

Surveyor 3's footprint and footpad on the lunar surface, showing how it bounced on landing. The extendable arm and scoop are visible on the left of the picture

Just three months later, in July, Surveyor 4 was not so lucky. After a textbook flight to the Moon, contact was lost with the spacecraft just 2.5 minutes before touchdown in the Sinus Medii (Central Bay) region and it crashed onto the lunar surface. It’s believed that the solid-fuel descent engine may have exploded.

Launched on 8 September, Surveyor 5 also encountered engine problems on descent to the lunar surface, with a leak in the spacecraft's thruster system. Fortunately, it survived to make a safe landing and returned over 20,000 photographs over three lunar days. Instead of a sampler arm, Surveyor 5 carried an alpha backscattering experiment, and had a bar magnet attached to one landing pad. It carried out the first off-Earth soil analysis and made one of the most significant finds of the Surveyor missions — that the Moon's surface is likely basaltic, and therefore suitably safe for human exploration.

Surveyor 5's alpha backscattering experiment, sometimes described as a chemical laboratory on the Moon

Surveyor 6 landed safely near the Surveyor 4 crash site in November 1967 carrying an instrument package virtually identical to Surveyor 5. The spacecraft transmitted a total of 30,027 detailed images of the lunar surface, as well as determining the abundance of the chemical elements in the lunar soil. As an additional experiment, Surveyor 6 carried out the first lift-off from the Moon. Its engines were restarted, lifting the probe 12 ft above the lunar surface, and moving it 8 ft to the west, after which it landed again safely, and continued its scientific programme.

Surveyor 7 – a Last Hurrah!
The successful completion of the Surveyor 6 mission accomplished all the goals that NASA had set for the Surveyor programme as an Apollo precursor. The JPL Surveyor team therefore decided that for the final mission they would aim for a riskier landing site, in the rugged highlands near the Tycho Crater. The engineers gave Surveyor 7 a less than 50-50 chance of landing upright due to the rough terrain in the area!

Tycho crater was the challenging landing site for NASA's last Surveyor mission

Launched on 7 January, Surveyor 7 is the last American robot spacecraft scheduled to land on the Moon before the Apollo astronauts. Its instrument package combines all the experiments used by its predecessors, in order to determine if the rugged terrain would be suitable for a future Apollo landing site.

During its first lunar day, the spacecraft’s camera has returned more than 14,000 images, including some views of the Earth! One of Surveyor 7’s innovations is the use of mirrors to obtain stereoscopic lunar photos. Laser beams directed at the Moon from two sites in the United States have also been recorded by cameras aboard Surveyor 7.

A view of the Earth captured by Surveyor 7's camera

Getting a Scoop
Surveyor 7’s versatile soil mechanics surface sampler is a key instrument on this mission. Designed to pick up lunar surface material, it can move samples around while being photographed, so that the properties of the lunar soil can be determined. It can also dig trenches up to 18 inches into the lunar surface to determine its bearing strength and squeeze lunar rocks or clods. The sampler is a scoop with a container which can be opened or closed by an electric motor. The scoop has a sharpened blade and includes two embedded magnets, to search for ferrous minerals and determine the magnetic characteristics of the lunar soil. So far, the moveable arm and scoop have performed 16 bearing tests, seven trenching tests, and two impact tests.

Only a few Surveyor 7 pictures are currently available, but this view of Surveyor 3 digging a trench into the Moon's surface shows how the scoop carries out this task

The scoop is mounted below the spacecraft’s the television camera so that it can reach the alpha-scattering instrument in its deployed position and move it to another selected location. In fact, the scoop helped to free the alpha-scattering instrument when it failed to deploy on the lunar surface. It has also been used to shade the alpha-scattering instrument and move it to different positions to evaluation other surface samples. During 36 hours of operation between January 11 and January 23, 1968, the sampler has performed flawlessly. Soil analyses have been conducted, as well as experiments on surface reflectivity and surface electrical properties.

Surveyor 7 is now “sleeping” through its first lunar night. If it survives this period of intense cold, hopefully it will continue to produce significant results during its next lunar day. But if it doesn’t, the scientists and engineers at NASA’s Jet Propulsion Laboratory are already describing the Surveyor programme as a “treasure house of information for landing a man on the Moon before the end of this decade”. This has to be a fitting epitaph for any space mission.

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Galactic Journey

Tag Archives: lunar module

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

[March 16, 1969] Flight of the Space Spider (Apollo 9)

[January 24, 1968] On Track for the Moon (Apollo 5 and Surveyor 7]

55 years ago: Science Fact and Fiction