OASI - One Small Step Retrospective

In December 1968, mankind passed a landmark in exploration when the first men travelled to the Moon and returned safely back. The three man crew of Apollo 8, Frank Borman, Jim Lovell and Bill Anders blasted off to test the Command and Service Module by orbiting the Moon. To my peers and I it was a personal thing - an endeavour in which we played an extremely minor part (much as the late Spike Milligan famously claimed to have played a part in Hitler's downfall!) In the late 1960s I was an Apprentice Instrument Maker, indentured at Marconi Elliott Flight Automations in Basildon, Essex. The firm, originally part of the Marconi Company, had been taken over by the American Company, Elliotts, who were sub-contracted by Grumann (the principle builder of the Lunar Excursion Module) to provide on board navigation systems for the LEM and it was our privilege, in the most sterile of workshops and under intense security to manufacture some of the switching panels. I had the great fortune to be in that particular workshop at the time and to assist with the panels as part of my training. By coincidence, in 1972 Elliotts sold the company back to Marconi, the Apollo programme was cancelled after Apollo 17 (December 1972), and I left engineering in pursuit of an entirely different career.

This article provides a retrospective on the Apollo missions leading up to the immortal One small step phrase of Neil Armstrong in July 1969. We should begin with a reminder of the events that brought NASA to undertake this monumental endeavour. A cynic might claim that the Moon landings were born entirely of a desire by America to beat the Soviet Union and to win a kind of moral or scientific/engineering victory. Personally, I believe that there is substance in that opinion, but it isn't the whole story and I contend that the ordinary men and women of NASA were made of better stuff than that. However, in 1957, at the height of the cold war, the western world was stunned when the USSR successfully put Sputnik One into orbit - its 'bleep bleep bleep' message galvanised public opinion to a view that the 'Reds' shouldn't have outer space for themselves. Another Soviet first compounded the matter when, in April 1961, Yuri Gagarin became the first human to enter outer space and orbit the earth. Despite constantly trailing Soviet space feats, NASA managed just one month later to successfully launch astronaut Alan Shepherd into a sub orbital space flight and a few days afterwards the 'space race' really began when President J F Kennedy threw down the following challenge to the American nation - in his words:

Gradually, via the single man Mercury and two man Gemini space vehicles, NASA achieved many technological and manned space flight firsts, seizing the initiative from the USSR. Also during this period, NASA sent unmanned Ranger probes on photographic missions, taking an abundance of pictures for transmission to earth before crashing into the lunar surface. NASA followed these with the Surveyor probes which soft landed on the lunar surface, supplying much needed data on surface composition and thousands of high resolution photographs.

All faith was pinned on NASA's long-planned manned lunar exploration endeavour - Project Apollo. This was to consist of a three-man capsule, capable of sustaining the astronauts in its Command & Service Module with a separate Lunar Module comprising landing and ascent vehicles for the Moon landings themselves. NASA had developed a new launch vehicle for Project Apollo - the mighty Saturn 5 rocket. The Apollo capsule was not without its critics for poor standards of workmanship and a general haste in manufacture.

	The mighty Saturn 5. This leftover from Project Apollo is on display at Kennedy Space Centre, Florida, USA.
	The giant exhaust nozzles of the Saturn 5.
	A side view of the exhaust nozzles of the Saturn 5 shows an intricate design.
	Model of the Lunar Module at Kennedy Space Centre. Dimensions: Overall height: 7.0 m Overall width: 9.5 m (diagonal across landing legs) Habitable volume: 4.5 m³
	Sketch showing relative sizes of the Saturn 1B and Saturn 5. The Saturn 1B is 68 m high, the Saturn 5 is 111 m high.
	Sketch showing the configuration of the CM, SM and LM inside the Saturn 5 rocket prior to the transposition and docking manoeuvre.

Apollo 1 was ready at the start of 1967 atop its Saturn 1 rocket at Cape Canaveral. On 27 January, its three man crew, astronauts Gus Grissom, Ed White and Roger Chaffee, were going through a full dress rehearsal for launch when an electrical spark ignited the pure oxygen environment inside the capsule, killing all three men. The nation, indeed the world, was stunned by the tragedy as a result of which NASA redesigned virtually the whole Apollo capsule and replaced the pure oxygen environment with a nitrogen/oxygen mixture. Meanwhile, the next five Apollo missions would be un-manned until all problems were ironed out of the systems.

Apollo 2 successfully launched in July 1967 to test the Saturn 1B booster system.

Apollo 3 launched in August 1967 to test the systems on the Command & Service Modules, along with the heat shield.

Apollo 4 launched in November 1967. This was the first time that the launch used the 363 ft tall Saturn 5 booster. The mission lasted over eight hours and included two earth orbits by the Command & Service Module to test re-entry systems.

Apollo 5 launched in January 1968, atop a Saturn 1B booster to test, for the first time, an unmanned Lunar Module.

Apollo 6 launched in April 1968 for a further test of the Saturn 5 booster and the Command & Service Modules. The Saturn 5 suffered a number of faults - ignition failures on the second & third stages and an oscillation in the rocket's flight attitude.

Apollo 7 marked the first successful manned flight of Project Apollo when, in October 1968, astronauts Wally Schirra, Donn Eisele & Walt Cunningham orbited earth in the Command & Service Module. The mission lasted eleven days and various minor faults manifested themselves and were easily resolved - however, things were not at all helped by the crew who suffered from heavy colds and became increasingly irritable as they were instructed by Mission Control at Houston, Texas, to undertake various tests which they considered trivial and of little practical importance. In fact, the three astronauts 'blotted their copybooks' and none were ever to return to space. Overall, however, the mission paved the way for the boldest leap yet.

Apollo 8. The technical success of Apollo 7 and fears over the Soviets' new Zond spacecraft, which had recently safely made unmanned lunar return flights, spurred NASA to bring a manned lunar orbital flight forward from its originally planned schedule on Apollo 9. Apollo 8 was originally to have been a proving manned earth orbit mission to test the Lunar Module. At 7.51am on 21 December 1969, Borman, Lovell and Anders blasted off atop a Saturn 5 from Launch Pad 39A at Cape Kennedy with just a Command & Service Module (no Lunar Module). After 2 hours 50 minutes of orbital flight, mission control gave the go-ahead for TLI (Trans-Lunar Injection) and a burn of just over five minutes of the third stage of the Saturn 5 raised the ship's speed to 24,226 mph, sending Apollo 8 away from earth. For the first time, mankind would see earth as a celestial body - arguably the most beautiful of all (unless you happen to be an observer of Saturn....)

Apollo 8 slowed to a mere 2,223 mph at a distance of 38,900 miles from the Moon before the latter's gravity began to exert itself on the ship. Eventually, some 69 hours into the mission, Apollo 8 reached the Moon. The Moon's gravity increased the speed of the craft to 5000 mph as it swung around the far side of the Moon on Christmas Eve. A 242 second burn of the SPS (Service Propulsion System), plus some further short burns for adjustment, placed the craft in an almost circular orbit at a mean altitude of 60 miles. After this frenetic activity had subsided and when asked by the mission control room what the Moon looked like, Jim Lovell's voice came back:

Lunar orbit lasted for 20 hours 11 minutes, during which time the astronauts undertook a hefty schedule of photographic work over five potential landing sites that NASA had provisionally settled upon. One photograph taken during their orbit has become a true icon of the space age: Earthrise, showing our planet at about two-thirds phase at a distance of 240,000 miles five degrees above the lunar horizon, which was approximately 430 miles from the spacecraft. In a famous TV transmission from lunar orbit on Christmas Day 1968 the crew quoted passages from the book of Genesis: In the beginning God created the heaven and the earth, and they closed with seasonal greetings to all of us back on the good earth.

The chilling prospect of the Apollo astronauts being trapped in eternal lunar orbit was happily unrealised when the SPS executed a 203 second burn on the far side of the Moon to propel it back towards home and the world knew all was well when Lovell's voice came on the radio saying: Please be informed there is a Santa Claus. On the sixth day of the mission a 363 ft high rocket had been reduced to just a 12 ft Capsule, which plunged back into Earth's atmosphere at 24,696 mph towards a splashdown four miles away from the aircraft carrier USS Yorktown in the Pacific Ocean and a world wide welcome as heroes.

The mission had covered a total distance of 6,000,000 miles at a cost of $310,000,000 - just two more test flights stood before the momentous first manned landing.

NASA took its next step towards reaching the Moon on 03 March 1969, when Apollo 9 blasted off from Cape Canaveral with astronauts James McDivitt, Dave Scott and 'Rusty' Schweickart on board. Their mission goal was to test the integrity of the whole Apollo system and, for the first time, fly the Lunar Excursion Module with a crew on board and practice separation, rendezvous & docking procedures. Their journey would involve a ten day flight and 151 earth orbits over a distance of some 4,350,000 miles.

When orbital height had been achieved the Command Module pilot, Dave Scott, began a critical manoeuvre by separating the Command & Service Module from the last stage of the Saturn rocket and turning it around to extract the LEM from its adapter & casing at the top of the 3^rd stage. This essential manoeuvre was known as transposition & docking. After transposition & docking, the final stage of the Saturn rocket fired its engine and sped away from earth into an eternal solar orbit. The crew spent the following 24 hours checking systems on the docked spaceships and resting. Schweickart had been designated Lunar Module Pilot. ('Pilot' was a loose term as the mission commanders actually flew the Lunar Module whilst the 'pilot' who, by NASA convention, was always the least experienced astronaut, acted as systems engineer). It was Schweickart's task to test the integrity of the space suits that astronauts would wear on the surface of the Moon by an extra vehicular activity (EVA) or spacewalk, climbing outside the LEM and standing on the steps plus retrieving various experimental samples from the side of the craft. However, NASA had to delay this part of the mission by four days as Schweickart was suffering from spacesickness.

On day five the most critical part of the mission began when McDivitt & Schweickart entered the Lunar Module and separated their craft from the Command & Service Module. At this point the Lunar Module (known by the nickname Spider) became mankind's first true spaceship by virtue of its having been built entirely for space use and having no terrestrial integrity. After an initial period flying around the Command Module (nicknamed Gumdrop) McDivitt fired Spider's descent engine and drew the craft 13 miles above Gumdrop - after two hours he increased the distance to 50 miles. The two craft later drifted back towards each other before McDivitt fired the engine again to simulate an actual lunar descent.

At a distance between the two craft of 100 miles McDivitt fired explosive bolts to separate and jettison the descent stage of Spider. He then fired the ascent stage engine to bring the ascent stage of Spider back to dock with Gumdrop. NASA had planned for the Lunar Module pilot to handle the redocking of the two craft but, after experiencing great difficulty stabilising the ascent stage, it was decided that all future dockings would be undertaken by the Command Module pilot who had the advantage of a heavier and consequently more stable craft. When the crew had transferred back into the Command Module, Spider was jettisoned to burn up in earth's atmosphere as its bottom half had done earlier.

The crew spent the next few days performing various experiments including the use of a revolutionary 'Earth Resources' camera - environmental matters were beginning to come to prominence in those days. NASA delayed splashdown by one orbit due to high seas in the Pacific and used the mission's alternative splashdown point in the Atlantic, with recovery by the USS Guadalcanal, 535 miles south of Bermuda. The craft of Apollo 9 had performed almost faultlessly.

The final stepping stone before a manned Moon landing began at 12.49pm on 18 May, 1969, with the lift-off of Apollo 10 on an eight day mission which would involve orbiting the Moon whilst the Lunar Module crew tested out the ship in a full dress rehearsal landing and redocking exercise. The crew consisted of Col Tom Stafford (Commander), Cdr John Young (Command Module Pilot) and Cdr Eugene Cernan (Lunar Module Pilot). The Command Module and Lunar Module were nicknamed Charlie Brown & Snoopy respectively. For the crew there was a slight tinge of 'what might have been' because Apollo 10 was originally conceived to be the first actual landing mission but the chain of events described above conspired against that plan and left Apollo 10 with an LEM which wasn't completely equipped for such a landing owing to difficulties with production schedules.

A great deal of publicity surrounded the mission and no less than 19 TV shows were transmitted during the flight. The transmissions were mostly light hearted, often extended beyond schedule and clearly intended to show the average American what all those tax dollars were buying! After a relatively routine journey, Apollo 10 entered lunar orbit on 21 May and, following 11 full orbits Stafford & Cernan entered Snoopy and separated it from Charlie Brown. Some months earlier, NASA had determined that Mare Tranquillitatus (the Sea of Tranquillity) offered the best chance of a smooth site for the first landing and Apollo 10 had been targeted to overfly the site, whilst practising and perfecting the navigation techniques that the crew of the next mission would need to use. Snoopy's descent engine was burned for 27 seconds, which allowed it to drop to just nine nautical miles (50,000 ft) above the lunar surface and, as the craft swept in low over Mare Tranquillitatus, Stafford said: There's enough boulders here to fill up Galveston Bay! On seeing the proposed landing site he described it as having a number of holes, but looking mostly smooth like a very wet clay - apart from the larger craters. (Subsequent analysis of the flight showed planners that they were actually some four miles too far south of the landing point at that moment and that error would prove useful in future final course corrections).

Stafford fired the explosive bolts holding the descent stage and, moments before the ascent stage engine was to be fired, Snoopy went into a violent spin for around eight seconds until Stafford could bring the craft back under control. Cernan obviously thought they were going to crash and his voice tapes indicate so in what one might charitably interpret from the expletives as something like Oh dear... (The culprit was an incorrectly set Abort Switch, which caused Snoopy to begin a programmed automatic return to Charlie Brown, whilst in a dangerous downward attitude towards the surface). A successful burn returned Snoopy to redocking with Charlie Brown and, after a total of 31 orbits, Apollo 10 burned the SPS engine for a homeward flight. After a total 830,000 mile journey, the Command Module splashed down just three miles from USS Princetown. So near and yet so far for the crew, the mission had been a huge success and nothing now stood in the way of a landing by Apollo 11 in two months time.

At 9.32 am local time on 16 July, 1969, the colossal form of a 363 ft high Saturn V rocket, powered by an unimaginable 7,650,000 lbs of thrust and creating an awesome noise slowly rose from launch pad 39A at Cape Kennedy. The spectacle will remain permanently etched in the memories of 1,000,000 plus spectators around Cape Kennedy (including countless invited VIPs and a 3,000 strong press corps) and many of the estimated 600,000,000 TV viewers world-wide. Sitting atop this colossus and carrying the prayers of the world with them were civilian Neil Armstrong (Commander), Lt-Col Michael Collins (Command Module Pilot) & Col Edwin Buzz Aldrin (Lunar Module Pilot). The Apollo 11 mission had begun.

Apart from TV broadcasts, the trip to the Moon was almost routine as the Command Module (Columbia) and Lunar Module (Eagle) flew at a maximum of 24,550 mph towards a 357 second burn of the SPS to place them in lunar orbit on 19 July. There followed a period of system checks prior to separation of the two craft. On that first day of orbit, the crew reported the north walls of the suspected volcanically active crater Aristarchus exhibiting a luminosity in the view through their binoculars. Ground based observers simultaneously and independently confirmed this Transient Lunar Phenomena¹ (TLP).

At 100 hours into the mission, Armstrong fired the descent engine on Eagle for 30 seconds to begin the approach towards the target landing area on Mare Tranquillitatus. At an altitude of 9.1 miles a further 756 second burn began for final approach. All went well until 47,000 ft when a series of programme alarms began to sound in Eagle. Quite simply, the on-board computer could not handle the heavy flow of information being fed into it. Steve Bales, the flight engineer in charge of computer systems back at mission control, surmised what was taking place and made the brave decision not to call an abort. At 1,400 ft Armstrong realised that the auto navigation systems were leading Eagle to a landing on unsuitably rough ground, strewn with large boulders and a large crater. Lunar landings were always timed so that the sun would be low on the horizon and behind the Lunar Module. On the monotone surface the long shadows cast assisted the pilots spotting boulders and craters as well as giving some indication of surface relief/topography beyond whatever the ship's instruments indicated. Armstrong immediately switched to manual approach and began, with Aldrin, to look for smoother ground. Although essentially a rocket, at one sixth of Earth's gravity the handling characteristics of the Lunar Module were very different and the attitude controls were configured in much the same way as a helicopter e.g. tilt forward to move forward. Within a few moments, Charlie Duke (Capsule Communicator - CAPCOM - at Houston) told the crew they had just 60 seconds of fuel remaining. That was expected, although the crew had hoped to be on the ground before then. When Duke told them that they were down to 30 seconds remaining - it was definitely time to land! Perhaps it would be best to quote direct from the voice recordings at this point:

The time was 21:18 hours BST on 20 July 1969. The actual landing site, some four miles further on than planned, is at co-ordinates 0.67 degrees North, 23.5 degrees East. The site is roughly one-third of the way from the craters Sabine & Ritter towards the crater Maskelyne and a little towards the crater Moltke (see map below). Note that the map uses the IAU nomenclature: East to the left, West to the right, South to the top and North to the bottom.

	Tranquillity Base, landing site of Apollo 11. Key to craters: Maskelyne Moltke Sabine Schmidt Ritter Dionysius Manners Arago Lamont
	The Moon on 23 July 1999 (just after the thirtieth anniversary of Armstrong's one small step). Image by James Appleton, 250mm SCT at prime focus, 1/15sec exposure on 50 ASA B&W print film.

A period of intense check routines followed. Some years after the landing, Buzz Aldrin recalled that he was so busy inside the Lunar Module that he didn't have time to look out of his window and that was his one regret on the mission. Having donned their life support packs and EVA suits (designed to sustain the astronauts on the surface in full solar radiation and extremes of temperature from +240ºF in sunlight down to -279ºF in shaded areas), it was time for the supreme moment of the mission and, perhaps, of all space exploration. Armstrong crawled out of the tiny hatch and down the ladder into the field of view of a crude black & white TV camera, whilst being watched by countless millions around the globe. The last rung of the Lunar Module ladder was some three feet above the footpad and Armstrong had to jump. Back to the voice tape:

It is 03.59hrs BST on 21 July 1969. First things first, Armstrong scooped up a small amount of surface dust and placed it in a special pocket on his spacesuit in case of any unforeseen problems which might lead to an early abort of the mission - at least they wouldn't go home empty handed. After a short while it was Aldrin's turn to join Armstrong in the EVA. Stepping onto the surface he uttered two words that seem to have captured and encapsulated all the descriptions given by all the astronauts to follow him: magnificent desolation.

Walking on the lunar surface in one sixth of earth's gravity and wearing a suit with a combined total weight of 300 lbs (equalling 50 lbs by earth standards) took some getting used to! The favoured method of walking was to spring/twist from the ankles, which would give the astronauts that curious loping/kangaroo hopping gait so familiar to us on the film records. Alan Bean (Lunar Module pilot on Apollo 12) was later to say that he felt immensely strong - almost as though he were an Olympic athlete. Armstrong went no further from the Lunar Module than just 100 yards; more spectacular sojourns would follow on later missions. Much time was spent erecting the Stars & Stripes and unveiling a plaque on one leg of the descent stage which bore the inscription: Here men from the planet Earth first set foot upon the Moon July 1969 AD. We came in peace for all mankind. The plaque bore the signatures of the three man crew and President Nixon. The astronauts placed other mementos around the landing site, including messages from world leaders and memorials to astronauts and cosmonauts who had died in exploration. Notable amongst these items but totally unofficial was an astronauts diamond-set gold pin badge which the wives of the Apollo 1 crew presented to Deke Slayton (NASA's Chief of Flight Operations) after the death of their husbands. President Nixon made a somewhat embarrassing telephone call to Armstrong & Aldrin when he took time off from answering awkward questions from Washington Post reporters to milk this historic moment for all its political worth. However, it wasn't all ceremony and the astronauts placed experimental equipment upon the lunar surface to measure the solar wind, a seismograph to monitor 'moonquakes' and meteor impacts and a laser reflector to facilitate accurate measurement of the Earth-Moon distance. The astronauts also took several core samples, bringing the earthbound lunar rock samples up to approximately 48 pounds in weight.

After 2hrs 14mins it was time for Armstrong and Aldrin² to return to the Eagle. Once inside they had a five hour sleep (as if anyone could sleep in those circumstances) in the cold and somewhat austere ascent stage. It was time for one of the most nail-biting aspects of the whole mission - would the ascent stage engine fire or would the astronauts be marooned for eternity on the surface? All went well and a 435 second burn of the ascent engine took them back to lunar orbit and eventual rendezvous with Mike Collins in Columbia. Mike had spent his lonely time photographing the lunar surface. During a press conference before lift-off he had caused much laughter by asking the media to hang onto all the TV recordings so that he could see what had taken place - the supreme irony being that he was one of the very few people who couldn't see Armstrong and Aldrin on the lunar surface live!

Following a flawless redocking and transfer of crew & samples, Eagle's ascent stage was jettisoned to crash onto the lunar surface (helping to confirm that the seismograph left at Tranquillity Base was functioning). Having made 30 orbits of the Moon over almost 60 hours the SPS on Columbia burned for 2mins 29secs on the far side to propel Apollo 11 towards home. The trip home was notable for a TV transmission in which the crew told millions of viewers around the globe of their feeling of elation - and how grateful they were to everybody who had anything to do with the Apollo project. (That transmission caused more than the odd goosebump for we minions back at Marconi's who had played our own extremely small part in the project.) Eight days after its awe inspiring lift-off, what remained of the mighty Apollo 11 spacecraft splashed down in the Pacific near Johnson Island, some 13 miles from the waiting carrier USS Hornet. On board ship was the President to greet the astronauts before they were sealed in a special unit for a three week period in case of any bacterial contamination from the Moon, fears of which were happily unfounded. The late President Kennedy's target of putting a man on the moon and returning him safely to Earth before the end of the decade had been brilliantly achieved.

Next time you are observing the Moon, why not take the time to observe Mare Tranquillitatus around the craters Maskelyne, Sabine & Ritter and ponder the momentous events which took place there in 1969.

One Small Step - Retrospective