Apollo 8

Apollo 8 has reached another historic milestone in its voyage as its crew of Frank Borman, Jim Lovell and Bill Anders become the first humans to be captured by an gravitational field other than Earth's. Having passed behind the Moon, they fired the spacecraft's large engine for a little over four minutes, slowing them down enough to stay in lunar orbit. The manoeuvre complete, they have just reappeared to the antennae of Earth and a highly relieved Mission Control are talking to them and looking at the telemetry that the spacecraft is sending down.

Verb 64 is called up on the DSKY (Display and Keyboard) which brings up a routine to operate their High Gain Antenna and properly acquire a link with Earth.

Jim doesn't think that Houston is reading them yet.

Environmental Control System experts in the back room at Mission Control are noticing that the cooling radiator temperatures are higher than normal. Normally, this would cause a water evaporator system to come online, and provide additional cooling by the sublimation of water. Houston suspects that the system has either "dried out", or is manual mode. Normally, the system is in Automatic mode, and support crews need to confirm this.

A 16-mm movie camera is aimed, we believe, out the left-hand rendezvous window. The Flight Plan calls for a frame rate of one frame per second. When replayed on Earth usually at the standard 24 frames-per-second, the effect will be to apparently speed up the motion across the lunar surface. One reason for the slow rate is to maximise the capture of photographic data with the minimum expenditure of scarce film.

Though the transcript mentions the DSKY, this may be a reference to one of the meters on panel 2 that monitors the spacecraft's cooling systems.

As will become apparent, the evaporator is prone to drying out. At this time of high activity in the spacecraft, many systems have been powered up for the LOI burn and the evaporator ought to be helping to remove the extra heat generated. If it has dried out, we would expect the temperatures at its outlet to rise. Bill will have to service the evaporator to restore its function.

On the left-hand side of the spacecraft is a blank panel that covers panel 382. Behind that are controls for the ECS (Environmental Control System).

The two controls near the bottom are those for the evaporators.

The crew tend to refer to the evaporators as 'boilers' because that is essentially what they do. Readers should be aware that this does not mean they operate at 100°C. The vacuum in which they operate means that the water boils at a low temperature, cold enough to form ice. This was a worry in the Command Module evaporators because if the water supply were to ice up, it could crack the pipes within the ECS unit and breach the spacecraft's pressure integrity.

Since the primary water evaporator isn't working, Houston is recommending that the secondary cooling system be turned on. This will certainly take care of their immediate cooling problems, but the long term solution is to get the primary evaporator working again. The secondary system has it's own evaporator which is entirely automatic.

Ground crews had noticed the tendency of this evaporator to dry out. Their conclusion, stated during the Flight Readiness Review of 19 November 1968 was that it wasn't a problem because the crew could always reservice the unit.

This determination of their orbit made by analysis of their range and Doppler effect as measured by the Earth stations agrees very closely with the on-board solution.

Bill is looking at the pressure generated by the water evaporation process. Technically, it is correct to say that the water vapor created is "steam", but this is not the hot, 100 degree C we think of when we say steam. Rather, it is cold water vapor, under very slight pressure (under 0.2 psi).

At times when the crew are not talking directly to Earth, their onboard conversation can be heard breaking through onto the comm circuit. Though highly distorted, occasional words can sometimes be discerned, Bill's reply here being an example.

Comm break.

Comm break.

Langrenus is a striking, large crater on the southeastern shore of Mare Fecunditatis (Sea of Fertility).

This photo, taken by the author (Woods), shows Langrenus with the Sun shining from the west. This low lighting shows the complex topography of the crater. Being sited near the eastern limb of the Moon, for Apollo 8, the Sun is already quite high over Langrenus, making its topography more difficult to distinguish. It is 132 kilometres in diameter, has a collection of central peaks and a complex system of terraces inside its rim, the result of large-scale slumping of its walls soon after its formation. The crater carries the latinised name of Michel Florent van Langren (circa 1600 - 1675), a Flemish mapmaker who pioneered the production of lunar maps.

Jim's impressions of what he sees have been replayed many times on documentary films of the Apollo program, especially his first sentence. Though his words are honest, they predate NASA's emphasis on science and geology that led to later commanders, Jim included, becoming accomplished field geologists themselves and enthusiasts of what the Moon's landscape has to offer. Perhaps as a consequence, his portrayal of the lunar surface as grey and colourless set a tone for the public's subsequent perception of the Moon as uninteresting.

Crater Pickering has since been renamed Messier A. It and Messier are a distinctive pair of craters in the middle of Mare Fecunditatis. Both are elongated with their long axis roughly aligned. A striking pair of rays splay across the mare surface to the west while fainter rays are cast north and south at right angles to these. The curious geometry of this pair have led to a range of formation scenarios, the most popular of which invokes a bouncing impactor. This holds that an object hit at an extremely shallow angle, travelling east to west. It gouged out Messier, flew a further 25 kilometres before forming Messier A. The craters are named after Charles Messier (1730-1817) who was a prolific discoverer of comets. To aid his work, he compiled a catalogue of fuzzy celestial objects for which he is now far better known.

The hatch window is not literally iced over. Rather, an outgassing of fumes from the sealant materials around the large windows is fogging them up.

One of the tasks assigned to Apollo 8 is to take a close look at one of the favoured sites for a future Apollo landing. Apollo site selection was, by this time, constraining the number of suitable sites to just five, two of which were smooth areas to the east of the Moon's near side. The easternmost site, east of the crater Maskelyne and near the southern shore of Mare Tranquillitatis, is the prime target for Apollo 8 even to the extent that the time of launch from Earth was chosen so that the lighting at the site would be similar to that expected on a real landing mission.

The second site in Mare Tranquillitatis was originally selected to be 12° further west from P-1, this being the distance the Moon's terminator moves in an Earth-day. Then, if the launch of a landing mission had to be postponed for a day, the lighting conditions would be repeated further west. In seven months, Apollo 11 would land at this second, more westerly site.

The rays coming from the Messier craters, like most rays on the Moon, are caused by shock-fractured rock being sprayed out over the mare. The fracturing exposes crystalline surfaces that catch the sunlight. Lovell seems to have been looking out for the rays adding a hummocky topography to the mare surface. Instead, he observes that they add only a thin veneer.

Coolant temperatures have now lowered to a point where the backup radiators are no longer needed.

Jim is looking towards the southern side of their current ground track, and as they pass across the centre of Mare Fecunditatis, he can see the mountain range that borders the eastern shore of Mare Nectaris.

The approaches to the landing sites included a couple of recognisable points the crews could use to check the timings of a landing trajectory. Jim has just called the second one of these the Triangular Mountain but later in the mission, he will label it Mount Marilyn after his wife. Though not official for many years, and having been included in the storyline of the 1995 movie Apollo 13., Mount Marilyn was adopted by the International Astronautical Union in 2017 as the name for this triangular formation.

The Mission Report includes a list of all the Targets of Opportunity that Bill has been tasked to photograph if possible.

Target of Opportunity 72 is a cluster of craters east of the crater Colombo, or to its left in this photograph composited from AS08-13-2215 to 2227 using low-resolution index scans. Colombo and Gutenberg are two large craters between Mare Fecunditatis and Montes Pyrenaeus. Also of note in this area is Goclenius. Gaudibert is beyond these three. Note that perspective effects mean that the top and bottom of this pan will have large geometric distortions. The target is the cluster of craters beyond and including Crozier. These craters all have a similar size yet have different floor morphologies. To the right of Crozier is one of only a handful of "doughnut craters" on the Moon. It is far from clear how these unusual crater-within-a-crater features formed. They all have a similar shape and size and both the outer and inner crater seem to have been formed together.

This image, AS08-13-2225, is part of the sequence in the earlier composite image. Note the impressive rille system can be seen within Goclenius. There are many of these large 'fractured floor' craters on the Moon but Goclenius stands out because it also straddles a set of graben-type rilles that border Mare Fecunditatis. By the fact that at least one of these rilles is superimposed on the crater floor, rim and surrounding mare shows how relative ages can be determined from this photograph. The crater itself is the earliest feature here followed by the smooth mare surface that surrounds it and laps against its exterior wall. The interior of Goclenius and the rilles that cross its surface probably also formed around this time. Finally, the immense weight of the dense basalts of Mare Fecunditatis caused the centre of the mare to sink. This stretched the landscape at the shore, forming the large arcuate grabens that now cut across Goclenius.

Goclenius is the latinised name of Rudolf Gockel (1572-1621), a German scientist. The crater, Colombo is named after the seafarer, Christopher Columbus (1451-1506) who discovered America in 1492. Johann Gutenburg (1398-1468) was the German inventor of movable type and the printing press, and Francis Crozier (1796-1848) was a polar explorer.

The Flight Plan gives coordinates for B-1 as 2.675° north, 35.025° east. This is located on the eastern side of Mare Tranquillitatis.

Maskelyne B is a 9.2-km crater about 20 km west of Maskelyne itself. At this time it is virtually on the terminator and since it is about 6° west of Apollo Landing Site 1 (P-1), the landing site is illuminated with a 6° Sun, close to what would be expected on a landing mission.

In today's world of real-time computer displays, it is often surprising that data in Apollo was usually recorded with pens drawing traces on long strips of paper. Rather than seeming archaic, this was considered a reasonable way of recording data, which allowed engineers to look at data in real-time and even mark up points of interest, as well as making a permanent record of the data.

Ground controllers still want to take a look at the data in more detail.

Target of Opportunity 90 is a 49-km crater Capella within the Montes Pyrenaeum range for which Bill took frames AS08-13-2228 to AS08-13-2237.

Most of these frames have been composited together to produce the above montage. The view looks across the terminator towards Capella. The low lighting shows the topography of the area well, especially the raised rims of the craters and the lines of the various rilles that make up Rimae Gutenburg. The crater was named after a fifth century lawyer who postulated that Venus and Mercury orbited the Sun.

Bill finishes his photography with mag E on this rev with three frames.

The near wall of Fracastorius, a large, 124-km walled plain, is missing and the lavas within open out onto Nectaris. Being right on the terminator, only its rim is illuminated. The spacecraft is now flying over the night-time side of the Moon though they are still in sunlight.

Frank had been amazed at the accuracy of the predictions by Mission Control, eliciting a joke from Bill that their boss had probably ordered the signal to be cut so as not to worry the crew if there was a slight error.

Writer Robert Zimmerman, in his book 'Genesis: The Story of Apollo 8', ascribes Frank's exhortation to a desire to ensure Mission Control are concentrating on the state of the spacecraft and the mission. Frank will return to Earth if there is any reason to doubt the integrity of CSM-103 and Mission Control must actively agree to allow each orbit to commence. There is no doubt who is in control of the spacecraft. TEI-1 is the next opportunity to return to Earth, and there is less than one hour to LOS. Frank is exercising his prerogative as commander of the mission to come home early if the spacecraft is not in perfect shape.

Comm break.

Bill is providing a running commentary of his photographic work on the voice recorder that was presumably meant to help researchers determine the context of the images. It certainly helps us in correlating the photographic index with the historic record.

The photographic index shows the first 29 frames of magazine A were used to take pictures of Earth or the S-IVB third stage of the Saturn V during their outward coast. There was one dark frame, then six frames including four of the 132-km crater Langrenus.

Despite Borman's comment about being in the dark already, they are still in sunlight.

Jim is carrying out another realignment of the spacecraft's guidance platform, known as a P52 after the program used for the operation. Capella is one of two stars Jim is sighting on as part of the realignment, the other being Regulus, the dominant star in Leo.

It is planned to complete one of these realignments during the dark pass of every orbit in case the crew have to leave the Moon's vicinity in a hurry. That way they will have an accurately aligned platform ready for the subsequent burn of their SPS (Service Propulsion System) engine. During coasting flight to and from the Moon, realignments are carried out at about 8 hour intervals and it is interesting to note that the figures given for platform drift are roughly the same for 2-hour or 8-hour intervals.

Comm break.

Jim's sighting on the stars has been very accurate as the computer has displayed five zeros (five balls) as being the star angle difference. In other words, the angle Jim measured between the two selected stars is identical to the known angle between them.

Jim has also read out the torquing angles from the P52. The gimbals that support the platform must be moved through these angles to restore perfect alignment. They are -0.077°, +0.017° and +0.065°.

Bill is making a check of the spacecraft's systems per the note in his column of the Flight Plan at 070:14.

Based on the bright results they had with an earlier TV transmission, it seems likely the red filter is being added simply to reduce the light levels going into the lens.

Comm break.

About now, Apollo 8 moves into the Moon's shadow, to reappear at about 71 hours GET.

The telephoto lens has a narrow, 9° field of view. This makes it particularly difficult to aim accurately at an object that is also photographically significant. With the wide-angle lens, a large vista can be imaged for the audiences on Earth.

At 067:35:29, before they entered lunar orbit, two PADs were read up that included the information that would allow the crew to return home after the first and second orbits have been completed. These are the TEI-1 and -2 PADs and would only be used in the event of an emergency. Their burn to enter lunar orbit is close enough to what was planned that the original TEI abort PADs are still valid.

The SPS engine has two independent systems for injecting propellants into the combustion chamber. The A bank was brought in first while the B bank was manually started a few seconds later. The engine does not achieve its full thrust until both banks are operating.

Verb 83 brings up numbers on the DSKY relating to parameters used during rendezvous, something that will not be happening on this mission. In this context, one number in particular is of interest as it gives the crew their angle relative to the local horizontal, known as theta. This is required to give the ORDEAL an appropriate starting point for displaying their local attitude on the FDAI (Flight Director Attitude Indicator) or "8-ball".

Long comm break.

Out on the end of it's arm, the HGA (High Gain Antenna) has a limited range of articulation, and the Flight Plan was carefully designed to allow it to maintain a link with Earth during lunar manoeuvres. In particular, if the crew are in a "heads-down" attitude, the windows will be facing the surface while the HGA, on the opposite side of the spacecraft, will have easy access to Earth. With the fogged windows affecting visibility, there is a possibility the crew might have wanted to adopt a "heads-up" attitude which would have brought the HGA around to the Moon's side of the spacecraft. Mission Control are reminding the crew that to keep the HGA pointing at Earth in this attitude, they would need to yaw to the right. However, Frank is for minimising changes to their packed schedule.

The GDC (Gyro Display Coupler) provides a backup attitude reference with information coming from the Gyro Assemblies. By the nature of this system, it is more prone to drift than the gyro system in the IMU, so occasionally, it's knowledge of the spacecraft attitude is updated with that from the IMU by pressing the GDC Align button.

Having held an inertial attitude since they entered lunar orbit, they will begin an orb-rate rotation to keep one side of the spacecraft aimed at the Moon. An initial attitude for this rotation is given in the Flight Plan though the figures given by Jim differ in somewhat in pitch.

After Apollo 8 reaches the sunlit side of the Moon, Jim is scheduled to carry out a series of sightings through the hatch window of various control points. Of course, the hatch window is fogged over to the point of being useless. We can assume that they are changing their attitude so that the rendezvous windows can be used. Here, Bill refers to the DSKY as a "keypunch". The phrase "keypunch" reflects the ubiquitous way data was entered into computers of the day. Personal computers certainly didn't exist, nor did even the "dumb terminals" that characterized computers in the 1970's. Cards had holes punched onto them that represented data, using machines like the IBM 029 keypunch machine. One of the editors (O'Brien) remembers fondly (yeah, right) of the hours spent keypunching programs on the 029.

Jerry Carr is referring to the O₂ purge of the fuel cells, used to clear out impurities in the system.

After emerging from the Moon's eastern limb, engineering data from the spacecraft, including the data from the LOI burn, was replayed to Earth. Once gathered at the Earth station, it has to be passed on to Houston before analysis of the engine's performance can begin. Frank is especially keen to know whether it performed well as they need it to get back home. It has been 15 minutes since Frank's original request for a review of SPS data, and it is 30 minutes until LOS. Frank is likely getting a bit impatient about the time it is taking to get an answer about an update on the status of the engine.

Comm break.

Comm break.

Pages 1-18 to 1-20 of the Flight Plan have forms for the crew to take note of these timings. They represent when the spacecraft passes significant points during its orbit and help the crew keep track of when events occur. Though the Flight Plan has many of these times marked, they are only approximate. These times are based on the spacecraft's measured orbit and are accurate. The map update is interpreted as follows:

• Loss of Signal (LOS) before start of rev 2: 073:04:57. This is the time they lose contact with Earth as they go behind the Moon for the second time.
• Spacecraft sunrise in orbit: 073:09:37. After LOS, the spacecraft returns to sunlight, crossing the Moon's sunset terminator soon after.
• Passing over meridian of 150°W: 073:19:01.
• Acquisition Of Signal (AOS): 073:48:53.
• Spacecraft sunset in orbit: 074:24:23. At this time, Apollo 8 will pass from lunar daytime into the lunar night a short time after passing over the sunrise terminator.
• Landmark Bravo-1: 074:16:24. The orbital evaluation of Apollo Landing Site (ALS)-1, known as B-1, is a major goal of the mission. This is a timing for its acquisition.

This map update is relevant to the second and third revolutions around the Moon.

Comm break.

Long comm break.

Long comm break.

This clip is very noisy. To try to improve intelligibility, a version with some noise reduction applied is included.

Comm break.

Having learned that the DSE tape has been dumped to Earth, Bill then uses it to leave a note of the progress of his photography.

Comm break.

Very long comm break.

The Public Affairs Officer is evidently elated at Apollo 8's achievement and shares the moment with the folk from the media once more.