It is 24 December 1968; Christmas Eve and Apollo 8 has completed three full orbits of the Moon. Its crew of Frank Borman, Jim Lovell and Bill Anders are well into the thick of their tasks. Prime among these is to extensively photograph the ground passing beneath the spacecraft and to visually appraise the approaches to two possible landing sites on the southern plains of Mare Tranquillitatis.
Around the far side, as they began flying over the sunlit half of the Moon, Bill began to take a long series of stereo photographs of the surface, as per the Flight Plan, using magazine D on a Hasselblad camera mounted in one of the forward-facing rendezvous windows. The camera is fitted with an 80-mm lens and controlled by an intervalometer t0 take frames at preset intervals, in this case every 20 seconds.
While the intervalometer operates one camera, Bill has been using another Hasselblad with a 250-mm lens to take photographs of so-called "targets of opportunity" on magazine E loaded with black & white film. Meanwhile, Frank flies the spacecraft and currently has it pointed vertically down so that the mounted camera gets a view of the ground below through window 2, one of the two rendezvous windows and the only two that are fully clear.
075:46:06 Lovell (onboard): What time are you supposed to be pitching up?
075:46:09 Anders (onboard): I don't pitch up until [garble].
075:46:10 Lovell (onboard): Okay.
075:46:27 Borman (onboard): Alright, we're going to roll.
075:46:33 Borman (onboard): Ready? Set.
As instructed by the Flight Plan, Frank executes a 180° roll to the right, a manoeuvre that is beautifully portrayed in the series of frames from the bracket-mounted Hasselblad by virtue of the camera being aimed along the spacecraft's roll axis.
Composite of AS08-12-2136 to AS08-12-2149. The image runs between the lines of longitude 122°E on the right and 105°E on the left.
This is a composite of images from frames AS08-12-2136 to 2149. As the spacecraft moves from right to left with the camera automatically taking regular images, the rotation of successive frames betrays Frank's manoeuvre. The whole of crater Meitner is vaguely visible near centre, revealed by its darker floor and the lightening of some of its inner rim. The composite stretches from 122° on the right to 105° on the left.
AS08-12-2136 - Image by NASA/Johnson Space Center.
AS08-12-2137 - Image by NASA/Johnson Space Center.
AS08-12-2138 - Crater Sherrington on lower right - Image by NASA/Johnson Space Center.
AS08-12-2139 - Crater Meitner J at top of frame with Meitner H to its lower right - Image by NASA/Johnson Space Center.
AS08-12-2140 - Craters Meitner J and H at bottom of frame. Eastern rim of Meitner at upper left of frame - Image by NASA/Johnson Space Center.
AS08-12-2141 - Crater Meitner C at top of frame, Meitner dominates the upper left of the frame - Image by NASA/Johnson Space Center.
AS08-12-2142 - Floor of Meitner. Meitner C at top right of frame - Image by NASA/Johnson Space Center.
AS08-12-2143 - Western rim of Meitner crater. Floor of crater is on the right - Image by NASA/Johnson Space Center.
AS08-12-2144 - Western rim of Meitner crater on right. Meitner R at bottom of frame - Image by NASA/Johnson Space Center.
AS08-12-2145 - Meitner R cut off at bottom of frame. Pasteur D cut off at top left of frame - Image by NASA/Johnson Space Center.
AS08-12-2146 - Meitner R cut off at bottom right of frame. Pasteur D cut off at top left of frame - Image by NASA/Johnson Space Center.
AS08-12-2147 - Image by NASA/Johnson Space Center.
AS08-12-2148 - Crater Pasteur G at bottom left of frame - Image by NASA/Johnson Space Center.
AS08-12-2149 - Crater Pasteur G at bottom of frame - Image by NASA/Johnson Space Center.
[Download MP3 audio file of PAO announcer recording. Clip courtesy John Stoll, ACR Senior Technician at NASA Johnson.]
This is Apollo Control, Houston. 75 hours, 47 minutes and we are, according to our projections, due to acquire just any second, via a whole host of stations; Ascension, Bermuda, MILA [Merrit Island Launch Area], Grand Bahama and Madrid as well as the Canaries. This is the fourth revolution around the Moon by a manned spacecraft. Our orbit is 60.4 nautical miles by 61.7 [111.9 by 114.3 km]. We've had no attempted comm yet. We can hear a little keying going on the background, but just any moment we should get an establishing call. A period of acquisition - this time is estimated at an hour and 11 minutes. See if we can get a chart, see if we're receiving telemetry yet. It is on this pass where - in which Bill Anders will do a - begin an extensive four-rev tracking task. He'll do vertical stereo photography, and in considerable detail, to chart all the approaches to several landing sites in - near the center line - in the center of 20 degrees - I'm sorry - on the face of the Moon, front face. And here goes up the first call from Mike Collins. Let's see what we can catch.
Frank's rotation of the spacecraft is bringing Bill's window, window 5 around to face their direction of travel. Meanwhile, Bill is using the DSE voice recorder as a log of his work.
075:46:47 Anders (onboard): The impact crater was at - just prior to subsolar point on the south side, in the floor of it, [garble] - There is one dark hole, and I couldn't get a quick enough look at it to see if it might be anything volcanic.
At this point, Bill looks out of window 5 and catches sight of a beautiful, coloured orb coming over the Moon's western horizon. The event becomes historic and the result is one of the most famous photographs to emerge from the Apollo program; the Apollo 8 Earthrise image.
075:47:30 Anders (onboard): Oh, my God! Look at that picture over there! Here's the Earth coming up. Wow, is that pretty!
[Download MP3 audio file of onboard audio. Clip courtesy John Stoll, ACR Senior Technician at NASA Johnson.]
075:47:37 Borman (onboard): Hey, don't take that, it's not scheduled. (Chuckle.)
In 2013, on the 45th anniversary of the Apollo 8 flight, the Scientific Visualization Studio at NASA's Goddard Space Flight Center used data and imagery from the Lunar Reconnaissance Orbiter to reconstruct the moment. It is presented courtesy of Ernie Wright who created the visualisation:
This video, narrated by Andrew Chaikin, presents the results of a painstaking analysis of the Earthrise event to ascertain the precise attitude and position of the spacecraft, the orientation of the windows, and the positioning of the crew.
From this video, we see that at 075:47:44, Bill takes a photograph, AS08-13-2329, on magazine E, the one loaded with black & white film. Interestingly, the sound of the camera is just audible on the onboard recording.
AS08-13-2329 - The first photograph taken of Earthrise taken by a human - Image by NASA/Johnson Space Center.
This is the first photograph taken of Earthrise taken by a human as he watched the event unfold. The effect of the fogged window is apparent. This is not the image that has become iconic over the years by virtue of the fact it is monochrome. Two colour photographs taken in a minute or so will become the images that are favourites of photo editors around the world. In this image, note how close Earth is to the lunar horizon. We are looking across the middle of Pasteur, a large degraded mini-basin at 224-km diameter. The lighting renders its rim invisible but the distinct crater in the central foreground is Pasteur G. A cluster of craters at the top of the frame are centred around Pasteur U.
The above presentation of this photograph is in the same orientation as it was shot, in the conventional manner for a sunrise or moonrise shot with the horizon running between left and right. However, Bill Anders has said that an alternative presentation, with the horizon running vertically, represents how he saw this image. They were orbiting around the Moon's equator and, with north being to the top, Earth came out from behind a vertical horizon. The following presentation reflects this with north at the top. The effect of the fogged-up window has also been edited out.
AS08-13-2329 - The first image of Earthrise taken by a human, with north at the top - Image by NASA/Johnson Space Center and edited to suppress the effect of a fogged-up window.
Journal reader, Syd Buxton has kindly supplied this rendering of Earth without cloud which shows South America in the noonday Sun and Western Africa at sunset.
Computer rendering of Earth at the moment of Anders' Earthrise photos. (Courtesy of Syd Buxton.)
Bill realises that the image of colourful Earth rising over a grey, barren lunar landscape would look far better with colour film. Since he already has the long lens on his camera, he needs to affix a colour magazine to it.
075:47:39 Anders (onboard): [Laughter.] You got a color film, Jim?
075:47:46 Anders (onboard): Hand me that roll of color quick, will you...
075:47:48 Lovell (onboard): Oh man, that's great!
075:47:50 Anders (onboard): ...Hurry. Quick.
075:47:54 Borman (onboard): Gee.
075:47:55 Lovell (onboard): It's down here?
075:47:56 Anders (onboard): Just grab me a color. That color exterior.
075:48:00 Lovell (onboard): [Garble].
075:48:01 Anders (onboard): Hurry up!
075:48:06 Borman (onboard): Got one?
075:48:08 Anders (onboard): Yeah, I'm looking for one.
075:48:10 Lovell (onboard): C 368.
368 refers to film type, SO-368, which is essentially an Ektachrome-type transparency film manufactured by Kodak. Bill is handed magazine B whose images will eventually get the prefix "AS08-14".
075:48:11 Anders (onboard): Anything, quick.
075:48:13 Lovell (onboard): Here.
075:48:17 Anders (onboard): Well, I think we missed it.
As the spacecraft continues its slow roll rotation, the spectacle is no longer visible from window 5. Instead, it now becomes visible in windows 4 and 3, the right-hand rendezvous window and the hatch window.
075:48:31 Lovell (onboard): Hey, I got it right here! [In the hatch window.]
075:48:33 Anders (onboard): Let - let me get it out this window. It's a lot clearer.
Jim, who tends to be in the centre of the cabin, can see Earthrise through the hatch window but Bill has managed to get enough of an angle on it through the rendezvous window in front of him and, as it is not fogged, it will give him a cleaner shot. Although these rendezvous windows are primarily intended for viewing along the spacecraft's X-axis, they are slightly canted away from the X-axis. The analysis by the team at the Scientific Visualization Studio shows that the line to Earth is only 43.5° away from a line perpendicular to the glass.
075:48:37 Lovell (onboard): Bill, I got it framed; it's very clear right here.
The first of two colour images of the Earthrise is taken at 075:48:39.
AS08-14-2383 - Anders's first colour image of Earthrise over the Moon - Image by NASA/Johnson Space Center.
This is Bill's first colour image of Earthrise over the Moon and is likely the photograph that has become an icon for environmental groups around the world. It manages to contrast the grey, rugged, hostile and barren landscape of the Moon with the dynamic, colourful life-giving sphere of Earth. The landmass that is visible near the terminator is western Africa. A little of South America can be seen near the limb on the left and Antarctica is at the bottom.
075:48:40 Lovell (onboard): You got it?
075:48:41 Anders (onboard): Yep.
075:48:42 Borman (onboard): Well, take several of them.
075:48:43 Lovell (onboard): Take several of them! Here, give it to me.
075:48:44 Anders (onboard): Wait a minute, let's get the right setting, here now; just calm down. Calm down, Lovell.
075:48:49 Lovell (onboard): Well, I got it ri - Oh, that's a beautiful shot.
075:48:54 Lovell (onboard): 250 at f/11.
The second colour image is taken at 075:49:09 after a minor exposure change.
AS08-14-2384 - A second colour image of Earthrise over the Moon - Image by NASA/Johnson Space Center.
Interestingly, in his book, 'Countdown', cowritten with Robert J. Serling, Frank Borman states that the famous colour image was taken by him. However, the analysis by the Scientific Visualization Studio clearly shows that Bill Anders must have taken all three. Ernie Wright, analyst at the SVS, suggests that what Frank is remembering is an occasion on orbit 7 when it appears he did take eight photos of Earthrise, AS08-14-2389 to 2396.
075:49:07 Anders (onboard): Okay.
075:49:08 Lovell (onboard): Now vary the - vary the exposure a little bit.
075:49:09 Anders (onboard): I did. I took two of them.
075:49:11 Lovell (onboard): You sure we got it now?
075:49:12 Anders (onboard): Yeah, we'll get - we'll - It'll come up again, I think.
075:49:17 Lovell (onboard): Just take another one, Bill.
As the crew enjoy an historic view of their home planet, the other Hasselblad in its mounting is still photographing the landscape below.
Composite of AS08-12-2150 to AS08-12-2163 including crater Hansky. The image runs between the lines of longitude 106°E on the right and 94°E on the left - Source images by NASA/Johnson Space Center.
This strip from the vertical stereo sequence passes through the northern half of Pasteur. The crater itself is virtually invisible in this image, but for reference, Pasteur G is slightly east of the crater's centre and its northwest rim runs roughly from Pasteur U around north of Pasteur Y.
AS08-12-2150 - Crater Pasteur G cut off at bottom of frame - Image by NASA/Johnson Space Center.
AS08-12-2151 - Image by NASA/Johnson Space Center.
AS08-12-2152 - Image by NASA/Johnson Space Center.
AS08-12-2153 - Crater Pasteur Y cut off at top of frame - Image by NASA/Johnson Space Center.
AS08-12-2154 - Crater Pasteur Y cut off at top right of frame. Pasteur U cut off at lower left of frame - Image by NASA/Johnson Space Center.
AS08-12-2155 - Crater Pasteur U dominates lower left of frame - Image by NASA/Johnson Space Center.
AS08-12-2156 - Crater Pasteur V in centre-left of frame - Image by NASA/Johnson Space Center.
AS08-12-2157 - Crater Pasteur V in centre-right of frame - Image by NASA/Johnson Space Center.
AS08-12-2158 - Crater Pasteur V on right of frame. Hansky F is cut off on left - Image by NASA/Johnson Space Center.
AS08-12-2159 - Crater Hansky F at lower left of frame - Image by NASA/Johnson Space Center.
AS08-12-2160 - Crater Hansky F at lower right of frame. Hansky is cut off at bottom left corner - Image by NASA/Johnson Space Center.
AS08-12-2161 - Crater Hansky cut off at bottom of frame - Image by NASA/Johnson Space Center.
AS08-12-2162 - Crater Hansky is cut off at bottom right corner. Hirayama K is cut off at left of frame - Image by NASA/Johnson Space Center.
AS08-12-2163 - Crater Hirayama K is at upper left of frame - Image by NASA/Johnson Space Center.
075:49:30 Collins: Apollo 8, this is Houston. Over. [No answer.]
075:50:08 Collins: Apollo 8, this is Houston. Over. [No answer.]
[Download MP3 audio file of PAO announcer recording. Clip courtesy John Stoll, ACR Senior Technician at NASA Johnson.]
And we're advised we're having antenna problems at our prime site. We have handed it to another site, Goldstone, I believe. You will notice, on some of these transmissions, a lot of background noise. That's being done on the smaller-powered antennas from the spacecraft. Around the High Gain Antenna - the one which transmits the television pictures and other data, the reception's much clearer. Another call has gone out, here's the conversation.
075:50:26 Collins: Apollo 8, this is Houston. Over
075:50:33 Borman: Go ahead, Houston. Apollo 8 here.
075:50:36 Collins: Roger. We've been having a little antenna problem on the ground here. We're reading you now with a lot of noise in the background. How me?
075:50:46 Borman: Loud and clear, Michael. [Long pause.]
075:50:59 Collins: Roger, Frank. We're still trying to get a bit better comm here. Stand by; you're unreadable.
Comm break.
Their current attitude is unfavourable for the High Gain Antenna (HGA) so communications will be via the omnidirectional antenna whose performance can be marginal at this distance.
075:52:26 Collins: Apollo 8, this is Houston. Over.
075:52:30 Borman: You're loud and clear, Houston. Apollo 8
075:52:32 Collins: Rog. Understand you're reading us loud and clear; we're barely reading you. Would you go to P00 and Accept, please? We're going to send you a P27 update.
075:52:45 Borman: Roger. Going to P00 and to Accept. [Long pause.]
075:53:47 Borman: We're in P00 and Accept, Houston.
075:53:51 Collins: Apollo 8, Houston. You're unreadable. We're going to delay that P27 until we get a little bit better lock on you. [Long pause.]
[Download MP3 audio file of PAO announcer recording. Clip courtesy John Stoll, ACR Senior Technician at NASA Johnson.]
This is Apollo Control, Houston. We are having antenna difficulties. We'll take the line... Oh, we are going to try some more. Stand by. Let's continue to monitor.
The vertical stereo sequence is still being taken, now looking at terrain that can be seen, if somewhat obliquely, from Earth.
Composite of AS08-12-2164 to AS08-12-2177 from 96°E to 82°E. This pan reaches the southern limits of Mare Smythii with flooded craters Helmert and Kiess - Source images by NASA/Johnson Space Center.
To the left of this image, compiled from frames AS08-12-2164 to 2177, the flooded craters Kiess and Helmert represent the southern limits of Mare Smythii. The three craters, Hirayama Q, M and K lie along the degraded southern rim of Hirayama itself.
These images are the last in the stereo sequence and Frank is about pitch the spacecraft away from its nose-down attitude.
AS08-12-2164 - Crater Hirayama K is upper right of centre, Hirayama M on the lower left - Image by NASA/Johnson Space Center.
AS08-12-2165 - Crater Hirayama K is cut off on the right, Hirayama M is bottom of frame - Image by NASA/Johnson Space Center.
AS08-12-2166 - Crater Hirayama M is cut off at lower right, Hirayama Q is cut off at upper left - Image by NASA/Johnson Space Center.
AS08-12-2167 - Crater Hirayama Q is at upper left - Image by NASA/Johnson Space Center.
AS08-12-2168 - Crater Hirayama Q is at upper right - Image by NASA/Johnson Space Center.
AS08-12-2169 - Image by NASA/Johnson Space Center.
AS08-12-2170 - Image by NASA/Johnson Space Center.
AS08-12-2171 - Flooded crater Helmert is on the upper left - Image by NASA/Johnson Space Center.
AS08-12-2172 - Flooded crater Helmert is on the upper centre - Image by NASA/Johnson Space Center.
AS08-12-2173 - Flooded crater Helmert is on the upper right - Image by NASA/Johnson Space Center.
AS08-12-2174 - Image by NASA/Johnson Space Center.
AS08-12-2175 - Large, flooded crater Kiess is cut off at the upper left - Image by NASA/Johnson Space Center.
AS08-12-2176 - Large, flooded crater Kiess is cut off at top of frame - Image by NASA/Johnson Space Center.
AS08-12-2177 - Large, flooded crater Kiess is cut off to the upper right - Image by NASA/Johnson Space Center.
075:54:11 Collins: As long as you're reading me okay, Frank, I'll bring you up to date on a couple of things. The P27 which we will be sending you is a state vector update going to the LM slot, and we'd like you, as per plan, to transfer that to the CSM slot by a Verb 47 Enter, and we'd like to just remind you that prior to doing your Verb 47 Enter, manually select P00 and wait for the computer activity light to go out. Did you copy? Over.
075:54:48 Borman: Roger. Roger. We copy. [Pause.]
The computer's knowledge of where it is and how fast it is going (the state vector) is about to be updated by information being uploaded directly into its memory by the flight controllers on the ground. There are two slots in memory where this information is stored, known as the LM slot (for when the spacecraft has a Lunar Module attached) and the CSM slot. The LM slot is being used as a back-up copy for this mission. There is a specific command, Verb 47, for the computer to transfer the contents of the LM slot to the CSM slot.
075:54:57 Collins: Okay, Frank. Are you still reading me loud and clear? Over.
075:55:03 Borman: Roger. Loud and clear.
075:55:05 Collins: All right. I'll go ahead with a map update when you're ready to copy. [Pause.]
075:55:17 Borman: Okay. Can you hold off a minute? [Long pause.]
075:56:17 Collins: Apollo 8, this is Houston. How are you reading now? [Long pause.]
075:56:34 Borman: Go ahead, Houston. This is Apollo 8. [Long pause.]
075:57:04 Collins: Apollo 8, this is Houston with a map update. Are you ready to copy?
075:57:12 Borman: Just a minute, Mike.
075:57:20 Collins: Roger. Apollo 8, Houston. Your map update for rev 4/5: LOS, 76:59:59; sunrise, 77:09:06; prime meridian, 77:15:47; AOS, 77:45:50; sunset, 78:22:03; IP-1 position time for control point 2, 77:29:42; IP-1 time closest approach for target B-1, 78:10:25. Over.
075:58:23 Borman: We'll have to get that data later on. [Pause.]
075:58:31 Collins: We'll try it again later, Frank.
075:58:38 Borman: Thank you.
Long comm break.
The map update will be read up at 076:20:26.
As they head towards the terminator, Frank begins pitching the spacecraft up to a 'sharp-end-forward' attitude. This manoeuvre results in the windows facing the black sky while the optics on the opposite side of the Command Module are directed downwards for Jim to make an evaluation of Landing Site 1. As the pitch manoeuvre progresses, the camera taking the vertical stereo sequence continues recording the view and shows the pitch motion occurring.
Animated GIF file of frames AS08-12-2178 to 2186.
This animated GIF shows the horizon pass through the field of view until Earth is at the edge of frame, at which point Frank stops the manoeuvre. The first frame of the animation shows a collection of craters between Kiess and Kastner. Just before the horizon goes out of shot, we see a glimpse of the eastern edge of Mare Fecunditatis towards the bottom of frame and Mare Spumans towards the top.
AS08-12-2178 - Image by NASA/Johnson Space Center.
AS08-12-2179 - Image by NASA/Johnson Space Center.
AS08-12-2180 - Image by NASA/Johnson Space Center.
AS08-12-2181 - Image by NASA/Johnson Space Center.
AS08-12-2182 - Image by NASA/Johnson Space Center.
AS08-12-2183 - Image by NASA/Johnson Space Center.
AS08-12-2184 - Image by NASA/Johnson Space Center.
AS08-12-2185 - Image by NASA/Johnson Space Center.
AS08-12-2186 - Image by NASA/Johnson Space Center.
Bill stops the mounted camera as it is no longer looking at anything useful. Magazine D will not be used again until after the Trans-Earth Injection (TEI) burn when it will be used to photograph the receding Moon.
[Download MP3 audio file of PAO announcer recording. Clip courtesy John Stoll, ACR Senior Technician at NASA Johnson.]
Apollo Control here. I want to correct something I apparently said; Frank Borman dedicated that prayer to St. John's Episcopal church. He is a member of St. Christopher's. The confusion is due to the fact, I believe that Jim Lovell is a member of St. John's Episcopal church, so we have two Episcopalians going to two different churches. I apologize. The correct name of the church is St. Christopher's. We have the correct town. Now let's get back and monitor.
We'll take the line down in view of the noise and record and come back up to you with anything significant. At 76 hours into the flight, this is Apollo Control, Houston.
076:06:12 Collins: Apollo 8, this is Houston. Over.
076:06:17 Anders: Roger, Houston. How do you read?
076:06:19 Collins: Reading you a lot better now, Bill. How are you reading me?
076:06:25 Anders: I'm reading you five - loud and clear, and are you copying our low bit data to record this - these tracking passes? Over.
076:06:35 Collins: That's affirmative. We are getting low bit data now.
076:06:41 Anders: Okay. I've played the - run the tape recorder back to the beginning. We have quite a bit of high bit, so all you'll have to do is start recording when you're ready. [Pause.]
076:06:55 Collins: Roger. Stand by one, Bill. [Long pause.]
076:07:27 Collins: Apollo 8, Houston. Stand by one on the tape recorder dump. We'd like you to look at your steam pressure. We think that the primary evaporator may have dried out, and if the steam pressure shows off-scale low, would you please close the back pressure valve and reservice the evaporator? Over.
076:07:50 Borman: Roger. [Long pause.]
076:08:49 Collins: Apollo 8, Houston. We're ready to send you the P27 LM state vector update when you are ready. Over.
076:08:58 Borman: You'll have to wait until this tracking exercise is over with, Mike.
076:09:02 Collins: Roger. Thank you.
Long comm break.
With the HGA being on the same side of the spacecraft as the optics, both of which are facing the Moon while Jim completes his tracking exercise, the communications with Earth are poor.
At 074:27:40, times were read up by the ground that included two which represented the acquisition times of two "initial points" that Jim would view on the lead up to tracking the B-1 landing site. Jim will take marks on these points and the landing site so that comparison with their orbit will allow accurate surface coordinates to be computed.
[Download MP3 audio file of PAO announcer recording. Clip courtesy John Stoll, ACR Senior Technician at NASA Johnson.]
Apollo Control here. 76 hours, 09 minutes into the flight. In the past few minutes, we've established a much cleaner communication with Apollo 8. Here's a sample.
076:18:14 Collins: Apollo 8, this is Houston. Were you calling? Over.
076:18:19 Anders: Roger. You can go ahead now and give you the computer, get the updates, and let's get going on the PAD messages.
076:18:26 Collins: Roger. [Pause.]
076:18:36 Anders: It's in P00 and Accept. [Pause.]
076:18:44 Anders: Okay, Houston. You ready to talk about the water boiler problem?
076:18:49 Collins: Rog. We copy you in P00 and Accept, and we're sending you a P27 LM state vector. On the water boiler, it looks to us like the evaporator has been reserviced. How does it look to you? Over.
Bill is in charge of the spacecraft's systems and he has had trouble with the evaporator since halfway through the translunar coast. If water was passing through the evaporator's cooling plates, the pressure of the vapour on the other side would be measurable. Mike Collins commented earlier that this steam pressure was lower than the sensor's range could show, so the implication is that the evaporator has dried out and is no longer functioning.
076:19:06 Anders: Roger. I reserviced it, put it to Auto, H2O flow to Auto; and the steam pressure went to zero again. So I tried reservicing it a second time for 1 minute, and again no results. I'm in the present process of closing the back-pressure valve manually. Over.
076:19:25 Collins: Roger. Understand you've tried to reservice it twice, both times steam pressure has gone to zero, and now you're closing the back-pressure valve manually.
076:19:36 Anders: Roger. Each time I've reserviced it, the steam pressure came up to about 0.07 to 0.1; but as soon as the steam and water were put to Auto, the steam pressure went right back down again.
076:20:01 Collins: Roger. We copy, and we're reading you loud and clear now, Bill. On your map update, did you copy that that I gave you previously? [Pause.]
076:20:13 Lovell: Negative. We have not copied it yet.
076:20:14 Anders: Negative.
076:20:17 Collins: Okay. I have it for you again when you're ready to copy.
076:20:24 Lovell: Ready to copy.
076:20:26 Collins: This is a map update for revs 4/5: LOS, 76:59:59; sunrise, 77:09:06; prime meridian, 77:15:47; AOS, 77:45:50; sunset, 78:22:03. Remarks: IP-1, acquisition time for CP2 is 77:29:42; IP-1 time closest approach for target B-1, 78:10:25. Over. [Pause.]
This map update refers to events and landmarks that will be encountered as the spacecraft ends the fourth and begins the fifth orbit around the Moon. It is interpreted as follows:
Loss of Signal (LOS) before start of rev 5: 76:59:59. (This is the time they lose contact with Earth as they go behind the Moon.)
Spacecraft Sunrise in orbit: 77:09:06. (At this time, the spacecraft will emerge into sunlight. About 6 minutes later, it will pass over the Moon's sunset terminator.)
Passing over Prime Meridian of 150°W: 77:15:47. (At this time, they will be passing over the eastern rim of the large far-side crater Korolev which coincides with the 150°W line of longitude.)
Acquisition Of Signal (AOS): 77:45:50. (Communications with Earth will be re-established 45 minutes, 51 seconds after LOS.)
Spacecraft sunset in orbit: 78:22:03. (As the spacecraft moves across the near-side face of the crescent Moon, this is the time it will pass from lunar daytime into the lunar night 6 minutes after it passes over the sunrise terminator.)
Jim has an exercise to track a control point on the Moon's surface about 150 km west of crater Keeler. To help him lead to it, he has a recognisable initial point that he can track which becomes visible earlier. He will acquire this point at 77:29:42. Additionally, he will make sightings of the possible landing site B-1 for which he also has an initial point. The update PAD includes the time of closest approach to this initial point, at 78:10:25.
076:21:52 Collins: That's right, and the prime meridian time is 77:15:47, and you got your computer back. We've got a good P27 update.
076:22:04 Borman: Okay. We will go to P00 and Transfer.
076:22:07 Collins: Roger. [Long pause.]
076:22:45 Borman: Houston, do you have a TEI-5 for us?
076:22:48 Collins: We're working on it now, Frank. Have it for you momentarily.
076:22:56 Borman: Roger. [Long pause.]
Each time they come across the Moon's near side, Houston gives the crew a PAD that would allow them to make an accurate return home in case of an emergency during their next far-side pass.
Apollo 8 has just passed into the Moon's shadow. Frank stops the spacecraft's orb-rate manoeuvre and instead adopts an inertial attitude while they coast through the Earthlit darkness. Bill aims the HGA.
076:23:27 Collins: Apollo 8, Houston.
076:23:32 Anders: Go.
076:23:33 Collins: Roger. On your back-pressure valve, we'd like to know how long after you closed the back-pressure valve the first time - how long it was from the time you closed it until you started the reservicing. We'd like you to wait about 15 minutes to prevent any ice from forming due to flash freezing. Over. [Pause.]
076:23:59 Anders: Okay. I start immediately to reservice it. [Long pause.]
[Download MP3 audio file of PAO announcer recording. Clip courtesy John Stoll, ACR Senior Technician at NASA Johnson.]
Apollo Control, Houston here. 76 hours, 24 minutes. Communication much improved now as we move out on the front side of the Moon. Here's how it is going."
076:24:17 Collins: Apollo 8, Houston. We showed that you closed it this last time about 4 minutes ago, so we'd like to wait another 15 minutes and then try to reservice it again at that time and then go to Auto. Over. [Pause.]
076:24:41 Anders: Roger.
What Collins is referring to as the back-pressure valve is the Steam Pressure Control Valve. This valve controls the flow of water vapour into space and therefore the degree of evaporation from the wick. If needed, it can be used to close the steam duct completely from the vacuum of space. If Bill closes the valve, he can restart the flow of water into the metal wick. However, when he first closes the Steam Pressure Control Valve, the space in the steam duct that has been isolated is still at a vacuum. Mission Control are aware that the sudden presence of water in a vacuum would cause quick evaporation, hence rapid cooling and possibly the formation of ice. This would be a dangerous situation as the expansion of ice could damage the structure of the evaporator and perhaps the integrity of the spacecraft's pressure hull. Waiting for 15 minutes would allow vapour to slowly build up in the closed-off steam duct and make the introduction of water into the wick a safer operation.
076:24:43 Collins: Roger. Thank you. The TEI-4 PAD which you have is still valid. We'll have a TEI-5 PAD for you shortly.
The Mission Report indicates that Jim has just perfomed a realignment of the guidance platform using stars 22 (Regulus) and 30 (Menkent).
076:24:55 Anders: Roger. And be advised we're presently in steam pressure, Manual, and we're in H2O flow, Auto; and are now in H2O flow, Off, as of about 5 seconds ago.
076:25:15 Collins: Roger. We copy that, Bill. [Pause.] And we confirm that's a good configuration.
076:25:28 Anders: Right now, I've got the H2O flow, Off. Do we stay that way?
076:25:32 Collins: Affirmative. [Long pause.]
076:25:45 Collins: Apollo 8, Houston. On your television update, we propose that you start the TV at the Flight Plan time of 85 hours, 37 minutes and simply extend the stop time a few minutes. You're currently scheduled to stop at 86 hours, and we'd like to keep it going until the terminator, which should be approximately 86:14. Over.
At 074:40:51 Frank asked for a slight readjustment of the Flight Plan during the ninth rev so that he could include TV imagery of the terminator while he and his crew make what will become an historic TV transmission to Earth.
076:26:13 Borman: Roger. [Long pause.]
076:26:27 Collins: Frank, I know you're busy up there. We've got the daily news for you whenever and if ever you'd like to hear it.
076:26:38 Borman: I'll give you a call.
Comm break.
076:27:46 Collins: Apollo 8, this is Houston.
076:27:51 Borman: Go ahead.
076:27:53 Collins: I have the TEI-5 PAD for you whenever you're ready to copy.
076:28:05 Borman: Okay. Go ahead.
076:28:07 Collins: Okay. TEI-5; SPS/G&N; 47 - correction - 45701; minus 0.43, plus 1.16; 079:21:26.03. Are you with me so far?
076:28:41 Borman: Roger.
076:28:43 Collins: Plus 3117.1, minus 0076.7, minus 0021.4; 180, 017, 001; not applicable, plus 0018.8; 3118.1, 2:59, 3100.3. Are you with me? Over.
076:29:44 Borman: Roger.
076:29:47 Collins: Roger. 40, 271.1 39.8; 033, down 04.3, left 2.3; plus 08.32, minus 165.00; 1295.6, 36208, 146:39:44; north set of stars remain Sirius and Rigel; roll, pitch, and yaw remain same angles, 129, 155, 010; ullage remains 2 quads for 20 seconds, quads B and D. Horizon on 4 degree line at TIG minus 3 minutes. Over.
The PAD is interpreted as follows:
Purpose: The PAD is for an emergency burn to return to Earth at the end of Rev 5.
Systems: The burn would be made using the SPS engine, under the control of the Guidance and Navigation system.
CSM Weight (Noun 47): 45,701 pounds (20,730 kg).
Pitch and yaw trim (Noun 48): -0.43° and +1.16°.
Time of ignition (Noun 33): 79 hours, 21 minutes, 26.03 seconds.
Change in velocity (Noun 81), fps (m/s): X, +3,117.1 (+950.1); Y, -76.7 (-23.4); Z, -21.4 (-6.5). The large positive number in the X direction implies a large prograde component, essentially adding to their orbital velocity, exactly what would be expected from an escape manoeuvre.
Spacecraft attitude: Roll, 180°; Pitch, 17°; Yaw, 1°. The desired spacecraft attitude is measured relative to the alignment of the guidance platform which itself has been aligned per the LOI-2 REFSMMAT.
Expected apogee of resulting orbit (Noun 44): Not applicable. Being initiated around the Moon, the apogee of the resulting orbit around Earth is irrelevant.
Expected perigee of resulting orbit (Noun 44): 18.8 nautical miles (34.8 km).
Delta-VT: 3118.1 fps (950.4 m/s). The total sum of the three velocity components.
Burn duration or burn time: 2 minutes, 59 seconds.
Delta-VC: 3,100.3 fps. A suitable figure to enter in the EMS to allow it to shut down the engine as a backup in case the G&N system fails.
Sextant star: Star 40 (Altair, or Alpha Aquilae) visible in sextant when shaft and trunnion angles are 271.1° and 39.8° respectively.
Boresight star: Star 33 (Antares, Or Alpha Scorpii).
COAS Pitch Angle: Down 4.3°.
COAS X Position Angle: Left 2.3°.
Expected splashdown point (Noun 61): 8.32° north, 165° west; which is in the mid-Pacific.
Range to go at the 0.05 g event: 1,295.6 nautical miles. To set up their EMS (Entry Monitor System) before re-entry, the crew need to know the expected distance the CM would travel from the 0.05 g event to landing. This figure will be decremented by the EMS based on signals from its own accelerometer.
Expected velocity at the 0.05 g event: 36,208 fps. This is another entry for the EMS. It is entered into the unit's Delta-V counter and will be decremented based on signals from its own accelerometer.
GET of 0.05 g event: 146 hours, 39 minutes and 44 seconds GET. This is the predicted time that the EMS will be triggered by a deceleration of 0.05 g.
GDC Align stars: Stars to be used for GDC Align purposes are Sirius and Rigel.
There are two additional notes given in the PAD. An ullage burn of 20 seconds should be made by two of the RCS jets to settle the contents of the half-empty SPS tanks prior to the burn. This is minimise the chance of helium gas being ingested when the engine ignites. A second note points out that if everything is proceeding as it should, the lunar horizon should line up with the 4-degree line at three minutes before ignition.
076:31:14 Borman: Roger. Here we go. TEI-5; SPS/G&N; 45701; minus 0.43, plus 1.16; 079:21:26.03; plus 3117.1, minus 0076.7, minus 00214; 180, 017, 001; N/A, plus 0018.8; 3118.1, 2:59, 3100.3; 40, 271.1, 39.8; 033, down 04.3, left 2.3; plus 08.32, minus 165.00; plus 1295.6, 36208, 146:39:44. Set stars are the same; ullage - we'd like - do you have any objection to using four quads for 15 seconds? [Pause.]
076:32:23 Collins: No objection to four-quad ullage, Apollo 8.
076:32:28 Borman: Okay. We'd like to just go ahead and use four quads at all times, unless we get a lot shorter on fuel than we are now.
076:32:34 Collins: Understand.
076:32:39 Borman: And is that 15 seconds?
076:32:42 Collins: Affirmative: 15 seconds, four quads.
076:32:49 Collins: Apollo 8...
076:32:50 Borman: Thank you, and horizon is 4 degrees at minus...
076:32:54 Collins: That readback is correct, Frank, and we'd like to advise that the voice quality on the high bit rate is excellent. Over.
076:33:04 Borman: Thank you. Mike, it's 4 quads for 15 seconds. Is that right?
076:33:12 Collins: That is affirmative, Apollo 8: 4 quads for 15 seconds.
076:33:18 Borman: Thank you.
Comm break.
[Download MP3 audio file of PAO announcer recording. Clip courtesy John Stoll, ACR Senior Technician at NASA Johnson.]
This is Apollo Control, Houston, here with 24 minutes left to run in this period of acquisition. We might make note of our velocity in this revolution; it's approximately 3,560 statute miles per hour. And here goes another call from Mike Collins."
076:35:53 Collins: Roger. For Bill, he can go ahead and do his standard reservice on the - on the water now. It's looking good.
076:36:05 Borman: Okay. You want us to reservice it now?
076:36:07 Collins: That's affirmative. And upon completion, go back to Auto.
076:36:19 Anders: Roger.
Long comm break.
[Download MP3 audio file of PAO announcer recording. Clip courtesy John Stoll, ACR Senior Technician at NASA Johnson.]
During this - Apollo Control here - during this lull, we've been looking at the biomedical data and the harness is switched over to Bill Anders. We're looking at a mean heart rate of 68. His high, during this particular reporting period, is 69; a low of 67. Mean respiration rate, 10; activity mode is listed as normal. Cabin pressure, 4.9 [psi, 33.8 kPa]; cabin temperature, 79 [degrees Fahrenheit, 26.1°C], that's a 2-degree rise from what we saw about an hour or so ago - 77 [°F, 25°C]. Now 21 - a little more than 21 minutes before Loss of Signal. We'll just leave the line open.
This is Apollo Control, Houston. Our time is 76 hours, 40 minutes, and I think Mike Collins is about to advise the crew that they have a Go. They have a Go for rev 5. Stand by.
076:40:28 Collins: Roger. We are still dumping your tape. The voice quality on high bit is coming through superb, and you are Go for next rev. And we'd like to get a brief status report on your rest between 60 hours and LOI-1, just to fill in some information for us. [Pause.]
076:40:56 Borman: We only got a couple of hours rest.
076:40:58 Collins: Okay. [Pause.]
076:41:06 Borman: We're tired right now, but we will have to wait until TEI before we get back to the regular cycle.
076:41:12 Collins: I suspect you're right.
Sleep has been an abiding problem throughout mission. Not only did the crew find it difficult to sleep in shifts due to the close quarters of the other crewmembers, they are now keyed up and very busy fulfilling the major goal of the mission around the Moon. They will struggle to get rested during their 20-hour stay in lunar orbit and yet must be alert enough to complete the complex procedures for the burn to get them home.
By the Flight Plan, Frank is due to begin his meal. For this, Bill should be taking his seat on the left ready to control the spacecraft in preparation for Jim's next tracking exercise.
076:41:17 Anders: Okay, Houston. The water boiler has been reserviced. Back-pressure valve closed for 1 minute; water, On, for 2; and it's now steam pressure, Auto; H2O flow, Auto.
076:41:30 Collins: Roger. We copy, Bill. [Long pause.]
076:41:56 Anders: If we have a problem, a similar problem, again on the back side in the sunlight, might be a good idea to crank up the secondary loop until we have AOS. What do you think about that?
As well as the primary cooling system, whose evaporator is prone to drying out, the spacecraft has a secondary circuit that can be brought into play should the primary fail to provide enough cooling. The evaporator in the secondary loop is entirely automatic.
076:43:25 Collins: Roger, Jim. In regard to your evaporator, we feel that if you do have a similar problem next time on the back side in the sunlight, check the evaporator outlet temperature, and if it gets above 60, we concur that it would be a good idea to bring up the secondary loop. Over.
076:43:47 Lovell: Roger. [Long pause.]
076:44:17 Collins: Apollo 8, Houston. When we say bring up the secondary loop, we mean bring up the evaporator only on the secondary loop. Copy?
076:44:28 Lovell: Roger.
076:44:29 Borman: Roger.
Long comm break.
Audio missing for the next five minutes.
076:49:51 Anders: Houston, Apollo 8. We got time for a little news.
076:49:56 Collins: Apollo 8, this is Houston. Over.
076:50:02 Anders: I say how about a little bit of that news you promised?
076:50:05 Collins: Roger. We got the Interstellar Times here, the December 24 edition. Your TV program was a big success. It was viewed this morning by most of the nations of your neighboring planet, the Earth. It was carried live all over Europe, including even Moscow and East Berlin. Also in Japan and all of North and Central America, and parts of South America. We don't know yet how extensive the coverage was in Africa. Are you copying me all right? Over.
076:50:38 Borman: You are loud and clear.
076:50:40 Collins: Good. San Diego welcomed home today the Pueblo crew in a big ceremony. They had a pretty rough time of it in the Korean prison. Christmas cease-fire is in effect in Vietnam, with only sporadic outbreaks of fighting. And if you haven't done your Christmas shopping by now, you better forget it.
076:51:02 Anders: Thank you.
076:51:04 Collins: A couple of [Houston] Oilers made the All Star team, Webster and Farr.
076:51:14 Anders: Roger. [Pause.]
076:51:22 Collins: And that's about all our news. How about your news?
076:51:28 Borman: Well, we'll be looking forward to a big burn here shortly.
076:51:34 Collins: Roger.
076:51:39 Lovell: Mike, I think I can say it without contradiction, it's been a mighty long dry spell up here.
076:51:48 Collins: I guess you can say anything you like without contradiction.
076:51:56 Borman: When do we dump water, Houston?
076:52:00 Collins: Say again, Frank.
076:52:04 Borman: When can we dump water?
076:52:06 Collins: Stand by.
Comm break.
Water builds up from two sources, the excess produced by the fuel cells and urine passed by the crew. It is the latter that Frank is most concerned with. Both are ejected through two ports on the side of the Command Module, as shown in this image of Charlie Brown, the Apollo 10 CM. As the water hits the vacuum of space, it quickly evaporates while at the same time freezing. By this vigourous evaporation, it imparts a tiny thrust on the spacecraft that has measurable effects on its trajectory. At some point, such perturbation must be compensated for.
076:53:32 Collins: Apollo 8, Houston.
076:53:38 Borman: Go, Houston.
076:53:39 Collins: We will get you the number after a while on your water dump. It looks like the quantity isn't increasing very slightly, and we're considering not only the quantity in regard to the dump, but also its effects on the trajectory relative to TEI and so forth, but we will have a good answer for you shortly.
076:54:00 Borman: We are not just thinking about the waste water tank: we're thinking about some other kind of water that has to get dumped out of the spacecraft, slightly used water.
076:56:36 Collins: Roger. We have about 3½ minutes to LOS. We'll give you back the DSE under your control, and in regard to your water dump, we're tentatively predicting a waste water tank dump at about 80 hours GET and any other dumps are your discretion, any time you'd like to make them.
076:57:00 Borman: Thank you. [Pause.]
076:57:08 Collins: People listening to the high bit rate down here say it's like sitting in your living room listening to a good hi-fi. [Pause.]
076:57:21 Borman: Sounds like a good idea. [Long pause.]
076:58:03 Collins: Apollo 8, Houston. Coming up on two minutes to LOS. We got a good reservice on the primary evaporator, and everything is still looking very good down here.
076:58:16 Borman: Okay. Thank you. [Long pause.]
The evaporator will function normally for the rest of their stay at the Moon. After they begin their coast home, they will deactivate it so that the vapour coming from the steam vent does not influence their trajectory. Prior to re-entry, it will be reactivated, only to dry out again.
[Download MP3 audio file of PAO announcer recording. Clip courtesy John Stoll, ACR Senior Technician at NASA Johnson.]
And this is Apollo Control, Houston. 76 hours, 58 minutes. The spacecraft will lose lock with Earth in about one minute and start its fifth - actually its sixth [it is in fact fifth] trip behind the Moon. It'll be the start of its sixth [means fifth] rev and when it gets to zero [longitude, on the back side of the moon].
076:59:12 Collins: Apollo 8, Houston. One minute to LOS. Are you still reading us loud and clear?
076:59:18 Borman: Loud and clear. Loud and clear.
076:59:20 Collins: Okay, fine. We've been noticing a little bit of increase in our background noise as you approach the back side.
076:59:30 Borman: Rog. We had to go off the High Gain. That's why.
076:59:35 Collins: Roger. [Pause.]
076:59:44 Collins: Have a good back-side; we'll see you next time around.
076:59:49 Borman: Okay, Mike.
Mike Collins has reminded the crew one minute to LOS and Frank says, "Loud and clear. Loud and clear". They'll say their goodbyes on, you heard nothing much from Bill Anders on this pass and you are not likely to for several more. He is an extremely busy photographer. His column in the Flight Plan is almost solid with instructions. He's moving from one couch to another. He's moving - using several kinds of cameras, changing lenses, and he is as busy as one man - one astronaut could be. Jim Lovell is working down at the G&N station, getting pointing data. And the Command Pilot [Commander, i.e. Frank Borman] in addition to flying the spacecraft, having lunch, is been carrying on a running conversation with his compatriot, Mike Collins, down here on the Earth. We have lost lock, we should be back with the crew in 44 minutes. This is Apollo Control at 77 hours into the flight.