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Apollo 14


Day 1, part 4: Settling Down & Navigation

Corrected Transcript and Commentary Copyright © 2020 by W. David Woods, Ben Feist, Ronald Hansen, and Johannes Kemppanen. All rights reserved.
Last updated 2020-10-03
Some six hours into the mission, Apollo 14 is zooming away from the Earth and towards the Moon. An early hurtle was also passed when they were initially unable to dock with the Lunar Module Antares, which is now securely joined onto the Command Module Kitty Hawk. For now, the crew will finally be able to take a small breather and appreciate their unique voyage, while also taking care of some less pressing chores.
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006:16:13 Fullerton: 14, Houston.
006:16:15 Mitchell: Go ahead.
006:16:16 Fullerton: Roger. As soon as you get to your attitude there, we'll be ready to uplink a new REFSMMAT to you.
006:16:23 Roosa: Okay.
Comm break.
REFSMMAT is one of those delicious acronyms that pepper Apollo dialogue and make it somewhat opaque for the casual reader. But like many other seemingly complex ideas in Apollo, once we look into the underlying concept, we will be able to grasp its meaning. REFSMMAT stands for 'Reference to Stable Member Matrix'. This definition certainly does little to increase our understanding of what it truly means, and hence we shall have to dwell deeper into the premises of Apollo inertial guidance.
The Inertial Measurement Unit gyroscopic platform, or the stable member.
The heart of the guidance system is the Inertial Measurement Unit, and at its core sits the stable member. Three gyroscopes for attitude determination and three accelerometers for velocity change determination sit on a platform that is stabilized on three gimbals. These gimbals allow the spacecraft to rotate around the platform while the stable member remains technically immobile, and hence maintains a known orientation in a selected coordinate system. With careful knowledge of the accelerations experienced on each direction, the spacecraft can be located in space.
The Basic Reference Coordinate System defines mathematical space in the Earth-sun system. The REFSMMAT defines the spacecraft's position in relation to this System.
For the inertial measurements to have any true value in terms of navigation and guidance, they have to be put into a proper context. For Apollo, this is accomplished with a system of navigational reference that is called the Basic Reference Coordinate System, or BRCS. The BRCS is defined by the relationship between the Earth-Moon system with the Sun, using their relative positions on January 1st, 1971, as the starting position. The X axis points towards the Sun on the ecliptic plane ,while the Z axis is formed into the direction of the Earth North pole. The Y axis is formed to a right angle of the X axis. Hence we now have a three-dimensional reference system, which can answer the two most important questions a space traveler requires - which way is up, and which way am I going to.
The Flight Director/Attitude Indicator photographed onboard the Apollo 13 Command Module Odyssey
But here our beautiful Basic Reference Coordinate System becomes problematic. While it is a useful mathematical model for the onboard computer to calculate position and direction, it is less than practical in terms of actual spaceflight. For starters, the definition of 'up' is very much different in various parts of the mission. When the Saturn V sits on the launch pad, 'up' is certainly away from the surface of the Earth, as it is also on Earth orbit. But while in the cislunar space between the Earth and the Moon, up becomes much less important in terms of practical spacekeeping. And what about on lunar orbit? 'Up' is now pointing away from the Moon. Once the Lunar Module is standing on the lunar surface, the crew certainly desires 'up' to be somewhere in the opposite direction to the dusty landscape below them.
The mathematical definition of REFSMMAT. From User's Guide to Apollo GNCS Major Modes and Routines. July 1 1970 revision.
The REFSMMAT comes to rescue here, both as a concept and a practical aid for the astronaut. By adding a mathematical 'filter', or a transformation matrix, between the values generated by the inertial platform in the reference coordinate space, and our desired spatial orientation, the IMU can supply the onboard instrumentation with the correct information. With the right REFSMMAT loaded into the computer for each phase of the mission, the FDAI indicators and the computer are able to display their attitude in relation to the Earth and the Moon in what is the most useful manner for each part of the mission.
The Apollo Inertial Measurement Unit gimbals diagram.
Another important reason for the use of the REFSMMAT is to allow the crew to get around a serious mechanical limitation of the guidance system. The IMU platform is stabilized with three gimbals, and in certain attitudes, an undesired condition may develop where these gimbals line up on the same plane. When this happens, the gimbal motors will become unable to maintain the free motion of the platform, and a situation known as the gimbal lock develops. As the platform stops moving freely, it loses its ability to measure attitude changes and hence becomes unavailable as an attitude reference. The gimbal lock can be avoided with relative ease by avoiding certain attitudes during the mission. The REFSMMAT scheme assists in keeping the platform out of the gimbal lock by allowing the crew to change the reference point and hence allows the spacecraft assume attitudes that would otherwise drive the IMU into the gimbal lock.
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006:18:40 Mitchell: Houston, 14. Do you want me to start a battery B charge?
006:18:44 Fullerton: Stand by, Ed. [Long pause.]
006:19:05 Fullerton: Ed, that's affirmative. Go ahead with the battery B charge.
006:19:08 Mitchell: Okay.
Long comm break.
Command Module batteries.
The Command Module has five batteries. Two silver oxide-zinc batteries are mounted in the Lower Equipment Bay and are only used for various pyrotechnic devices on the spacecraft (CM/SM separation, parachute deployment and separation, S-IVB separation, launch escape tower separation among other functions). These 'Pyro Batts' are not recharged. Three more silver oxide-zinc batteries have a dual role in the spacecraft. They supplement the power from the fuel cells during busy periods such as engine burns. They are recharged from the fuel cells when demand from the rest of the spacecraft is low, thereby providing a load that keeps the fuel cells operating in a comfortable range. The rechargable batteries also provide power for the CM after the SM has been jettisoned, through entry, landing and post-landing operations. The controls for the electrical system are on the right of the Main Display Console, where Ed is seated. To charge battery B, he must ensure it is not online to the spacecraft's power distribution buses before switching it to the output from the battery charger. The voltage of the battery can be monitored while it is charging by switching the DC indicator to the charger.
Besides this standard complement of batteries, the Service Module has been equipped with a 400-amp-hour Auxiliary Battery located under the O2 and H2 tanks in Sector IV. Originally a design used on the Lunar Module's Descent stage to supply primary power on the lunar surface, on the CSM it acts as an emergency power supply should an Apollo 13-like loss of fuel cells power happen again. The auxiliary battery is non-rechargeable and will not be tapped into during a normal flight.
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006:22:45 Roosa: Houston, 14.
006:22:52 Fullerton: Go ahead.
006:22:53 Roosa: Hey, Gordon. I can - got a beautiful view of the S-IVB now, out of the left-hand window, and she's stable as a rock.
006:23:03 Fullerton: Roger, Stu. [Long pause.]
006:23:14 Mitchell: And, Houston, I've initiated battery B charge.
006:23:18 Fullerton: Roger, Ed. Would you give us Omni Charlie, Ed?
006:23:28 Mitchell: You have it.
006:23:30 Fullerton: Roger. And at about 6:25:20, the LOX dump should start on the S-IVB. You might keep an eye on it at that time. I'll give you a warning about 10 seconds prior.
006:23:43 Roosa: Okay.
Comm break.
CapCom Gordon Fullerton was advising the crew that the dump of the liquid oxygen remaining in the S-IVB will occur at 6 hours, 25 minutes, 20 seconds Ground Elapsed Time. This is the propulsive venting of the liquid oxygen which is aimed to increase the separation distance between the Lunar Module and the booster third stage and also is targeted to impact the S-IVB on the lunar surface near the Apollo 12 seismometer.
We're now at 6 hours, 25 minutes; some 20 seconds away from the liquid oxygen dump.
006:25:08 Fullerton: Apollo 14, Houston. That LOX dump should start at about 10 seconds.
Comm break.
Booster reports the dump is initiated.
006:26:18 Fullerton: Apollo 14, Houston. The LOX dump should be complete now. Did you see anything of it?
006:26:24 Shepard: Yeah. It's a beautiful sight, Houston. The Sun was shining from the side; it was streaming out. We tried to get a couple of Hasselblad shots of it from the corner of the window. It's really fantastic.
006:26:38 Fullerton: Roger, Al. [Long pause.]
That was Apollo 14 commander, Al Shepard reporting a very spectacular sight with good sunlight on the liquid oxygen particles streaming out of the nozzle of the S-IVB. The LOX dump is scheduled to be followed by an additional...
There is a sequence of 14 Hasselblad shots of the S-IVB after the LM had been removed on magazine L, using SO-368 Ektachrome MS film. The LOX dump is not visible on any of these. They are AS14-72-9923 to 9936.
006:27:01 Shepard: Okay, Houston. You have P00 and Accept.
006:27:04 Fullerton: Roger, Al. We'd like you to try to bring up the High Gain now. Use a pitch of plus 28 and a yaw of plus 317. Over.
006:27:19 Mitchell: Roger. 28 and 317. [Long pause.]
Once the High Gain Antenna is brought into play, we should see a marked increase in signal strength. The LOX dump from the S-IVB will be followed by an additional maneuver to target the S-IVB to the proper impact point. That maneuver, performed with the Auxiliary Propulsion System.
The High Gain Antenna is steered using controls and displays on the lower right side of panel 2 on the Main Display Console.
The HGA controls on panel 2 of CM-109 Odyssey.
(Click image for a larger version.)
Two knobs allow control of the antenna's pitch and yaw directions. Above them, two meters indicate the actual positions of the antenna. Between these meters is a signal strength meter. If the HGA is being manually aimed, the crewman can adjust the pointing of the antenna to maximise the reading on the signal strength meter. This meter is really an indication of the Automatic Gain Control (AGC), a technique common on radio systems whereby the gain of an amplifier is controlled by the strength of the incoming signal. A weak signal is amplified more while a strong signal requires less amplification. The voltage that controls the AGC also provides a handy output for the meter.
The HGA can also aim itself, using the output from the AGC to drive the servomotors in order to achieve a maximum signal. This is now seen as a relatively crude method of pointing an antenna. Modern systems would know where Earth was using computers and these would accurately drive an antenna to point in that direction. The Apollo systems implies that there will always be an error that had to be corrected and so the aim is always less than optimal.
The HGA's designers were aware that the spacecraft spends a lot of its time rotating, either during Passive Thermal Control or while orbiting around the Moon in orbital rate rotation. This meant that Earth would regularly move outside the HGA's articulation range. They gave it a reacquisition mode (Reacq) whereby if the antenna lost lock with Earth, it would automatically move to preset angles which had been calculated to bring Earth back within the antenna's beam as it came around the other side.
006:27:35 Mitchell: Okay. You're in Auto and locked up, Houston.
006:27:39 Fullerton: Roger. [Long pause.]
006:28:08 Fullerton: Ed, this is Houston. We're having a little problem with our read-out of High Gain Antenna angles here. Would you read out your onboard pitch and yaw angle?
006:28:17 Mitchell: Rog. I have a pitch of plus 29 and yaw of about 320 - 330.
006:28:28 Fullerton: Say again the Yaw.
006:28:31 Mitchell: About 330.
006:28:32 Fullerton: 330. Roger.
Comm break.
As can be seen seen from the photo above, the position meters for the HGA have quite coarse displays that make precision difficult.
006:28:58 Shepard (onboard): I'm not having any trouble at all with weightlessness.
Unusually for an Apollo crew, Shepard, Roosa and Mitchell have very little weightlessness experience between them. Both Roosa and Mitchell are rookies and Shepard had only a few minutes of zero-g aboard the first US spaceflight on 5 May 1961. Even then, he was so restricted inside his tiny Mercury spacecraft that there would have been no freedom to move around. All three would have had extensive zero-g practice during parabolic aircraft dives but these are limited to only 20 to 30 seconds at a time. This is their first experience of extended weightlessness.
006:29:01 Mitchell (onboard): I'm not either, Al.
006:29:06 Shepard (onboard): How are you doing, Stu?
006:29:07 Roosa (onboard): Well, so far, so good.
006:29:09 Shepard (onboard): Really very comfortable.
006:29:11 Roosa (onboard): Yes, I - I guess I'm a little surprised at - at the fighting to stay down...
006:29:17 Shepard (onboard): Yes.
006:29:18 Roosa (onboard): ... if any.
006:29:19 Mitchell (onboard): Well, I think a lot of this is due to these hoses we got on here. Once we get rid of them, it'll be a little different.
006:29:25 Roosa (onboard): There are a jillion stars out there.
006:29:28 Mitchell (onboard): I think you've got a whole bunch of little things to look at.
006:29:34 Shepard (onboard): Venting of the S-IVB.
006:29:35 Mitchell (onboard): In fact, you've got a - Let me help you with that [garble].
006:29:46 Roosa (onboard): Okay. I think we'll start - I'm going to start clearing my pockets out, in preparation to get this suit off.
006:29:54 Mitchell (onboard): Good show.
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006:30:36 Fullerton: 14, Houston. We have the REFSMMAT and trunnion bias zero in there. It's your computer.
006:30:46 Roosa: Okay.
Passive Thermal Control REFSMMAT used while the Apollo stack is in cislunar space.
Earlier, we learned that the REFSMMAT - while intimidating at first - is really a handy tool for the crew to maintain a meaningful attitude reference and to keep their platform working without issues during their long and varied voyage. So far, they have been running a REFSMMAT that uses the Florida launch pad as the initial starting point. Now that they are thousands of kilometers away and in free space, this REFSMMAT is no longer useful for them in terms of controlling the spacecraft. For now, Mission Control has uplinked to their computer a fresh RESFMMAT that is based on the relationship of the Earth and the Moon.
Very long comm break.
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This is Apollo Control at 6 hours, 33 minutes. We'll be coming up soon on a change of shift press briefing. At that time we will take down the live air to ground circuits and record any conversation with the spacecraft for playback following the change of shift briefing. One bit of information from the flight surgeon. Flight surgeon reports that Commander Shepherd's biomedical data, primarily heart rate, resumed spontaneously at 1 hour, 30 minutes Ground Elapsed Time. At that time, the CapCom asked if he did anything to fix the sensor and Shepherd replied nope. The readings on all three crewmen during the docking attempts are approximately as follows. During most of the unsuccessful attempts, Stu Roosa, who was piloting the Command Module at that time, had a heart rate of about 120 beats per minute. The other two crewmen, Shepherd and Mitchell, were averaging around 70 beats per minute. And during the final successful docking attempt, Roosa's heart rate went from 120 to 144. At the present time, the Apollo 14 crew is performing a 'Program 52'. This is a platform alignment. The spacecraft traveling at a velocity of 10,739 feet per second [3,273 m/s] and now at a distance of 31,236 nautical miles [57,849 km] from Earth.
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006:41:24 Mitchell: Houston, 14. [No answer.]
006:41:34 Mitchell: Houston, Apollo 14.
006:41:38 Fullerton: Apollo 14, Houston. Go ahead.
006:41:40 Mitchell: Rog. Did you get our Noun 93s?
006:41:45 Fullerton: That's affirmative. We copied them.
006:41:47 Mitchell: Okay. [Pause.]
006:41:53 Fullerton: Ed, would you give us the torquing time?
006:41:57 Mitchell: Rog. 006:40:35.
006:42:02 Fullerton: 6:40:35.
Long comm break.
Stu has completed the second realignment of the CSM's guidance platform to the launch orientation, the attitude in space of the launch pad at the time of launch. For this exercise, using P52 in the computer, he sighted on stars 17 (Regor, or Gamma Vela) and 14 (Canopus, or Alpha Carinae). When the error in the platform's alignment had been calculated, it was shown on the three displays on the DSKY. The alignment errors were 0.127° in X, -0.060° in Y and -0.011° in Z. Since the DSKY displays are telemetered to the ground, their values were copied down by a flight controller. Stu's sightings were accurate, as indicated by the fact that his measured angle between the two stars is the same as the actual angle between them.
It is worth noting that the name for Gamma Vela is not an official name. 'Regor' is 'Roger' spelled backwards. When the Apollo 1 crew were training for their mission, they found that three of the stars chosen for the Apollo star list had no common names so they used derivations of their own names instead; 'Regor' for Roger Chaffee, 'Navi' for Virgil Ivan Grissom and 'Dnoces' for Edward White II (the Second). These names were kept after their tragic death in the Apollo 1 spacecraft.
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This is Apollo Control at 6 hours, 45 minutes. At the present time, Apollo 14 is traveling at a speed of 10,555 feet per second [3,217 m/s] and at a distance of 32,283 nautical miles [59,788 km] from Earth. Change of shift briefing is ready to begin now in the MSC News Center. We'll record any conversations with the spacecraft during this period of time and play them back following the press briefing. Also there will be questions from Cape Kennedy following the - following the briefing during the course of the question and answer period. At 6 hours, 46 minutes; this is Apollo Control.
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006:50:46 Fullerton: Apollo 14, Houston. Over,
006:50:48 Mitchell: Go ahead.
006:50:50 Fullerton: Okay. If you haven't already, we'd like you to continue on through the rest of the procedures in the Flight Plan after the P52 down to 6 hours, except don't do the O2 fuel cell purge or the waste water dump.
006:51:05 Mitchell: Okay. That's what we're planning to do.
006:51:07 Fullerton: And, then, Ed, I have a - a longer update; I want you to do a P23, the one that's scheduled for about 9:50 in the Flight Plan - correction 9:30, and if you'd turn to that, I'll give you some new stars and other information to go there. [Long pause.]
P23 or Program 23 is a computer program that permits the crew to perform their own navigation to and from the Moon. It is only used as a backup technique because the primary means is Earth-based, using the air/ground radio system to determine the spacecraft's position and velocity (its state vector). If the radio system were to fail however, the CMP can carry out his own navigation and he maintains his proficiency throughout the periods when they are coasting through cislunar space. His efforts can then be compared to those of the ground-based engineers.
As the spacecraft coasts between worlds on its ballistic trajectory, these bodies will appear to move against the background of stars as seen from the astronaut's point of view. The angle between these bodies and the stars can be measured. The resulting angle depends both to the trajectory that is being followed and the time that the angle measurement is made. The upshot of this is that a series of star/planet angle measurements can be used to determine the spacecraft's trajectory and thereby calculate its state vector. This is the job of P23.
Diagram of how a star/planet angle can be used to determine a spacecraft's state vector.
The crewman selects which star and which planet's horizon he is going to use for the measurement. In this context, the word 'planet' includes the Moon despite the conventions of astronomers and planetary scientists. Selection of the planet also requires that the crewman indicates whether the measurement is being taken with respect to the horizon nearest the star in question or that which is furthest away. One or the other will be in darkness so only the illuminated horizon can be used. The computer can then compensate appropriately for the offset from the planet's centre.
Diagram of star/planet angle measured to both near and far horizons.
One of the issues when performing a P23 is deciding exactly where a planet's particular horizon is. In the case of Earth, the atmosphere distorts and blurs the precise curve of the planet's limb, and the Moon's limb is decidedly rough thanks to the eons of bombardment suffered by its surface. Command Module Pilots practised in specialised simulators to locate a horizon that they could hit consistently. When they had settled on where in the limb they would mark, then a bias value could be included in the sums to compensate for their offset. What was important for them was not that they measured on the correct horizon but that they took their marks on a consistent horizon.
As the spacecraft moves away from a planet, it becomes easier to mark on its horizon because the thickness of the atmosphere is becoming less of an issue. However, the P23 technique was more accurate when the spacecraft was near a planet by virtue of the fact that this was where the greatest apparent movement of the planet against the stars occurred.
006:51:30 Mitchell: Stand by. [Long pause.]
006:52:11 Mitchell: All right Houston, I have the Flight Plan open to 09:30.
006:52:17 Fullerton: Roger. Stand by 1. [Long pause.]
006:52:34 Fullerton: Okay, Ed. On the P23, the optics Cal attitude is the same as listed there. Like you to change the P23 sighting attitude to roll, 184; pitch, 2... [Long pause.]
006:52:52 Mitchell: Hold it, hold it.
006:52:54 Fullerton: Okay.
006:52:55 Mitchell: Okay. I'm ready; go again.
006:52:57 Fullerton: Okay. It's listed there at 42. Roll, 184; pitch, 283; and yaw, 310. [Long pause.]
006:53:11 Mitchell: Okay. The sighting attitude is 184, 283, 310.
Fullerton is referring to 09:42 on page 3-14 of the Flight Plan where there are attitude angles to which the spacecraft should be manoeuvred in order to make his P23 angle measurements. Mission Control are altering this attitude and the stars that are going to be used.
006:53:17 Fullerton: That's right. And we have a change in the order of doing the stars, plus a couple of substitutions. I'd like you to use the listed star number 3, that's Gamma Centauri, number 53. I want you to do that star first. [Long pause.]
006:53:38 Mitchell: Hold it a minute.
006:53:47 Mitchell: Okay, 53, Gamma Centauri is first.
006:53:50 Fullerton: Roger. And then the star that's listed number 2, number 2 - 36, will be the second star.
006:54:00 Mitchell: Roger. Delta Ophiuchi.
006:54:03 Fullerton: Okay. And then the third star is a different one, a new one. It will be star 161, Iota Centauri - and Earth far horizon. [Long pause.]
006:54:27 Mitchell: Okay, star 3 is 161, Iota Centauri, EFH.
006:54:34 Fullerton: Roger. The Noun 70 for that star is the same as the Noun 70 on star number 1. It ought to be easy just to write it down. That'll be 00 all balls on the first register, all balls on the second register, and 00120 on the third register. [Long pause.]
006:54:58 Mitchell: Understand.
006:55:00 Fullerton: And Noun 88 is completely different. First register, minus 75603; second register, minus 27129; and third register, minus 59566. Over. [Long pause.]
006:55:34 Mitchell: Roger, stand by a minute. [Long pause.]
006:56:01 Mitchell: Okay. For Iota Centauri, Noun 70 is all zeroes, all zeroes, 00120; Noun 88; minus 75603, minus 27129, minus 59566.
Noun 70 and Noun 88 are required to be entered near the start of the P23 sequence. Noun 70 allows the star to be identified to the computer, Noun 88 gives the X, Y and Z components of a vector to the planet.
It is notable that the list of four stars includes stars that are outside the usual star list used on Apollo. The guidance computer's programming includes a catalogue of 37 stars, each given an octal code and each with a set of numbers that describe the vector that points in the direction of that star, essentially marking the position of that star.
the Apollo star code list
The Apollo star code list.
These stars were selected early in the program for navigation purposes and were carefully chosen to be well distributed across the celestial sphere. As the program matured, an additional list of stars was drawn up to give an increased selection of objects that could also be used for navigation. However, these are not encoded into the already packed core-rope memory installed in the spacecraft. Instead the octal codes and vectors for these stars were given in the Flight Plan, requiring the CMP to enter this data manually as part of running P23.
For each star from the extended list, two nouns are given that will be entered into the computer. Noun 70 contains the star' code in R1 which is zero, indicating that this is not in the pre-programmed catalogue of stars. R3 contains either 00110 or 00120. The former indicates to the computer that the near horizon of the planet will be used for the angle measurement, the latter means that the far horizon will be used. Noun 88 gives the position of the star in question expressed as a vector.
006:56:24 Fullerton: Roger, Ed. Readback correct. Okay, the fourth star will be star number 24, Gienah, Earth's far horizon. And Noun 70 will be: first register, 00024; second register, all balls; third register, 00120; and you don't need a Noun 88 for that one. Over. [Long pause.]
006:57:13 Mitchell: Okay. The fourth star is 24, Gienah, EFH; Noun 70 is 00024, all zeroes, and 00120.
006:57:26 Fullerton: Roger. That readback's good. After you finish that P23, we'd like you to do the O2 fuel cell purge and the waste water dump. And then the - the activity to follow is still under discussion here; we're talking over possibly removing the drogue and taking a look at it at that time and possibly cranking up the TV to give us a picture of it back here. So the decision to start PTC after finishing the P23 will depend on whether we're going to request you to give us a TV shot of the drogue and probe. Over. [Long pause.]
006:58:10 Mitchell: Okay. Understand, and the - following this P23, you want us to press on with the O2 fuel cell purge and waste water dump that's listed about 11:25. Is that correct?
006:58:23 Fullerton: I guess it's listed there, and it's also the same thing you skipped back there at 5 hours and 55 minutes. I guess that's the...
006:58:37 Mitchell: Do you want us to do it immediately after the P23, or wait until 11:25.
006:58:45 Fullerton: Roger. Stand by. I'll check on that to be sure. Do that immediately after the P23, Ed.
006:58:55 Mitchell: Rog.
006:58:58 Fullerton: And one other thing, while you have a pencil in hand, is a 'Lift-off plus 15' P37 block data when you're ready.
The 'Lift-off plus 15' block data provides the information to abort the mission at 15 hours GET. Should something happen in the next 8 hours that requires them to return home immediately, this is the plan they might use.
Comm break.
Flight Plan page 3-012
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007:00:56 Mitchell: Houston, go ahead with the P37 for lift-off plus 15.
007:01:00 Fullerton: Okay, Ed. GET of ignition is 015:00; Delta-VT, 5700, minus 165; GET for 400K, 045:04. Go ahead.
007:01:23 Mitchell: Okay. GET is 015:00; 5700, minus 165; 045:04.
007:01:37 Fullerton: Roger, Ed. Your readback's good.
Comm break.
This P37 block data is interpreted as follows:
Purpose: This PAD provides the details of a long burn of the SPS engine that would occur 15 hours into the mission to achieve an emergency return to Earth. It only comprises four items of information.
Time of ignition: 15 hours GET.
Delta-VT: 5,700 fps (1,737 m/s). This is the total change in velocity the spacecraft would experience.
Longitude of expected splashdown point: 165° west; in the Pacific Ocean.
Time of of Entry Interface (400,000 feet or 121 km altitude): 45 hours, 4 minutes GET.
007:02:45 Mitchell: Houston, 14.
007:02:47 Fullerton: Go ahead, Ed. [Pause.]
007:02:56 Fullerton: 14, Houston; go ahead.
007:02:59 Mitchell: Roger, Gordon. We didn't quite understand when you wanted us to start this P23 that you passed the info on.
007:03:08 Fullerton: Right now, whenever you're ready.
007:03:12 Mitchell: Okay. Stu's going to get out of his suit here, and we'll be ready in a few minutes.
007:03:16 Fullerton: Roger.
Very long comm break.
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007:15:26 Roosa: All right, Houston; 14. How do you read?
007:15:32 Fullerton: Apollo 14, Houston. Go ahead.
007:15:33 Roosa: Okay, Gordon, I just wanted to check and make sure that I was back on the comm here.
007:15:39 Fullerton: Roger, loud and clear.
Very long comm break.
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This is Apollo Control at 7 hours, 25 minutes. During the change of shift briefing, we advised the crew that it is being considered to have them remove the probe and drogue assembly from the docking tunnel, pull it down into the Command Module and activate the television so that we on the ground and the crew can get a good look at that particular piece of equipment. A decision to do so will not be made in all probability for another 30 to 40 minutes. At that time, it will then require something like an additional two hours to get the necessary lines up between the receiving end - the receiving station at Goldstone and Houston, so that the television transmission can be routed here to the control center. We'll play back the tape conversations which we accumulated during the change of shift briefing and then continue to follow any other conversations live.
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007:29:14 McCandless: Apollo 14, this is Houston. Over.
Bruce McCandless in Mission Control during Apollo 14.
Taking the CapCom headset now is astronaut Bruce McCandless II. Selected in April 1966 as part of Astronaut Group 5 - just like crewmembers Stu Roosa and Ed Mitchell - he had previously supported Apollo 11, including the first Moonwalk.
007:29:18 Roosa: Go ahead, Houston.
007:29:20 McCandless: Roger, Stu. When you get ready to commence your P23, we have a change to the sighting attitude, based on your current estimated time of starting. Over.
007:29:33 Roosa: Okay. And, hey, could you give me an estimate on - on this? Are you wanting us to press on into that right now, or do you want us to go ahead and get the suits stowed, so forth?
007:29:43 McCandless: That's - that's really your option, Stu. Whenever you conveniently get ready to run a P23, why don't you check with us, and we'll make sure you've got a current attitude? Over.
007:29:56 Roosa: Okay.
Very long comm break.
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This is Apollo Control at 7 hours, 38 minutes. That completes the playback of the taped conversations between the spacecraft and Mission Control. We'll now continue to follow for any live conversations with the crew. The capsule communicator at this time is astronaut Bruce McCandless. McCandless relieved CapCom Gordon Fullerton. At the present time, Apollo 14 is traveling at a velocity of 9,776 feet per second [2,980 m/s] and the spacecraft is 37,248 nautical miles [68,983 km] from Earth.
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007:45:09 Roosa: Okay, Bruce. How do you read?
007:45:14 McCandless: Go ahead. [Pause.] Apollo 14, this is Houston. Go ahead.
007:45:22 Roosa: Okay, Houston. I'm getting ready to start the - this P23, and - and I guess that last P52 will still be good for this, and I'll start into the Optics Cal attitude and then get your Verb 49 attitude to start after that.
Three distinct steps are being discussed. A P52, to ensure that the platform's alignment is good, then a calibration of the optical system to ensure that when it is pointed at a star, it is properly reading the position correctly. Finally, Verb 49 is an automanoeuvre, whereby the computer will operate the RCS thrusters appropriately to change the spacecraft's attitude to requested angles, in this case, an attitude suitable for making Earth/star angle measurements.
007:45:41 McCandless: Okay. And I'll check and see if we want to update our attitude from the one I got here in front of me, and we'll pass it up to you when you're ready.
007:45:52 Roosa: Okay. [Long pause.]
007:46:02 Roosa: And, Bruce, I guess I want to verify we do not need another P52. It's been - what - an hour since that last one?
The platform's alignment drifts very slowly, which is why a P52 has to be carried out regularly. Stu wants to check that, based on the realignments so far and the rate of drift that has been determined from them, engineers are happy that the platform is near enough perfect alignment for him to proceed with his navigation exercise.
007:46:13 McCandless: That's verified.
007:46:18 Roosa: Okay.
Very long comm break.
Flight Plan page 3-013
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008:01:54 McCandless: Apollo 14, this is Houston. Over.
008:01:56 Mitchell: Go ahead.
008:01:59 McCandless: 14, this is Houston. We'd like you to acquire us with the High Gain Antenna. Pitch, minus 75; and Yaw, plus 99. Over.
008:02:12 Mitchell: Roger. Minus 75 and plus 99. [Long pause.]
008:02:28 McCandless: Apollo 14, this is Houston. Change Yaw angle to plus 120.
008:02:36 Mitchell: Okay, Houston. We've locked up Auto Track.
Comm break.
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008:05:31 McCandless: Apollo 14, this is Houston. Ed, we'd like you to read out the Pitch and Yaw position meters on the High Gain Antenna for us, if you would, please.
008:05:42 Mitchell: Roger. The Pitch is reading - minus 90, and Yaw is 150.
008:05:51 McCandless: Roger. Minus 90 and plus 150. [Long pause.]
008:06:19 Mitchell: No, make that about 180 - I mean about minus 80 and 150.
008:06:23 McCandless: Roger, 14. Minus 80 and plus 150.
Long comm break.
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008:09:48 Roosa: Okay, Bruce, how about that attitude for the P23?
Stu has completed his calibration of the spacecraft's optical system and is ready to commence his P23 navigation exercise. The first required item is a note of the attitude that the spacecraft needs to be in so that Earth and the appropriate stars are within the range of the sextant's moveable line of sight. The navigation fix that Stu achieves will not be used directly. Rather, his measurement of the state vector will be compared with the one determined from Earth.
008:09:53 McCandless: Roger, Stu. The attitude will be roll, 179; pitch, 280; yaw, 310. Over.
008:10:07 Roosa: Roger. 179, 280, 310.
008:10:13 McCandless: Roger. Out.
Very long comm break.
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This is Apollo Control at 8 hours, 12 minutes. At the present time, the crew aboard Apollo 14 is preparing to begin a series of star sightings. They will do this in computer program 23. Taking sightings and marks on 3 stars to update the onboard guidance system's knowledge of where it is and where it's going. At this time, here in Houston at the Manned Spacecraft Center and also at North American in Downey, California, teams of engineers are in the process of putting together a set of procedures and evaluating the tasks involved in running through a set of checks on the probe and drogue assembly on board the spacecraft. Once this set of procedures is worked out, and the Flight Director and team of flight controllers here in Mission Control had a chance to evaluate them, a decision will be made as to whether or not to attempt at removing the probe and drogue assembly and also bringing up the television to transmit television pictures of the evaluation back to Earth. Once that decision is made, it's estimated that it will take about 2 hours to get the lines up between Goldstone and Houston so that we can receive the television picture. We still have some 3 hours, 50 minutes of acquisition time remaining at Goldstone before a handover is made to the Honeysuckle station. The estimate is that it would take probably on the order of 6 hours time to get circuits up between Honeysuckle and MSC to allow transmission of television from Honeysuckle to here. And, more than likely, any television received at Honeysuckle would be recorded for later playback and would not be transmitted live to Houston. However, the plan would be to transmit television live from Goldstone some 2 hours after a decision to remove the probe and drogue was made. Best estimate on when that decision might be made is that it would probably be no sooner than 30 to 40 minutes. We'll keep you advised on any changes in that. At 8 hours, 15 minute; this is Apollo Control.
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This is Apollo Control at 8 hours, 30 minutes. Apollo 14 now traveling at 9,163 feet per second [2,793 m/s]. Spacecraft is 41,842 nautical miles [77,491 km] from Earth. The Flight Dynamics Officer reported that there appears to be a very small amount of venting occurring on the S-IVB. The venting is not probably causing any significant affect to the trajectory to the vehicle, however, it does affect the tracking data on it, and makes it difficult for the Flight Dynamics Officer to get a good vector on the S-IVB and from that to compute a predicted impact point. However, it is possible to compute the impact point based on the known position at the time the last propulsive maneuver occurred, the LOX dump, and from that to compute an impact point. Based on the Flight Dynamics Officer's computed impact point, the Booster Officer will compute a needed Delta-V, and at 9 hours Ground Elapsed Time, command an Auxiliary Propulsion System maneuver with the S-IVB, targeted to impact at near the Apollo 12 seismometer. There's been no communications with the spacecraft for the past 30 minutes or so. The crew is scheduled to begin a sleep period at about 16 hours. At 8 hours, 32 minutes; this is Apollo Control standing by.
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008:45:23 McCandless: Apollo 14, this is Houston. For your information, the booster people are planning an APS burn on the S-IVB at 9 hours GET even. Over.
008:45:34 Mitchell: Roger. Thank you. [Long pause.]
008:46:07 Mitchell: Houston, 14. Have you any idea where we should look to see it? [Long pause.]
008:46:40 McCandless: Stand by on that one, Ed. And, if we can get some good angles and stuff for you, we'll send them up.
008:46:48 Mitchell: Okay. We've just been moving around here. We've lost track of it.
008:46:53 McCandless: Roger.
Very long comm break.
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This is Apollo Control at 8 hours, 59 minutes. We're standing by now for the beginning of the S-IVB Auxiliary Propulsion System maneuver which will target the Saturn third stage to an impact point near the Apollo 12 seismometer. That will be a 4-minute and 12-second burn targeted to put the third stage in at about 1.56 degrees south latitude and 33.25 west.
Flight Plan page 3-014
009:00:03 McCandless: Ed, this is Houston. Coming up on the S-IVB APS burn, and - we don't have a good attitude for you to look out right now.
009:00:13 Mitchell: Okay. We'll kind of look around and see what we can see.
009:00:16 McCandless: Roger.
009:00:24 Mitchell: Give us a hack on it, Bruce.
009:00:26 McCandless: Roger. It's going now. It's about a 4-minute burn.
Comm break.
009:02:10 Mitchell: Houston, we've been unable to spot the S-IVB. [Long pause.]
009:02:30 McCandless: 14, this is Houston. You can try looking out the right-hand side window and - with your line of sight depressed a little bit from the straight-out position.
009:02:47 McCandless: I guess where the engine bell lies.
009:02:50 Mitchell: Rog. The Sun's coming in that window. [Pause.]
009:03:01 McCandless: Okay. That's probably going to make it pretty difficult to spot.
009:03:08 Mitchell: Makes it a little hard on the eyes. [Long pause.]
009:03:25 Mitchell: Bruce, we've been sincerely busy with housekeeping up here. We haven't had a chance to - describe anything we've been seeing. We'll get around to that after a while.
009:03:36 McCandless: Say again what you're going to get around to.
009:03:38 Mitchell: I was saying, we'll get around to - doing a little description for you after a while.
009:03:44 McCandless: Roger. [Long pause.]
Booster Officer reports the burn is complete.
009:04:25 McCandless: And the S-IVB burn has been completed, Ed. [Long pause.]
009:04:30 Mitchell: Thank you, Bruce.
009:04:49 Shepard: Bruce, we've been wondering if you found your headset all right when you got back to the MOCR. [Pause.]
009:05:01 McCandless: Yes, I've got it on. I didn't notice anything wrong with it. You may be a little subtle for me, but go ahead. [Pause.]
009:05:16 Mitchell: You obviously found it. It is working.
Very long comm break.
EECOM legend Sy Liebergot photographed in Mission Control.
Shepard's query about McCandless's headset is the resolution of a 'Gotcha' carried out on the CapCom. In his book, 'Apollo EECOM: Journey of a Lifetime' by EECOM Sy Liebergot (Apogee Books, 2003, page 158), the story is told of how Sy had noted how the very meticulous McCandless had studiously labelled the locker where he stored his headset as 'CapCom Locker'. Sy made sure that, prior to McCandless's shift, every one of the 48 lockers were similarly labelled, as was the way to his console, his chair, both armrests and his monitor. Everyone in MCC as well as the crew were in on the joke.
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009:18:55 McCandless: Apollo 14, this is Houston. I have a Flight Plan update for you.
009:19:01 Mitchell: Understand. [Long pause.]
009:19:29 Shepard: Okay, Houston, go ahead with your Flight Plan update.
009:19:32 McCandless: Roger, 14. We have a P52 that was previously scheduled in the Flight Plan at 9 hours GET. We'd like you to hold off on that P52 until after PTC is established, and then run it while in the PTC mode. After your P23s are complete here, we'd like you to perform the oxygen purge and waste water dump. Also perform the Delta-V test and null bias checks, as called out in the Flight Plan at 9 hours and 20 minutes GET previously. And then you can deactivate the primary evaporator at your convenience. And we'll be having instructions for you on what we want to do on - with respect to the probe and drogue, and I guess that we'd like your commentary or your feelings on how you'd feel about pulling it out and reinstalling it this evening before you turn in. Over.
009:20:51 Shepard: Okay. You want the P52 originally scheduled for 9 to be done after PTC is commenced. You want O2 purge and water dump, and [garble] now and we'll do the Delta-V test and null bias check here momentarily, as soon as 23's been completed. We'll talk about the probe and call you back.
009:21:22 McCandless: Roger. And...
Comm break.
009:22:43 Roosa: And, Houston; 14.
009:22:45 McCandless: Go ahead, 14.
009:22:47 Roosa: Okay, Bruce. I just wanted to say a word about that P52 that we had just before the P23 there. Went to that P52 attitude and PICAPAR - I went to pick the star that was occulted by part of the LM. So you probably saw me dial in another star. And the stars weren't probably separated too far, as far as the criteria goes. So if anybody's looking at that, that's the reason.
009:23:19 McCandless: Roger. We copy.
Long comm break.
PICAPAR is a facility within the computer whereby it picks a pair of stars to be used for the realignment of the platform. Since the computer knows the attitude of the spacecraft and therefore where the optics are pointed, it can select a couple of stars within the range of view of the moveable line of sight. Unfortunately, it has managed to select one that is obscured by the LM.
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This is Apollo Control at 9 hours, 27 minutes. Apollo 14 now 46,539 nautical miles [86,190 km] from Earth, travelling at a speed of 8,544 feet per second [2,604 m/s]. We're still awaiting the arrival of a list of questions and procedures from the engineering support room. These questions will be passed up to the crew, asked of the Apollo 14 crew, and used in part as a basis for a decision as to whether or not to ask the crew to remove the probe and drogue assembly from the docking tunnel of the Command Module.
009:27:31 Shepard: Houston, Apollo 14.
009:27:34 McCandless: Go ahead, 14.
009:27:37 Shepard: Regarding the probe, I don't think we'd mind taking it out tonight, discussing it with you, letting you look at it, and then leaving it out for the night.
009:27:50 McCandless: Okay, 14. We copy. And as I mentioned earlier, we haven't really gotten all the inputs yet on what we want to do, whether we'd like to do this tonight or whether we might want to wait until tomorrow, but I'll get back to you as soon as we - we have and we'll incorporate your feelings into the decision down here and send them back to you. And did you copy on my Flight Plan update? We'd like to get the primary evaporator deactivated whenever it's convenient with you all. [Long pause.]
Crew training material diagram of the evaporator.
The evaporator is part of the ECS (Environmental Control System). It's function is to reduce the temperature of the fluid in the cooling circuit. However, given that the same fluid also flows through radiator panels on the side of the spacecraft, the evaporator only needs to be used during busy periods when a lot of electronic systems are operating and generating more waste heat than usual. During quiescent periods, the radiators are sufficient for the role. The evaporator works by introducing waste water to a vacuum through a wick where it turns to a vapour, thereby taking heat with it. The pipes carrying coolant are passed through this assembly where the temperature of their contents, a water/glycol mixture, is reduced.
009:28:28 Shepard: Okay. It has been deactivated.
009:28:32 McCandless: Okay. Thank you.
Long comm break.
That last remark came from Al Shepard. Shepard stated that the crew would not mind removing the probe and drogue assembly tonight, but they would prefer not to have to reinstall it tonight before beginning their sleep period. And as you heard, CapCom Bruce McCandless advised the crew that the decision has not as yet been made as to whether or not the crew will be asked to remove the drogue and probe assembly. Discussions are going on at this moment around the Flight Director's console and we're still awaiting the engineering data which will also serve in part in making that decision. At 9 hours, 30 minutes; this is Apollo Control, continuing to stand by.
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009:34:08 Shepard: Houston, on the EMS null bias check, we had a start at minus 100 and terminate with minus 99.4.
009:34:19 McCandless: Okay, Al. We copy. You started with minus 100 on a null bias check, and you terminated with minus 99.4.
Entry Monitoring System functional block diagram.
The null bias check is to see if the accelerometer within the EMS is showing any bias in its measurement of acceleration. Page 2-5 of the CSM G&C Checklist gives the procedures for both a delta-V check and the null bias check, though only the second of these two is being carried out at this point.
The delta-V test requires a pre-determined number (1586.8 fps) to be entered into the EMS's delta-V display. A test signal is then fed into the electronics for ten seconds which should cause the display to decrement almost to zero. As long as the remaining number is between -0.1 and -41.5, the test is good. The null bias check uses the weightless condition of the spacecraft to see that the accelerometer is correctly measuring no acceleration when there is none. A value of 100 fps is dialled into the delta-V display and the unit is left to measure for 100 seconds. During this time, the CSM's attitude is allowed to drift rather than being constantly corrected. If the display changes by less than 1 fps, the unit is good. A value that has changed by between one and ten feet per second may require a bias to be applied to compensate. If the amount of change is more than 10 fps, then the EMS is to be considered faulty.
Note that Al says they entered minus 100 fps at the start of the test. It appears that a hyphen in the relevant line of the checklist has been interpreted as a minus. Someone has scribbled on the copy available to the journal that the hyphen is not a minus. Nevertheless, the reading has varied by only 0.6 fps, an excellent result.
009:34:29 Shepard: That's correct. The O2 purge has been completed and the waste water dump is in progress.
009:34:35 McCandless: Roger, Al. [Long pause.]
009:34:48 McCandless: 14, this is Houston. Would you prefer to take time out to have something to eat or press on with the drogue operations now?
009:34:59 Shepard: I think we could do both simultaneously.
009:35:01 McCandless: Roger.
009:35:03 Shepard: [Garble] the drogue, Bruce, is to get it out, look at it, discuss it with you, and give you some time to think about it, and tie it down here with us while you're thinking about it.
009:35:15 McCandless: Roger. We're tentatively looking at taking the probe out, doing that, tying it down, and we may want to take the drogue out, but we thought you could just lock the drogue back in place, and then the hatch, to go to sleep for the evening.
009:35:30 Shepard: Sounds good.
009:35:32 McCandless: Okay. And be right back at you in about a minute with the hot smoking word. [Pause.]
009:35:46 Roosa: Hey, Bruce, are we going to get in - start PTC before we start in on the drogue?
009:35:52 McCandless: That's unresolved right now, Stu.
009:35:55 Roosa: Okay.
Comm break.
009:37:31 Mitchell: Houston, 14. This is a pretty fine snow storm we have going on here.
009:37:37 McCandless: Roger. We copy.
Long comm break.
Presumably Ed's snowstorm is as a result of the waste water dump. As the fuel cells consume hydrogen and oxygen to produce electricity, they yield water that is fit to drink. But it is more than the crew can consume for drinking, food preparation, and washing. Some is evaporated to help cool the spacecraft. The rest is periodically dumped overboard via a heated nozzle.
This is Apollo Control at 9 hours, 39 minutes. The decision that's been made with respect to the drogue and probe is that the crew will be asked to remove the assembly. They will also be asked to unstow the television camera, get television coverage of it. However, the television lines will not be put up between Goldstone and Houston. In order to avoid a 2-hour delay, the TV signal would be recorded at Goldstone for playback later. And the evaluation that would be done this evening would be a verbal evaluation from the crew with the TV to be recorded for playback at some later time. At 9 hours, 40 minutes; Apollo 14 is travelling at a speed of 8,438 feet per second [2,572 m/s]; now 47,557 nautical miles [88,076 km] from Earth.
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This is Apollo Control at 9 hours, 42 minutes. There's been a slight modification to that plan as far as the TV is concerned. The crew will begin as soon as convenient to remove the probe and drogue assembly. However the lines will be brought up from Goldstone. This will probably require an hour to an hour and a half and any television that is received at the time the lines are up will be released live. And television, until that time, will be recorded. And so there is a possibility that we will get some live television toward the end of the probe and drogue activities aboard the Command Module. And the Network controller is taking steps now to get those lines up between Houston and Goldstone. The estimate is that it will take, at this point, an hour and a half or perhaps a little longer.
009:44:15 McCandless: 14, Houston. We're showing about 15 percent on the waste water on telemetry now.
009:44:21 Shepard: Rog. We've just shut it off. We're showing 22.
009:44:27 McCandless: Roger. Out.
Very long comm break.
The onboard gauge on Panel 2 can be selectd to display either potable water tank (with maximum capacity of 36 pounds (16.3 liters) of drinking water) and waste water tank, which holds 56 pounds (25.4 liters)
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