Apollo 16

This is Apollo Control at 7 hours, 3 minutes. The spacecraft will shortly be maneuvering to the proper attitude to take a series of ultraviolet photographs of Earth using the electric Hasselblad camera which is mounted in the right side window of the Command Module. We expect that as the spacecraft maneuvers, we'll lose lock with the High Gain Antenna and the communications will probably momentarily drop-out or become quite noisy until we reestablish [a] solid lock-on. The crew, by this time, should have completed their, what would amount to lunch. They're coming up now on the series of ultraviolet photographs of Earth and this is an experiment which gathers ultraviolet photos both of the Earth and later of the Moon for studies of planetary atmospheres. Also prior to what will amount to their evening meal or dinner, the crew will be doing a series of mid-course navigation sightings and also will be changing the lithium hydroxide canister and setting the spacecraft up in a Passive Thermal Control mode, a slow rotation of about three revolutions per hour to maintain the proper temperature equilibrium. At the present time we show Apollo 16 33,696 nautical miles [62,405 kilometres] from Earth, spacecraft velocity 10,358 feet [3,157 metres] per second.

This is Apollo Control at 7 hours, 22 minutes. At the present time the LM Systems Engineer is going through the handbook to try to pinpoint the precise location that Charlie Duke was describing on the Lunar Module. Charlie said that they appeared to have found the surface that is giving off the particles that were reported earlier. He said that they can see about five to ten particles per second, shredding off a surface where the coating appears to have degraded, as best we can tell from his description. He says the surface looks like shredded wheat and it's spitting off particles. At the present time, we - we haven't pin pointed precisely what location he's talking about although we expect the LM systems engineer will come up with that location from the description shortly. And then the procedure will be to determine what, if any, effect the loss of that coating might have. Presumbly the concern if any exists would be for thermal considerations. Most of those coatings are on there to maintain the proper temperature conditions within the vehicle.

This is Apollo Control at 7 hours, 38 minutes. We appear to have pinned down on the diagrams a little more precisely where the thermal skins that Charlie Duke described shredded and spitting off particles are located. Perhaps the best way to describe this would be to ask you to visualize the Lunar Module as if you were looking at the Ascent Stage of the LM facing the porch - the front porch - or the part of the LM that looks like a face, and visualize the docking target, which is on an upper surface slightly behind and to the left of the commander's position. The panels extend downward from this docking target. Would involve several square feet of area - of surface area downward to the bulbous tank that is underneath thermal skins and that protrude from the right side of the Lunar Module. We have very little data on the Lunar Module at the present time. The only data that we're monitoring is the amount of power being transferred from the Command Module to the Lunar Module. So we have very little information to go on in assessing what the effect might be. As I mentioned previously, the primary purpose of these skins, which generally consist - although they vary from place to place on the LM - generally consist of layers of coated Mylar, Kapton, which are thin plastic-like materials, the sole purpose of which is to maintain the proper temperature conditions for the equipment, tanks and so on that are underneath. Among the equipment underneath this section of the Lunar Module, is RCS System A, oxidizer and helium tanks. We understand there's also a water tank in that area. We are investigating or discussing the possibility that a leaking tank might have something to do with shredding of the material - I think that the primary concern at this time is what is causing the material to shred. Among the things that have been discussed are turning the TV on, getting the people on the ground a look. The response that Flight Director Pete Frank got to that suggestion was it probably wouldn't do us a great deal of good, although that one is still an open possibility. And the LM systems engineer is continuing to evaluate the situation and we'll be coming back with additional recommendations. At the present time Apollo 16 is 37,181 nautical miles [68,859 km] from Earth. Spacecraft velocity is down now to 9,826 feet per second [2,995 m/s].

That last description came from Ken Mattingly. Ken describing the - the appearance of that thermal skin as looking like an old barn in need of paint, where the paint or whatever the coating is, is lifting up and kinda peeling back.

And our LM systems engineer, who has done a bit more digging into the nature of the skins at that portion - at that point on the LM, describes it as an aluminum skin about 4 mils [0.1 millimetre] thick and painted. So that would - would go along with the crew's description of paint peeling. This, as we mentioned previously, the skins at various portions on the LM differ. Typically they would be the Mylar type of material, but there are also skins that are aluminum.

This is Apollo Control at 8 hours, 5 minutes. Apollo 16, at the present time, is maneuvering to the proper attitude for calibrating the optics system that'll be used in a series of star sightings. These are taken routinely on the trans-Earth and translunar legs of the flight. The information is fed into the onboard guidance system and is used to update the onboard system's knowledge of so called state vector - the trajectory - that the vehicle is currently on. This data is then compared with the - with the ground figures. And as the spacecraft maneuvers into this attitude, we lose lock with the High Gain Antenna and have a momentary drop out in communications. Again, to reiterate the description that we've gotten from the crew, what appears to be paint peeling from a portion of the Lunar Module thermal skins, about 45 minutes ago or at about 7 hours and 17 minutes, Charlie Duke came on the circuit to describe the location of the Lunar Module from which a series of white particles, that have been described earlier as drifting past the Command Module, appeared to be emanating from. He said it was on the side of the Lunar Module between the omni antenna and the - one of the LM tanks, and had the appearance of skin that was torn or shredded, with particles coming off at the rate of about five to ten per second. The initial reaction here in the Control Center that was one of the Mylar or Kapton skins, which are stretched over the Lunar Module surface for maintaining the thermal control - proper temperatures within the vehicle, had shredded and it was these particles coming off. This is very fragile material physically and since the Lunar Module, of course, does not have to withstand aerodynamic forces, these - these surfaces can be very light weight and consequently are quite fragile. The initial concern was for what had shredded the material. Later, Ken Mattingly gave us a further description and also we coupled that with information from the LM systems engineer here in the Control Center. Ken's description was that the material appeared to be paint peeling back from a hard surface. The LM systems engineer verified that the skins at that point on the Lunar Module are very thin aluminum. He said that they were four mils [0.1 millimetres] thick and are painted which would indicate that the skin itself - the aluminum structure - is not damaged, but that the paint, which is also on there for thermal purposes, is apparently peeling back. At the present time, we're continuing to evaluate what effects that might have thermally on the equipment beneath the area. The panels the thermal skins are over; RCS System A - one of the two RCS systems' tanks, the oxidizer tank, helium tank and also a water tank was reported in that area. One of the things that has been discussed and is still under consideration is the possibility of having the crew enter the Lunar Module, power it up enough to give us a look at some of those systems and perhaps allow us to draw some further conclusions as to what might be happening. And as we mentioned previously, the only measurements that we have on the Lunar Module at the present time are the power measurements. We're monitoring the amount of power that is being supplied from the Command Module to the Lunar Module.

This is Apollo Control at 8 hours, 15 minutes. The LM systems engineer has...

This is Apollo Control at 8 hours, 20 minutes and the import of that last series of exchanges with the crew, as we are instructing them to enter the Lunar Module. We'll power it up sufficiently to look at some of the systems and try to determine from the data what, if anything, out of the ordinary is happening. The additional description that we got a minute or so ago was from John Young. John described the particles coming off as, on further evaluation, to have the appearence of some sort of a vent. He said that the material appeared to have a brownish color, and appeared to be propelled away from the Lunar Module with some force. He said it was coming out in a stream, sometimes particles and sometimes as longer streams. And the main thing that we'll be looking for, when the LM is powered up, is the propellant pressures and temperatures particularly in that area of the Lunar Module.

It appears at this point that the crew is opening the LM hatch. Total time probably would be around 15 minutes from the time they started the procedures of getting into the LM until they're in and began turning on some of the switches so that we can look at - look at those Lunar Module systems.

Both Charlie Duke and John Young will be entering the Lunar Module. They're in the process of doing that right now. And at the present time, Apollo 16 is 41,141 nautical miles [76,193 kilometres] from Earth, traveling at a speed of 9,298 feet per second [2,834 m/s]. We have asked Ken Mattingly to get out the TV camera and we expect that once Duke and Young are in the Lunar Module, cleared out of the way so he can get to the area where it is stowed, that he will get it out and we would expect to get a TV picture hopefully showing the area of the Lunar Module where the particles are coming from. And shortly after that, we should also get some data from the Lunar Module which is, of course, the thing of greatest interest to the controllers here in Mission Control. Particularly, they are interested in looking at the propellant pressures and temperatures of RCS System A which is in the vicinity of the Lunar Module where we're seeing the materials - particles emanating.

This is Apollo Control at 8 hours, 33 minutes and that last transmission from Charlie Duke indicates to us that Duke and Young are in the Lunar Module going through the Activation Checklist at the present time, getting the LM partially powered up so that we can get a look at some of the critical systems, and the pertinent systems in this case, in an attempt to determine what if anything out of the ordinary is happening. And, as we mentioned previously, we do expect to get some television from the Command Module. Ken - Ken Mattingly advised us that he would be getting the camera unstowed and in operation as soon as possible.

We have the data from the Lunar Module now. We're looking at it and we'll get an evaluation.

Our LM Systems Engineer's report, from the data we've seen so far, that everything looks good. Looks normal, no evidence of any propellant leaks or pressura - pressurization leaks and we're standing by now for television from the Command Module.

And we are getting a black and white picture.

At the present time we're looking at the picture in black and white waiting for the color converter to lock up.

This is Apollo Control, the picture we're getting right now is the interior of the Command Module. All three crewmen back in the Command Module, now. And after the look we got at the Lunar Module, on the telemetry data, everything appeared to be normal. We've had a group of very interested engineers and project management people here in the control center, looking at the television picture. And can see very clearly the panel which had the shredded appearance what Charlie Duke described earlier as appearing like shredded wheat.

This is Apollo Control at 9 hours, 8 minutes. Again, to recap the situation after having the crew get in, power up the Lunar Module and taking a look at the external area where the material on the skin was shredding, particles were coming out. We can find nothing obviously wrong and that's obviously reassuring to have all of the data on the propellant tanks, and the pressures and quantities looking normal. At the present time, the thing that we're looking into is the possibility of an unusually large number of jet firings at some point from the Command Module Reaction Control System thrusters that might have perhaps degraded or burned the surface or chemically caused it to peel up the way it appeared to be in the television picture. But, I would say at this point that there is somewhat of a relaxed or at least not overly tense mood in the Control Center and certainly it was reasuring to see all of the - the data looking good when we did power up the Lunar Module. Apollo 16 at the present time is 44,921 nautical miles [83,193 kilometres] from Earth and the spacecraft velocity, continuing to drop off slowly; down now to 8,851 feet per second [2,698 m/s]. And Charlie Duke reported also that the Lunar Module looked extremely clean when they got inside. No particles floating around. There have been times in the past where the Lunar Module has had particles, on one occasion, from some docking tunnel insulation that had gotten in there and also have been occasion where when the LM was depressurized, glass covers on some of the instruments had broken. But, apparently no problems of that nature. As Duke reported, the LM looked very clean.

At the point the crew will pick up their Flight Plan, they'll be about one hour, perhaps a little bit more, behind where they would have been had this problem not cropped up. This is, however, a relatively slack period in the Flight Plan. We would expect them to be able to make up the time without a great deal of difficulty. They're scheduled to be taking some navigation sightings through the Command Module optics system. These will be used to update the onboard guidance system's knowledge of its position and trajectory.

This is Apollo Control. As a point of interest, that entire exercise in the Lunar Module took about one hour. We reached the conclusion here in the Control Center that we were going to ask the crew to enter the LM at about 8 hours, 13 minutes Ground Elapsed Time. A couple of minutes after that John Young came up with a further report of what appeared to be particles venting from the LM which reinforced and further confirmed the decision to go into the Lunar Module. The crew, Young and Duke, to our best estimate were in the LM by 8 hours, 30 minutes Ground Elapsed Time and spent about 16 minutes in the Lunar Module, during which time we got a good long look at all of the critical systems and could find nothing out of the ordinary. And again, to repeat Charlie Duke's description, the LM looked extremely clean and that his evaluation would apply equally as well to what we saw on the ground and what the crew saw onboard.

And CapCom Don Peterson has just advised the crew that Midcourse Correction Number 1 will not be required. That opportunity for the midcourse is scheduled at 11 hours, 39 minutes. And by the time we get around to the opportunity of Midcourse Correction Number 2, the amount of velocity change it appears would be required at somewhere on the order of 12 feet per second. By dropping Midcourse Correction 1, of course, that will give the crew a bit of help in making up the time that was lost in going into the Lunar Module and we would expect that they would have most of that time made up by the time they're ready to begin their rest period. Apollo 16 at this time is 45,817 nautical miles [84,853 kilometres] from Earth and traveling at a speed of 8,750 feet per second [2,667 m/s].

This is Apollo Control at 9 hours, 58 minutes. We've had virtually no conversations with the crew since they completed the exercise in checking out the Lunar Module, some 45 minutes or so ago. And it's been relatively quiet here in the Control Center. We've had no further discussions of the problem, or apparent lack of a problem with Lunar Module. The situation, to recap, began prior to this shift's coming on, shortly after the Translunar Injection with a crew report of particles apparently coming off the Lunar Module. And at the time it was not known where they were coming from or what the nature of them might be. At Ground Elapsed Time of 7 hours, 17 minutes Charlie Duke came on the circuit and reported that the white particles appeared to be coming from a portion of the Lunar Module below the docking target, and this would be on the right side of the LM as you are facing the Lunar Module looking towards the front porch and what's commonly or frequently described as the face of the Lunar Module ascent stage. He described the surface as having an appearence of paint or coating, peeling and giving the texture of shredded wheat. The immediate reaction here in the Control Center was one of concern for the possible thermal effects that this might have since the skin is on the Lunar Module, primarily to provide thermal protection to the tanks and electrical equipment, so on, underneath. And it was also a matter of concern as to what might have shredded the skin or coating. We had very little data from the Lunar Module at this time. The only information we had was the amount of electrical current being provided from the Command Module to the LM. At about 8 hours, 13 minutes after evaluating the possibilities and determining that the skin was over an area of the Lunar Module which contained the Reaction Control System thruster tankage for RCS system A. It was decided here in the Control Center to recommend to the crew that they enter the Lunar Module, power it up and let us take a look on the telemetry at the pertinent tanks, pressures, temperatures, and so on. It was also decided to request that Ken Mattingly unstow the television and give us a look at the exterior of the LM. Shortly after this at 8 hours, 15 minutes John Young gave us a further report which perhaps increased the level of concern here in the Control Center a bit. Young reported that the particles did appear to represent venting. He said he could see them coming out with some force in a stream as if they were being propelled away from the LM. At this time we passed up to the crew the request that they get into the Lunar Module and power it up partially to let us take a look the other telemetry at those systems. About 15 minutes later, at about 8 hours, 30 minutes; Young and Duke were in the Lunar Module and reported that they had switched over to LM power, and shortly thereafter we got a good solid look at the telemetry data. And everything looked fine - all of the tank pressures were normal, the quantities were normal, and the temperatures were also normal. We looked at the telemetry long enough to assure the LM systems engineers that we had had no leaks and that there were no leaks in progress, and there was nothing to indicate any problem whatsoever. Charlie Duke on coming out of the Lunar Module reported that everything inside looked very clean, and at about that time we also got television picture from the Command Module camera which Ken Mattingly was operating and could see here in the Control Center a very clear picture of the few square feet of panels that were involved on the Lunar Module. These are aluminum skins about 4/1000 of an inch [0.1 millimetres] thick, and they are painted. And the description that Charlie Duke appeared - gave appeared to be very accurate. The TV picture that we saw here in the Control Center indeed looked very much like shredded wheat. The surface had the paint curling up as if it had grass growing on it, or shreds of shredded wheat on the surface scattered around on what should have been a smooth relatively shiny surface. Seeing nothing to explain the problem. The last thought that was discussed here in the Control Center was the possibility that some effect from one of the Reaction Control System thrusters on the Command Module [means Service Module] had caused the surface to degrade - possibly heat or chemical components, or something of that nature, and there appeared to be no problem associated with it. There's been no further discussion since that time, and appears to be no further concern at the moment over what could have been a problem. The crew is presently involved in a series of star sightings, using the optical equipment, the sextant on the Command Module. Ken Mattingly is performing this exercise, taking sightings on a series of four stars, and then marking, pushing a button which enters the information into the Command Module guidance system.

That was Ken Mattingly.

That was Ken Mattingly giving a subjective evaluation of the optics and the program used in computing these midcourse navigations. Mattingly noted that there was a reflection in the CSM sextant, the optical device that he was looking through in lining up a star, in this case over the Earth horizon. Once the star is lined up in the proper position, Mattingly pushes a button and the computer automatically notes the time and the angle between the star and the Earth horizon. And from this computes and updates its knowledge of the spacecraft position's trajectory. Mattingly noted that the - there did appear to be some - somewhat of a reflection in the optics and he said it's primary affect was that it tended to wash out the cross hairs but that this was not particularly a problem. He said it was not as clean as he would like it, but we can verify it from the results that he's getting which we're watching here on the ground, but he is indeed having no problems, the Flight Activities Officer who is watching the entries that are made into the computer said that the data that Mattingly is getting is better than was expected preflight.

This is Apollo Control. Ken Mattingly is still involved in taking the midcourse sightings through the CSM sextant. On completing that activity the Flight Plan becomes relatively unencumbered. We don't have very many additional scheduled activities and we expect that the crew will be able to make up the hour that was lost in getting into the Lunar Module and checking - checking out what appeared to be a possible problem resulting from - noting that the - one of the skins on the Lunar Module was peeling and the material flaking off and the possibility that something underneath - one of the tanks or something connected with the LM thrusters and Reaction Control System was possibly venting and as we mentioned previously on getting into the Lunar Module, checking things out, everything appeared to be normal. The one thing that we did notice when we had the television on the area of the LM which was affected, one of the aluminum panels several square feet in area, was that when one of the thrusters on the CSM was firing and in particular forward firing Service Module thruster that the material which had flaked off appeared to be disturbed and this would cause it to float off or to be propelled away from the Lunar Module. Flight Director Pete Frank feels that the most likely effect of the thruster is in disturbing the degraded surface and he feels that it is less likely that the thruster impinging on the surface itself actually caused the problem, although at this point any - any hypothesis as to what what caused the degradation of this thermal skin is purely speculative. We've seen nothing in the data to indicate any problem; however, the skin does appear abnormal and we have no explanation for it at this point. The midcourse correction maneuver which was in the Flight Plan, the opportunity for that midcourse correction at 11 hours, 39 minutes will not be required. The spacecraft is very close to the preplanned trajectory. The Flight Dynamics Officer reported that a maneuver of only about 8 feet per second would be required. This is so small that it will not be performed at this opportunity, but will be allowed to continue until the second midcourse correction opportunity at which time the amount of change in velocity that would be required would have grown to only about 12 feet per second. By deleting this midcourse correction that reduces the amount of things that the crew has to accomplish before their rest period which is scheduled to begin about four and a half hours from now and makes it appear quite likely that they will back on the normal Flight Plan by that time. At 100 or rather 10 hours, 27 minutes; this is Apollo Control, Houston.

This is Apollo Control at 10 hours, 57 minutes. The Flight Activities Officer has just reported that the crew is completing the midcourse navigation exercise using Program 23. After that, they will align the spacecraft guidance platform which is used as an attitude reference. Flight Activities Officer said that they will be back on the normal Flight Plan prior to the time that they're scheduled to begin their rest period. There's been no further discussion here in the Control Center of the peeling thermal skin on the Lunar Module. The data that we saw when John Young and Charlie Duke entered the Lunar Module and powered it up partially pretty well removed any concern that any of the tanks were leaking or that we had any thermal problems associated with that peeling skin. The only thing that we can connect with it at the moment is that when one of the forward-firing thrusters on the CSM was activated, we could see the particles fly off the panel and move outward from the Lunar Module. But as Flight Director Pete Frank put it, we don't necessarily know that the thruster was the cause of the problem. The only thing we can say at the moment is that it's very perplexing as to what caused the skin, or the paint on the skin to degrade. But at this time, there's no undue concern about it. And again, to repeat, all of the data that we've seen, the reports from the crew and what we could see on the television picture that was transmitted back to us, indicates that we have no problem with the Lunar Module at the present time. Apollo 16 at this time is 53,562 nautical miles from Earth, and the velocity has now dropped below 8,000 feet per second. We're down now to 7,989 feet per second, and we'll see that velocity continue to drop off until we reach the point that the spacecraft passes into the Moon sphere of influence where the dominant effect of the Moon's gravity begins to speed us up again toward the Moon.

This is Apollo Control at 11 hours, 59 minutes; and it's continued rather quiet here at Mission Control. We've had relatively few conversations with the crew aboard Apollo 16 in the last 45 or 50 minutes. The activities aboard the spacecraft have been primarily housekeeping sorts of things. Dumping the waste water; these tanks gradually fill up from excess water produced by the fuel cells and at a given level, they are dumped back down to about ten percent of their capacity. The crew has aligned the guidance platform used as a reference for attitude. They'll be changing out the lithium hydroxide canister that - one of the canisters that removes carbon dioxide from the spacecraft atmosphere. They also purged the fuel cells, running oxygen through the fuel cells at a high flow rate to remove any impurities. And they're scheduled to be taking another series of ultraviolet photographs of Earth. Prior to beginning their rest period, they'll also set the spacecraft up in the so-called Passive Thermal Control mode where the entire vehicle is rotated about its longitudinal axis at the rate of about three revolutions per hour to maintain the proper temperature equilibrium. And they're scheduled to begin their sleep period in about three hours. At the present time, Apollo 16 is 58,133 nautical miles [107,662 km] from Earth and traveling at a speed of 7,604 feet per second [2,318 m/s].

This is Apollo Control at 13 hours. Apollo 16 will shortly be going into its Passive Thermal Control mode with the spacecraft rotating at about the rate of three revolutions per hour to maintain proper temperatures. And we do have from the Flight Dynamics Officer now a preliminary estimate on the time and location that the Saturn third stage, the S-IVB, will impact the Moon. This event is tentatively now expected to occur at 75 hours, 6 minutes, 28 seconds. And the preliminary target point - we expect that this will change somewhat as we get additional tracking on the Saturn stage - is latitude 1 degree, 12 minutes north; 22 degrees, 38 minutes west. This is about seven and a half degrees off of the planned target point, 30 degrees west was the nominal impact point for the S-IVB, but as I said, we expect that these coordinates will be updated as we get additional tracking on the vehicle. We're now essentially back on the Flight Plan and having made up the approximately one hour that was lost in going into the Lunar Module earlier to check the Lunar Module after it was noted that paint was flecking from one of the thermal control panels - one of the aluminum skins on the Lunar Module. And we've essentially now made up that time with the crew back on the regular Flight Plan.

This is Apollo Control at 14 hours and we're in the process of a shift handover here in Mission Control. Flight Director Gerry Griffin and his team of flight controllers coming on now to relieve the Pete Frank team. And we do expect to have a change of shift press briefing. That will begin in about 15 minutes and will be held in the MSC News Center Briefing room. Apollo 16 at the present time is 66,450 nautical miles [123,065 km] from Earth and the spacecraft velocity is 6,990 feet per second [2,130 m/s].

This is Apollo Control. The change of shift press briefing momentarily to begin in the small briefing room in the News Center; any air-to-ground conversation from Apollo 16 will be recorded for playback at the conclusion of the Press Conference. At 14 hours, 32 minutes Ground Elapsed Time, this is Apollo Control.

This is Apollo Control. During the - just completed press conference some minute and half of tape from the air-ground from Apollo 16 was accumulated. We'll play back that tape at this time and rejoin any subsequent conversation prior to the time the crew goes into their eight-hour rest period. At 14 hours, 43 minutes; playing back tape and going live, this is Apollo Control.

And the communications officer here in Mission Control has reported that the crew has indeed turned off the voice switch onboard the spacecraft, and are settling in for a night's sleep. The spacecraft analysis status report, dated at 14 hours Ground Elapsed Time, less than an hour ago; most of the entries state no change or performance is normal. For example, in propellant usage on the CSM Reaction Control System propellants, they are now 349 pounds [158 kg] over the predicted budget for this time in the flight. Fuel cells are working normally. All the cryogenic tankage are in normal condition. The S-band High Gain Antenna was stowed at 12 hours, 48 minutes; prior to the time they set up the rotisserie or Passive Thermal Control barbecue mode in which they spin at about 3 revolutions per hour to stabilize the thermal response of the spacecraft. Although their quantities of hydrogen and oxygen are well within predicted limits, batteries are all up operating normally, with the required amp-hours loaded. About a half hour ago, there was a brief discussion of the change - a slight change or drop noted in the suit compressor Delta-P or differential pressure when they changed the lithium hydroxide canister. These lithium hydroxide canisters scrub the carbon dioxide from the cabin atmosphere. There was no concern voiced however, by the flight control team and it was merely a matter of curiosity. Apollo 16 now 70,213 nautical miles [130,034 km] out from Earth. Velocity, 6,744 feet per second [2,055 m/s]. Crew has signed off for the night and unless some reason arises to talk either back to Mission Control or for the flight control team to contact the crew, we shouldn't hear from them for the next eight hours. At 14 hours, 58 minutes Ground Elapsed Time; this is Apollo Control.

This is Apollo Control, 16 hours and 1 minute Ground Elapsed Time. Crew of Apollo 16 having some 6 hours, 58 minutes remaining in their programmed sleep period. About 20 minutes ago, the Flight Surgeon reported that, from his biomedical telemetry, that none of the crew was asleep at that time and that apparently Mattingly, because of a somewhat higher heart rate, was probably doing some exercising. For those persons who are interested in numbers and statistics, the halfway point in distance for Apollo 16, that is from surface to surface, Earth-Moon, will take place at a Ground Elapsed Time of 25 hours, 20 minutes when the distance to both bodies, Earth and the Moon, will be 104,676 [nautical] miles [193,859 km]. The halfway point in time between lift-off and Lunar Orbit Insertion will be at 37 hours, 14 minutes and 18 seconds; at which time the spacecraft will be 135,502 [nautical] miles [250,949 km] from Earth and 78,778 [nautical] miles [145,896 kilometres] from Moon. The so-called sphere crossing, where the spacecraft leaves the Earth's influence and enters into the Moon's gravitational influence - this is an arbitrary point in space, actually, where the displays here in the Control Center become Moon-referenced - will take place at 59 hours, 13 minutes, 26 seconds; and the distance from the Earth will be 178,646 [nautical] miles [330,852 km]. From the Moon; 33,820 [nautical miles, 62,634 km]. Midcourse Correction burn Number 1 was not done, and the present predicted change of velocity for Midcourse 2, should the option be exercised for a maneuver at this time, would be 12.7 feet per second [3.9 m/s]; a two-second burn with the SPS. This would be at 30 hours, 39 minutes; however, no decision on Midcourse 2 has been made and probably won't be for many hours to come. Apollo 16 presently is 74,420 nautical miles [137,825 km] out from Earth, continuing to decelerate. Velocity now; 6,487 feet per second [1,977 m/s]. And at 16 hours, 4 minutes Ground Elapsed Time; this is Apollo Control.

This is Apollo Control at 17 hours, 1 minute Ground Elapsed Time; slightly under six hours remaining now in the Apollo 16 crew rest period. Spacecraft is now 77,898 nautical miles [144,267 km] out from Earth. Velocity now 6,288 feet per second [1,916 m/s]. In a continuing refinement of the predicted S-IVB impact statistics, we have yet another set of numbers. The lastest predicted impact for the S-IVB stage on the lunar surface is at 0.93 north latitude by 22.35 west longitude at a Ground Elapsed Time of 75 hours, 6 minutes, 22 seconds. These figures likely will be updated as more tracking is obtained and processed on the S-IVB. Apollo 16 continuing the Passive Thermal Control mode, PTC barbeque roll. No further communications from the crew of Apollo 16 since they signed off sometime ago. And at 17 hours, 3 minutes Ground Elapsed Time; this is Apollo Control.

This is Apollo Control, 19 hours and 1 minute Ground Elapsed Time into the mission of Apollo 16. Apollo 16 presently 84,895 nautical miles [157,225 km] out from Earth. Velocity 5,920 feet per second [1,804 m/s], continuing to decelerate. While it may be a little premature, the space flight meteorology group here in Mission Control is already forecasting that the splashdown weather conditions, some 12 days away here, are going to be good. Possibly a few rain showers in the area near Christmas Island. Some four hours remaining in the crew's sleep period. Spacecraft still in the Passive Thermal Control mode. Will be in that Bar-B-Que role for a total of about 16 hours. At 19 hours, 2 minutes Ground Elapsed Time; this is Apollo Control.

This is Apollo Control, 20 hours and 1 minute Ground Elapsed Time in the mission of Apollo 16. Some 3 hours remaining in the scheduled sleep period for the crew. Spacecraft is now some 88,262 nautical miles [163,461 km] distant from Earth. Velocity now 5,755 feet per second [1,754 m/s]. The numbers for the predicted S-IVB impact continue to vary as the tracking is further refined. The latest numbers from the Flight Dynamics Officer gives an estimate of impact at 2 degrees, 16 minutes north latitude by 23 degrees, 11 minutes west longitude with an impact time of 75 hours, 7 minutes and 4 seconds Ground Elapsed Time. And this will likely change several more times before the actual impact. At 20 hours, 2 minutes Ground Elapsed Time; this is Apollo Control.

This is Apollo Control; 21 hours, 1 minute Ground Elapsed Time into the mission of Apollo 16. The Apollo 16 spacecraft is now 91,524 nautical miles [169,502 km] out from Earth. Velocity now 5,602 feet per second [1,707 m/s]. Apollo 16 crew at this time apparently all sleeping rather well. They signed off just before 3 am CST for the scheduled eight-hour sleep period. According to flight surgeon Dr. Sam Pool, Young and Mattingly were awake for perhaps an hour past the signoff time and Duke still an hour beyond that. Only two of the crewmen are hooked up to the biomedical telemetry, but as Dr. Pool mentioned, apparently all three are asleep. But it's not too easy to determine the quality of sleep from the telemetry that he sees on the flight surgeon's console. The best description of the quality of the sleep is from the crewmen themselves after they wake up. And at 21 hours, 2 minutes Ground Elapsed Time; this is Apollo Control.

This is Apollo Control; 22 hours, 1 minute Ground Elapsed Time in the flight of Apollo 16. Here in Mission Control, the flight control team of Gene Kranz is being briefed for the next eight-hour shift, as Gerry Griffin's Gold Team plans to - makes preparations for retiring 'til tomorrow morning. There will not be a change of shift press briefing with the Gold Team Flight Director and as much as the entire shift with the exception of about the first 30 minutes have been - has consisted of the crew being asleep. Distance at this time: Apollo 16 is 94,738 nautical miles [175,455 km] out from Earth. Approaching the Moon at 5,458 feet per second [1,663 m/s]. Total spacecraft weight; 103,078 pounds [46,755 kg]. At 22 hours, 2 minutes Ground Elapsed Time, this is Apollo Control.

This is Apollo Control, Houston at 22 hours, 28 minutes Ground Elapsed Time. The handover in Mission Control between the two Flight Control teams has been completed. The team of flight controllers headed by Gene Kranz are now all onboard. Our CapCom for this shift will be astronaut Tony England. We presently show Apollo 16 at an altitude of 96,103 nautical miles [177,982 km] from Earth and travelling at a velocity of 5,399 feet per second [1,646 m/s]. Our clock in Mission Control shows that we're approximately 31 minutes away from time of crew wakeup. At 22 hours, 28 minutes continuing to monitor; this is Apollo Control, Houston.