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Apollo 17

Day 1: Launch and ascent to Earth orbit

Corrected Transcript and Commentary Copyright © 2017 by W. David Woods and Ben Feist. All rights reserved.
Last updated 2019-06-05
Apollo 17 is the final lunar mission of the Apollo programme and it is the the only launch of a Saturn V vehicle scheduled for night time. The launch window for the mission opens at 21:53 Eastern Standard Time on 6 December 1972 (02:53 GMT on 7 December) but a technical problem will delay lift-off until after local midnight. In the event, Apollo 17 will launch at 12:33:00 EST (05:33:00 GMT) on 7 December 1972.
T-002:37:22 - This is Apollo Saturn Launch Control; we're at T minus 1 hour, 22 minutes and counting. Cabin purge has now been completed and the Boost Protective Cover has been closed. The 65-percent nitrogen/35-percent oxygen mixture will now be enriched to a 60/40 mixture at lift-off. Just completed were some preflight command tests with the Manned Spacecraft Center in Houston. These tests are to ensure that Houston can send commands, and that they are being received on or by the launch vehicle. Also just completed was a first motion signal. This is the first motion of the vehicle as it lifts off the pad. A test signal is sent to the Eastern Test Range and to the Manned Spacecraft Center in Houston to assure that they will get this signal at lift-off. Also, we just received a final Go for a Jimsphere release. The Jimsphere is a weather balloon which is the final weather balloon to go up before launch indicating the wind direction. C-band beacons are in check at this time. The C-band beacons aboard the launch vehicle are used in tracking. They give indications of range velocity during the power phase of flight. Q-ball sim command was just sent. The Q-ball is an angle-of-attack meter which is perched above the Launch Escape System, and it's read by the spacecraft commander in the spacecraft. It would indicate any deviation from the planned flight through. It reads zero as it sits on the pad and during the test a simulated command is sent to it, and Gene Cernan in the spacecraft reads off what he is reading in the spacecraft during that sim command. The checks in the spacecraft continue to run somewhat ahead of schedule. The Spacecraft Test Conductor Skip Chauvin indicated they're running ahead and looking good, to which Cernan replied, "we're looking good up here too." The countdown continuing to move along well at this time; T minus 1 hour, 21 minutes and counting; this is Kennedy Launch Control.
From NASA Technical Note TN D-6373, Aerodynamic Properties of Rough Spherical Balloon Wind Sensors: "The Jimsphere, a roughened balloon two meters in diameter, is widely used in the aerospace and meteorological communities to obtain accurate, high resolution measurements of the wind profile in the first 18 km of the atmosphere. An internal pressure of about 5 mb is maintained to insure constant volume. The 398 conical roughness elements, each approximately 7.5 cm wide at the base and 7.5 cm high, serve to control vortex shedding in the supercritical Reynolds number region below 11 km; i.e., they decrease the spectral bandwidth of aerodynamically induced motions."
From Moonport, NASA SP-4204, P524: "The countdown proceeded. At T-82 minutes launch control reported the cabin purge had been completed, and the booster protective cover closed. The spacecraft was pressurized and checked for leaks. Houston tested its command signals to the launch vehicle, and the first-motion signal was checked out with Houston and the Eastern Test Range; the next time, it would bring them word of lift-off. The last weather balloon was released to determine wind direction.
"In the meantime the C-band and Q-ball tests were in hand. The first was used in tracking to report range velocity during the powered phase. The Q-ball, perched above the Launch Escape System, would warn the spacecraft commander of deviations in the first stages of flight. Cernan reported things looking good 'up here.' His next task was to check out the emergency hand control for the Service Module engine, normally operated by a computer. Far below him, little white wisps marked the topping off of the propellant loads."
T-02:26:58 - This is Apollo Saturn Launch Control; we're T minus 1 hour, 12 minutes and counting. At this time, spacecraft commander Gene Cernan and the Spacecraft Test Conductor Skip Chauvin are going over some command checks. During these checks the spacecraft commander actually gimbles or moves, swings the main engine in the Service Module. He does this using his flight hand controller and this is a system which is done so that if there is a problem with the computer which normally flies these, he can take over and manually fly it. Normally, however, all burns of this engine are done by the computer. Out at the pad, the space vehicle is surrounded by searchlights producing some 225 foot candles of light, a total of 7,220 kilowatt xenon lights and 260 kilowatt xenon searchlight banks provide this illumination. At lift-off, approximately 7,500 foot-candles [80 lumens per square metre] will be produced from the flame of the Saturn V first stage engines. This is almost equivalent to daylight. Searchlight will also illuminate the Apollo 17 for the first 60 feet of it's flight. Our countdown continuing to go smoothly now as we approach the 1-hour mark. T minus 1 hour, 11 minutes and counting; this is Kennedy Launch Control.
T-02:15:33 - This is Apollo Saturn Launch Control; we're at T minus 1 hour and counting. T minus 1 hour and counting. Just completed were the C-band beacon checks. These are checks of the beacons, two of them aboard the Instrument Unit of the space vehicle. These are used in conjunction with C-band radar here at Kennedy Space Center to check the space vehicle during powered phase of flight. A check was just made with the Superintendent of Range Operations who ran through the camera coverage looking at the weather around the various areas to see what camera coverage, and that appears to be satisfactory. Meanwhile, at the pad, the close-out crew has completed securing the white room area, and they are clearing the pad area themselves at this time. Just before they left, they indicated to Cernan that they were completed their jobs going back away from the pad area. Cernan said "We'll see you when we get back." The pad leader responded that "The next face you see had better be a frogman or you're in trouble." The weather appears to be satisfactory. We've been tracking some local buildups, but at this time they're just - they do not seem to be posing any problem for an on-time launch at 9:53 p.m. EST. Now, T minus 59 minutes, 32 seconds and counting; this is Kennedy Launch Control.
From Moonport, NASA SP-4204, P525: "At T 1 hour, the close-out crew had secured the white room and was clearing the pad area. The elevators were set at the 96-meter level, for the astronauts' use in an emergency. At T 50 minutes the Launch Control Center initiated the power transfer test, switching the vehicle momentarily onto its own battery power and then restoring external power. Some five minutes later, swing arm 9 - the access arm to the spacecraft - retracted 12° to a standby position. Range safety test signals were flashing to the still unarmed destruct receivers."
T-02:10:54 - This is Apollo Saturn Launch Control; we are at T 55 minutes, 54 seconds and counting. Stoney, astronaut Bob Parker, the Capsule Communicator here in the firing room who has a variety of functions during this mission; one of which is to set the elevators at the 320-foot level. He actually commands the elevators which are part of the egress system, emergency egress system, for the astronauts. He has just reported that the elevators have now been set at the 320-foot level. In an emergency, the crew could come out of their spacecraft into these elevators where they would be lowered at a high speed, 600 feet per minute, to the ground floor or A level floor where they can exit from there into a variety of escape modes; one of which would be down a chute into a blast danger area or a safety area, or they could continue on out and be picked up by armored carriers. Underway at this time with the launch vehicle are some checks of the secure range safety systems aboard the vehicle. These are actually checks of the receivers in that system. A Range Safety Officer could terminate the flight of Apollo 17 if it became erratic by initiating emergency cut-off, or if necessary a propellant dispersion command. These systems are located on each of the flight stages. There are three stages of the Saturn V. Two receivers in each stage, and they would receive a signal from the Range Safety Officers and then sending through them, through these receivers, they could perform the propellant dispersion. These actions, of course, will be taken only if the vehicle were so erratic that it were endangering some land areas, and of course, only after the crew had used one of the escape options open to them. The test going well at this time. Our countdown continuing; T minus 54 minutes, 6 seconds and counting; this is Kennedy Launch Control.
T-02:05:53 - This is Apollo Saturn Launch Control at T minus 50 minutes, 55 seconds and counting. Preparations are underway in the Launch Control Center at this time for a critical power transfer test. The space vehicle at this time is being fed from an external power source, but shortly before lift-off it will be transfered to the internal flight batteries. This test is to ensure that all electrical systems aboard the vehicle function properly on the internal flight batteries. The test takes about five minutes during which time the various elements of the launch team monitor their systems and report on then to the Test Supervisor Bill Schick here in the control room that everything looks good during the test. Depending on local weather conditions the various areas around the United States, the flight of Apollo 17 will be monitored or be able to be seen by people as far as 500 miles away. This is the flight as seen of the first stage of powered flight. This would include a large portion the southeastern United States, northern tip of Cuba and the Bahama islands. The power transfer test is now underway; first stage, second stage, third stage, Instrument Unit now all going to internal power. Countdown continuing to go well, T minus 49 minutes, 35 seconds and counting; this is Kennedy Test Control.
T-02:00:55 - This is Apollo Saturn Launch Control; we're now T minus 45 minutes, 55 seconds and counting. Various elements of the launch team reporting in to Test Supervisor Bill Schick that they experienced no problems during the power transfer. We now transferred back again to an external power source, which will feed the vehicle systems until approximately 50 seconds before lift-off, at which time the final power transfer to Internal takes place. At the T minus 45 minute mark, we'll be watching for swing arm number 9, that's the swing arm which gives access to the spacecraft, to swing back to a retract position 12° back from the spacecraft. This is a park position, a standby position, where it remain down until the final moments of the countdown. T minus 5 minutes, it swings back to the full retract position. Once it swing backs, the Launch Escape System aboard the - atop of the spacecraft can be armed and this system could be used to pull the astronaut crew to safety in any disaster. Now T minus 44 minutes, 52 seconds and counting; this is Kennedy Launch Control.
T-01:55:34 - This is Apollo Saturn - This is Apollo Saturn Launch Control; we're at T minus 40 minutes, 51 seconds and counting. Swing arm number 9 just retracted a few minutes ago, and, as it retracted, the astronaut crew aboard the space field - could feel it moving away from the spacecraft. Eugene Cernan, the spacecraft commander commented, "We're really hanging out here in the breeze now." Spacecraft Test Conductor, referring to the weather, indicated that that was just a small breeze. The Launch Escape System has been armed. The system now could be used to carry the astronauts to safety if necessary. It's also used during the initial phases of powered flight to carry the astronauts away in an emergency. It would fly away in a high arc pulling them to a height, enough so that their parachute systems could deploy, and they could make a normal landing. The system is about 33 feet long. The motor develops 147,000 pounds [654 kN] of thrust. This is almost twice the amount of thrust of the Redstone rocket which powered astronaut Alan Shepard, America's first man into space. The countdown continuing to move along smoothly now. T minus 39 minutes, 36 seconds and counting; this is Kennedy Launch Control.
T-01:50:47 - This is Apollo Saturn Launch Control; we're at T minus 35 minutes, 11 seconds and counting. Spacecraft commander Gene Cernan just reported back to the Spacecraft Test Conductor Skip Chauvin. He said, "You've delivered us the best now it's our turn. Thank the guys we want to see them as soon as we can when we get back and I guarantee you we'll do that." Meanwhile C-band beacon checks are going on with the space vehicle. The liquid hydrogen/liquid oxygen fully aboard and being replenished at this time to ensure a full load at lift-off. Countdown continuing to go smoothly as we approach the half hour mark; T minus 34 minutes, 34 seconds and counting; this is Kennedy Launch Control.
T-01:45:53 - This is Apollo Saturn Launch Control; T minus 30 minutes, 54 seconds and counting. Manned Spacecraft just indicated to the Test Supervisor Bill Schick that we are go for the terminal countdown sequences. Final propulsion checks have been completed and the C-band readouts, once again repeated, have been completed. Beach boss reports the launch site recovery force helicopters are on station and ready. Digital range safety command checks are now underway as the countdown continues smoothly aiming for the T minus 30-minute mark. Now at T minus 30 minutes, 24 seconds and counting, this is Kennedy Launch Control.
T-01:40:53 - This is Apollo Saturn Launch Control, T minus 25 minutes, 54 seconds and counting. Command Module Pilot Ron Evans at this time has armed the Reaction Control System aboard the Service Module. He does this by allowing the hypergolic fuels to move down the lines to the engines. At this time he is reading out the temperatures, pressures and fuel quantities in that system. Our weather continues to look good. The major frontal area which had been of some concern earlier, has remained well west of the launch area. Also some smaller buildups which we have been monitoring do not appear to be coming close enough to cause any concern for our 9:53 pm launch time. That launch will be aiming Apollo 17 for the Taurus-Littrow area of the Moon. This area is named after the Taurus Mountains, these in southern Turkey, and the Austrian astronomer, Littrow. The site is expected to yield some of the oldest and some of the youngest lunar samples returned during the Apollo flights to the Moon. Now T minus 24 minutes, 50 seconds and counting; this is Kennedy Launch Control.
T-01:35:53 - This is Apollo Saturn Launch Control; T minus 20 minutes, 55 seconds and counting. Short time from now we will begin chilling the propulsion systems aboard the second and third stage of the Saturn V vehicle. This is necessary to condition them for the flow of the super-cool liquid oxygen and liquid hydrogen. Just a few moments ago, the crew aboard spacecraft America was given an updated weather forecast. Cernan reported, "I hope it's as beautiful out there as it is in here." Countdown continuing to move smoothly at T minus 20 minutes, 24 seconds and counting. This is Kennedy Launch Control.
T-01:30:54 - This is Apollo - This is Apollo Saturn Launch Control; T minus 15 minutes, 52 seconds and counting. The Vice-President of the United States Spiro Agnew has entered the Launch Control Center now. He'll observe the final portions of the countdown from here and also the launch. Arming and checking of the Service Module Reaction Control System has now been completed and in progress is the chilldown of the S-II, or second stage start tank. Checkouts continuing to go well, some running a little bit ahead of schedule, all on time. T minus 15 minutes, 20 seconds and counting; this is Kennedy Test Control.
The S-II has not one but five start tanks, one on each of the five J-2 engines. These are filled with an appropriate quantity of hydrogen at sufficient pressure. This is so that during the ignition sequence to start an engine, a valve can be quickly opened to discharge the contents through two turbopumps, thereby spinning them up.
T-01:25:53 - This is Apollo Saturn Launch Control at T minus 10 minutes, 55 seconds and counting. At this time, some computer checks being run with the launch vehicle. The spacecraft has now gone to full internal power. Up to this point the spacecraft fuel cells have been sharing the power load with an external source. Also going on at this time are some checks of the Astro comm circuit. This is the circuit which is used by the Launch Operations manager, Spacecraft Test Conductor, Stony, and the three astronauts at launch time. This is to ensure that they are not getting any extraneous voices or are having to listen to any of the other network which might be carrying on a conversation which they don't need at that time. Countdown proceeding smoothly T minus 10 minutes, 15 seconds and counting. This is Kennedy Launch Control.
T-01:22:59 - This is Apollo Saturn Launch Control, T minus 8 minutes and counting. T minus 8 minutes and counting. The Vice-President in the firing room at the Launch Control Center, observing the final minutes of the countdown and he'll watch the launch from here. The countdown has proceeded smoothly since picking up at 11:53am this morning. Weather continues to look good as we aim toward a 9:53 pm Eastern Standard Time launch. Now T minus 7 minutes, 37 seconds and counting; this is Kennedy Launch Control.
T-01:21:10 - This is Apollo Saturn Launch Control, T minus 5 minutes, 54 seconds and counting. At this time, entering the final phases of the countdown, various elements of the team reporting into Test Supervisor Bill Shick with the Go/No-Go for launch. At launch time, a water deluge system at the pad will spray water over the entire area of the pad, some 400,000 gallons of water. More than the average family would use in three years will be spread over the pad and the swing arms protecting them from the searing flames of the Saturn V first stage. Various elements reporting in now. First stage reporting they are Go. Range Safety, Superintendent Range Operations they are Go. Launch Operations Manager reports he is Go for launch. Launch Director Walter Kapryan has given a Go for launch. We've passed the 5-minute mark; T minus 4 minutes, 55 seconds and counting and swing arm No. 9 now coming back to the fully retracted position. The Launch Escape System sitting atop the spacecraft, spacecraft named America by the crew, now could pull the crew to safety if there were any problem while the vehicle remains on the pad or during the early portions of the flight. At the T minus 4-minute mark we'll be standing by for word from the Launch Vehicle Test Conductor Norm Carlson, giving a clear for launch, for the launch vehicle ignition. At T minus 3 minutes, 7 seconds we'll go on an automatic sequencer. It's called the terminal countdown sequencer. The astronauts on the Astro comm circuit now reporting and thanking the launch team for all their prayers and all their help. T minus 3 minutes, 55 seconds and counting. Apollo 17, the launch team wishes you good luck and God speed, reports the Launch Operations Manager over the Astro comm circuit. T minus 3 minutes, 40 seconds; the countdown continuing to go along smoothly. Once we go on the terminal countdown sequencer, the countdown will be automatic from there on out. The countdown sequencer will initiate the various functions from that time on; however, the men here in the firing room will be monitoring their consoles, watching temperatures, pressures, various readouts. They could override that terminal sequencer if necessary. Moving up now to the time when we'll go on that terminal sequencer.
T-01:18:21 - T minus 3 minutes, 10 seconds and counting. Spacecraft ready light has come on indicating that the spacecraft is ready. We are now on the terminal sequencer. Launch sequence has started. The flowing of that water on the pad will begin at the 1-minute mark flowing on the flame deflector below the launch vehicle on the launch pedestal itself and along the swing arms which will be coming back at lift-off. Instrument Unit ready light has come on. Emergency Detection System ready light is on. All indications are we are Go for launch as we approach the 2-minute, 30-second mark. Pressurization of the various propellant tanks now aboard the space vehicle is starting. At two, our second stage liquid oxygen tanks now pressurized. These propellant tanks are pressurized with helium to ensure that during the flight, the fuel flows properly down through the engine. It's quiet here in the firing room now as the men are monitoring their consoles, looking at the temperatures, checking pressures and a variety of parameters to ensure everything is in a Go condition. Pressurization continuing on the fuel tanks at this time. We'll go to the critical power transfer at the T minus 50-second mark in the countdown. At that time we'll transfer external power source to the flight battery aboard the space vehicle. The final action by the crew aboard the spacecraft America will be a final guidance alignment conducted by the spacecraft commander Gene Cernan. The flight of Apollo 17 will be able to be seen, depending on weather conditions, some 500 miles [800 km] away as it goes into Earth orbit. Pressurization continuing, liquid hydrogen tanks now aboard the second stage have been pressurized. All propellants aboard the second stage now pressurized. A cover aboard the Q-ball, this is the Q-ball system on top of the Launch Escape System will be pulled off just shortly before launch.
Schmitt, from Oral History 2000: "We went into the final countdown and got to thirty seconds, and everything had come alive beneath us. The gimbals were moving and the rocket, you could feel it. You're lying there on your back, you could feel the engines moving down a football field below you or more, as it prepared for ignition."
From Moonport, NASA SP-4204, P525: "At T - 3 minutes and 7 seconds, the automatic sequencer took over. This sequencer, the oldest and most reliable piece of automation on LC-39, chose this moment in the launching of the last Apollo to cause trouble. At T 30 seconds it went into an automatic cutoff indicating that one of the essential operations leading to the launch of the space vehicle had not been properly completed. Besides halting the countdown, the cutoff started a series of "safing" procedures which included the return of swing arm 9 to a standby position."
Cernan, from 1973 Technical debrief: "Ground communications with the spacecraft and all the launch preps for a nominal on-time launch went well. There were no spacecraft anomalies or problems during the launch prep. All systems checked out well. Controls and displays went well through T minus 30 seconds, when there was an automatic sequencer hold due to a potential problem that the ground support equipment saw on S-IVB pressurization. However, to the best of my knowledge, the S-IVB was GO on the cockpit displays. The S-IVB pressures were nominal, but, nevertheless, we had an automatic hold in the sequencer at T minus 30 seconds. From then on, for 2 hours and 40 minutes, we had a series of 20-minute recycles. I don't know exactly how many now. Did we ever get down to 8 minutes one time in the count?"
Evans, from 1973 Technical debrief: "No. Once we got started below 20 minutes, we went all the way."
T-01:16:01 - First stage propellant tanks have been pressurized. Now past the 1-minute mark and we are going on internal power. Now all systems to internal power. We'll be looking for the engine start sequence at the 8.9-second mark in the countdown. Engines will build up to a thrust of 7.6 million pounds.
T-01:15:40 - T minus 30 seconds, we have a cut-off, we have a cut-off at T minus 30 seconds. We are standing by at T minus 30-second mark. We'll bring word to you just as soon as we get it. We have a cut-off at T minus 30 seconds. T minus 30 seconds and holding. This is Kennedy Launch Control.
Gene Kranz briefing Neil Hutchinson and Gerald Griffin at Mission Control during Apollo 17 launch delay.
T-01:14:40 - This is Apollo Saturn Launch Control. We're holding at the 30-second mark. This was an automatic cut-off. Cut-off by the terminal sequencer. As mentioned, this sequencer initiates various actions. Each action must take place and must be completed before the next one can be initiated. If anything does not get completed in time there will be an automatic cut-off. This cut-off was automatic, done by the sequencer. We're standing by now to check just what the problem was. Now at T minus 30 seconds and holding; this is Kennedy Launch Control.
T-01:13:34 - This is Apollo Saturn Launch Control. The astronaut crew aboard the spacecraft going through their various safing now. Safing of all systems and the launch team here continuing through their emergency procedures. We'll be standing by to check out the problem just as soon as we can get word. T minus 30 seconds and holding, this is Kennedy Launch Control.
T-01:11:34 - This is Apollo Saturn Launch Control. The safing procedures continuing at this time. Up to the T minus 30-second mark, the countdown had been proceeding smoothly. Weather conditions at launch were predicted to be and appears to be good at that time. However, we had an automatic cut-off from the terminal countdown sequencer and we're standing by to see just what caused that automatic cut-off. All systems being safed at this time. T minus 30 seconds and we are in a hold. This is Kennedy Launch Control.
T-01:08:24 - This is Apollo Saturn Launch Control. We're continuing in our hold at the 30-second mark, while the launch team assesses our problem. The swing arm, swing arm number 9, will be brought back to it's park position which is 12 degrees back from the space vehicle. Continuing the safing procedures this time and assessing the problem. Holding at T minus 30 seconds, this is Kennedy Launch Control.
Schmitt, from Oral History 1999: "The one thing that you don't want to do is have an aborted launch on a launch pad and have to recycle and come back a month later and go through another month of simulator training. You're ready to go when you're ready to go. And I think everybody felt that way."
Schmitt, from Oral History 2000: "You certainly don't want to recycle for another month. That was the first thought we had on the launch pad when we did, in fact, have a delay, was that, well, let's hope that we don't have to go through this for another month. You would have gotten into it and done it and then never noticed the difference, but still at the immediate point of being ready to launch, you're ready to launch, there's no question about that."
T-01:03:00 - This is Apollo Saturn Launch Control. We're continuing in our hold at the T minus 30-second mark as the launch team assesses our problem. At this point swing arm number 9 is going back to the 12-degree park position. This is a position about 15 to 20 feet from the spacecraft. All safing procedures have proceeded normally. We're continuing our hold while we assess our problem. At T minus 30 seconds, this is Kennedy Launch Control.
Schmitt, from Oral History 2000: "Somewhere in the deep dark past of computer programming, a programmer had told the final sequencing checks that the computer was going to do - to look to see if a signal to pressurize a booster oxygen tank had been sent. Not whether it had been received and acted upon, but had the signal been sent."
Schmitt, from Oral History 2000: "Well, when they went through that particular point where that signal was supposed to have been sent and the tank pressurized, the signal didn't get sent. The computer didn't send the signal, but the person in the Launch Control Center saw that that didn't happen and just pressed a button and pressurized the tank. So everything was fine, but the computer didn't know it. When they went through the final sequence, the computer saw that that signal hadn't been sent, and it said 'Hold.'"
Schmitt, from Oral History 2000: "So the computer just shut everything down. That's what you want them to do, it's just that it was programmed wrong. Garbage in, garbage out. So what they did, they actually went into the launch computers, tracked down that point and hard-wired around that particular sensor so that the next time the computer went through, it would believe that the signal had been sent. Sure enough, it believed it, and off we went. We were two hours and forty minutes late, but, nevertheless, we were on our way."
T-01:01:12 - This is Apollo Saturn Launch Control. The swing arm number 9 is now back to that retract position at the 12-degree position. Point out that the window we have tonight extends to 1:31am. So we have some time here to assess the problem and then continue - recycle and continue our countdown. We're continuing to hold at the 30-second mark at this time. 30 seconds and holding, this is Kennedy Launch Control.
A dramatic photo of the Apollo 17 Saturn V on pad 39-A at dusk. Research: J.L. Pickering
T-00:54:05 - This is Apollo Saturn Launch Control. We're at T minus 30 seconds and continuing our hold. The problem was with the terminal countdown sequencer, which failed to give the command to pressure, pressurize the third stage LOX tank. The crew in the firing room, realizing this - were seeing this happen, pressurized the tank manually but this did not happen fast enough to satisfy the automatic sequencer. As was mentioned earlier, during this sequence everything must happen at a certain time before the next step in the sequence can take place. The next step that was to take place was the retraction of swing arm 9, and at the time that was to take place the terminal sequencer had not had an indication that the third stage LOX tank had been pressurized. The plan now is to recycle to the T minus 22-minute mark in the countdown. Now this recycling procedure will take an additional 35 to 40 minutes. This still puts us well within our launch window. While we're recycling, we'll continue to review the data to determine just what the problem is and whether or not we can proceed from the T minus 22-minute mark for a launch later in the window. The crew aboard the spacecraft has been alerted to the problem and understand what is happening. They're standing by there at this time. Now at T minus 30 seconds and holding, this is Kennedy Launch Control.
Launch director Skip (Clarence) Chauvin explained the situation to the crew. Schmitt managed to nap during the delay.
Schmitt, from Oral History 2000: "Right at thirty seconds, Skip Chauvin came over the line and said we have a hold. I think Gene was more concerned than the rest of us, because none of us knew whether everything in the spacecraft and in the rocket knew we were in a hold. But we went through that thirty-second period and it was quiet for a few minutes. Then Chauvin came back on the line and said, 'We have a problem with the launch computer. It's not a major problem. We're going to fix it and when we have it fixed, we'll recycle.' I think it was eight minutes for a planned hold and then go through it again. That is exactly what happened."
Schmitt, from Oral History 2000: "At that point I felt very comfortable. I'd worked with Skip in many chamber tests and things like that, so we knew him very well, and from the sound of his voice, it didn't sound like anything that wasn't going to be fixed. So I fell asleep. Anytime you put fans humming or a little bit of vibration, things like that, I can go to sleep. There's no problem. So I got an hour or so dozing sleep while we were waiting for that problem to be fixed."
T-00:49:04 - This is Apollo Saturn Launch Control. We're remaining still in the T minus 30-second mark. We'll remain here for some period. It will take approximately 35 to 40 minutes to recycle back to T minus 22 minutes where we'll resume the count. To explain again, what had happened was we were in what was called the terminal countdown sequencer. At 3 minutes, 7 seconds in the countdown we go on to an automatic system called the terminal countdown sequencer. This countdown sequencer initiates various actions, the final actions in the count. Each of these must occur on schedule and in sequence. Now what happened at this particular time was, the third stage liquid oxygen tank was not automatically pressurized as it should have been. The launch crew here in the firing room, when they saw this, manually pressurized that system, but it was too late to satisfy the sequencer. The next event in the sequence was the retraction of swing arm number 1, swing arm going over to the first stage and at that time, the sequencer did not see that the tank had been pressurized and sent an automatic cut-off. So we had an automatic cut-off at the 30-second mark. We're standing by at the 30-second mark to go back to T minus 22 minutes and we are reevaluating the problem, looking at the - what caused the sequencer not to automatically pressurize that tank, seeing what that problem is and seeing if there is a possibility if we go ahead and do this manually early in the sequence, if that will satisfy the sequencer and we can proceed. Now holding at the T minus 30-second mark in our countdown, this is Kennedy Launch Control.
T-00:46:40 - This is Apollo Saturn Launch Control. We're continuing to stand by here at the T minus 30-second mark in the countdown. The crew remaining perfectly calm in their spacecraft. They've gone through their safing checks. The various safing checks of the launch vehicle have been completed. We are now going through preparations for recycling to the T minus 22-minute mark. Standing by at this time at T minus 30 seconds. T minus 30 seconds and holding in the countdown for Apollo 17, this is Kennedy Launch Control.
T-00:45:21 - This is Apollo Saturn Launch Control. We're continuing our hold at the 30-second mark. We'll recycle to the T minus 22-minute mark. The T minus 22-minute mark is chosen as the recycling point because this is the point where we start the chilldown as was mentioned during that point in the countdown. We start the chilldown of the second and third stages to prepare them for the influx of the liquid hydrogen, the cold liquid hydrogen and the cold liquid oxygen. This chilldown has some very specific parameters and must be started at a certain time and cannot go beyond a certain time. So it's best to go back to that point in the countdown under these circumstances and to resume our count at the T minus 22-minute mark when a determination is made that we can resume. Continuing to look at the data here is see exactly what happened. There is no indication of ignition. Ignition was scheduled to come at the 8.9-second mark. Here in the control room a number of the people were looking through the remote cameras which have the capability out at the pad of zooming in on specific areas and a number of people here were looking right at those first stage engines and there was no indication whatsoever of engine ignition. We're continuing to evaluate all the data at this time as we hold at the T minus 30-second mark. This is Kennedy Launch Control.
T-00:43:30 - This Apollo Saturn Launch Control, still in our hold at the 30-second mark. While the launch team here is busy recycling to the T minus 22-minute mark, the mission team out at the Manned Spacecraft Center also preplanning some of the new times for the mission. They are also at this time busily preplanning the new launch azimuth. The azimuth now if we go at the next opportunity would be the 81.06 degrees. This will be automatically fed into the Instrument Unit of the Saturn V vehicle from the Manned Spacecraft Center. All elements of the launch team now putting everything together, checking over data and doing their best to put us back into a recycle position ready to pick up the count at the T minus 22-minute mark. Still evaluating data, however, and we have not at this time been given a Go for that resuming of the count. T minus 30 seconds and holding at this time, this is Kennedy Launch Control.
T-00:42:05 - This is Apollo Saturn Launch Control, continuing our hold at the 30-second mark. Back at the Mission Control Center in Houston, the flight controllers returning to their seats now after some consultations. They're back now giving a status check and getting ready in case we are - it is determined that we can pick up the count. In the firing room here, the Apollo Program Director Rocco Petrone has moved into the viewing area where the President - Vice President Spiro Agnew and NASA administrator James Fletcher are and he's giving them a briefing and a run down on our problem. We're standing by at this time. The clock has now been recycled to the T minus 22-minute mark; however, we have not picked up the count at that mark. We are now at T minus 22 minutes and holding, this is Kennedy Launch Control.
T-00:40:53 - This is Apollo Saturn Launch Control; we're continuing to stand by at the T minus 22-minute mark in the countdown. Recycling operations have gone well. We're back to the T minus 22-minute mark and at this mark which we will pick up the count if we are given a Go to resume. Check has been made of the Mission Control Center team at the Mission Control Center in Houston. All elements of that team reporting that they are ready to resume as soon as they get the word. Now standing by here at Kennedy Space Center, while data is reviewed and determination will be made if and when we can resume our countdown for Apollo 17. Now at T minus 22 minutes and holding, this is Kennedy Launch Control.
Saturn V on the pad.
T-00:39:55 - This Apollo Saturn Launch Control. We're continuing to standby at the T minus 22-minute mark. We're hoping to resume the count shortly. The problem has not been resolved. We're continuing to look into it; however, it has been determined that a resolution one way or the other should be able to be made shortly. So right now we are continuing our recycle procedures, hoping to pick up the count perhaps just minutes from now. If the problem is not resolved by the time we reach the T minus 8-minute mark after we continue to count down, the clock will be hold - will be held again. Right now we are continuing the recycling procedures hoping to pick up shortly at T minus 22 minutes. We are now T minus 22 minutes and holding, this is Kennedy Launch Control.
T-00:38:47 - This is Apollo Saturn Launch Control. We're continuing to stand by at the T minus 22-minute mark. We've been given the word here in the firing room now that the count will be resumed at 11 pm at T minus 22 minutes. At this time there still has not been a resolution to the problem, but we'll continue looking at that. We could continue on counting down while this problem is looked at. To reiterate what the problem was; the terminal countdown sequencer failed to give the command to pressurize the third stage liquid oxygen tank. The crews monitoring this function saw that that happened and immediately manually pressurized the tanks, but this did not occur in time in the sequence and when swing arm one was to retract, it had not received this signal. As a consequence an automatic cut-off was sent. There are several possible workarounds to this. They are being looked into at this time, and we plan to resume our countdown at the T minus 22-minute mark at 11 pm. Now holding at T minus 22 minutes, this is Kennedy Launch Control.
T-00:37:32 - This is Apollo Saturn Launch Control; we're at T minus 21 minutes, 10 seconds and counting. The countdown picked up, the launch team here made a quick check of the various elements, all reporting in to the Test Supervisor Bill Schick, indicating that they were ready to resume the count. Now counting at T minus 20 minutes 53 seconds, and we'll continue to countdown here as we look at the problem which caused the hold at the T minus 30-second mark. Now at T minus 20 minutes, 42 seconds and counting; this is Kennedy Launch Control.
T-00:31:19 - This is Apollo Saturn Launch Control; we're at T minus 14 minutes, 35 seconds and counting in our countdown for Apollo 17. Back at the Mission Control Center, the men there are updating the launch azimuth. Launch azimuth standing now at 82.54 degrees. This will automatically be fed into the Instrument Unit. The swing arm, swing arm number 9, the access arm to the spacecraft, remains at the 12-degree position. It will remain there until the T minus 5-minute mark in the countdown. Going on at this time are the recycling of some of the vents for the liquid hydrogen and the liquid oxygen. These are the vents which allow the venting of these gases as there is some boil-off occurring. It's necessary to continue venting these to ensure they do not freeze in either an open or a closed position. The countdown proceeding smoothly now. T minus 13 minutes, 43 seconds and counting; this is Kennedy Launch Control.
T-000:26:38 Evans: Alpha. Okay, EDS Auto is On, Up now.
T-000:26:26 Evans: ...verify Auto. Launch vehicle rates, verify Auto.
T-000:26:20 Evans: RCS Command is Off. Release.
T-000:26:20 Cernan: One at AC1, Main A. Two, AC2, Main B.
T-00:26:17 - This is Apollo Saturn Launch Control. We're at T minus 9 minutes, 36 seconds and we are counting. However, we do plan to continue the hold at the T minus 8-minute mark. We can hold at that point for 20 minutes and plan a 20-minute hold while the launch crew here satisfies themselves that they have worked out a good solution and a workaround to the problem. The crew has been alerted aboard the spacecraft. Cernan indicated that perhaps they could start a nice conservation about a good book, Thomas Hardy or something like that. Countdown continuing now, aiming toward the 8-minute mark at which time we'll hold. T minus 9 minutes now, T minus 9 minutes and counting; this is Kennedy Launch Control.
T-000:25:59 Schmitt: Okay, that's going to latch.
T-000:25:37 Cernan: Roger, ATC. Understand Challenger is Go for launch.
T-000:25:12 Schmitt: Okay, secondary Pump switch is Off.
T-000:25:09 Schmitt: Mark it.
T-00:24:38 - This is Apollo Saturn Launch Control, we're now holding at the 8-minute mark as planned. The hold at this time is planned for approximately 20 minutes. The crew feels that they have - that they have a workaround to the problem, working around the indication going to the terminal sequencer that the tank has not been pressurized, when actually it had been done manually. They are checking all of their data, however, to ensure that this is the proper method to workaround the problem and that this will result in a smooth countdown from here on. Now at T minus 8 minutes and holding, this is Kennedy Launch Control.
T-000:24:13 Cernan: Okay, we'll be looking for them.
T-00:23:41 - This is Apollo Saturn Launch Control, we're continuing our hold at the 8-minute mark. The Launch Operations Manager has gone over with the launch team their proposed solution, a workaround. The team appears to be satisfied that it is the proper one. They are now briefing management personnel on the problem and the workaround. Out at the pad the liquid oxygen continues to vent from the vehicle and is replenished. Liquid hydrogen is also vented from the vehicle as there is some boil-off. However, because it is quite a volatile fuel it is vented through a burn pond at the side of the pad. That burn pond is at the north side of the pad and there it can be seen burning in a controlled condition at this time. This is a normal condition, actually during the day this burns in such a pure manner that it cannot be seen. However, at night it is clearly visible. Our countdown continuing to hold at the T minus 8-minute mark at this time. T minus 8 minutes and holding this is Kennedy Launch Control.
T-00:22:25 - This is Apollo Saturn Launch Control. We're continuing to hold at the T minus 8-minute mark. Meantime, the crew is getting a variety of updates in the spacecraft, updating them on various aspects and the changes to their mission due to this hold period. Also, at the Manned Spacecraft Center, they're continuing to update the flight azimuth as they get new times for the launch. Launch Operations Manager Paul Donnelly just went through quite an extensive briefing with the Spacecraft Test Conductor to pass on to the crew what they feel the problems were and how they plan to work around it. The crew aboard the spacecraft indicated that if the launch team was satisfied with these solutions, that they certainly were confident themselves. Now continuing our hold at the T minus 8-minute mark, this is Kennedy Test Control.
T-000:21:58 Cernan: Okay, understand; full retract.
T-000:21:47 Cernan: Skipper, thank you. We - we plan to, babe.
T-000:21:40 Cernan: We're going to do our best, and we're also going to have a ball.
T-000:21:21 Cernan: We thank you for the hardware, and the help, and the prayers, and everything else that goes into making a good mission.
T-00:21:17 - This is Apollo Saturn Launch Control, we're continuing in our hold at the T minus 8-minute mark. At this time, it's been determined to take an additional 20 minutes, add an additional 20 minutes to that planned hold period. The reason for this is, the crews would like to take the workaround that they have devised, and at Marshall Spaceflight Center, where the Saturn V launch vehicle was developed, they have what is called a breadboard or a system which is similar to this one, and run through the sequence and ensure that it does operate properly. The crew aboard the spacecraft was informed of this additional 20-minute hold. They indicated that they expected to use all three stages of this Saturn V and they were happy to have the 20-minute hold if that was going to assure that all three were going to work properly. Now continuing our hold at the T minus 8-minute mark, this is Kennedy Launch Control.
T-000:21:14 Cernan: I sure do, I've got 5 good bright ones.
T-000:21:04 Cernan: Stony, you're loud and clear.
T-000:20:57 Cernan: We thank you, very much. Loud and clear.
T-000:20:49 Evans: Verify program 02. Okay, we've got a Verb 75, do not Enter. Please.
T-00:20:06 - This is Apollo Saturn Test Control. We are continuing our hold at the T minus 8-minute mark. The reason the T minus 8-minute mark is chosen for this hold, as mentioned earlier, has to do with the chilldown of the thrust chambers in the S-II or second stage and the third stage. Both of these stages use liquid hydrogen, an extremely cold cryogenic fuel, and the thrust chamber must be conditioned prior to flight so that it's ready at the time of ignition in-flight to receive these fuels coming in. To achieve the proper temperature, the thrust chamber chilldown should not exceed 20 minutes, but it must be on for at least 7 minutes and 40 seconds. So rounding that off the hold was called at the 8-minute mark. We can continuously hold it at this point whereas if we continued on down we would have to watch these parameters very closely so that we did not exceed that 20-minute accumulated cooling time. At this point we can continue our hold and that continuation can be determined by the problem and we can pick up then at any time or continue as long as necessary. We're continuing that hold now at T minus 8 minutes and holding, this is Kennedy Launch Control.
T-000:20:06 Cernan: Roger. 3 minutes, Bob. Forward and [garble].
T-000:19:14 Cernan: It's pull the bypass, Skip.
T-000:19:04 Cernan: Roger. 2 Minutes.
T-00:18:28 - This is Apollo Saturn Launch Control. We're continuing in our hold at the T minus 8-minute mark. Back at the Marshall Spaceflight Center in Huntsville, Alabama, the crews there are at work on a breadboard, or a mock-up of the system in question, where they're putting it through its paces, checking out the workaround solution, that is, jumping around this erroneous signal, and ensuring that everything works properly. The crew still standing by in the spacecraft, updating various systems there, updating their Flight Plan, all continuing to go well there. The crew at the Manned Spacecraft Center also doing considerable amount of updating. They'll be continuing to update the azimuth. And the Launch Control Center here at Kennedy Space Center, the launch team manning their consoles, standing by to pick up the count when we're given the word to go. However, we're standing by still. At this time, we have no word from the Marshall Space Flight Center. We're expecting that to come within 10 to 15 minutes from this time. Now at T minus 8 minutes and holding, this is Kennedy Launch Control.
T-000:18:24 Schmitt: Roger. Bus ties going on. The AC's on. DC's on.
T-000:18:06 Cernan: Roger. 1 Minute.
T-000:17:59 Cernan: CDR Pad Comm is Off. LMP?
T-000:17:49 Cernan: Roger. GDC align, and ball number 2 is coming in.
T-000:17:25 Cernan: Roger. Understand, cut-off.
T-000:16:55 Cernan: That's affirm, understand. We're just holding fast here.
T-00:16:53 - This is Apollo Saturn Launch Control; we're continuing in our hold period at this time. Test Supervisor Bill Shick just announced here in the Firing Room that the hold is expected to last approximately 20 more minutes. Liquid oxygen and liquid hydrogen continue to be replenished aboard the 3 stages of the launch vehicle at this time. That replenishing will continue during the hold period and during the final minutes of the countdown. The countdown continuing in the hold, T minus 8 minutes and holding, this is Kennedy Launch Control.
T-000:16:33 Cernan: Okay, we'll just standby, hold fast.
T-00:16:00 - This is Apollo Saturn Launch Control at one minute to midnight, one minute to midnight. We're continuing to hold at the T minus 8-minute mark. Work's still going on at the Marshall Space Flight Center in Huntsville, Alabama. Updating of the tracking continuing at the Manned Spacecraft Center in Houston. And the launch team here at Kennedy Space Center preparing to pick up the count. Hopefully, we'll be given a go-ahead to pick up the count in approximately 10 to 12 minutes from this time. We're continuing to standby, waiting to hear from the testing going on at the Marshall Space Flight Center in Huntsville. To recap the activities earlier today, the countdown picked up at 11:53 am after a planned hold period, picked up at T minus 9-hour mark. Shortly after that time, the pad was cleared and we began loading the cryogenic fuels, that's the liquid hydrogen and the liquid oxygen aboard the space vehicle. Those operations actually went a little bit ahead of schedule. The astronaut crew went out to the pad, entered their spacecraft, began checking it out and those operations also running a little bit ahead of schedule. We went on to our terminal countdown sequencer at the 3-minute, 6-second mark as scheduled. Everything seemed to be proceeding fine. At the T minus 30-second mark, we got an automatic cut-off. It was determined that this cut-off came because pressurization of the liquid oxygen tank aboard the third stage was not initiated automatically as it should have been. When it was done manually, the terminal sequencer did not sense that this had been done, and therefore gave the automatic cut-off. We're working the problem right now, continuing to hold at the T minus 8-minute mark. T minus 8 minutes and holding, this is Kennedy Launch Control.
T-000:15:45 Cernan: Okay, push to normal.
T-000:14:08 Cernan: Roger. TVC servo 1 is Off, and 2 is Off. Roger, Reac valve to Normal.
T-00:13:42 - This is Apollo Saturn Launch Control, continuing to hold at the T minus 8-minute mark. The hold continues to be planned for approximately 5 to 7 more minutes. However, the launch window, it should be pointed out, tonight extends to 1:31 am. Now if for any reason we could not make it in that launch window, we could recycle under our present configuration and resume our count aiming for a 9:53 pm Eastern Standard Time launch tonight. The window for tonight is the same as it was for last night and this morning - 9:53 pm to 1:31 am. However the launch team appears to be optimistic with the solution they've found to the problem. They are just waiting for verification and confirmation from the testing going on at the Marshall Space Flight Center in Huntsville, Alabama. The time now is 7 minutes after midnight, we're continuing to hold at T minus 8 minutes. T minus 8 minutes and holding, this is Kennedy Launch Control.
T-000:13:27 Evans: Okay, I've got a Verb 34. Enter. Uh. Off. That's affirm.
T-000:13:10 Cernan: STC, CDR. The 5 engine lights all went on about thirty seconds ago.
T-000:12:58 Schmitt: Roger, going Off and then Auto. AC. DC.
T-000:12:28 Cernan: Okay, CDR's Pad Comm. And LMP's T/R.
T-00:12:14 - This is Apollo Saturn Launch Control, continuing to hold at the 8-minute mark in the countdown. Still awaiting word from the Marshall Space Flight Center in Huntsville, Alabama, and the result of the test being run at this time up there. Meanwhile, here in the firing room, all elements of the launch team are assessing their position. They are assessing the effect of the hold and this amount of hold time on each of their systems. Everyone, at this time, busily at work here in the firing room, also at the Mission Control Center in Houston, busy there with their flight updates. Now continuing to hold at the T minus 8-minute mark, this is Kennedy Launch Control.
T-000:11:37 Cernan: TC, CDR. You're busy Skip, I just wondered if think it's going to be a Go for a recycle here. Okay.
T-00:11:13 - This is Apollo Saturn Launch Control. We're at 15 minutes past the hour, continuing to hold at the T minus 8-minute mark. The supervisor just indicated that we plan to pick up the clock at the T minus 8 minute mark in 10 minutes. Planning to pick up the clock at 25 minutes past the hour. The tests being run - or have been run now at the Marshall Space Flight Center and indicate that our system is good, the way it has been reconfigured. All elements now during this 10 minutes will be preparing their various systems to pick up the clock at the T minus 8-minute mark. Meanwhile, out at the Manned Spacecraft Center, the flight controllers there also planning to pick up the clock. We just received a Go from the Superintendent of Range Operations indicating that the range has been cleared around the new flight azimuth. The Manned Spacecraft Center, Houston, Flight indicate that they are go to pick up the clock at 25 minutes past the hour. Now at T minus 8 minutes and holding, this is Kennedy Launch Control.
T-00:09:48 - This is Apollo Saturn Launch control. We're continuing our hold at the T minus 8-minute mark. We have approximately 5 more minutes remaining in that hold. It's been determined that the workaround is a correct and satisfactory one. A breadboard or a sample system at the Marshall Space Flight Center was used to run through the entire sequence as it's now configured and that operated satisfactorily. What happened was the - during the terminal sequencer, the liquid oxygen tank was not pressurized automatically. When this was done manually, the indication did not get to the sensors in time so that we had an automatic cut-off. The liquid oxygen tank aboard the third stage, it has been determined, will be pressurized manually early in the terminal sequence and jumpers have been installed so that we can then feed the information to the sequencer so that it will not have an indication that the LOX tanks have not been pressurized. This - a breadboard situation of this has been constructed at the Marshall Space Flight Center in Huntsville and this has operated satisfactorily. So, it's been determined to go ahead with our countdown on this basis. We'll be planning to pick up the count at the T minus 8-minute mark, some 4 minutes from now. Now T minus 8 minutes and holding, this is Kennedy Launch Control.
T-000:09:20 Cernan: Okay. Skip, we're just sitting tight. Okay. Yeah, I'll get my pencil out, I guess.
T-000:08:14 Cernan: Roger. Coming back to Park.
Cernan, from 1973 Technical debrief: "The problem turned out to be apparently in the software of the Ground Support Equipment. The workaround was caught up, checked out through the Cape and Marshall, and once the count picked up, we had two azimuth updates."
Evans, from 1973 Technical debrief: "We had two azimuth updates, because the first recycle was more than 20 minutes, wasn't it? It was more than 20 minutes and we recycled to that point and then they found out that they weren't going to be able to pick it up again in 20 minutes. And we stopped at 20 minutes and made the second azimuths."
Cernan, from 1973 Technical debrief: "The point here being, both azimuth updates in the spacecraft went well. The CMP put them in the computer. The computer took it. I watched the IMU torque. After each one of those, they had to reset the GDC, which worked fine. So we launched with a good GDC following the platform. The only difference was a small roll angle, and it was reversed, because we had gone through 90 degrees on the azimuth change. But that didn't really bother anything because the roll came in on time in a reverse direction. It was a small roll that culminated in just a few seconds."
Prior to launch, three guidance systems must be aligned to match the expected orientation of the launch pad at the time of lift-off. Additionally, one of the axes will be aligned to the launch azimuth, the bearing of the vehicle's groundtrack from the pad. That launch azimuth is designed to place the spacecraft at the correct starting point for the TLI burn which, in just under three hours into the flight, will send them to the Moon. But each time the launch is delayed, the launch azimuth has to change to compensate for Earth's continued rotation. This entails realignment of all three systems
Within the Instrument Unit sits an ST-124 stabilised platform which is mounted within three supporting gimbals. When a new launch azimuth is calculated, the platform aligns itself to face that azimuth with reference to a light shone from a theodolite placed 210 metres south of the vehicle. Windows in the IU and the platform's spherical housing are provided for this and a servoloop control system keeps it locked until just before launch to stop the platform 'gyrocompassing' or appearing to turn as Earth turns.
Within the Command Module is another stabilised platform, part of the Primary Guidance, Navigation and Control System (PGNCS). Since this is going to act as a backup to the IU's guidance system for the ascent, it too must be aligned with respect to the launch azimuth and launch pad. Its initial alignment was achieved by using the direction of gravity and by sensing the gyrocompassing effect, achieved with Program 02. The desired launch azimuth was entered as part of this alignment and if it changes, the updated launch azimuth can be entered and the computer will torque the platform appropriately.
The third system that must be aligned at this time is the gyro system at the centre of the spacecraft's Stabilization and Control System, the SCS. This consists of Body Mounted Attitude Gyros (BMAGs) that sense the rate of rotation of the ship. Being fixed to the spacecraft's structure, they are not directly aligned. Rather, the electronics that keep note of the BMAG outputs have their notion of the spacecraft's current attitude fed to them from the primary system. This then proves an accurate starting point for their calculations. These electronic devices are called the Gyro Display Couplers (GDCs) and aligning them is achieved merely by pressing a button labelled 'GDC Align'.
T-00:07:59 - This is Apollo Saturn Launch Control. We're now resuming the count. T minus 7 minutes, 54 seconds and counting. At this time in the spacecraft, updates being given to the spacecraft commander Eugene Cernan. The swing arm still at the 12-degree position, that is the park position, standing by at the spacecraft. That will be brought back to the full retract position at approximately T minus 5 minutes in the countdown. The Flight Director just ran through the - his team - a status report from his team at the Mission Control Center. That team all reported they are in a Go condition. Now at T minus 7 minutes, 20 seconds and counting; this is Kennedy Launch Control.
T-00:05:43 - This is Apollo Saturn Launch Control; T minus 5 minutes, 40 seconds and counting. At this time the various elements of the launch team have been reporting in to Bill Shick, Test Supervisor, indicating that we are Go to continue. Mission Director Chet Lee just verified that we are Go for launch. Safety indicates that we have a Go. First stage test conductor, this is the man who has charge of those five first stage engines which will give us the lift-off, has indicated a Go for launch. Launch Operations Manager Paul Donnelly, also giving us a Go for launch, and finally the Launch Director Walter Kapryan says we are Go for launch. We've passed the five-minute mark now and swing arm number 9, this is the access arm to the spacecraft, is coming back to the full retract position. It moves back alongside the mobile launch tower and it will remain there now through the final portion of the countdown and the launch. At the T minus 60-second mark, 20 nozzles will start flame deflector deluge of 13,000 gallons per minute of water pouring down on that flame deflector, so a great deal of what is seen at launch time, which looks like smoke, is actually steam as this water is burned off. This water to cool the pad area and to cool the equipment alongside of the launch tower as the water also pours across the swing arms on the launch tower. We're approaching the 4-minute mark in the countdown now; T minus 4 minutes, 5 seconds and continuing to count. At the 4-minute mark, we'll stand by for a final Go from Norm Carlson, the Launch Vehicle Test Conductor. He's given a Go. The Launch Operations Manager now switching over to the Astro comm circuit, this is the circuit that the astronauts, the Launch Operations Manager and the spacecraft communicator will remain on. They have this private circuit to keep extraneous talk off of their circuit. They are checking in, they are checking in now on the Astro comm circuit Indicating that they are Go. Spacecraft has indicated they are ready. Instrument unit ready light has come on. S-IC, that's the first stage, preparations are now complete as we approach the 3-minute mark. There's quiet in the firing room now as the engineers and technicians are monitoring their consoles. They're monitoring the various rates, pressures, temperatures. They can override the terminal sequencer if they sight a problem that it has not picked up. We are on that terminal sequencer now, we've passed the 3-minute mark. T minus 2 minutes, 47 seconds and counting as we are on the terminal sequencer. At the T minus 50-second mark, we'll be looking for that critical power transfer. This is where we transfer from the external power source, which has been feeding the 3 stages of the launch vehicle, to internal power, to the flight batteries aboard the space vehicle. It's expected that given proper weather conditions people will be observing this flight from as much as 500 miles away. This includes a large portion of the southeastern United States, the northern tip of Cuba and the Bahama islands. Now approaching the 2 minutes, 2-minute mark, Mark, T minus 2 minutes and counting and the countdown continues to move along smoothly. Now in the terminal countdown portion. The automatic sequencer has stopped the replenishing of the liquid oxygen and the liquid hydrogen. We're standing by now to begin pressurization of the fuel tanks, the second stage fuel tank pressurized, third stage fuel tank pressurized. The countdown continuing to move along smoothly. T minus 90 seconds, T minus 90 seconds. Countdown continuing smoothly. S-IVB propellants pressurized, the indication now using the work around showing the S-IVB propellant has been pressurized. Now looking at the liquid hydrogen tank, as they become pressurized. LH2 aboard the second stage pressurized. All propellants now aboard the second stage pressurized as we approach the 1-minute mark in the countdown.
T-000:04:08 Cernan: Okay. We'll be ready when you are.
T-00:01:00 - Mark. T minus 1 minute and counting. Now in the final minute of the countdown. At T minus 45 seconds, Gene Cernan will make the final guidance alignment - this is the...
Cernan, from 1973 Technical debrief: "The count and lift-off, through the yaw and the roll program, were nominal once we got through T 0. Distinction of sounds in launch vehicle sequence countdown to lift-off - I think the only thing that really comes across in there is that at some point you get a good vibration. At some point in the countdown, you get a good vibration as you're sitting up there. It's not part of the CSM's operation, so you're not sure what's going on. And this happened in the CDDT and, of course, all we did was check and find out we were doing something with the booster."
Prelaunch
Evans from 1973 Technical debrief: "When they ran through some gimbaling programs."
Cernan, from 1973 Technical debrief: "The major portion of the launch count has to do with checking out the systems, so the commander stays very busy and many times on separate loops. The entire EDS system checked out very well. We only checked it out once in the initial count and during most of the recycle we stayed in EDS Auto and then we de-armed EDS Auto but still maintained a manual EDS capability to abort during that recycle time. We picked EDS Auto as part of the T minus 20 recycle for final lift-off."
T-00:00:44 - Mark. T minus 45 and Gene Cernan made that final guidance alignment. That's the last action taken by the crew aboard the space vehicle. Now approaching the half minute mark. T minus 33, T minus 30 seconds and continuing on now - continuing on at T minus 26 seconds...
T-000:00:30 Overmyer: 30 to go.
T-000:00:29 Cernan: Okay, Robert. We're ready and we're GO up here.
T-00:00:25 - Mark. T minus 25. We'll get a final guidance release at the T minus 17-second mark. T minus 17, final guidance release. We'll expect engine ignition at 8.9 seconds...
T-00:00:21 Overmyer: Minus 20.
T-00:00:10 - 10, 9, 8, 7, ignition sequence started - all engines are started - we have ignition, 2, 1, zero - we have a lift-off.
T-000:00:10 Overmyer: 10, 9, 8, 7, ignition, 6, 5, 4, 3, 2, 1...
Cernan, from 1973 Technical debrief: "The S-IC ignition - The lights started going out at 7 seconds, and somewhere around 3 seconds they were completely out. You could feel the ignition. You could feel the engines come up to speed. Just prior to lift-off and during the first few seconds of lift-off when we were near the pad, both the CMP and I could see the reflection of the engine ignition out the left-hand window and the hatch window in the BPC. We could not see the fire but could see a red glow through the windows reflecting apparently off the surface. Ignition was like a big old freight train sort of starting to rumble and shake and rattle and as she lifted off. We got a good tower clear."
Apollo 17 Launch.
T-000:00:01 Cernan: Look at the light!
000:00:00 Overmyer: ...lift-off.
000:00:00 - We have a lift-off and it's lighting up the area, it's just like daylight here at Kennedy Space Center as the Saturn V is moving off the pad. It has now cleared the tower.
000:00:01 Cernan: Roger. The clock has started. We have yaw.
Cernan, from 1973 Technical debrief: "It was dark and we didn't see anything until S-IC ignition."
Lift-off.
Evans, from 1973 Technical debrief: "I really wasn't watching the lights because I guess I didn't expect the thing to shake quite as much as it did. To me, I felt like I was really vibrating. I wanted to find out what was making me vibrate. I wasn't expecting that much vibration when the S-IC lit off. At lift-off, again, once it got vibrating, I didn't feel the yaw. I was watching the needle on the thing but didn't feel the yaw, though."
000:00:05 Evans (onboard): Woo-hoo!
Lift-off.
000:00:08 Overmyer: Clear of the tower.
Cernan, from 1973 Technical debrief: "Powered flight - During the actual powered flight of the S-IC you could not see anything at all. You couldn't see out the cockpit, as we had the lights up fairly bright."
000:00:10 Cernan: Roger; tower. Yaw's complete. We're into roll, Bob.
The huge, 110-metre [363-feet] tall Apollo 17 space vehicle (Spacecraft 114/Lunar Module 12/Saturn 512) is launched from Pad A, Launch Complex 39, Kennedy Space Center (KSC), Florida, at 12:33 am (EST), 7 December 1972. Apollo 17, the final lunar landing mission in NASA's Apollo program, was the first nighttime lift-off of the Saturn V launch vehicle. Aboard the Apollo 17 spacecraft were astronaut Eugene A. Cernan, commander; astronaut Ronald E. Evans, Command Module Pilot; and scientist-astronaut Harrison H. Schmitt, Lunar Module Pilot. Flame from the five F-1 engines of the Apollo/Saturn first (S-IC) stage illuminates the nighttime scene. A two-hour and 40-minute hold delayed the Apollo 17 launch.
000:00:13 Overmyer: Roger, Geno. Looking great. Thrust good on all five engines.
Lift-off.
000:00:17 Cernan: Okay, babe. It's looking good here.
000:00:21 Cernan: Roll is complete. We are pitching.
000:00:27 - This is Mission Control. Gene Cernan reporting the launch vehicle maneuvering to the proper attitude, everything looking good at this point.
000:00:28 Schmitt: Wow woozle!
000:00:29 Cernan (onboard): Okay, babe. Let's check the angles.
000:00:31 Evans: Thirty seconds. We're going up. Man, oh, man!
000:00:34 Cernan: Thirty seconds, and 17 is Go.
000:00:37 Overmyer: Roger, 17. You're Go.
000:00:40 - First stage looks good. Altitude, 1.1 [nautical] miles [2.0 km].
000:00:45 Evans (onboard): Okay, 1 minute and 68 degrees.
000:00:47 Cernan (onboard): Okay.
The crew's main task during ascent is to intensely monitor its progress for signs of problems. Using program 11 in the computer, they can watch the numbers on its display while an 8-ball attitude indicator lets them see their attitude with respect to their starting point. They compare them with values on a cue card that indicate the ideal trajectory. Ron is stating that, according to this card, they should be at a pitch angle of 68° one minute into the flight. Note that they started pointed straigh up so this represented a pitch angle of 90°.
Cue card from Apollo 17's ascent showing columns for Digital Event Timer (DET), Theta (angle with respect to pad horizontal at time of launch, inertial velocity (fps), vertical speed (h-dot in fps), and altitude (h in nautical miles). Courtesy of Nick Howes.
000:00:48 Schmitt (onboard): Everything looks great over here, Gene.
000:00:49 Cernan (onboard): Okay. Okay, stand-by for Max - coming through Max Q. We'll be at 68 degrees.
000:00:57 Schmitt (onboard): ...Okay.
000:00:58 - Booster says we look good. We're now at 2.5 [nautical] miles [4.6 km].
000:00:59 Overmyer: 17, stand by for Mode I Bravo.
000:01:01 Overmyer: Mark. Mode I Bravo.
000:01:03 Cernan: Roger. I Bravo; we're Go at 1 minute.
000:01:06 Overmyer: Roger, Gene. You're looking great. Right on the line.
000:01:08 - Everybody says 'Looking great - Right on the line.' We're now 1 [nautical] mile [1.85 km] down range. Launch vehicle 4.2 [nautical] miles [7.8 km] high.
000:01:09 Cernan (onboard): Okay, we got the RCS command.
000:01:10 Overmyer: 17, you are feet wet - feet wet.
000:01:12 Cernan: Roger. Feet wet.
As the launch vehicle tilts to the east from its initial vertical rise, it eventually crosses the nearby Florida coastline. 'Feet wet' is the US Naval aviator radio call for flight over the coast from land to sea. Gene, Ron and CapCom Robert Overmyer are all naval aviators.]
Schmitt, from Oral History 2000: "I think everybody [who] rode a Saturn V was tremendously stimulated by the experience. It's a very heavy vibration. Very slow acceleration at first, but heavy, heavy vibration as the five F-1 engines in the first stage, the S-IC, are fighting each other to some degree. You build up, over two minutes and forty-five seconds, about 4gs acceleration."
000:01:14 Evans (onboard): Man, this thing shakes like a son-of-a-gun.
000:01:15 Cernan (onboard): Yes, that's Max Q. Wait until we get out of Max Q. Stay down there Q-meter.
000:01:20 Evans (onboard): Man.
Cernan, from 1973 Technical debrief: "As you go through Max Q, as in the past, it gets very rough and much noisier, but I don't think we ever had any trouble hearing each other in the spacecraft. I had my intercom very high and all my S-bands and tweaked everything up prior to lift-off. We went through Max Q and the only unusual thing going through Max Q, considering wind components that we had, was that I saw 25 percent on the Alpha [meter] going through Max Q. The yaw needle was right on, but the pitch needle had dropped to a degree and a half at the most. I guess I didn't really expect it because of the predicted wind components. After we got through Max Q, you could still certainly tell the bird was burning as we pressed on toward staging, but it got much quieter and it was very evident that you were through Max Q when that time came."
Evans, from 1973 Technical debrief: "The shaking increased a little bit up to Max Q and then there was a different type of shaking. It was more of a vibration, I think, going through Max Q. And there was more noise associated with going through Max Q."
000:01:25 - Coming up on maximum dynamic pressure at this point. 4 [nautical] miles [7.4 km] down range, 8 [nautical] miles high [14.8 km] and the velocity approaching 3,000 feet per second [1,000 m/s].
000:01:27 Cernan (onboard): Okay. 1:30 and about 50 degrees.
000:01:32 Evans (onboard): 50 Degrees. Okay, right on.
As the vehicle tilts towards the horizontal, the pitch angle decreases.
000:01:33 Cernan: 01:30, and we are Go, Bob.
000:01:36 Overmyer: Roger, Gene. You're looking great.
000:01:37 Cernan (onboard): 2gs. 2½gs. See it quiets out after Max Q.
000:01:42 Evans (onboard): Yes. Quiets out.
000:01:43 Cernan (onboard): Pushing 3gs.
000:01:45 Evans (onboard): I can't - can't hold my hand up there anymore. [Laughter.]
000:01:48 Cernan (onboard): Okay, we're out of Max Q.
000:01:50 Evans (onboard): Okay. Cabin's still looking good.
000:01:52 Cernan (onboard): Alpha's PC.
000:01:54 Evans (onboard): Okay, standby for...
000:01:55 Overmyer: Stand by for Mode I Charlie, 17.
000:01:57 Cernan (onboard): ...I Charlie.
000:01:58 Overmyer: Mark. Mode I Charlie.
000:02:00 - And the Flight Dynamics Officer says we look good on all sources, right on the trajectory.
000:02:00 Cernan: Roger, I Charlie. 2 minutes EDS.
Mode IC is used for aborts occurring between 30.5 km (16.5 nautical miles) and the jettison of the tower. As the air is now very thin, the airflow around the pair of canards at the top of the tower would have little aerodynamic effect during an abort. Instead, the tower and BPC would be jettisoned and the Command Module's RCS used to control the orientation of the spacecraft. The safe range of vehicle motion rates are now defined as not exceeding ±9° per second in pitch and yaw, ±20° per second in roll.
000:02:02 Evans (onboard): EDS.
000:02:02 Cernan: EDS is Off and we are Go.
Having passed Max Q, they are into a much thinner part of the atmosphere and the Emergency Detection System with its fast reactions to possible aerodynamic breakup is no longer required. The sorts of failures that would have required hair-trigger responses earlier in the flight are less of a threat. An engine out or an engine hard-over would result in a slower rotation that gives the team a chance to make decisions before commanding an abort of the mission.
000:02:05 Overmyer: Roger, 17; you're Go.
000:02:06 Cernan (onboard): 3gs. 3½. Standby for inboard.
000:02:09 - Flight Director Gene Kranz taking a status for staging, we say we look good for staging.
000:02:11 Overmyer: 17, you are Go for staging.
000:02:13 Cernan: Roger. We're Go here.
000:02:14 Cernan (onboard): Did you get your Verb 82?
000:02:15 Evans (onboard): No.
Verb 82 is a request to the computer to display the parameters of their orbit. The three displays on the Display and Keyboard (DSKY) will show the altitudes of their apogee and perigee, and the time to free fall (TFF) to ground impact. Perigee is meaningless at the moment as they are still on a suborbital trajectory, but once it displays a positive altitude that is similar to the apogee, then they will know that they have achieved sufficient horizontal speed for a sustained circular orbit around the planet.
000:02:17 Cernan (onboard): Standby for inboard.
As propellant is consumed at a rate of over 13 metric tons per second, the vehicle lightens considerably. Additionally, atmospheric pressure is quickly falling which allows the exhaust gases to leave the F-1 engine nozzles at a faster speed, thereby improving their efficiency by up to 20% over the S-IC burn. The combined result is that the acceleration experienced by the crew is ramping up markedly. To keep it below 4g, the centre engine of the S-IC stage is shut down early. This reduces the acceleration from about 3.8g to 3.1. For the remaining 22 seconds of the burn, the acceleration will climb back up to nearly 4gs.
000:02:18 Evans (onboard): Okay. That's Verb 82.
000:02:20 Cernan: Inboard cut-off.
000:02:21 Overmyer: Roger. Inboard.
000:02:24 - Inboard engines shutting down on-time as planned.
000:02:24 Cernan (onboard): Okay, now hold on after staging guys.
000:02:26 Schmitt (onboard): Standby gang.
000:02:27 Evans (onboard): Okay. Here's 20. Where's the safety?
000:02:28 Schmitt (onboard): Okay, it's 19.
000:02:30 Cernan (onboard): Now at 41. It's 41. [Garble] seconds
000:02:32 Cernan (onboard): 3½ gs.
000:02:33 - Crew will experience maximum g forces of about 4gs at shutdown.
000:02:35 Cernan (onboard): Hold on!
Cernan, from 1973 Technical debrief: "If you want to put them in more layman terms, I think the S-IC acted and performed like some big, old, rugged, shaky, big monster. It has to be noisy, has lots of vibration, and smoothed out somewhat after Max-Q, but still was a rumbling bird."
Schmitt, from 1973 Technical debrief: "I think that it is good to do a lot of simulation about malfunctions during launch, but up through Max Q, it is a little bit unrealistic to think that you are going to analyze a malfunction in the spacecraft."
Cernan, from 1973 Technical debrief: "To sum up the S-IC, I personally didn't think it was any different than my previous ride on the S-IC and up through this point being a night launch really didn't make any difference at all. The only thing I did different that I hadn't really thought a lot about until I sat on the pad and began to think about staging was, just prior to staging, I took my hand off the abort handle and held the support arm rather than the translation control handle until after staging. I did this just a couple of seconds prior to staging. I had talked about it with John Young a little bit prior to the flight and it turns out that's what he did, also. Probably a good thing."
000:02:37 Cernan (onboard): Okay. 5 seconds. [Garble] gs. 4gs.
000:02:40 - Coming up on first stage shutdown. And we've had shutdown on time on the first stage.
000:02:41 Evans (onboard): Jesus Christ!
000:02:41 Cernan (onboard): I told you to hold on. Look at that son-of-a-bitch. Man!
Evans, from 1973 Technical debrief: "Of course, with the shutdown of the S-IC, I think that was about 4½g."
Cernan, from 1973 Technical debrief: "We pushed 4g."
Schmitt, from 1973 Technical debrief: "Just pushing 4g on the thing and it quits just like that. I was prepared for it because Gene had said, 'Hey, brace yourselves because it is going to happen,' and it happened all right. It just flat quit when we went from 4g to 0."
Cernan, from 1973 Technical debrief: "The great train wreck."
Schmitt, from 1973 Technical debrief: "I think in all those booster cut-offs, it's hard to see how rapidly the g-level decreases."
Schmitt, from Oral History 2000: "Very slow acceleration at first, but heavy, heavy vibration as the five F-1 engines in the first stage, the S-IC, are fighting each other to some degree. You build up, over two minutes and forty-five seconds, about 4gs acceleration. At that point everything shuts down. You drop off the first stage and then you ignite the second stage, the S-II, and you're back on your way, but only at 1½gs. So there's a big change, it's from 4gs to minus 1½ gs, as the whole stack unloads, to plus 1½gs, as you go on on the second stage. And that all happens in just slightly over a second. So that is probably the most dynamically exciting point in the mission, certainly in the launch part of it. From then on it's pretty straightforward. You get into orbit in about ten minutes using all three stages."
The Apollo 17 Saturn V illuminates the Florida sky as it streaks to the Moon. Research: J.L. Pickering
000:02:46 Evans (onboard): Jesus crimany! [Laughter.]
000:02:49 Cernan: Okay, Bob. I guess we got all five.
Cernan, from 1973 Technical debrief: "We had center engine shutdown on time. We had staging on time. ... At staging, the S-IC shut down, something that you don't see in the daylight is that the fireball overtook us."
Evans, from 1973 Technical debrief: "It sure did."
Cernan, from 1973 Technical debrief: "When the S-II lit off, we literally for a nanosecond flew through the bright yellow fireball that was left over from the S-IC. ... I don't think it's ever been recorded on a daylight launch before, but as soon as the S-IC shut down during the time involved in recycling and getting the staging sequence going and the S-II lit off, apparently the trailing flame of the S-IC overtook the spacecraft when we immediately went into that zero-g condition. And, for just a second, as the S-II lit off, we went through the flame. It was very obvious. We could see it out of both windows. I particularly could see it out of the left-hand rendezvous window of the BPC. It was not a smoke; it was not an orange fireball; it was just a bright yellow fire of the trailing flame of the S-IC; and it happened for just a split second. Then we got off on the S-II and things got very quiet and very smooth and was a very long, quiet, smooth ride."
000:02:51 Overmyer: Roger. They're looking here - looking good.
000:02:53 Evans (onboard): Okay, standby to ...
000:02:55 Schmitt: Sure felt like it.
000:02:55 Cernan (onboard): Standby. Hold it.
000:02:56 Schmitt: I think we saw them all from here.
000:02:58 Overmyer: Roger, Jack. And the thrust is Go on all five of them. They're running good.
000:03:03 Cernan: Okay; 3 minutes and we're Go. See how smooth...
000:03:06 Overmyer: Roger, 17.
000:03:07 Evans (onboard): Geez, this is smooth. Okay, got some tower switches...
000:03:09 Cernan (onboard): Come on, baby! Go!
000:03:11 Evans (onboard): Okay, 13.
000:03:13 Cernan: Okay, we do have skirt sep.
000:03:16 Evans (onboard): 19, 15, 17.
Cernan, from 1973 Technical debrief: "We got skirt sep right on time. I could feel skirt sep going."
000:03:18 Overmyer: Roger. We confirm skirt sep.
000:03:19 Cernan (onboard): Watch it, Jack!
000:03:20 Evans (onboard): 16, there it goes...
Cernan, from 1973 Technical debrief: "We had tower jett, which was really sort of spectacular at night. I think the LMP is going to add something to it, but from the left-hand rendezvous window, I could not only see the flame, but the inside of the BPC seemed to be lit up. Of course, it doesn't stay there very long; it's gone in just a split second. But it was a very spectacular sight at night to see that tower go against the blackness of space out there."
Cernan, from 1973 Technical debrief: "Tower jett was very evident. You could see the flash and I could see the entire BPC. I could see underneath it. It was lit up underneath. The whole thing was lit up."
Schmitt, from 1973 Technical debrief: "On the tower jett, I wouldn't say a split second. As a matter of fact, I was surprised it lasted as long as it did. It was a few seconds."
Evans, from 1973 Technical debrief: "I couldn't see the rocket go. All I could see was an orange glow out the center window."
000:03:21 Cernan: There goes the tower.
000:03:22 Evans: Wow, there she goes!
000:03:23 Overmyer: Roger. The tower; you're Mode II.
000:03:25 Cernan: Roger, Mode II.
000:03:30 Cernan (onboard): Okay, [garble] command.
000:03:34 Evans (onboard): Okay, alpha [garble].
000:03:34 Overmyer: The steering has converged. The CMC is Go. You're going right down the pike, 17.
Cernan, from 1973 Technical debrief: "We could see guidance come in very definitely. It was not as big a pulsation as I've seen on the simulator but I did see the needle and the spacecraft did change its attitude slightly. You could see the mixture ratio shift. It was just a long, smooth, quiet ride."
000:03:38 Cernan: Okay, Bob. I do confirm guidance.
While the S-IC was powering Apollo 17 through the atmosphere, no active guidance was occurring. Instead, the rocket was tilting over according to a preprogrammed sequence designed to minimise sideways aerodynamic forces. The final act in this 'tilt sequence' was 'tilt arrest', bringing rotation of the vehicle to a stop in readiness for staging. Nevertheless, the Saturn's guidance system had kept track of the trajectory throughout. Now that the S-II burn is established, a different form of guidance comes into play. This is the Iterative Guidance Mode (IGM) which is closed loop in its nature. In other words, it is now actively steering the vehicle based on a knowledge of where it is and how fast it is going in order to achieve the desired final conditions; to be at a certain point, at a certain time, travelling at a particular velocity.
000:03:40 Evans: And, ELS SEP circuit breakers when you get a chance there, Gene.
000:03:43 - That's the automatic guidance system, the inertial guidance system, performing properly.
000:03:45 Cernan: Okay, Bob, I got the ELS SEP circuit breakers. And we've seen it all: ignition, staging, and tower.
000:03:52 Overmyer: Roger. Got you.
000:03:54 Schmitt (onboard): By the way, the cabin's sealed. [laughter.].
000:03:58 - Apollo 17 now 65 [nautical] miles [120.4 km] high.
000:03:58 Cernan (onboard): Okay guys, we've got a long way to go.
000:04:00 Evans (onboard): Okay, I'll tell you where in the hell we're going here.
000:04:03 Cernan: Okay; 4 minutes and we're Go here, Bob.
000:04:06 Overmyer: Roger, Gene. We're going round the room. Looks Go here.
000:04:09 Cernan (onboard): 21 degrees. We're Mode 2, Ron.
000:04:11 Evans (onboard): Okay...
000:04:11 Overmyer: You're looking real good, Gene. Right down the line.
000:04:15 Evans (onboard): Okay, H and H-Dot looks pretty good.
000:04:18 Schmitt (onboard): We got a 30 and a 430. I can't really see that, let's see.
000:04:28 Cernan: Okay; 04:30 and we're still Go onboard.
000:04:30 Overmyer: Roger, 17. You're Go.
000:04:34 Cernan: Let me tell you, this night launch is something to behold.
000:04:38 Evans (onboard): Okay, H and H-Dot are good.
000:04:46 Cernan (onboard): Okay, I don't know if you'll be able to pick up any horizon.
000:04:47 - Coming up on 5 minutes. Everything still looks very good in the launch of Apollo 17. The launch vehicle spacecraft now 80 [nautical] miles [148.2 km] high, 230 [nautical] miles [426 km] down range.
000:04:50 Evans (onboard): No, it's too dark - too light in here.
000:04:52 Cernan (onboard): Yes.
000:04:55 Cernan (onboard): Okay, let's keep - on. One g.
000:04:58 Schmitt (onboard): I got some stars out on the right, but I don't see...
Cernan, from 1973 Technical debrief: "While we were on the S-II, we would see no indication of light from the engines. We were just thrusting out in the darkness of space. I tried to see stars for potential Mode IV and, of course, at that time, mode II abort and turned the lights down on the left side once or twice. But even with the lights down on (we had the LEB lights relatively low), in my estimation, it would have required all the lights in the spacecraft to have been off and certainly more than a few seconds to become night adapted to be able to see through the windows and pick up stars that would have been able to help in an abort situation had you lost the computer and the SCS. We had looked - potentially planned to use those stars in an abort condition if we had to. We had excellent constellations to look at. They obviously were there, but I could not see through the low glow reflection on the window even with our lights, floodlights, turned almost all the way down. I even went to the extent of trying to shield my eyes on the S-II and looked out the window and I still could not pick up anything that I could have recognized for an abort. I also could not pick up any night horizons during that point in time which I thought I might be able to base on seeing where the stars cut off and where they do not."
Schmitt, from 1973 Technical debrief: "We had another indication of that during entry when we were looking for a night horizon and finally saw it, but it was extremely hard to find."
000:05:02 Overmyer: Five minutes, Geno, and you're Go down here. You're looking great.
000:05:05 Cernan (onboard): [Garble] Jack, Okay.
000:05:06 Cernan: Okay, Robert. We're Go here at 5.
000:05:13 Evans (onboard): Coming up on S-IVB to COI.
000:05:14 Cernan (onboard): You guys believe me about that S-I staging now?
000:05:16 Evans (onboard): [Laughter.] I can't...
000:05:19 Schmitt (onboard): I can't believe how smooth this is.
000:05:20 Evans (onboard): I can't - I can't believe how smooth this is.
000:05:21 Cernan (onboard): Okay, let's keep this mother burning. We've got a long way to go. We're only half way there.
000:05:24 Overmyer: 17, Houston. Your times are nominal. Level sense arm at 8 plus 36; S-II shutdown at 9 plus 20. Nominal times.
000:05:33 Cernan: 8 plus 36 and 9 plus 20. Roger.
The S-II burn will be terminated when the liquid level in the tanks indicate that depletion is near. A set of ten sensors, one each at the outflow ducts to the engines, signal when they are no longer surrounded by liquid. When two sensors in one tank are uncovered, the IU begins the operation to shut down all five engines. In order to avoid incorrect signals causing an unintentional early shutdown, the sensing system is not armed until a point has been passed whereby, if the sensors erroneously caused the S-II to shut down early, the margin in the S-IVB would be able to make up the deficit. This point is called 'level sense arm'.
000:05:36 Schmitt (onboard): Coming up on gimbal motors, Geno.
000:05:37 Cernan (onboard): Okay. [Garble].
000:05:38 - CapCom Robert Overmyer advising Gene Cernan and the crew aboard Apollo 17 the second stage shutdown at about 9 minutes, 20 seconds Elapsed Time. That shutdown about 3 and a half minutes from now.
000:05:52 Cernan (onboard): I forget anything yet, Ron?
000:05:54 Evans (onboard): Nope.
000:05:54 Cernan (onboard): Okay, we're still Mode 2, coming up on...
000:05:56 Overmyer: Standby for S-IVB to COI capability.
000:05:59 Overmyer: Mark. S-IVB to COI capability.
000:06:01 Cernan: Roger. S-IVB to COI. We're Go at 6.
Should the S-II quit on them now, the S-IVB would have sufficient capability to get them to orbit, the so-called Contingency Orbit Insertion, or COI. This would, of course, use up the propellant intended to send them on to the Moon and would render Apollo 17 as an Earth-orbit mission.
000:06:03 Cernan: Good. Gimbal motors?
Another abort scenario available to the crew is to use the Service Module's main engine to send the spacecraft into Earth orbit if the third stage fails. This is known as Mode IV and in preparation for this possibility, the motors that operate the engine's gimbals are powered up. This allows the nozzle to be steered in order to ensure the thrust axis acts through the spacecraft's centre of mass. Each axis has both a primary and a secondary motor, four in all.
000:06:04 Evans (onboard): Go ahead.
000:06:05 Overmyer: Roger, Geno.
000:06:06 Cernan (onboard): Pitch 1.
000:06:06 Evans (onboard): Got it.
000:06:07 Cernan (onboard): And Yaw 1.
000:06:08 Evans (onboard): Got it. Go ahead. ...
000:06:13 Cernan (onboard): Pitch 2.
000:06:15 Evans (onboard): Got it.
000:06:15 Cernan (onboard): And Yaw 2.
000:06:15 - Apollo 17 still right on the nominal trajectory at an altitude now of about 92 nautical miles [170.4 km].
000:06:16 Evans (onboard): Got it. Okay, got a plus 15.8 and a plus 19. [Garble].
000:06:21 Cernan: Okay, Bob. We're got four good motors and we're Go at 06:20.
000:06:25 Overmyer: Roger. And, 17, we copied the gimbals and watched them and they looked good.
000:06:29 Evans (onboard): One g? Just like sitting on the pad, isn't it? A [garble].
000:06:35 Schmitt (onboard): Okay, our calibration on that tank changed a little bit again, apparently.
000:06:39 Cernan (onboard): Okay.
000:06:40 Schmitt (onboard): Down at 90%.
000:06:41 Evans (onboard): 90? On the Tank 2?
000:06:44 Schmitt (onboard): On the hydrogen.
000:06:45 Evans (onboard): Hydrogen. Tank 3, I mean.
000:06:46 Overmyer: Stand by for S-IVB to orbit capability.
000:06:49 Cernan (onboard): Roger, Bob. [Garble].
000:06:49 Overmyer: Mark. S-IVB to orbit capability. And we'd like Omni Delta, Jack.
000:06:54 Schmitt: Roger. You've got it.
The stack is flying in an almost horizontal attitude with the crew in a heads-down orientation. One of four omnidirectional antennae flush mounted around the periphery of the CM is selected for comms with Earth. In this case, Omni D is favourable owing to its position on the outside near Jack's head.
000:06:56 Evans (onboard): Okay, 7 minutes [garble].
000:06:58 Overmyer: Roger.
000:07:00 Cernan (onboard): 7, and I'm 6 degrees. How does that sound?
000:07:01 Evans (onboard): Okay, that's good. 17, 3. Let's see, 119. We go to [garble] half a mile high.
000:07:01 - Now 7 minutes in and we have sufficient velocity to make orbit with the Saturn third stage should we have an unexpected early shutdown of the second stage.
000:07:08 Cernan: Seven minutes, Bob. We're looking good onboard.
000:07:11 Overmyer: Roger.
000:07:17 Cernan (onboard): Am I glad I took my hand off that abort handle!
000:07:19 Evans (onboard): [Laughter.] Man!
000:07:20 Schmitt (onboard): So am I. [Laughter.] I'll tell ya. [Laughter.]
000:07:24 Cernan (onboard): Okay, we've got to get through this one, and then through staging. Standby for inboard. Okay. [garble].
000:07:27 - We're now less than 2 minutes from second stage shutdown and ignition of the Saturn third stage. And the center engine will be shutting down as scheduled in about 10 seconds.
000:07:34 Cernan (onboard): Standby for inboard.
As with the first stage, the centre engine of the second stage is shut down earlier than the other four. The reason behind it is, however, completely different. Apollos 8 and 9 had exhibited severe pogo, a term for a longitudinal vibration, in their S-II stages which had occurred towards the end of their burn. Rather than try to engineer it out, it was decided from Apollo 10 onwards that the centre engine would simply be shut down about 1.5 minutes early.
000:07:35 Evans (onboard): Okay. Okay, we're at a g-and-a-half. Standby.
000:07:40 Cernan: We have inboard cut-off.
Cernan, from 1973 Technical debrief: "Inboard cutoff was right on time. You could feel it, a definite physiological feeling. Of course, the g-meter saw it also"
000:07:43 Overmyer: Roger, Gene. Inboard on time.
000:07:46 - And that inboard shutdown looked to be on time.
000:07:50 Cernan (onboard): Okay, she pitches up just like the simulator.
000:07:51 Evans (onboard): Yep. Sure does. Pitches...
000:07:53 - Apollo 17 now 625 miles downrange, 93 miles in altitude.
000:07:55 Schmitt (onboard): [Grunting noise.]
000:07:56 Evans (onboard): Is that hard to reach, Jack?
000:07:57 Schmitt (onboard): Yes. Why don't you take it down, I can't quite - g-and-a-half is too much.
000:08:01 Cernan: Eight minutes, and we are Go.
000:08:03 Overmyer: Roger, 17. You're looking great.
000:08:08 Cernan (onboard): Okay, [garble] standby for a PU shift.
The five J-2 engines powering the S-II have the ability to alter their thrust by changing the mixture ratio [MR] of hydrogen to oxygen. Upon ignition, the MR was 4.8:1 but moved to the 5.5:1 setting five seconds later and it has stayed there for the majority of the burn. When a predetermined velocity has been achieved, the MR will revert to be 4.8:1. The reason for this is an attempt to maximise propellant utilisation, hence 'PU'. in other words trying to ensure that fuel and oxidiser are depleted at about the same time. For earlier flights of the S-II, this was done by active measurement of the dropping levels and calculating the change based on that. This was discarded when mathematics demonstrated that there was a better chance of geting it right by making the change when a particular velocity was reached. For a discussion of the schemes to improve S-II propellant utilsation see Schemes For Enhancing The Saturn V Moon Rocket’s Translunar Payload Capability.
000:08:12 Evans (onboard): Is that what that was?
000:08:14 Cernan (onboard): Yes, I think it was.
000:08:15 Evans (onboard): Yes, I think that was it.
000:08:17 - The spacecraft guidance systems agreeing very closely with the Saturn guidance. It looks good.
000:08:18 Cernan (onboard): Okay, Ron. That level sense arm will be at 36.
000:08:20 Evans (onboard): 36. Okay.
000:08:21 Overmyer: 17, Houston. You are Go for staging.
000:08:24 Cernan: Thank you, Bob. We are Go for staging up here.
000:08:29 Cernan (onboard): A little over a g.
000:08:31 Schmitt (onboard): There's a little chug.
000:08:32 - Staging now less than 1 minute.
000:08:34 Cernan (onboard): Okay, we've got to get through this one. Coming in, we're level sense arm now.
000:08:40 Overmyer: You have level sense arm at this time, Gene.
000:08:42 Cernan (onboard): Roger, Bob. Level sense arm.
000:08:46 Cernan (onboard): Okay, Ron. Our next thing will be standby for Mode IV, and we'll have staging. I will call it out to you.
000:08:48 - Apollo 17 traveling at 21,000 feet per second [6,400 m/s]. It's achieved about 83 percent of the velocity required for a minimum orbit.
000:08:52 Cernan (onboard): And little S-IVB burn, baby burn. Gimbal [garble].
000:09:01 Cernan: Nine minutes, Bob, and 17 is Go.
000:09:04 Overmyer: Roger, 17. You're Go here.
000:09:06 Cernan (onboard): Okay, standby.
000:09:07 - And about 10 seconds to staging.
000:09:09 Cernan (onboard): 10 seconds.
000:09:16 Overmyer: Standby for Mode IV capability.
000:09:20 Cernan: S-II cut-off.
000:09:21 Overmyer: Mark. Mode IV capability, and we copy cut-off.
000:09:23 Cernan: Roger. Mode IV. And we do have S-IVB ignition.
000:09:28 Overmyer: Roger. We see it, and the thrust is looking good on it.
000:09:30 Cernan (onboard): God, you see that glow [garble].
000:09:31 Evans (onboard): Geez!
000:09:31 Cernan: We saw that one, too, Bob.
000:09:33 Overmyer: Roger.
000:09:33 Cernan (onboard): Did you see it go past us?
000:09:34 Evans (onboard): Yes.
000:09:35 Schmitt (onboard): We're right in the flame.
000:09:36 Cernan (onboard): Yes, that's what the Titan used to do. Used to fly through the flame of that thing. Let's, let's press on here we've got a lot to do. We're Mode IV.
Cernan, from 1973 Technical debrief: "The S-I cut-off, as Jack said, is again very sharp, almost instantaneous, from almost 4g to 0. But on the S-II, although it's sharp and a very hard hit, you don't unload the entire stack like you do when you're on the S-IC. The staging was very smooth. It did not seem like an exceptionally long time before we separated and the S-IVB lit off."
Cernan, from 1973 Technical debrief: "I could see nothing on S-II until S-II shutdown. I could see the glow of S-IVB ignition. I say the glow of S-IVB ignition, it very easily could have been the fireball of S-II which tried to overtake us but couldn't quite make it. But there was a glow right during the period of S-II shutdown to S-IVB ignition. During the S-IVB burn, you could see the glow of the aft engines throughout the burn and throughout the orbital [operation?]"
Cernan, from 1973 Technical debrief: "We got lit off on the S-IVB, and, unlike the flame we flew through on the S-II, we did not do that on the S-IVB. I don't know where the reflection came from, but I could see the reflection from somewhere out the forward window. Either it was the S-II trailing flame trying to overtake the vehicle but didn't quite make it, or it was S-IVB ignition reflecting off the S-II because there's no atmosphere up there at that point. But I did not see a flame, but a residual back light out that window just for a short period of time, either right at staging or just at S-IVB ignition. As I think back, my best guess would be that the same thing happened on the S-II, that the trailing flame, when you go from 4g to 0 instantaneously, tends to overtake the vehicle. But in the case of the S-II, it's not nearly as big a pattern and just didn't quite make it up the stack. I just saw some of the glow of it. That's my best guess. After the S-IVB ignited, we never saw anything except the APS firing throughout that burn. You could see the mixture ratio shift."
Schmitt, from 1973 Technical debrief: "But PU shift, both vehicles, was surprisingly noticeable."
Cernan, from 1973 Technical debrief: "The S-II was a Cadillac: quiet, less than 1g flight most of the time until we built up our g-load prior to staging. It was quiet, smooth, had very little noise, or feeling of rumbling or anything else."
000:09:45 - We're up to 23,000 feet per second [7,000 m/s] - we'll be shooting for something over 25,000 [7,600 m/s].
000:09:46 Evans (onboard): Yes.
000:09:47 Cernan (onboard): Okay, we're at - a little less than a half a g.
000:09:49 Evans (onboard): Less than half of a g.
000:09:50 Cernan (onboard): Okay, 10 minutes, Ron. I'll be at about forty [garble]...
000:09:55 Overmyer: 17, the steering has converged and the CMC is Go. You're looking great.
CMC is Command Module Computer.
000:09:59 Cernan: Roger. The CMC is Go, 10 minutes, and 17 is Go onboard.
000:10:02 Evans (onboard): Okay, H-Dot's a little bit low, but not bad.
Ron is noting that their vertical speed is a little less than desired. At this point in the flight, they should actually be descending a little, at 5 fps [-1.5 m/s]. It is unclear whether he means it is descending at a slower speed than this or whether it is still ascending to their high point.
000:10:07 Overmyer: 17; Houston. You are Go for orbit - Go for orbit.
000:10:11 Cernan: Those are kind words, Robert. We're Go for orbit here.
000:10:15 Overmyer: Good show, Gene.
000:10:18 Cernan (onboard): Okay, coming up on 3.0, Ron. Let's...
000:10:20 Evans (onboard): Okay.
000:10:20 Cernan (onboard): ...doublecheck everything.
000:10:21 - Coming up on 10 minutes, 30 seconds after lift-off and the spacecraft launch vehicle now 11,000 - 1,100 [nautical] miles [2,037 km], rather, downrange. Altitude, 93.4 [nautical] miles [173.0 km].
000:10:22 Evans (onboard): 3.0, 347 degrees. 23.9. Okay, we're a little bit high.
000:10:28 Cernan (onboard): I couldn't see a star if I had to right now.
000:10:29 Schmitt (onboard): I couldn't either. Velocity's a little high.
000:10:31 Cernan: Okay. 10:30 and we're Go.
000:10:33 Evans (onboard): H-Dot's a little high. A little bit low...
000:10:34 Overmyer: Roger, 17. You're looking great.
000:10:36 Cernan (onboard): Okay, the cutoff is VI plus 100. [Garble] copy [garble]...
000:10:37 Evans (onboard): VI plus 100. Okay, I'll count you down.
000:10:49 Cernan (onboard): I just want to hit the [garble] that's all there is to it.
000:10:52 - And we're about 1 minute from shutdown, about 1 minute from orbit insertion.
000:11:04 Cernan: Eleven minutes and we are Go.
000:11:06 Overmyer: Roger, Gene. And cut-off will be at 11 plus 47, 11 plus 47.
000:11:13 Cernan: 11 plus 47. Roger.
000:11:31 Cernan: Okay. 11:30 and we're Go here. And - Standing by.
000:11:35 Overmyer: Roger, Gene. Cut-off time is still holding good, 11 plus 47.
000:11:43 Cernan: Okay. Cut-off at 42.
000:11:47 Overmyer: Understand. Cut-off at 42. Roger. We copy.
000:11:54 - And that looked like a near nominal shutdown. At shutdown we show 25,600 feet per second [7,803 m/s]. That also looks very close.
Cernan, from 1973 Technical debrief: "Communications throughout the booster phase were excellent. I never had any problem hearing either Stony or CAPCOM. Controls and displays performed super. Crew comfort through powered flight - I felt very comfortable throughout the entire flight in orbit."
Cernan, from 1973 Technical debrief: "As far as I'm concerned, there was no pogo on the burn."
Evans, from 1973 Technical debrief: "No, none."
Cernan, from 1973 Technical debrief: "Summing up the birds. If you want to put them in more layman terms, I think the S-IC acted and performed like some big, old, rugged, shaky, big monster. It has to be noisy, has lots of vibration, and smoothed out somewhat after max-q, but still was a rumbling bird. The S-II was a Cadillac: quiet, less than 1g flight most of the time until we built up our g-load prior to staging. It was quiet, smooth, had very little noise, or feeling of rumbling or anything else. The S-IVB: a light little chugger is probably the best way I can describe it, which is not different than I remember it in the past. It just sort of rumbled on, not anywhere near the extent of the S-IC, but just sort of continued to rumble on through the burn. After a while, especially during TLI, it got to be a very pleasant, warm feeling that she was burning like she should burn."
Evans, from 1973 Technical debrief: "Chugging, I think, has two different connotations. I felt the S-IVB was more of a very light rumble in the background, something that is kind of rumbling as opposed to chugging. A chug to me is a bang-bang type thing, and to me it was more of a rumble."
Schmitt, from 1973 Technical debrief: "I agree, it may be a sense of rumbling but the ride was smooth. I could sense some activity behind it, but I wouldn't have said that it was chugging."
Cernan, from 1973 Technical debrief: "I'll modify chugging to say it was a hummocky chug, just a rolling type. Nothing different, and, as I say, the best recollection, similar to the S-IVB I had the opportunity to ride on before, but probably even more steady and continuous flow of light rumbling."
Members of Government-Industry team that launched Apollo 17 Saturn V space vehicle applaud remarks by Vice President Spiro T. Agnew in the Launch Control Center. Research: J.L. Pickering
000:12:00 Cernan: We're looking at 93.1 by 89.5 [nautical miles, 173.2 by 165.8 km].
000:12:07 Overmyer: Roger, Gene. We're copying the DSKY.
000:12:12 Cernan: Okay, Jack. Give...
000:12:16 - Gene Cernan reporting the onboard Indication of an orbit of 93.5 by 89.5 [nautical miles, 173.2 by 165.8 km]. Now we'll be getting tracking and confirming that here on the ground.
000:12:20 Overmyer: And the local horizontal maneuver has initiated, Gene.
000:12:45 Cernan: And, Houston, the - looks like the - tank pressures are venting.
000:12:54 Overmyer: Roger, Gene. The range safety is safe and we - you are in a Go orbit, nominal.
000:13:00 Cernan: Roger. Go orbit, nominal. Thank you.
Cernan, from 1973 Technical debrief: "Evaluation of insertion parameters - We got a good onboard orbit. Ground gave us a GO for orbit. The postinsertion systems configuration systems checkout and the complete spacecraft and booster preparation for TLI went extremely smooth and extremely rapid."
Cernan, from 1973 Technical debrief: "Earth orbit - I might comment that the availability of stars for a Mode II or Mode IV abort was pretty poor for two reasons. Number one: night adaptability because we had lights very bright. When we turned the lights down in the cockpit, I could not pick out distinct constellations such as Orion, which I was planning on using for a Mode IV abort. If we would have had an SCS and G&N problem, it would have been very difficult to pick out stars for that abort."
000:13:15 CC: And, 17, I'll be unable to update that AOS time, but 52:20 is looking good.
This is the time for Acquisition Of Signal (AOS) at the Carnarvon ground station in Australia.
000:13:23 Cernan: Roger.
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