Post-landing Activities

Down the Ladder

 

EVA-1 Preparations

Corrected Transcript and Commentary Copyright © 1995-2018 by Eric M. Jones.
All rights reserved.
Audio clips by Dave Shaffer. Last revised 15 January 2018.

Audio Clip starting at about 115:15:47

115:17:12 Cernan: Bob, we'll give you a call in a minute. We just made a couple of suit adjustments.

115:17:16 Parker: Okay. Copy that.

[Gene and Jack donned their suits at about 107:40, prior to undocking, and then donned their helmets and gloves at about 10 minutes prior to PDI. After the landing and once they were sure that the LM was in good shape, they took the helmets off at about 113:18, about 16 minutes after touchdown. However, since they plan to make a full EVA during this first day on the Moon, they have left their suits on and, as they will tell Houston in a couple of minutes, they are now adjusting drink bags and food sticks inside their neckrings for use once they get outside.]

[Comm Break.]

115:20:43 Cernan: Go ahead, Bob.

115:20:46 Parker: Okay, Challenger; we've just lost about 16 dB (decibels) on your high-gain signal strength there. We're wondering if you happened to hit the switch there, has it moved, or could you give us a check on it?

115:21:01 Cernan: We're nowhere near it. Stand by one. (Long Pause)

115:21:22 Parker: Okay. And, Challenger, that should be a Pitch of 21 and a Yaw of minus 45.

[Cernan - "The high gain (antenna) had a pitch axis and yaw axis. I don't think it had a roll axis. I don't think they were particularly related to the inertial axes of the spacecraft."]

[Gene's memory is correct. From the LM, Earth is at an elevation of 45 degrees and at a bearing 30 degrees south of west; therefore, these pitch and yaw numbers are not simply related to the direction of Earth in the local sky.]

115:21:38 Parker: Okay

[Long Comm Break. Based on Jack's mention of the Buddy SLSS (Secondary Life Support System), or BSLSS, at 115:27:18 and Bob's comment at 115:29:10, they are in the middle of the left-hand column of checklist page Surface 2-1. On this page they are stowing loose items, putting a 500mm lens on a Hasselblad camera, stowing film magazines and other gear in the Equipment Transfer Bag (ETB) which they will take outside with them, propping up a pair of cue cards for their pre- and post-EVA equipment procedures on the panel in front of them, turning on a heater for the urine disposal line - they will empty the urine collection bags in their suits when they get to the top of page Surface 2-5 - and attaching a lanyard (the LEC or Lunar Equipment Conveyor) to the ETB and clipping some pages containing emergency procedures to the instrument panel in front of them. These pages are 2-3, and 2-4.]

115:26:41 Parker: Stand by on that. (Pause) Leave it alone. It seems to have gone away, Jack. It may have been a ground problem. (Pause) Did you guys adjust it, Jack?

115:27:03 Schmitt: Yeah, Bob. (Mis-understanding the question) We had to fix the drink bags and a couple other things.

115:27:08 Parker: No. Did you guys adjust the high-gain antenna?

115:27:14 Schmitt: No. I didn't touch it.

115:27:16 Parker: Okay. Copy that.

[For the next few seconds, Jack thinks he is in the Push-to-Talk mode of communication but actually has a live microphone. Bob will call his attention to the fact in about a half minute.]

[The Buddy SLSS (Secondary Life Support System) is an apparatus which would allow the crew to share PLSS feedwater in the event that one of the PLSSs failed. The apparatus consisted of a hose to provide feedwater from the astronaut with the working PLSS to the astronaut with a failed PLSS. The apparatus also included a tether to couple the two suits together to avoid pulling loose the connection to either suit. See Gene's comments starting the the third paragraph below 115:44:19.]

115:27:30 Cernan: (Garbled) in there?

115:27:32 Schmitt: I thought it was over on your side. (Pause) Okay? (Pause) Okay, that's over there. Bigger than it used to.

115:27:51 Parker: And, Challenger, we have you hot miked.

115:27:57 Schmitt: Well, because ...(Hearing Bob) Huh?

[Comm Break]

115:29:08 Cernan: Go ahead, Bob.

115:29:10 Parker: Okay. When you guys get to the top of page 2-5...And I assume you're down still in the ETB, from what your comments were on the hot mike there. When you get to the top of page 2-5, we'd like you to put both Demand Reg's to Egress. Over.

[They are loading cameras, film, and other gear for the EVA into the ETB. By putting the oxygen demand regulators in the Egress position, they will cut off any addition of oxygen to the cabin except through the suit circuit. This is not a standard procedure at this point in the mission and Houston's request suggests they are checking some aspect of the ECS operation.]

115:29:29 Parker: Roger. Thank you.

[Comm Break]

115:31:05 Parker: Okay. I copy that. Never did find Ron's, huh?

115:31:11 Cernan: No, sir, and I couldn't just leave him up there starving to death.

115:31:15 Parker: Roger on that.

[This suggests that they are in the middle of the right-hand column of page 2-1.]

[Schmitt - "Each of us had a pair of scissors which normally traveled with us, but Ron lost his on the trip out from Earth. We had a lot of fun kidding him on the way out and all the way back about losing his scissors in a spacecraft which was, after all, not very big. But the complication was that the whole timeline on the surface was geared to having two pairs of scissors. With two pairs, Gene and I could leave one pair in the cabin and take the other pair outside - probably as a contingency tool - and not have to worry about taking it up and down (the ladder). However, because you needed the scissors to cut the plastic food bags, we finally condescended to leave one pair with Ron so that he could eat. And ultimately his scissors were found. I found them as we were preparing stowage for re-entry; but was able to signal to Gene that I'd found them without Ron knowing it. We continued to give him a pretty hard time and said that, in fact, we didn't think he'd lost them at all but he was trying to get away with these scissors as a memento of the flight and that ultimately the IRS (Internal Revenue Service) would be very interested in his activity. They were fancy, surgical scissors. At the splashdown party we had at the Flight Control Division - probably a month after the mission - we presented the scissors to Ron with great fanfare. We'd had to do an awful lot of preparation because, in order for the inventory of the spacecraft not to be confused, I had to let the crew assistance people in on the secret. I think what I did was put his scissors in my Personal Kit - my little bag of personal items. So there were two pairs of scissors in there. And that kit was supposed to come to us personally. That's probably what I did. I've forgotten exactly how we did the transfer without screwing up the inventory. It would have been a little hard to secretly carry the scissors up into the helicopter with us, because then, in the helicopter we changed out of our constant-wear garments into flight suits for our arrival on the carrier. So, I guess what I must have done is put the scissors in my flight bag."]

[Photo AS17-162-24096 shows a pair of scissors floating in front of Ron during the trip out from Earth.]

115:31:26 Parker: Stand by. (Pause)

[Bob consults with Bob Overmyer, the Command Module CapCom.]

115:31:48 Cernan: I'm glad to hear that. (Pause) That was no surprise, Bob. We wouldn't have taken it if it wasn't going to work.

115:32:02 Parker: I thought about that after I said it.

[Comm Break. Apparently, the sounder had been giving trouble either on prior flights, in pre-flight testing, or during pre-landing orbital activities. Obviously, it was not politic for Bob to mention these troubles on the air and Gene properly corrected him.]

115:33:12 Parker: Copy that. (Long Pause)

[Use of the heater keeps urine from freezing in the line before it reaches a sump in the descent stage. They have finished loading the ETB and are in the middle of the right-hand column of page 2-1.]

115:33:29 Parker: Beautiful. The Surgeon's happy.

[Comm Break]

115:34:42 Parker: Okay. We'd like you to have Demand Reg's, both of them, go to Egress, please.

115:34:49 Cernan: Yes, sir. (Pause) Okay, they're Egress now.

115:34:52 Parker: Okay, thank you.

[Comm Break. The controls are on a panel behind Jack's station at about waist height.]

115:37:43 Parker: Okay; copy that.

[Long Comm Break. They are verifying closure of their suit zippers and are getting their EVA boots out of storage at the back of the cabin. They have finished emptying the urine bags.]

115:44:19 Parker: Okay; we copy 5800. (Long Pause)

[The Oxygen Purge System (OPS) is an emergency supply of oxygen, mounted on top of the PLSS. The OPS contains 5.7 pounds of oxygen stored at high pressure, and is designed for use in the event of a partial failure of a suit seal, a suit puncture, or any one of several possible PLSS malfunctions. An actuator cable is mounted on the right side of the RCU and allowed the astronaut to open his OPS shutoff valve, thereby releasing high pressure oxygen to a regulator which then introduces oxygen into the suit at 3.7 psi. In the event of a non-critical failure, such as a slow suit leak or a failure of the PLSS regulator, the PLSS fan would continue to circulate oxygen and, although the crew would promptly return to the LM, there would be no great urgency. The OPS actually contains more oxygen than does the PLSS itself (1.8 pounds at 1400 psi for the PLSS), certainly enough for a few hours of operation. In the event critical failure, such as a loss of cooling, a suit puncture or even a complete PLSS failure, the astronaut could activate his OPS and open a purge valve installed on the lower right chest. The purge valve has two settings: a low flow setting of 4 pounds per hour and a high flow of 8 pounds per hour and, at the high setting would have oxygen and cooling for about 30 minutes.]

[Cernan - "The purge valve is nothing but a regulator, with two settings, in an open-loop system. You start with a supply (of oxygen) at one end and you regulate it out at the other end. It's just like a pressurized cabin in an airplane. In the case of an airplane, you pressurize the air from the engines, it goes into the cabin, and the pressure is controlled by an outflow regulator - which you could call a purge valve. It will stay closed if you need to get the pressure up, or it will open to dump as much incoming air as it has to keep the pressure to a certain level."]

[In circumstances where the astronaut's own PLSS still provided cooling or he and his crewmate were able to use the Buddy Secondary Life Support System (BSLSS) to share cooling water, he would use the low-flow setting and would have about one hour of oxygen available. The BSLSS consists of a set of hoses and connectors and is designed so that LCG cooling water can be shared while riding in the Rover. BSLSS connection procedures can be found on checklist page CDR-47. In the event that BSLSS can not be used, the purge valve would be put in the high-flow setting and the astronaut would have about 30 minutes of oxygen/cooling available.]

[Cernan - "At some point there had been a suggestion that we would have to stay close enough to the LM that we could get back in the case of a double failure of both the Rover and a suit. I didn't like that and, obviously, we (the Astronaut Corps) ended up winning the argument. There were lots of things you could do to share oxygen. Suppose that Jack's PLSS failed and he had to go on his OPS. The first thing I'm going to do is take my OPS off my suit and put it in his lap. Then I wouldn't have an emergency supply but he'd have two. I don't think that was ever written down anywhere, but if that had happened, he'd have had an hour of OPS oxygen and we would have been headed for home (the LM). That's the kind of thinking that went on. Now, particularly in the early Gemini days, we did stretch things and did some things that we would never do today. Do you think that we would go out today, in the Shuttle, in an EVA suit with a backpack with hot gas and you were so scared that the hot gas was going to burn a hole through your suit that you made the pants out of woven steel? But we did that in Gemini. Before we had more than twenty minutes of EVA experience, we were going to send somebody out - namely, yours truly - with a hot-gas backpack. With fire coming out. We were burning hydrogen peroxide. We were going to put fire down our suits."] [Journal Contributor Rene Cantin asked, in a 2012 e-mail, if the astronauts were prepared for a solo return to lunar orbit in case one of them died on the lunar surface, say from a fatal heart attack or a catastrophic suit failure. I asked Andrew Chakin is he was aware of any training the astronauts might have done for flying a solo ascent. He replied: "There's really nothing for the crew to do until the various burns, so we're really talking about solo rendezvous -- and now that I think about it, the CMP was trained to come get the LM as long as it achieved insertion -- so there's another reason such training would not have been required."]

[Jack Schmitt provides some additional thoughts: "By flying 100s of hours in the LMS (Lunar Module Simulator), both together and individually, we inherently were cross-trained to fly solo. The checklists would lead you through it with help from Mission Control if you needed it and had comm. We did train for a CSM active rendezvous in several mission simulations and Evans trained for this by himself a lot. The main problem with any suit failure (puncture, cable break) or incapacitation during EVA would be getting the affected crewman up the ladder, through the hatch, and back into the LM. That actually might have been something to train for, but we never did."]

115:44:50 Parker: (Making a mis-identification) Copy that, Jack.

115:44:57 Cernan: (Retaliating) Okay, Hank. (Long Pause)

[Gene recalls that Bob had a great deal of trouble telling the two of them apart during simulations. Hank Hartsfield was an Air Force pilot who, with six colleagues, joined the Astronaut Corps when the Air Force's Manned Orbiting Laboratory program was cancelled in 1969. He first flew in space, as a Shuttle Pilot, in 1982.]

115:45:35 Parker: Copy that, Challenger.

[Long Comm Break]

[As indicated in the OPS checkout procedures in Section 4.2.1 of Volume II of the Apollo 15-17 EMU Handbook, the expected OPS regulator gage reading is 3.7 ± 0.30 psi. Jack is alerting Houston to the fact that both OPS readings are near the upper end of the range.]

115:50:02 Parker: Okay. Copy that, Challenger.

[Long Comm Break. They are in the middle of the right-hand column of Surface 2-5. An anti-fogging agent is wiped on the inside of the bubble helmets prior to each EVA. The helmet assembly consists of the clear, bubble helmet which is an integral part of the pressure suit, a visor assembly, and an outer, white-colored, thermal protection layer. Meanwhile, Houston is still fiddling with the estimated landing site coordinates. They are now giving DM.6, 82.1. People in the back room are still trying to make sense of the crew descriptions and now seem to be giving greatest weight to the supposed location relative to Rudolph and Trident 1.]

115:57:16 Parker: Okay. Copy that, Challenger.

[Comm Break. Because they will soon don their helmets, they can now get the helmet storage bag out of the way. "BRA" is probably an after-the-fact, made-up acronym. It was a mesh bag with two compartments and was used to keep the helmets out of the way during in-cabin operations. The name undoubtedly comes from its resemblance to a brassiere.]

[That is, they are putting on Jack's backpack. They are at the top of page 2-6.]

[Very Long Comm Break]

[The following audio sequence was accumulated in Houston using voice-activated circuitry.]

116:10:17 Cernan: Okay. The LMP has got the RCU connected to the PLSS.

116:10:25 Parker: (Making a mis-identification) Copy that, Jack.

[Comm Break. They are near the top of the right-hand column of page 2-6. They have mounted a Remote Control Unit on Jack's suit chest and are making connections to the PLSS. The top surface of the RCU has an oxygen quantity gauge, an oxygen fan switch, and a variety of warning flags. Communications switches are located on the bottom and the switch which controls the flow of PLSS water through the Liquid-Cooled Garment is on the left side. Once outside the LM, Gene and Jack can mount their 70 mm cameras on brackets attached to the front of the RCUs.]

116:11:48 Parker: Okay, Geno. Copy that.

[They will now repeat the PLSS donning procedures for Gene.]

[Cernan - "Getting the PLSSs on was very difficult. It was a two-man operation. The PLSSs were strapped to the side walls, at working height, and you had to back up against yours and the other guy would then unhook it from the wall and help you get it strapped to your back. The LM was so small that it was a very difficult operation, even in soft (unpressurized) suits."]

[Gene is partly mistaken. While his PLSS was stowed on the wall behind his station, until they started EVA-1 preps, Jack's PLSS was secured to the floor immediately aft of the hatch. Frank O'Brien has provided photos he took in 2002 at the Cradle of Aviation Museum of a LM simulator, showing the LMP PLSS ( 0.7Mb ) and the CDR PLSS ( 0.7Mb ) is the stowed positions.

[They are checking to make sure that Gene's PLSS sublimator exhaust is clear. The sublimator, which provides suit cooling, is described in more detail at 116:52.]

[Very Long Comm Break]

[Gene's next transmission is not present on the PAO tape used to generate the audio clip.]

[Note that this is a separate checklist from the Lunar Surface Checklist which has been in use up to this point. Both contain the same EVA prep information but the EVA prep list is printed on stiff cards which are much easier to handle than the relatively bulky book which contains the full list of procedures to be followed while the crew is in the cabin. In the Surface Checklist, they are starting the section labeled "PLSS Comm Check" on page 2-6. The Powerdown Circuit Breaker configurations are shown on pages 1-4 and 1-5.]

116:23:00 Cernan: Circuit breakers are configured.

116:23:07 Parker: Houston copies.

[Comm Break. Once they have verified the circuit breakers, they start the comm check, beginning with Jack. We don't hear any of this activity until they get to the section labeled "Audio (CDR)" in the middle of the left-hand column of page 2-7.]

116:25:38 Parker: That's affirm. Loud and clear. (Pause)

116:25:48 Cernan: (To Jack) Just Audio breaker. Your Audio breaker, that's all. Want some help with that? (Long Pause)

[Here, Jack gets off of LM comm and on to PLSS comm. They are at the top of the right-hand column of page 2-7.]

116:26:35 Parker: Roger. We're following you. (Long Pause)

[The next item is closing Jack's audio circuit breaker.]

116:27:16 Schmitt: A.

116:27:17 Cernan: Okay; tone, On; Vent Flag, P.

116:27:20 Schmitt: Got a weak tone and a Vent Flag, P.

116:27:24 Cernan: Okay.

[The tone and flag indicate that Jack's suit isn't pressurized and also show that the sensors and indicators are working.]

116:27:25 Cernan: Press Flag, O; and O2...

116:27:26 Schmitt: (Garbled) O and...

116:27:28 Cernan: ...momentarily.

116:27:29 Schmitt: ...O2 (Flag) still there.

[The oxygen warning flag indicates that there is no oxygen flow to the suit. It is supposed to appear in the RCU window briefly and then disappear. This is indicated in the next to the last line on Surface 2-7. Press Flag - O, O2 Mom. Most of the astronauts vocalized "Mom" as "momentary". For example, see 142:06:07 during Apollo 16 EVA-2 Preps.]

116:27:32 Schmitt: It's gone.

116:27:35 Cernan: What's your PLSS O2 pressure gauge?

116:27:37 Schmitt: The O2...

116:27:39 Cernan: Give Houston a call and give it to them.

116:27:40 Schmitt: I'm reading 100 percent, Houston.

116:27:43 Parker: Roger, Jack. And we're reading you slightly garbled but loud.

116:27:50 Schmitt: Okay. Well, you're loud and clear, Bob.

116:27:54 Cernan: Okay, Jack. You got that, and I'm reading you. How you reading me?

116:27:57 Schmitt: You're loud and clear.

116:27:59 Cernan: Okay. We will not unstow the (PLSS/OPS) antenna. You are a skosh garbled, but very readable. (Pause) Okay. Stay where you are. I'm going to get mine. Okay. Audio breaker is...

[Comm Break. The checklist suggests raising Jack's PLSS antenna if comm is too garbled, but they decide that the comm is acceptable. Having made the audio check on Jack's PLSS comm, Gene now pulls his Audio circuit breaker, going off LM comm for a few minutes until he gets his own PLSS comm hooked up.]

116:29:37 Cernan: B. Okay. I got a tone.

116:29:38 Schmitt: (Reading from the checklist) "Vent Flag, P."

116:29:39 Cernan: I got a Vent Flag, P.

116:29:41 Schmitt: "Pressure flag and O2 momentarily."

116:29:43 Cernan: Pressure flag, and I still got an O2 Flag.

116:29:46 Schmitt: Off with your tone.

116:29:47 Cernan: Okay. The tone is gone. The O2 flag cleared.

116:29:50 Schmitt: Okay. "PLSS O2 quantity."

116:29:53 Cernan: Okay; and I'm reading 100 percent.

116:29:57 Schmitt: Okay.

[They are now at the top of page 2-8.]

116:30:06 Parker: Roger, CDR. Houston reads you loud and clear.

116:30:13 Schmitt: (Still broken as heard in Houston) I read you loud and clear, Gene. How me?

116:30:16 Cernan: I'm reading you loud and clear.

116:30:17 Schmitt: Okay.

116:30:18 Cernan: Give me a call again.

116:30:19 Schmitt: Okay. How do you read, Gene? 1, 2, 3, 4, 5.

116:30:22 Cernan: Give me again.

116:30:23 Schmitt: 1, 2, 3, 4, 5.

[Because they don't yet have their helmets on, Gene can't be absolutely certain that he's hearing Jack through the comm system or directly.]

116:30:32 Schmitt: Going B. (Pause) Try that. B ...

116:30:45 Cernan: Okay. How do you read me, Jack.

116:30:47 Schmitt: (Comm much improved) You're loud and clear, and I got a tone.

116:30:52 Cernan: Okay. Give me a short count once.

116:30:54 Schmitt: Counting. 1, 2, 3, 4, 5.

116:30:58 Cernan: You're great.

116:31:00 Schmitt: Okay.

116:31:01 Cernan: I had a tone, too. I still got a Pressure and a Vent Flag.

116:31:03 Schmitt: And, Houston, how do you read the LMP?

116:31:06 Parker: Roger, LMP. We read you loud and clear.

116:31:10 Cernan: Okay, Bob. I'm reading you loud and clear, and he's not reading you in this mode. How me?

116:31:14 Parker: I read you loud and clear also, Gene.

116:31:19 Cernan: Very, very, good. We're both going AR, now. Let's go.

116:31:23 Schmitt: Okay.

116:31:24 Cernan: Ought to get a tone.

116:31:26 Schmitt: I didn't, but my Vent Flag did clear.

116:31:28 Cernan: There it is. Tone and a Vent Flag.

116:31:31 Schmitt: There's my tone and Vent Flag.

116:31:33 Cernan: Okay, Jack. The wheel is Houston and the blade is me. Hello there, Houston. How are you reading CDR?

[Cernan - "There were two volume controls on the RCU and we obviously had Jack's switches set so that the wheel-like control controlled the volume on his comm circuit to Houston and the blade-like control controlled his circuit with me."]

116:31:52 Schmitt: Okay.

116:31:53 Cernan: (Garbled)...

116:31:54 Schmitt: How do you read, Houston? This is the LMP.

116:31:57 Parker: Houston reads LMP loud and clear now. You're much clearer than you were before, Jack.

116:32:03 Schmitt: Very good.

116:32:05 Cernan: Okay. Jack, we gave them our (oxygen) quantities already; so, Squelch, VHF B LMP, Full Decrease.

116:32:11 Schmitt: Squelch B is to Full Decrease, huh?

116:32:14 Cernan: That's affirm.

116:32:16 Schmitt: Okay. It's Full Decrease.

116:32:17 Cernan: Okay. On (circuit breaker panel) 16 ( CB(16) ), leave that (Liquid Cooled Garment) Pump breaker Closed.

116:32:19 Schmitt: Okay.

[Up to now, the circuit breaker for the LCG pump has been open. By closing it, they turn the pump on and get a flow of cool water next to their skins.]

116:32:27 Schmitt: Okay. Is that a verify?

116:32:29 Cernan: That's a verify.

116:32:30 Schmitt: Okay. It's Closed.

116:32:31 Cernan: Suit Fan Delta-P, Open.

[This circuit breaker controls a sensor which responds to a pressure difference (delta-P) across the suit circuit fans.]

116:32:34 Cernan: And Suit Fan number 2 (circuit breaker), Open.

116:32:36 Schmitt: 2's open.

[For redundancy, there are two fans in the suit circuit. Prior to this point, both circuit breakers had been closed and the fan selector switch had been set to fan number 1. Here, they are opening the circuit breaker for fan number 2 and then selecting for the disabled fan.]

[Cernan - "The 'fan' was a circulatory pump that moved oxygen through the suit hoses. What is happening here is that we are disconnecting ourselves from the spacecraft ECS (Environmental Control System). We've turned off the suit fans by pulling a circuit breaker because, without oxygen flowing in from the spacecraft, the fan wouldn't be pumping anything and might cavitate and burn out; plus, the fan would also use battery power and we wanted to conserve that. We had two indications that the fan was off. One was the simple fact that we could hear it, and the other was the Master Alarm which, of course, we expected. With us disconnected from the spacecraft, the sensing system thought that the fan had just failed and gave us the expected warning."]

[They are also waiting for a sensor to indicate that the water separator has run down. Next, Jack will change the settings of various ECS valves located on panels behind him.]

116:32:57 Schmitt: Okay. Diverter is Pull-Egress.

[Here, they are closing a valve which, in the Cabin setting, would allow oxygen to flow out of the suit circuit and into the cabin. It is a push-pull valve. With the valve pushed in, it is in the Cabin position. It is pulled out for Egress.]

116:33:03 Schmitt: Return is Egress.

[Here, they are closing a valve which, in the Open or Auto positions, would let oxygen flow from the cabin back into the suit circuit.]

116:33:07 Schmitt: Relief is Auto.

[In the Auto position, this valve will open if the pressure in the suit circuit exceeds 4.3 psi and will vent the excess oxygen to the cabin. They have reached the bottom of page 2-8 and are about to connect their OPSs. Although they are using cue cards, the procedures they will do next are also shown on 2-9).]

116:33:17 Schmitt: Yep.

116:33:18 Cernan: Okay. Suit Isol(ation Valve), Activate Override.

116:33:21 Schmitt: Okay. Override.

[The Suit Isolation Valve has been in the Suit Flow position so that oxygen could flow from the suit circuit into the suits. In the event of a suit circuit malfunction, a signal from a pressure sensor would release a spring-loaded activator which would return the valve to the Suit Disconnect position, thereby isolating the suit so that the astronauts could hook up to an OPS or a PLSS. Here, they are about to disconnect the LM O2 hoses and need to manually close the isolation valve by pushing the Actuator Override lever.]

116:33:26 Schmitt: Okay. LM O2 hoses are disconnected.

116:33:28 Cernan: Okay. And they're stowed, right?

116:33:29 Schmitt: Right.

[Because the ECS is behind them and the hoses come from behind them, they will stow the hoses somewhere to the rear of the spacecraft.]

[The Pressure Garment Assembly (PGA) is the suit. They are mating the blue end of the hose to a blue connector in the suit torso.]

116:33:34 Cernan: Okay. It's sticking right...Turn around. No, that's not right.

116:33:37 Schmitt: No, that's the water.

116:33:39 Cernan: Could you turn towards me a little bit? Turn to the left. There you are, because I got to...Okay. Here it comes, right here. OPS hose under...No; right here.

[They are putting the OPS hose under Jack's arm.]

116:33:50 Cernan: Let me get it. I'll get it under your electrical cable. (Pause) Because you're going to want a purge valve in a minute.

[The purge valve is used in the case of a PLSS failure to make a purposeful hole in the suit so that oxygen from the OPS would flow.]

[Each of the hose connections has a ring lock and, in the ring, a 'lock-lock' which ensures that the ring won't accidentally rotate open.]

116:34:05 Cernan: I will in a second. (Pause) Move your arm. I can't see.

116:34:08 Schmitt: I'm trying to. (Pause)

116:34:19 Cernan: Okay. We're right here (on the checklist). Okay. And I'm going to "Connect OPS hose to PGA blue to blue, retrieve Purge valve." Let me give you a purge valve, and I'll pick that up, Jack. The cockpit's just as small as the mock-up. (Handing Jack the purge valve to verify it's set properly) Okay. Here you are. You verify it's in Low (flow). (Confirming that he's read the checklist properly) Low.

116:34:37 Schmitt: Okay. It's in Low.

116:34:40 Cernan: Slip to the right just a skosh.

116:34:41 Schmitt: Yeah; slipped it to the right just a skosh.

116:34:44 Cernan: Oh, man, that's easy.

116:34:47 Schmitt: (Laughing) Whee. Okay. Pin's installed. (Pause)

[Jack has installed a one-inch-long latching pin in the purge valve.]

[Cernan - "Here, we were pre-cooling ourselves with spacecraft water before we disconnected. We didn't turn the sublimator on until we got the cabin depressurized and the hatch opened. The sublimator wouldn't work if it wasn't in a vacuum."]

[The sublimator will not work efficiently unless the cabin pressure is very low. On Apollo 12, moments after Pete Conrad had gone down the ladder to the surface, Al Bean accidentally knocked the hatch shut while he was making a final check of cabin before going out himself. During the next few minutes, the sublimator put out enough water vapor that, despite outflow through the dump valve, there was enough of a pressure build up in the cabin to inhibit further operation of the sublimator. The pressure build up was very slight and Bean had no trouble re-opening the hatch.]

116:35:06 Cernan: Okay. (Verifying his own purge valve) My Purge valve's (set in the) Low (flow position), (It's) locked, and the pin's in. (Pause) Want some help with that? I want to take a look at it.

116:35:18 Schmitt: There's the old Master Alarm.

116:35:21 Cernan: Okay. That should be the Water Sep(arator).

116:35:22 Schmitt: Yeah.

[The suit circuit contains a redundant pair of water separators, located downstream of the suit fans. The separators remove excess water from the oxygen stream. A caution light has just come on to indicate that the separators are no longer working. The response has come about three minutes after the fans were turned off. The nominal interval is about one minute.]

116:35:24 Schmitt: Yeah. It's barely on. You're going to have to push my lock-lock down.

116:35:29 Cernan: I'll get it.

116:35:30 Schmitt: I don't know why, but...

116:35:31 Cernan: Why don't you check mine, too. Let's see it. I'm going to have to check you anyway.

116:35:37 Schmitt: See if I can turn it this way.

116:35:39 Cernan: Okay. (Long Pause) That's why; because it wasn't locked. Is that where you want it; facing down or in? You don't want it there, do you?

116:36:08 Schmitt: No, I don't want it there. Must have had it in the wrong...(Garbled, possibly with a "Thank You" in the garbled section) (Pause)

116:36:11 Cernan: Is that the way you want it?

116:36:11 Schmitt: Yeah.

116:36:12 Cernan: Okay. It's there.

116:36:13 Schmitt: Good.

116:36:14 Cernan: The lock-lock is down and it's verified Low (flow) and the pin still is in. Okay. Look at mine while you're there.

116:36:25 Schmitt: Okay. It's facing in. Lock's in. Stand by; it's Low (flow). Pin's in; it's good.

[Now, they will connect Gene's OPS.]

116:36:46 Schmitt: Okay.

116:36:47 Cernan: I think that'll be better, isn't it?

116:36:49 Schmitt: Yup. Okay. It's there and locked.

116:36:54 Cernan: Verify lock-lock.

116:36:56 Schmitt: It's locked.

116:36:57 Cernan: Okay.

116:36:58 Schmitt: And the (dust) cover is going on (over the connector).

116:36:59 Cernan: Okay. (Pause) Look pretty good under that...

116:37:04 Schmitt: Yeah, it does.

116:37:05 Cernan: Yeah. That's fine.

116:37:06 Schmitt: Good. Okay. You're covered.

116:37:10 Cernan: Okay. I think we're getting to our favorite part here. (Laughs)

[Cernan - "We were getting ready to put the helmets on and pressurize the suits; and that was never a favorite part inside the Lunar Module because it was so hard to move around. With two guys in pressurized suits and both wearing PLSSs, it was almost impossible to move."]

116:37:20 Schmitt: Okay. It's vertical.

[As shown in Figure I-23 in the EMU Handbook, the diverter valve is part of the oxygen inflow connector and gives them the option of directing the PLSS oxygen flow entirely into the helmet (the vertical position) or partly into the suit torso (the horizontal position). Generally, the astronauts put the diverter valve to horizontal only when they were in the cabin and were trying to dry the suits out a little. In the hoizontal position, used in the cabin, all the incoming oxygen stream is divided between a duct leading to the helmet vent and a duct leading the vents in the torso. In the vertical position, used outside, all the oxygen goes to the helmet vent. Figure I-10 from the EMU Handbook shows the layout of the ducts.]

116:37:27 Schmitt: Okay.

["Commander repeat" means repeat OPS connection and purge valve installation procedures on Gene's suit. They've just finished doing all of that, so they now take a final drink from the descent-stage water supply before shutting it off.]

116:37:41 Schmitt: Oh, those little jar covers are next. (Pause) Okay. (Long Pause)

[We have been unable to translate "little jar covers".]

116:38:09 Cernan: (I've) had enough water today (that) you could say you discovered me. I'm "water on the Moon". Okay. Let's turn the descent water off, and let's stow this ( water gun (photo by Mick Hyde) and hose).

[One of the important discoveries made from the Apollo samples was that the lunar rocks and soils are extraordinarily dry, lacking even water locked up in mineral structures that one almost always finds in Earth rocks. Because a local source of water would be very useful in the operation of a permanent lunar base, discovery of water of any kind would have been of great interest.]

[Jack is closing the valve on the Descent Stage water tank.]

116:38:34 Schmitt: Okay; mikes are good.

116:38:35 Cernan: Top of the page.

[They are starting the top right-hand column on the cue card. In the Surface checklist, which contains the same information, they are starting the section labeled "Helmet/Glove donning" at the bottom of the left-hand column of 2-9.]

116:38:45 Schmitt: No, not in my way.

116:38:47 Cernan: Pretty good. Let's...

116:38:49 Schmitt: (Garbled) though. Do you want to put this (garbled)?

116:38:53 Cernan: Yeah. (Pause) That's probably a little bit better.

116:38:58 Parker: 17, Houston. Over.

116:39:00 LM Crew: (Garbled)

116:39:03 Schmitt: Go ahead, Houston.

116:39:05 Parker: Roger. We're still seeing the commander's Suit Disconnect valve's in Connect. (Pause)

[Houston has noticed that the valve setting is incorrect. There is some telemetry from the ECS but very little from the suits: water and oxygen quantities and water temperature, only.]

116:39:17 Parker: Yep, there it goes. We got it. Thank you.

116:39:22 Cernan: Okay, Bob. (Pause) (To Jack) Okay. We got to get the PLSS fan on. Don't forget that's (operating on PLSS) battery power. (Reading) We can don our helmets, check our drink bags, don our LEVAs, protective visors (down), secure our tool harness. (Pause) Our O2 umbilicals are already stowed. CDR's under the handhold. Verify the following. Now, where we pick up our...(Pause)

116:39:54 Schmitt: Have to put the helmets on, I think.

[Schmitt - "The helmet itself was a clear plastic bubble with a padded head rest inside at the back. The Lunar Extravehicular Visor Assembly (LEVA) was everything else that sat on top on the helmet. It contained the sun visors and also passive thermal protection."]

116:39:58 Schmitt: I reckon.

116:40:00 Cernan: Yep, there it is. Okay. Well, let's do one at a time here.

116:40:05 Schmitt: That's mine.

116:40:06 Cernan: That's yours. Okay. Do you want to turn your (PLSS) fan on for circulation (in the suit)?

116:40:11 Schmitt: Well, I guess I better. Fan's on.

116:40:13 Cernan: I'll pull this out just to get it out of your way.

116:40:15 Schmitt: Okay. (Pause)

116:40:24 Cernan: Okay. Okay. All your candy bars and lemonade, and all that jazz are all clear. Water, I should say. (Pause)

[Cernan - "We were going to be locked in the suit for maybe nine hours and we had a little water bag that we suspended from the inside rim of the suit. The bag hung on your chest and had a little one-way valve on the top of it so that you could turn your head and take a drink. It was like sucking on a nipple. And then we also had one of these high protein or high calorie sticks shaped like a ruler. It was a soft stick and you could chew it. We had it inside a little bag, and it was probably about eight inches long. It, too, was Velcroed just inside the helmet ring and we could put our chin down and pull a little bit out with our teeth, take a bite, chew it for some energy. It was typical candy-tasting stuff. It was nice to be able to suck up a few ounces of water now and then and have something to chew on. That was it; I mean, we had no way of eating or drinking anything other than that. But having some water and a little candy was a real help; it really was. I remember that both the 15 and 16 crews had trouble with their drink systems. We didn't have any problems that I can remember; and I remember that, in training, it had to do a lot of times with the way you placed the bag. I don't think there were any great design changes; although, maybe, the one-way valve was worked over."]

[The in-suit drink bag was first used on Apollo 14. On Apollo 15, both Scott and Irwin had trouble getting theirs to work properly. Post-flight testing indicated that "the problem was associated with the positioning of the in-suit drinking device within the suit. After each EVA, the in-suit drinking device was removed from the suit and all of the water consumed, thus verifying proper operation of the in-suit drinking device valve. Ground tests using suited subjects and other equipment configurations indicated that the existing equipment provides the optimum configuration. The tests also showed that personal experience is essential to obtaining optimum individual positioning. Crew training is to include more crew experience in making the position adjustment required for the individual's needs."]

[While getting suited for Apollo 16 EVA-1, John and Charlie forgot to install John's drink bag before he got the suit on. Once he was suited, they realized their mistake and, after some difficulty, got it installed. However, during the EVA, John was unable to reach the drink valve and went without water until they were back in the LM. They got his bag properlay installed for the two other EVAs and was able to quench his thirst from time to time.]

[After Apollo 16, the crew wrote that "on each occasion that the drink bag was installed in the suit, the crew encountered leakage due to interference between the drink bag nozzle and the left microphone boom. In the case of the Lunar Module Pilot, this interference resulted in an estimated 4 to 5 ounces of orange juice leaking on (the inside of) his helmet, his face, and the pressure suit neck ring. After the second EVA, the effect of leaking orange juice on the neck rings of both crewmen caused both pressure suit helmets to be practically impossible to remove. It was necessary to thoroughly clean the helmet neckring with water to remove the orange juice. The drink bags carried in the suit are a necessity to provide the crew with liquid while they are working 7 to 8 hours on the lunar surface, but the bags must not leak." The Apollo 16 mission report is otherwise silent on the matter of the drink bags and it seems likely that an effort was made prior to Apollo 17 to make sure that the crew understood exactly how to position the bags to avoid either the Apollo 15 or the Apollo 16 problems. The effort was successful, because neither Gene nor Jack had any troubles with their drink bags. Note that the Apollo 15 and 17 crews had water in their bags. Because of heart irregularities noted in both Scott and Irwin - although far more noticeably in Irwin - which were ultimately traced to a potassium deficiency, the Apollo 16 crew had potassium-laced orange drink in their drink bags. However, because of the problems they had with the sticky juice, Gene and Jack got their extra potassium in their meals and used only water in their drink bags.]

[There is a solid, audible click as Jack's helmet locks into place.]

116:40:51 Schmitt: Guess so.

116:40:56 Cernan: Okay. Enjoy it in there; you're going to be in there for a few hours.

116:41:01 Schmitt: Can't think of any place I'd rather be right now.

116:41:04 Cernan: Sounds like you're in there, too. Oh, too far back. Okay, that's better. (Pause) I'm freezing my "you-know-what" off.

116:41:16 Schmitt: Me, too. (Both laugh)

[They are still pre-cooling themselves with spacecraft water.]

116:41:21 Schmitt: Looks pretty good.

116:41:23 Cernan: Okay. Let me...

116:41:24 Schmitt: Wait a minute. (Pause)

116:41:30 Cernan: (Grunting) Let me get this down around. Okay. That's around behind you; thermally protected back there. That's below the OPS hose.

[Gene is adjusting the back flap of Jack's LEVA.]

116:41:47 Cernan: Okay. You're thermally...Let me double check that. The helmet is locked. Your visor is locked. It's one thing you don't want to lose among some others. (Pause) Okay. Okay, you want to give me a hand?

116:42:11 Schmitt: Not particularly. (Laughs)

116:42:15 Cernan: (Possibly referring to something that's blocking the neck ring) Oh, man. Where did that come from?

116:42:20 Schmitt: Watch your nose, drink bag, candy bars, popcorn! (Pause) Click, click, click.

116:42:33 Cernan: Squeeze hard back there.

116:42:35 Schmitt: Want your fan (on)?

116:42:36 Cernan: Yep.

116:42:39 Schmitt: Looks good.

116:42:40 Cernan: Okay. I can hear the fan running. Oh, man. Whew! (Long Pause) Looks good here.

116:43:21 Schmitt: Yeah. That's all right.

116:43:23 Cernan: There you go.

116:43:25 Schmitt: It's new. Never been used before!

116:43:27 Cernan: Make sure that (LEVA) flap in back goes below that OPS hose. (Pause)

116:43:36 Schmitt: Want to put your protective visor down? (Pause)

116:43:44 Cernan: Yeah, if you got that thing all...You got it all down?

116:43:47 Schmitt: Yep.

116:43:49 Cernan: You happy with it (the LEVA flaps) back there?

116:43:50 Schmitt: Yes, sir. You're nice and protected.

116:43:52 Cernan: Okay.

116:43:54 Schmitt: Good Velcro. Okay. You're all covered here.

116:43:59 Cernan: Okay. Not my other one is it? No.

116:44:01 Schmitt: No.

116:44:02 Cernan: Okay. Ohhh! (Pause) I think we've got to get tool harnesses here. "Don LEVAs." Look at that scratch right in the middle of that thing. Okay. "Don LEVAs and lower protective visor."

116:44:21 Schmitt: Okay.

[They are near the bottom of the lefthand column on page 2-9.]

[The self-doffing straps are secured to the side of the visor assembly and can be used to release the tool harness.]

116:45:17 Cernan: Okay. You check me. I'll read them. "Helmet and visor, aligned and locked."

116:45:22 Schmitt: Okay. That's locked.

116:45:23 Cernan: Okay. O2 cover's all locked. There's a peek at them.

116:45:28 Schmitt: That's locked.

116:45:31 Cernan: "Purge valve"; everything down there.

116:45:33 Schmitt: That's locked; that's locked.

116:45:36 Cernan: "Comm carrier."

116:45:37 Schmitt: Stand by. That's locked.

116:45:39 Cernan: Okay. "Diverter Valve is vertical."

116:45:41 Schmitt: Comm is that way. Diverter Valve is vertical.

[With the selector in the vertical position, Gene is getting all of his oxygen flow into his helmet. With the valve in the horizontal position, he would direct part of the air flow into the torso.]

116:46:25 Schmitt: Okay. Comm; you checked, too.

116:46:29 Cernan: Yes, sir.

116:46:30 Schmitt: Okay. Verify your old white dots.

116:46:32 Cernan: Okay. Old white dots. My old white dots (pause) look good to me.

[Cernan - "I think that, in order to make things easier and save time, all of the circuit breakers that had to be opened for an EVA were indicated with a white dot (on checklist pages 1-4 and 1-5). That way we could just go down the panel and shut off all of the things that we didn't want running while we were out on the surface. And all the switches that had to be changed had decals on them to show the proper EVA positions. It not only saved time, but it also cut down on mistakes; it was a lot riskier to read down a list of breakers that had to be pulled and switches that had to be thrown than to just take care of all the ones with white dots or decals. You'd done all the thinking ahead of time and, when it really counted, you almost didn't have to do any thinking."]

116:46:40 Cernan: Yeah, I'll move.

116:46:41 Schmitt: Okay.

[Jack needs to turn so that he can look at his circuit breaker panel. With both of them in suits and wearing PLSSs, there isn't much room to spare and Jack needs to have Gene change his position slightly so that he can turn.]

116:46:48 Schmitt: That's right. (Pause)

[This is a reference to training exercises. They had practiced donning full-sized PLSSs inside the LM and then trade those for smaller, lightweight units once they were outside. Danny Schaiewitz was the engineer who handed them in. He worked for the manufacturer, Hamilton-Standard. According to Ed Brisson, who headed up the Hamilton-Standard operation at the Cape, Schaiewitz was well liked by the crews and socialized with many of them. Some of the other suit techs and engineers who were involved in Apollo 17 were Hamilton-Standard employees Jeff Robert, Ray Arnold, Gerry Goldstein, and NASA employees Al Rochford (shown with Al Shepard on 31 January 1971), Byron Smith, and Troy Stewart. The NASA engineers who made up the so-called Integration Team and made sure that the equipment and procedures used in training and in flight were all compatible included Dave Ballard (Team Leader, shown with the crew at the pre-launch breakfast on 6 December 1972), Terry Neal, Ray Malone, John Covington, Dan Bland (shown at a simulator console on 29 August 1966) , Ron Blevins, and Jim Ellis. This list was provided by Brisson and Rochford with additional information from Neal.]

116:46:57 Cernan: Okay. I want the EVA decals, also, Jack.

116:46:59 Schmitt: Yup.

116:47:00 Cernan: White dots plus decals.

116:47:02 Schmitt: Rog.

116:47:04 Cernan: Okay, Bob, we're turning the page (that is, turning the cue card over).

116:47:07 Parker: Roger. We're right with you. (Long Pause)

[In the Surface Checklist, they are in the middle of the right-hand column of 2-9.]

116:47:25 Cernan: Okay; on...

116:47:27 Schmitt: Is that it?

116:47:29 Cernan: That's it. "Don EV gloves." Doing a little greasing in here.

[Gene used lubricants on both the wrist rings and on his hands to protect them from abrasion. Here, he is probably greasing one of his hands. Jack used nylon glove liners in an effort to protect his hands. Note that Gene and Jack have taken care of all of the circuit breakers and switches prior to donning the bulky gloves.]

116:48:20 Schmitt: (Laughs)

116:48:21 Cernan: What?

116:48:26 Schmitt: Guess what?

116:48:28 Cernan: They don't go on any easier in one-sixth g, do they?

116:48:30 Schmitt: They break just as easily, too.

[One of the glove tie-straps may have broken. If so, it is a matter of no great importance.]

116:48:43 Schmitt: I never had that happen in training; you did.

116:48:47 Cernan: It's locked. That's about as locked as it can go. Boy, I'd hate like the devil to have that (glove lock ring) pop open. Okay; that's very good. You want me to help you with one, or can you get it?

116:49:04 Schmitt: Well, I don't know. I've only worked on one so far.

116:49:08 Cernan: I've got a free hand before I grease it up.

[Cernan - "I'd gotten one of my gloves on at this point, so this was my last chance to help Jack with an ungloved hand."]

116:49:25 Cernan: I'm telling you, from the looks of that soil out there, that drill may have a job ahead of it.

116:49:29 Schmitt: Yeah, I didn't have a chance to mention that. I don't think the regolith is very thick, and I think you've got rocks below it. (Pause)

[During this EVA, Gene will drill three 2.5-meter-deep holes, two for a heat flow experiment and one for a deep core. If the soil layer had been thinner than 2.5 meters, Gene would have had a difficult drilling task ahead of him. However, as Gene's drilling and other bits of information will show, the soil is actually about 5 meters deep and he will have relatively little difficulty.]

116:49:38 Schmitt: Well, how does it look?

116:49:40 Cernan: Let me take a look. (Pause) No.

116:49:45 Schmitt: Didn't make it, huh?

116:49:47 Cernan: Yeah, well, let me...Hold your hand up here. Hold it up here.

[Gene is helping Jack don his glove.]

116:49:55 Schmitt: Good over here.

116:50:56 Cernan: Okay. Let me pull this (wrist cover) down for you. (Pause) Okay?

116:50:08 Schmitt: Thank you.

116:50:12 Cernan: Get the old other hand. (Long Pause)

116:50:52 Schmitt: Okay. That's locked. (Pause)

116:51:03 Cernan: And my other glove is locked. (Pause) Now for the fun in back. (Laughing) Oh, me; oh, my. (Pause)

[Gene may be having trouble with one of his own glove straps.]

116:51:37 Cernan: Pull it and let go. Isn't that the word?

116:51:39 Schmitt: That's what they tell me. Want me to get it?

116:51:41 Cernan: I got mine...No, I got it. (Have you) verified yours (is) locked?

116:51:44 Schmitt: Yes, sir.

116:51:45 Cernan: Okay. Both my gloves are verified locked. (Pause) How does that grab you?

116:51:54 Schmitt: Okay; feels good.

116:51:57 Cernan: Is your mirror on tight enough? Checklist on tight enough. (Pause) That's the best I can do; I guess.

[Here, Gene is referring both to a small mirror that Jack has strapped to his left wrist (along with a watch) and to the cuff checklist on his other arm. As Gene mentions in a comment that follows 163:19:53 during preparations for EVA-3, the wrist mirror could be used to examine the front of the suit. However, on the landing missions, wrist mirrors were only flown on Apollo 16 and 17, primarily for reading the frame counter on the right-hand side of each Hasselblad magazine. On those two flights, the LM crews expected use considerable film during the geology traverses and the mirrors gave them the opportunity to better monitor usage, especially while seated on the Rover.]

116:52:20 Schmitt: Now what?

116:52:22 Cernan: Wrist rings are covered. "Note if PGA biting." No, mine's all right. Your's okay?

116:52:26 Schmitt: No; it's fine.

[They are both now sealed inside their suits but have not yet pressurized their suits with PLSS oxygen. The PLSS fans are on and, as air moves through the backpacks and carbon dioxide is removed by the LiOH canisters, the suit pressure decreases and the suits can slowly collapse around them and "bite". The Apollo 12 crew experienced some discomfort at this stage and suggested that, if other crews had the same problem, they briefly turn the PLSS oxygen on to partially inflate the suits and alleviate the biting.]

116:52:30 Schmitt: Yes.

[Cernan - "During my Gemini flight we had tried to use the flow of oxygen through the suit for cooling but decided that that wasn't adequate. So we developed the liquid-cooled garment. The way it worked was that the PLSS had two separate supplies of water. One was a closed-loop supply which was moved by a pump through the liquid-cooled garment. Then you had a sublimator which had another, physically-separate, open-loop supply of water. There was a cooling coil in the sublimator where the water in the closed loop could transfer heat to the open-loop supply and a diverter valve that determined how much of the suit water went through the coil. Because the open-loop supply was allowed to sublimate into the vacuum, it cooled the coils and the closed-loop supply. You could divert around that sublimator if the suit was too cold or you could divert through it and get more cooling. Here, as we've already discussed, we had the sublimator turned off and were running cold LM water through the LCG, cooling down before we disconnected the LM water. We didn't turn the sublimators on until we got the hatch open."]

116:52:34 Schmitt: Okay.

[Jack is turning off the flow of LM water by pulling the LCG circuit breaker open.]

116:52:42 Schmitt: Okay; breaker's open.

116:52:43 Cernan: Okay.

116:52:44 Schmitt: Let me turn around this way.

116:52:45 Cernan: Okay. Go ahead and I'll...(Pause)

116:52:52 Schmitt: Okay. You want to get mine or you...

116:52:54 Cernan: No, I'll get yours.

116:52:55 Schmitt: Okay.

116:52:56 Cernan: Okay. First of all I'm going to take that (LM water hose) off. (Pause) (Connecting Jack's PLSS water hose) Okay. Now let me get your other one. There it is. Okay. We did this before. Stand right there. (Pause) It's locked, Jack.

116:53:27 Schmitt: Okay.

116:53:28 Cernan: It is locked. (I'll) get the (dust) cover on. (Pause) Okay. The cover is on. Okay. Yours off?

116:53:43 Schmitt: Get that in a second.

116:53:44 Cernan: Okay. Yours is just laying there, too.

Audio Clip

116:53:49 Schmitt: Okay. Hang on.

116:53:50 Cernan: Okay. I'll push towards you. Make sure that thing falls in the hole, because yours didn't right away. (Pause) Did it fall in?

116:54:07 Schmitt: Yeah. Yeah, it's in the hole. Okay.

116:54:13 Cernan: Dust cover on?

116:54:15 Schmitt: Dust cover's on.

116:54:16 Cernan: And my PGA is going to start biting here if we don't get going. (Pause) Okay. "PLSS diverter..." I've got to turn my oxygen on a second, Jack.

116:54:29 Schmitt: Yeah, so do I. (Pause)

[They are adding a little oxygen from the PLSS tanks to slightly inflate the suits.]

[Cernan - "We were telling the spacecraft ECS system that we were going into an Egress mode and are about to depressurize the cabin on purpose."]

[Houston had requested the changed setting at 115:29:10.]

116:55:10 Cernan: Okay, my pump's on. I can feel it running.

116:55:12 Schmitt: Keep talking.

[They are now finished with 2-9 and are about to start a suit pressure integrity check at the top of 2-10.]

[They will inflate the suits so that they can check for leaks while the cabin is still pressurized.]

116:55:20 Cernan: Okay. PLSS O2 On. Mine's on. "Pres(sure) Flag and O2 Flag (will) clear, 3.1 to 3.4 (psi)." (Pause) Okay. I'm coming up. I know that. (Looking at his watch) Gee, it's 10 minutes to 6 at home.

[That is, it's 5:50 PM Central Standard Time on 11 December 1972 in Houston. Gene and Jack are probably getting ready to start the stopwatch function on their Omega Speedmaster Professional wristwatches. The cuff checklist indicates planned EVA elapsed times at which various activities are to start and, by setting their watches, they will not have to depend on Houston to know what the elapsed time is. They will start the stopwatch function once they complete the pressure check and begin the final depressurization. There is an entry at final depressurization that reads "Start Wrist Watch :00." The figure ":00" is the EVA elapsed time of zero minutes. See Gene's comment at 118:29:57.]

116:55:48 Cernan: Okay. I'm still coming up (in pressure).

116:55:50 Schmitt: Keep coming up. Just got mine on.

116:55:54 Cernan: Oh, okay. Well, I'm ahead of you then. (Pause) Okay. The Press Flag will clear 3.7 - correction - 3.1 to 3.4 (psi).

116:56:06 Schmitt: What do you want me to do when I'm pressurized?

116:56:08 Cernan: Well, we want to make an integrity check.

116:56:10 Schmitt: Yeah; but then what?

116:56:11 Cernan: Can you reach those (LM) water hoses right there? By chance? Before you get too hard?

[The suits get relatively inflexible once they are inflated, making it even more difficult to turn or bend.]

116:56:48 Schmitt: Still got an O2 Flag on the LMP.

116:56:50 Cernan: Okay, you're not up (to 3.1 to 3.4 psi) yet; I suppose.

116:56:52 Schmitt: No.

116:56:58 Cernan: Okay. I'm going to take my PLSS O2 Off for one (minute). Counting 1 minute; 57. Let me know when you're up, Jack, and I'll give you a minute hack.

[They will turn off the PLSS oxygen supply and spend a minute looking for indications of suit leaks.]

116:57:11 Cernan: Okay. You up?

116:57:12 Schmitt: Yep.

116:57:13 Cernan: You can turn your PLSS O2 off any time. Let me know when. Can you reach it? If you can't, I'll get it for you. (Pause)

116:57:29 Schmitt: Why don't you get it.

116:57:31 Cernan: Okay. (Pause) Okay; Mark it.

116:57:35 Schmitt: Okay.

116:57:37 Cernan: You're on the 30-second mark, and I'm on the minute mark.

[The second hand on Gene's watch was at 0 when he started his integrity check and at 30 seconds when Jack's started.]

116:57:42 Cernan: Okay. I'll give you a hack when...(Pause) Okay. I'm coming up on 45 seconds. (Pause) Okay. I'm one minute; I'm going back on. Okay, Houston. Commander went from 3.8 to about 3.67. I'll get yours on when you need it on, Jack.

[This slight decrease in suit pressure is normal and indicates good suit integrity. The decay is due partly to the fact that it takes the oxygen a while to fill all the nooks and crannies, and partly to breathe-down. Once they start a continuous flow of oxygen, the PLSS will maintain a pressure of about 3.8 psi.]

[They are still only 20 minutes behind schedule.]

116:58:29 Parker: Okay. (Pause)

116:58:31 Cernan: Okay, Jack. I'm turning on. Did you mark it?

116:58:35 Schmitt: Okay, Houston; 3.8 to 3.6. (Pause)

116:58:45 Schmitt: Hello, Houston; you copy the LMP?

116:58:47 Parker: Roger. Copy the LMP. Okay; and Challenger...

116:58:51 Cernan: Okay. Standing by for your Go for depress.

116:58:53 Parker: (Already prepared to give permission) You'll be glad to know you are Go for depress.

116:58:57 Cernan: Thank you, Robert. I understand we are Go for depress.

116:59:00 Parker: That's affirm.

[A little formality in the proceedings, the only one after the permission to stay for T-2.]

116:59:06 Schmitt: Well, let me turn around here.

116:59:08 Cernan: Okay, on (circuit breaker panel) 16...First, around on 16. Cabin Repress, Open.

[They are pulling a circuit breaker on panel 16 so that the LM's oxygen system won't try to repressurize the cabin when they open the dump valves in the forward and overhead hatches.]

116:59:18 Cernan: Cabin Repress, Open.

116:59:21 Schmitt: Circuit breaker is coming open.

116:59:22 Cernan: Okay, and Cabin Repress valve, Closed on the panel.

[The repress valve is behind Jack's station on the right side of the cabin.]

116:59:27 Cernan: Okay. If you can't reach it (the dump valve on the forward hatch), I guess I can.

116:59:31 Schmitt: Okay. I just had a momentary tone.

116:59:32 Cernan: So did I. I got it, too.

116:59:33 Schmitt: Okay.

116:59:34 Cernan: I think it was when you closed the Repress valve. (Pause) Can you reach it (the forward dump valve)? If not, I'll reach the overhead one.

116:59:42 Schmitt: I think you better reach the overhead one.

[Opening the dump valve in the forward hatch requires bending over slightly against suit pressure. Reaching the overhead valve requires raising an arm and can be a less difficult maneuver in the cramped confines of the LM, especially for a six-footer like Gene. Training photo KSC-72PC-540 shows the overhead valve at the upper right.]

[Jack must be facing inboard. Gene wants him to lean toward the window so that Gene can reach behind him to get the overhead valve. In order to reach up with his right arm, Gene must also be facing inboard.]

117:00:08 Cernan: Yeah, wait a minute. I'm not there yet.

117:00:10 Schmitt: Well, I just want to make sure that I'm watching (the cabin pressure gauge).

[While Jack watches the cabin pressure gauge, Gene will open the overhead valve and let the pressure decrease from 5 psi to 3.5 psi. At that point, he will reclose the valve by putting it in the Auto position. In Auto, the dump valve will open only if the cabin pressure exceeds 5.4 psi. The suit pressure regulators will try to track the decreasing cabin pressure, and keep the difference at 3.9 psi. Because of a finite response time, the relative suit pressure will go up initially - to about 5.3 psi - and then decay. This is a last test of suit integrity prior to full cabin depressurization.]

117:00:19 Schmitt: Stand by Auto. (Cabin) Repress (valve) is Closed.

117:00:24 Cernan: Say when.

117:00:25 Schmitt: Okay.

117:00:27 Cernan: You ready?

117:00:28 Schmitt: Wait a minute, wait a minute, wait a minute.

117:00:29 Cernan: Okay.

117:00:30 Schmitt: Got the wrong place (in the checklist). "Open, then Auto at 3.5." Okay; go ahead.

117:00:37 Cernan: Okay. Here it comes. I can see daylight through it.

[Cernan - "The valve, as I recall, was just a little circular disk that was held against a seal by the pressure in the cabin. It had a little lever and I could get enough mechanical advantage to crack it a little bit and vent some of the air. I want to remember that we had some screw-type vents on the hatch of the Command Module; but I'm sure that this LM valve wasn't like that. Nothing in the LM was very fancy unless it absolutely had to be. Everything had to be as lightweight as possible, and that usually meant very unsophisticated designs."]

[The valve is a bit more complex than Gene remembers it but, still, is basically a simple device.]

117:00:53 Schmitt: Mark. 3.5.

117:00:54 Cernan: Okay. It (meaning the overhead valve)'s off.

117:00:57 Schmitt: Okay. And your cuff gauge should not be below 4.6, and mine's at...

117:01:03 Cernan: Mine's at 5.0.

117:01:04 Schmitt: 5.1. (Pause)

117:01:10 Cernan: Okay?

117:01:12 Schmitt: Okay. The suit circuit is locked up at 4.5.

[The Suit Circuit Relief (Valve) is in the Auto position and will open only if the suit circuit pressure is greater than about 4.3 psi. Note that the suits were disconnected from the suit circuit when Jack closed the Suit Isolation Valves at 116:33:21 and 116:39:14.]

117:01:26 Cernan: So am I.

[Pressure regulators on the suits are gradually reducing the pressure difference to 3.8 psi.]

117:01:31 Cernan: Okay. I'll start my watch.

[The are starting the stopwatch function on their Omega Speedmaster watches as per the comment following 116:55:20.]

117:01:38 Schmitt: Watches started.

117:01:41 Schmitt: Okay. "Overhead or Forward Dump Valve, Open".

[They will now reopen the dump valve and let the cabin pressure fall to zero. This is the start of the EVA.]

117:01:46 Schmitt: And it's going down.

117:01:47 Cernan: You going to want me to put this in Auto afterwards or not? So, I can turn around, Jack.

117:01:57 Schmitt: Stand by.

117:01:58 Cernan: (Garbled) Open...

117:01:59 Schmitt: (Garbled)...

117:02:01 Cernan: ...leave it Open.

117:02:02 Schmitt: Leave it Open.

117:02:03 Cernan: No, we don't (put it in Auto), because then we don't want that hatch to get closed. (Pause)

[Cernan - "We wanted to leave the dump valves open because we were going to close the hatch for thermal reasons while we were outside. By leaving the dump valves open, we were making sure that, if any air bled into the cabin for any reason, then pressure couldn't build up inside the LM and make it tough to get that hatch open. Now, I also think that we did have an ability to open the dump valve (in the forward hatch) from the outside. I really believe we did, as I remember. But it was obviously still safer to leave the dump valves open."]

117:02:33 Cernan: Boy, you sure get heavy (meaning "stiff") at 5 (psi), don't you?

[As the cabin pressure drops, the relative suit pressure increases for a while.]

117:02:44 Schmitt: We're right here, huh? (Pause)

[They are at the top of the right-hand column on 2-10, waiting for the cabin pressure to drop low enough - to about 0.2 psi - that Gene can open the hatch.]

117:03:02 Cernan: What's cabin (pressure), Jack? (No answer) Do you read, Jack?

117:03:11 Parker: Jack, this is Houston.

117:03:12 Cernan: Wait a minute.

117:03:13 Parker: CDR, we're not reading the LMP either.

117:03:16 Cernan: Now, how do you read, Jack?

117:03:20 Schmitt: Okay. You're loud and clear.

117:03:21 Cernan: Okay. (Pause)

117:03:23 Schmitt: We got a switch in the wrong place as usual, Bob.

117:03:27 Cernan: I just hit the Mode Select; that's all.

117:03:28 Parker: Okay. We copy.

117:03:30 Schmitt: Okay. "Partially open the forward hatch", when we can.

117:03:33 Cernan: Okay. Can you zap over to the left as much as you can?

117:03:37 Schmitt: To the right, you mean?

117:03:39 Cernan: Yeah. To the north.

[Jack must be facing forward now.]

117:03:41 Cernan: The north.

117:03:42 Schmitt: The north. (Both laugh) Okay, it's about 0.2 (psi), Gene.

[Fully open, either the forward or overhead dump valve will reduce the cabin pressure from 5 psi to 0.08 psi in 180 seconds. With both valves open, the time would be 90 seconds. Including the 17 seconds used to bleed the cabin to 3.5 psi, they are now 141 seconds into the depress.]

117:03:49 Schmitt: You going to be able to get to it?

117:03:50 Cernan: Yep. (Pause) You betcha. I've come this far. I'm not going to miss getting that hatch open. (Pause)

[Cernan - "The lunar module, in contrast to the command module, was nothing but a tin can that buckled when you pressurized it; a lightweight tin can just strong enough to hold the pressure we needed. When we depressurized the LM, all the skin surfaces relaxed; and when we got back in and pressurized, the hatch would bow out and you could sort of feel and see the panels bow out. The hatch was nothing but a flimsy little piece of metal with a seal on it. And it didn't have a big fancy lock. It just had a little lock like you might find on a barn door: a little lever that fit into a slot. You didn't really have to lock it, because the pressure held it closed."]

[Jack is probably looking out his window and has seen a bit of debris and/or ice expelled by the escaping air. They are about 153 seconds into the depress.]

117:04:04 Schmitt: Gosh, look at those trajectories. (Laughs)

117:04:06 Cernan: Yeah. Put just enough air in here, we're...Okay; it's open, babe.

117:04:11 Schmitt: Okay.

[Gene has pulled the hatch open against about 0.2 psi of cabin pressure, and that is enough of a pressure difference to create a noticeable wind blowing out the hatch. The flow of air is visible because the moisture in it turns to ice crystals as it expands, and also because the wind picks up stray bits of paper and/or other debris.]

117:04:18 Schmitt: Okay. "Final prep, PLSS (sublimator) primary H2O." I've got to figure out how to open that now.

117:04:25 Cernan: Okay. (Pause) When you're at 5 psi, it's (hard to reach the PLSS controls)...

117:04:40 Schmitt: We never did really train for this in the right way.

117:04:44 Cernan: Yeah, we did.

[Schmitt - " I know I had done this once in the KC-135 aircraft, but I don't remember whether or not that was an actual training exercise. We only got about 20 seconds at a time of one-sixth g in the airplane. And maybe we never even tried to open the PLSS (sublimator) water valve for lack of time. It was certainly harder on the Moon."]

[Cernan - "Another explanation is that we may not have trained with a 3.5 psi pressure difference. If not, then we wouldn't have had 5 psi suit pressures at this point in training."]

117:04:48 Cernan: And my water is Open. (Pause; breathing heavily) Okay. Well, let's see; "Rest until cooling sufficient; 3.7 to 4.6 (psi)." I'm to 4.9; coming down.

117:05:11 Schmitt: Yeah, I am, too. Coming down.

[Cernan - "When you moved around, like we were here, inside the lunar module, and then when we were getting out and going down the ladder, it was work even in one-sixth gravity. We had heart rates going up at times, on the lunar surface, to 140 beats a minute. And I think probably through most of the EVA that I did breathe heavy because I've got a fairly good lung capacity - I've never smoked - and I tend to do that. Throughout many of these tapes on the lunar surface activity, you'll find me taking deep breaths and sounding like I'm "breathing heavily". But it really isn't labored breathing so much as me just taking fairly deep, open-mouthed breaths."]

117:05:16 Schmitt: See a PREAMPS, and I see ECS. Barely.

[Schmitt - "The ECS light came on in response to cabin depressurization. The fact that it came on confirmed that we were depressurizing; and showed that the warning system was working properly."]

117:05:22 Schmitt: Water...Excuse me, Water Sep.

[The water separator is a centrifugal device used to control humidity in the suit circuit.]