MP3 Audio Clip ( 21 min 20 sec )
119:05:46 Scott: (Burst of static) Okay, Houston; Hadley Base. We're ready to go into a PLSS comm check, if you're ready. (Static clears)
119:05:56 Allen: Roger, Dave. We read you about 3 by.
[Scott - "Five-by-five means 'loud and clear'."]119:05:58 Allen: Stand by until I get a go-ahead from INCO here.
[Jones - "So Joe is saying it's a little faint and muddy."]
[The fact that they are using aviation terminology generated the following discussion.]
[Scott - "A lot of what we did, as you can see, was based on aircraft operations - which is one of the keys to the success of Apollo. When they started it, they brought in a lot of people who had aircraft operations and hardware experience. The group from Langley that formed NASA from NACA and the group from Langley that moved to Houston were all from the airplane testing world. And then they brought in the initial group of crew, who were all engineering test pilots. So there was a lot of flow through, in terms of operational procedures and the language was a result of that. And we experienced a number of occasions when engineers, per se, would try to design an operational system or concept, and it just didn't work. As many people will tell you, if a mathematician builds an airplane, it will never fly; so it was essential, in my opinion, to have these operational people and operational perspectives. And you can see, as it flows through there, that their influence and culture permeates everything we did. And if somebody wants to, in the future, start this all again, if they started with just engineers and mathematicians and scientists, it'll be very, very difficult, because they will have to learn what the pilots and operational people already brought to the program."]
["As a little sidelight, I told you about the attitude gyros, the 8-balls. Well, at one point when Apollo was being designed, the engineering community concluded that what the pilot should be looking at, in terms of attitude, were three gauges, three dials, which displayed Euler angles. Now, when one tries to translate Euler angles into what we call body angles of a spacecraft, mentally, it's impossible. Well, maybe not impossible for a (World Class chess player like Bobby) Fischer or a (Boris) Spasky, but very impossible for the likes of me. Euler angles just won't work; but, at one point, there was a discussion - early on - that I sat in on where the pilots finally did convince this engineering group that Euler angles aren't going to do it for you. They, the engineers, lived in Euler angles and they were very familiar with them; but they didn't have to fly anything. So that perspective is very important. And, there again, one of the reasons why this worked was the combination of talents and cultures that got put in there. When Joe says 'three by', that's part of the culture and it works better than saying, 'well, I can't hear you very well'."]
[Jones - "And Joe and Jack and some of the other scientists in the Astronaut Office spent a fair amount of time soaking that up from you guys."]
[Scott - "They went to flying school. See, when Joe and Jack and the others in that group - Henize, Parker, Kerwin, Garriott - were sent to flying school, so they got that culture."]
[This conversation reminded me of two incidents related to the voyages of the great British explorer, Captain James Cook. The first of the Cook voyages began its life as a proposal to the British Government by the Royal Society to send a ship into the Pacific to observe the June 3, 1769 passage of the planet Venus across the face of the Sun, a very rare event that would allow astronomers to determine absolute distance scales in the Solar System. The Royal Society proposed one of its own, Alexander Dalrymple, to lead the expedition but, not surprisingly, the Royal Navy declined that offer and appointed a man with considerably more practical nautical knowledge, Cook. And then prior to the second voyage, Gentleman-Scientist Joseph Banks, who had accompanied Cook on that first voyage, began to believe a bit too much in his otherwise-justly-deserved reputation and ordered extensive modifications to one of the expedition vessels to house a larger staff of assistants and servants. Before long, it became apparent that the modifications would make the ship unseaworthy and, in the end, Cook ordered the extra construction ripped off. Readers interested in further details about the Cook Voyages - probably the world's first scientifically-oriented voyages of exploration - should consult J.C. Beaglehole's definitive The Life of Captain James Cook.]
119:06:07 Scott: (Clear comm) Okay. (Pause)
119:06:17 Allen: Okay, Dave. We're go on the FM and high power. We've got it down here.
119:06:25 Scott: Okay. We'll be talking to you.
[Comm Break]119:07:44 Scott: (Reading Surface 3-7 at the bottom of the left-hand column) (sensitivity) VOX Max. VHF A to T/R; B to Receive. Okay. CB(16) Comm: SE Audio, open, and you connect to the PLSS comm. (Long Pause)
[In this section of the audio tape, there are definite instances of words and/or parts of words not picked up due to slow VOX activation, also called clipping. This is a sensitivity problem that plagued Buzz Aldrin throughout the Apollo 11 EVA. Here, the problem will disappear shortly and, on the whole, the comm will be the best received from any crew while suited in the LM.]119:08:44 Scott: Okay, CB(16) Comm: SE Audio, close. PLSS PTT (Push-to-Talk) ... Maintain right, verify. Okay, PLSS mode, A, wheel counter-clockwise.
119:08:54 Irwin: (Some interference) ... mode A. And wheel is full counter-clockwise.
119:08:58 Scott: Okay. Tone-on, vent flag P, Press flag O, O2 momentary.
119:09:03 Irwin: Okay; they're on.
119:09:05 Scott: Okay. PLSS O2 pressure gauge greater than 85 (percent).
119:09:09 Irwin: Verified.
119:09:10 Scott: Okay. You've made your comm check with me. Give Houston a call.
119:09:13 Irwin: Houston, how do you read the LMP?
119:09:16 Allen: Jim, you're loud and clear. There's a squeal in the background.
119:09:23 Irwin: Roger. I have that squeal, also. (Pause)
119:09:31 Allen: Jim, stand by; we'll...(Stops to listen)
119:09:33 Irwin: I'll turn the squelch down a little bit to see if that...
119:09:36 Allen: Roger. And, Jim, stand by; we're thinking about that tone a minute here...(correcting himself) about the squeal in the background.
119:09:44 Irwin: Okay. I'm standing by. (Long Pause)
119:10:16 Allen: Jim, this is Houston. Could you turn your volume down a little bit for us, please? (Pause) And that's volume on the wheel.
119:10:30 Irwin: Okay. The volume's down now.
119:10:31 Allen: That's...
119:10:32 Irwin: Okay. It's down about three quarters of the way. How do you read now?
119:10:34 Allen: Jim, that's beautiful. The squeal's gone and you're 5 by. (Pause) And we're ready to go to the next step.
119:10:41 Irwin: Okay; very good.
119:10:42 Allen: Rog. We're ready to go to the next step.
119:10:46 Scott: Okay. CB(11) Comm: CDR Audio, open.
[Comm Break, as they get Dave off of LM comm and on to PLSS comm.]119:12:08 Scott: Okay. I have a tone-on, vent flag P and pressure flag O. O2 pressure gauge is reading about 94 percent. And, how do you read me, Jim?
119:12:22 Irwin: I read you loud and clear.
119:12:24 Scott: Okay. You need to make a comm check with Houston then.
119:12:27 Irwin: Houston, how do you read the LMP?
119:12:29 Allen: Jim, you're 5 by. (Pause) And, Dave, you're 5 by. Sounds beautiful.
119:12:34 Irwin: You're the same.
119:12:36 Scott: (Garbled) he can't (clipped) talk to me.
119:12:38 Irwin: Understand.
[As is mentioned on Surface 3-8, in the current configuration Houston can hear both Dave and Jim, and they can hear each other, but Dave cannot hear Houston. Note that, while Dave and Jim are wearing the Snoopy headsets, which muffle all sounds but those coming through the earpieces, they have not yet donned their bubble helmets and, obviously, could talk even if the headsets weren't connected.]119:12:41 Scott: Okay. PLSS mode LMP to...Now you won't be able to hear Houston.
119:12:45 Irwin: Yeah.
119:12:46 Scott: PLSS mode, LMP to B and CDR to A.
119:12:50 Irwin: (Garbled) on B.
119:12:52 Scott: Okay. I'm in A; how do you read?
119:12:56 Irwin: I read you loud and clear, Dave.
119:12:58 Scott: Okay; I read you loud and clear. Houston, how do you read the CDR?
119:13:01 Allen: Dave, you're 5 by; and Jim's 5 by.
119:13:07 Scott: Okay. PLSS mode, both, to AR, tone-on. [Short whistle]
119:13:13 Irwin: Okay; I'm AR.
119:13:16 Scott: Okay; I'm AR, and you're loud and clear to me. How me to you?
[The comm quality is now excellent.]119:13:19 Irwin: Same.
119:13:21 Scott: Okay, Houston. How do you read the CDR?
119:13:24 Allen: Dave, you're loud and clear.
119:13:30 Scott: Okay. And we need a TM (telemetry) check with you, and O2 quantity on the CDR is 94, and give them yours, Jim.
119:13:37 Irwin: Okay, I'm reading about 92.
119:13:41 Allen: Roger. We copy. (Pause) And, Falcon, the data looks good. We have the TM check.
[Here, they have made sure that Houston is seeing the same oxygen quantities that they are seeing on their suit gauges.]119:13:48 Scott: Okay. CB(16) ECS: LCG Pump (circuit breaker), closed. (Responding to Joe) Okay. Understand, a good TM check. Good.
[This is one of only a few occasions when there is any noticeable effect of the 2.5 second -two-way communications delay on the flow of information between Joe and the Falcon crew.]119:13:57 Irwin: Okay. LCG Pump going closed, now.
[Scott - "When Joe pauses, the delay gets us. Because he'll say something, and he'll wait a couple of seconds to say something else and, in that break, we tend to respond. So, in the future, they ought to think about building those delays into their simulations. We probably should have done that to get the mindset going."]
[Jones - "It's going to be especially valuable for Mars. Because it's going to be a whole different style of operation."]
[Scott - "Oh yeah. But you probably won't do that for Mars. It's too far away. I mean, you're not going to build into your simulation a 40-minute delay."]
[Jones - "Aren't you going to have to do some simulated Mars missions on the lunar surface?"]
[Scott - "Oh, of course!"]
[Jones - "With that time delay built in."]
[Scott - "But you won't be using Mission Control like we used it. You can't."]
[Jones - "But you are going to be using it in some fashion."]
[Scott - "But not this way. There's too much delay. I can think of ways to use it, but not in the back-and-forth, conversation mode. Depending on where Mars is, it can be 20 to 40 minutes. You can't be going back and forth. Which means Mars is tougher."]
[Jones - "But don't you have to learn how to do that, to try out a mode of operation? Or do you just assume that you're operationally isolated except for the ability to send and receive messages and get advice and opinions."]
[Scott - "Yeah. And, in my opinion, the difference between Mars and the Moon is one word: Remoteness. Mars is totally remote. The Moon is not. Therefore, when you go to Mars, you're going to have a completely different operation relative to linkage with the Earth. You will be on your own, and that's why the composition of the crew at Mars will be different from the composition of the crew at the Moon."]
[Jones - "Why don't we talk about that now?"]
[Scott - "Okay. Briefly, one approach is similar to Apollo in that you have three people. Each member of the crew will have a primary and secondary discipline in which they are fully qualified relative to the rest of society, but they are better at one, with more background. You have the Commander whose primary discipline is operations with geology as his secondary discipline. That's already been demonstrated in lunar operations: you can teach pilots to do some geology. I think the second person will be a scientist - a geologist type person - with a secondary discipline that will be medical. The person who is scientifically oriented, anyway, would probably be able to accommodate a medical secondary discipline more easily than the operational person. The third person will be a full-time physician who has a background of operations, because that has been demonstrated in flight surgeons. Many flight surgeons, as an example, are very good pilots. So, that crew of three mixes the three things you want to do at Mars: operations, science, and medicine. You're remote and you have to have a doctor of some sort. You have to have somebody who is skilled in the art of medicine, a full-time practicing physician. Mars is remote and, once you start, you're going for a long time. And that's not wasting anything, because that kind of person can be a very good pilot."]
["Now, this is only looking at the first crew, because that's going to be a major expedition. I mean, people talk about a 6000 kilometer traverse on Mars. Yeah, but not in the next century. They may mount one expedition to Mars, which will be get 'em out and get 'em back because the world doesn't want to have them wait around. Go take a look, bring some things back. Very similar to the Moon. The mechanics of that and the propulsion system will depend on the technology of the time. But, from the human perspective, if you're going to go to a place that remote, you've got to be absolutely self-sufficient; and, therefore, you've got to have people who are qualified to handle the day-to-day operations and any particular emergency without any advice. You can get advice. You can call back and, a half-hour later, you'll have some advice. In emergencies, that won't be fast enough."]
["So, in my opinion, having given it a little thought for a workshop I went to, a crew of three isn't bad. It worked pretty well. Probably, at Mars, you'll bring the third person down with you, because you'll need to have that third expertise. You've got to have the scientist on the ground, you've got to have the Commander on the ground. And, since you're probably going to be on the ground on the order of a month, you've got to have the doctor on the ground to backup the Commander. I think that's a nice crew. That's two-cents worth of what I would advise, based on what we did in Apollo. 'Cause, you know, in the beginning, people criticized the three-man crew. You're going to have conflicts, they said, and all this psychological stuff. But, of course, that didn't happen. Once we all got airborne, any personality conflicts which may have existed - from what I know - completely disappeared."]
[Jones - "There's a very interesting paper by a guy named Al Harrison at USC (University of Southern California). It's the first paper I've ever seen by a psychologist in this business that I thought made sense. It said, 'You've got a bunch of highly motivated people who want this thing to succeed. Use that fact.' He said that the psychological profession is going about it all wrong in interacting with the people in the program. They want to see what's wrong with these guys, what the conflicts are. And they - the psychologists - are perceived as a threat by the crews. The only thing a shrink can do is get you de-qualified for the flight."]
[Scott - (Laughing) "That's right!"]
[Jones - "So the pilots say 'I'm as normal as John Wayne.' And the truth is that they are so motivated toward success that they are going to figure out how to work together, no matter what. They are going to make their personal goal happen."]
[Scott - "Yeah. And that's been demonstrated. I mean, early on in Apollo, there were flights with personalities that would make you say, 'Don't put those three guys in the same room together.' But it worked. And another motivation thing with regards to a Mars trip, is that people worry about the long trip and the boredom. In my opinion, if you pick the right crew, they're not going to be bored. I mean, Jim and I wished we'd had more days or even weeks to study the geology at Hadley before we got there. And I would love to be on a trip to Mars where I got turned loose for six months and I could sit with two other highly motivated, intelligent, stimulating people with whom you could carry on conversations for hours and hours. Going to Mars - goodness gracious! - you're not going to be bored. There's going to be too much to prepare. You're going to get all wound up in it; and, besides, you can look out at the stars and you can do a lot of experiments on the way to Mars. I don't think there's going to be any boredom on the way to Mars. We were never bored."]
[Jones - "And you're going to have comm systems and data rates that will let you talk to the people at the equivalent of (the US Geological Survey planetary science office at) Flagstaff and they can send you their latest thinking on the landing site, with high resolution maps and photographs. You'll be able to have real dialogs with them, and do your own thinking about it and make inputs."]
[Scott - "Sure. The last six months of training will be on the way. And the first six months of the post-flight analysis will be on the way home. I'm thinking, boy, I wish we'd had six months to sit down with this stuff and go through it with all the experts with whom we'd been working for so long, and digest it and think about it and feed it back to them. You can do that on the way home from Mars."]
["So, people who are worried about this long trip and all the boredom...I don't think so. I think that, for the people who go, it's going to be a very short trip. When they get back in 18 months or whatever, they're going to say, 'Wow, boy, did the time go fast.'"]
[Jones - "Have you written any of this down?"]
[Scott - "No, not really. I gave a little paper once at a workshop at Caltech with six or eight viewgraphs, on 'Maximizing the Effectiveness of the First Humans on Mars'. It was mostly scientists, most of whom were going to have these people stay for six months. Maybe they will. But I don't think society or the system will let them. They'll say, 'Get 'em out, get 'em back'. And then we'll go stay for six months. Just like Apollo. You've got to prove the hardware. You've got to prove the operations. You've got to prove the concept. (You've got to prove) that you can keep people alive for that length of time and bring them home without a major problem. Or, even if you have major problems, that you have a method or concept by which major problems can be solved."]
["If I were the manager, I would say, just from a practical point of view, on the first mission, science is secondary. It has to be. But, then, God, Yes! Let's do the six-thousand-kilometer traverses. Just like Apollo. When we got to the J-missions (Apollos 15, 16, and 17), the hardware had all settled down. Once we got into the suit and got the PLSSs going and all that, we never thought about it. On Apollo 12, Pete and Al had to think about the systems that were keeping them alive. They still had that uncertainty in the hardware and the procedures and all that. But, by the time of our mission, much of that had been worked out. So I think Mars, when it happens, will be the same thing. Even if they don't read this, they'll figure it out. It'll just take them longer. You get them out and get them back, and then you take the next step. And it will be a quicker step and a longer step, because they will have had the benefit of this (Apollo experience), hopefully, and they will have had the benefit of a first trip to Mars."]
["Maybe the trip to Mars leaves from the Moon. It may leave from Earth orbit. Who knows how that's going to work out? It doesn't really matter when you look at the objective of putting some people on the surface of Mars for some period of time on the first mission, which is the only one you really ought to worry about in the beginning because that is going to be the ultimate challenge for that generation. Six thousand kilometer traverse? That comes maybe ten years later. 'Cause the Martian windows are so long. On the Moon we could pop them off. I mean, Neil went in July, Pete went in November. Bang, bang, bang. You can't do that for Mars, unless you get a lot of energy in the propulsion systems. Not real soon. But it's interesting to contemplate, because the value in this exercise (compiling the Apollo Lunar Surface Journal) is not only for the next lunar explorers, but for space explorers in general. 'How did it work?'"]
119:14:02 Scott: Okay. I hear the pump. (Pause)
119:14:04 Scott: Okay. LCG cold as required.
119:14:06 Irwin: I feel it already. It feels good.
119:14:09 Scott: Yes. It sure does, doesn't it?
[They are circulating LM water through the Liquid Cooled Garments, cooling down prior to disconnecting the LM water hoses. They won't be able to operate the PLSS cooling system until the cabin has been depressurized.]119:14:12 Scott: Okay. CB(16) ECS: Cabin Repress, close; verify.
119:14:15 Irwin: Verified.
119:14:16 Scott: Suit Fan Delta-P, open.
119:14:17 Irwin: Open.
[Here, they are disabling a sensor which detects a pressure difference across the fans in the ECS when the fans are operating.]119:14:19 Scott: SUIT Fan 2, open.
119:14:20 Irwin: Open.
[Here, they are turning the fans off.]119:14:21 Scott: Suit Fan, select number 2, and I'll get that. (Pause) ECS caution, H2O Sep Component lights on. (Pause)
[With the fan now off, the water separator slows to a stop and warning light comes on after about a minute. This is primarily a convenient check to make sure the sensor is working.]119:14:39 Scott: Okay. And I've got a Press flag O and a vent flag P.
119:14:41 Irwin: Same here.
[These flags are telling them that the PLSS fans are not yet turned on and, as with the LM warning system, that the PLSS warning system is working. Next, they will verify that the ECS is still in the proper configuration for cabin depressurization.]119:14:42 Scott: Okay. It's gone. Okay. ECS caution lights are (still) out. (Pause) Okay. Suit Gas Diverter (Valve), Pull Egress; verify.
119:14:55 Irwin: That's verified.
119:14:56 Scott: Okay. Cabin Gas Return (Valve) to Egress; verify.
119:15:59 Irwin: That is verified.
119:15:00 Scott: Suit Circuit Relief (Valve), verify?
119:15:01 Irwin: That's verified.
119:15:03 Scott: Okay. OPS connect (as per Surface 3-9). (Pause) Suit Isolation (Valve) to Suit Disconnect. And disconnect the LM O2 hoses; and secure that to PGA. (Pause)
119:15:17 Irwin: Okay. Dave, let's take those one at a time.
119:15:20 Scott: Oop. We got a Master Alarm. See what it is.
119:15:23 Irwin: I think it's just the second one on the fan. ECS. Let's see. Water Sep (which has finally slowed down enough to trip the sensor).
119:15:34 Allen: [Over a garbled crew exchange] Guys, it looks okay. It's a Water Sep light.
119:15:40 Irwin: Yeah. Read those next steps there, Dave. I didn't...One at a time
119:15:45 Scott: Yeah, okay. (Pause) "Connect the OPS O2 hose to the PGA, blue to blue."
[Next, they will connect Jim's OPS hose to the appropriate connector on the front of his suit.]119:15:52 Irwin: Okay; let me find that. I might have to turn around and let you do that.
119:15:57 Scott: Yeah, I can get it. Here. (Pause)
119:16:03 Irwin: In fact...
119:16:05 Scott: Yeah, why don't you turn around?
119:16:06 Irwin: Yeah. (Garbled) (Pause)
119:16:12 Scott: Hey, that's pretty good cooling. Isn't it?
119:16:14 Irwin: Beautiful.
119:16:16 Scott: You had enough? [They both laugh]
119:16:18 Irwin: I'll turn this (garbled) up. Yeah, we'll need it. We ought to cool down as much as we can (before disconnecting from LM water).
119:16:22 Scott: Yeah. (Pause)
[Scott - "We've talked about how good the LCG was and how cool it kept us. In fact, it would freeze you. We never got hot. And we were never on max cooling. I mean, that was a great suit."]119:16:26 Irwin: Wait.
[Jones - "And what you're doing here is running LM water through the LCG because, once you disconnect from LM water, it's going to be a while before you can hook up to the PLSS and get the hatch open."]
[Scott - "Yeah. And the basic concept of a liquid-cooled garment is another excellent piece of an optimum approach to lunar operations."]
[We then discussed the air-cooling system that was used with varying success during Gemini. Dave had been scheduled to conduct the first extended zero-g EVA on Gemini VIII but never did because of a stuck thruster that caused a premature abort of the mission. On Gemini IX, Gene Cernan had considerable difficulty during his EVA and, in particular, got tired, overheated, and, finally, was unable to see out of his badly fogged helmet. During the Apollo 17 mission review, Cernan indicated that, although the lack of handholds and footholds was a major contributor to his difficulties, he did not believe that the air-cooling system was really adequate to the task. Dave suggested that, on later flights, Mike Collins, Dick Gordon, and Buzz Aldrin where able to complete their tasks without difficulty - thanks to the addition of handholds and footholds. Journal Contributor Mike Poiszuk notes, however, that " Dick Gordon actually got overheated and sweaty during his Gemini EVA. He first had difficulty installing a sun visor before he left the cabin, then had great difficulty installing a tether on the Agena docking target. Lack of footholds affected him there. Buzz Aldrin was the first Gemini spacewalker to have all his spacewalks productive and successful."]
[Scott - "It depends on who's doing what and how. And where you are. I think that system would have worked. Did Gene use anti-fog? (He did not.) Because, later on (for Mike Collins' EVAs on Gemini X), people said 'Gee, put anti-fog on the visor, isn't that a great idea?' Yeah, well, when I flew on Gemini VIII, we had anti-fog for the visor. And that came very early on. And I ran chamber tests for Gemini VIII with all that gear and doing all that work, and air-cooling was fine. Gene may have had a bad unit. Obviously, he couldn't bring it back to be checked, so it may not have been a generic problem. Because my experience with the same equipment on Gemini VIII was that it worked very well."]
[In a 1996 draft review, Dave added, "Gemini IX was terminated due to faceplate fogging. This was traced and verified to have been the result of no anti-fog compound on the face plate. See On the Shoulders of Titans: A History of Project Gemini, page 338. The suit system worked fine with the anti-fog in a post-flight chamber run." Dave also noted that the basic design for the Apollo EMU, including liquid cooling, was approved before Ed White's pioneering Gemini IV EVA.]
[Scott - "When we started in on this exercise (planning for Gemini VIII), we started with a chest pack, which was an updated version of the one Ed White used, and it was in very bad shape. In fact, we had a Black Friday once. Neil was the boss and we went out to AiResearch in California who were making it, and went through this thing technically. Pete (Conrad, Neil's backup) and Dick (Gordon, Dave's backup) and Neil and I. And it had 126 squawks (noted deficiencies) on it and we had this big meeting back in Houston because of all these problems with this thing. They had tried to upgrade it too quickly. I mean, there were things like nozzles that would have frozen up 'cause they were too small. It was in bad shape. But, then, they fixed it all. So it had been exercised quite a bit and, as I recall, I ran that stuff in the (vacuum) chambers and it worked extremely well."]
["As we've discussed, lot of this stuff goes way back and a lot of these ideas got generated long before the program got going. von Braun built Peenemünde and Cape Kennedy looked like Peenemünde. On the pressure suits, in particular, the Air Force had a lot of experience with high altitude pressure suits. U-2's, and they were flying for hours and hours at very high altitude, and they were wearing partial pressure suits. There was quite a bit of experience when NASA started. When I was at Edwards (Air Force Base, California) zooming 104's, we flew pressure suits and checking them out in the chambers, and they were pretty good."]
[Journal Contributor Harald Kucharek notes that the "104" is the Lockheed F-104 Starfighter. In a 2000 e-mail, I asked Dave if he was talking about the NF-104, which was a modified Starfighter with a 6,000-pound thrust liquid fuel rocket engine in addition to the conventional jet engine. His reply: "Nope, this was pre-NF-104. But the standard 104 did a very nice job, often up to 90,000 feet (altitude), sometimes 100,000." The first NF-104 was delivered to Edwards in 1963, the year Dave joined the Astronaut Corps.]
[Returning to the subject of pressure suits and the cooling problem.]
[Scott - "Now, you couldn't do any work on the Moon (in an aircraft pressure suit), but certainly you could sit in a cockpit of an airplane and you could function in a fully pressurized configuration, quite well." [Jones - "Or you could sit in Gemini and function perfectly well. I believe that, During the (Apollo) 15 EVAs, you did go to max (cooling) while you were drilling, but most of the time you were at minimum."]
[Scott - "Did I? I would believe that! That was hard work."]
[Readers should note that the workloads of the Apollo crews were much greater then those of the Gemini crews and that water cooling was essential to the success of Apollo.]
119:16:28 Scott: Am I hooked? (Pause)
119:16:30 Irwin: Yeah. Here, let me get it. Your hooked on the handle for the PLSS. Can you get down a little bit? (Pause)
[Scott, from the 1971 Technical Debrief - "We started having some problems hanging up in the cabin. I think that they were magnified by the one-sixth-g environment because we didn't compress the suits as much as in one g, and I think we were both riding a little bit higher, and a little lighter. Turn-arounds within the cabin were very difficult, and my hang-up problems were on the mounting lever, or shaft, that holds the PLSS in the recharge station. Jim finally figured that I was hanging up on that handle, and we put some tape on it, across the handle (opening) on subsequent EVAs, which did help. It was also hanging up on the corner of the Flight Data File, which is a sharp corner, and also on the DSEA (Data Storage and Electronics Assembly) guard, the wire cover. It's very crowded in there, and it takes a lot of time in moving about the cabin to prevent hang-ups. And I think we lost, overall, quite a bit of time. I wouldn't be surprised if we didn't lose a total of a half an hour (during the three EVA Preps). (To Jim) Do you remember when you were hanging up?"]119:16:34 Scott: Okay.
[The data file is located behind Dave's station, on the leftside bulkhead above the place on the wall where his PLSS is stowed when not in use. LInked photo taken in 2002 by Frank O'Brien of a LM simulator at the Cradle of Aviation Museum. A mock-up of a CDR PLSS is below the data file compartment and the 'sharp corner' is undoubtedly the one at the lower right on the data file compartment. The front of the cabin is on the right.]
[Irwin, from the 1971 Technical Debrief - "One thing was the water hose (at about 119:20:09). The other was - you know, after you disconnected your umbilicals, they were not stowed as far aft as they probably should have been."]
[Dave got hung up on his hose at about 119:44:37 while trying to get into position to exit the spacecraft.]
[Scott, from the 1971 Technical Debrief - "We got that corrected on the second one (that is, the preparations for EVA-2)."]
[Irwin, from the 1971 Technical Debrief - "Yes, once we pushed them way back in the aft, it was alright."]
119:16:36 Irwin: See if we can put that...
119:16:38 Scott: It's in all the way.
119:16:39 Irwin: (Garbled) it out. (Pause) You had hooked the PLSS harness on the handle.
119:16:43 Scott: Yeah, okay. (Laughs) Okay. Going through here and I'll just hook you. (Pause) PLSS/OPS O2. (Pause)
[The OPS hose goes under Jim's right arm.]119:16:56 Irwin: I'm gonna have to go to Suit Disconnect.
[Jim has just noticed that they've forgotten to changing the setting of the Suit Isolation Valve to Suit Disconnect, thereby shutting off the flow of ECS oxygen into his suit.]119:16:58 Scott: Okay, I'll get it. (Pause as Dave reaches behind Jim) Okay, you're Suit Disconnect. (Long Pause) Okay, it (the OPS hose)'s locked and lock-locked.
119:17:16 Irwin: Okay, we take the (LM) O2 hoses off. (Pause)
119:17:21 Scott: Okay, they're off. (Pause)
117:17:23 Irwin: Okay, "secure about the PGA (Pressure Garment Assembly, essentially the suit)."
119:17:25 Scott: (Garbled) Okay.
119:17:29 Irwin: Okay, "connect OPS"...Okay, already did that. "Retrieve the purge valve."
119:17:34 Scott: Okay. (Pause)
119:17:41 Irwin: (Verifying the condition of his purge valve before handing it to Dave for installation) Okay. It's closed; it's in Low (flow) position.
[The purge valve can be operated at one of two flow rates. In the event of a suit puncture or the failure of the PLSS fan or regulator, Jim would leave the purge valve in low flow, which would let about 4 lbs of oxygen per hour flow from the OPS into the suit and out the purge valve. In the event that there was also no PLSS cooling available, he could switch to the High flow rate of 8 lbs per hour. In Low flow, he would have about a 60-minute oxygen supply and, in High flow, about 30 minutes.]119:17:48 Scott: Button it in. (Pause) Okay. "Purge valve in PGA, red to red." (Pause)
119:17:55 Irwin: Lined up about right?
[ They installing the purge valve, which is red in color, in a red-colored connector at the lower right in the connector cluster on the torso of Jim's suit. Hence "red-to-red". In an emergency, Jim would ready the purge valve by pulling on a line to remove a pin from the valve housing. At the free end of the cord, there is a red-painted ball, sometimes called the Red Apple, to make the cord easier to grasp. Once the pin was pulled, the valve could be opened.]119:17:56 Scott: Yeah, it looks okay. (Long Pause as Dave installs Jim's purge valve) Okay, purge valve's in. Lock-lock.
[Scott - "For high-altitude bailout from aircraft, the emergency oxygen bottle in a parachute harness is activated by pulling a similar 'green apple'."]
119:18:15 Irwin: Okay, PGA diverter valve's on vertical. (Pause) Okay, you repeat the OPS connect.
119:18:23 Scott: Okay.
[With the PGA diverter valve in the vertical position, all of the oxygen flow will be directed into vents at the neck ring. If they put the diverter valve in the horizontal position, some of the flow would be diverted to torso vents. Now, they will get Dave's OPS connected.]119:18:24 Irwin: Okay. You go to Suit Isolation; go to Suit Disconnect.
119:18:27 Scott: Okay, Suit Isol(ation Valve); Suit Disconnect.
119:18:30 Irwin: I'll disconnect your O2 hoses. (Long Pause) Okay, and we'll secure those about the PGA, here. (Pause)
119:18:57 Irwin: Okay. I'll connect the OPS O2 hose. (Pause) Okay. (Garbled)
119:19:07 Scott: Yeah. (Pause)
119:19:14 Irwin: Connected and locked.
119:19:16 Scott: Okay?
119:19:16 Irwin: Okay. "Retrieve the purge valve. Verify closed, lock-pin in, and Low." (Pause)
119:19:28 Scott: (Checking his purge valve) Okay. It's Low; lock-pin in; and it's closed. (Long Pause)
[Scott - "Going through all this, and knowing that we're going to go outside pretty soon on our first EVA, this was real boring! But essential. But it's like a little kid on Christmas morning. How can you sit in here and do this when you know what's out there? But you have to do it. 'Man, just spray me with my suit and let me get on out there and get on with this exercise!'"]119:19:40 Irwin: Okay; it's in.
[Jones - "Let me step into the cabinet and let the suit put itself on."]
[Scott - "One other little side comment. One reason why I enjoyed working with Jim Irwin so much is that he is so patient, so calm, so stable, so persistent. It was easy to do this boring stuff, because Jim would keep a nice pace. Whereas I would be a little more anxious to get on with it. Jim was steady as she goes and was a very good guy to work with."]
119:19:42 Scott: Okay. (Pause) (Garbled)
119:19:42 Irwin: In; and it's locked.
119:19:54 Scott: Okay. Now...
119:19:58 Irwin: "PGA diverter valve, vertical." Vertical. Okay; take a drink.
119:20:01 Scott: Take a drink, and I think I've had about enough of the LCG (cooling), huh?
119:20:09 Irwin: Now let's...(Pause)
[They are unstowing a water gun (photo by Mick Hyde) so that they can take a drink before closing the valve on the descent stage water tank.]119:20:18 Scott: Here, let me get it. That thing catches...
119:20:20 Irwin: Caught on the net.
[There is some loose-weave netting at the sides and back of the Ascent Engine Cover to prevent things from falling to the floor where they would be very difficult to retrieve.]119:20:21 Scott: Yeah. I don't know why they have that little hook...Oh, it's a safety wire. (Long Pause)
119:20:54 Irwin: Here you go.
119:20:55 Scott: Yeah. (Long Pause) Okay; I'll get it. (Pause) Okay; it (the water guns)'s stowed.
119:21:24 Irwin: Okay; descent water (valve) going closed. (Pause) Okay. Ready for helmet and glove donning.
119:21:34 Scott: Okay.
119:21:36 Irwin: "Position mikes."
119:21:40 Scott: Yeah, Dick's got them today.
[This is undoubtedly a reference to backup Commander Dick Gordon but, twenty-plus years after the fact, Dave had no idea what he meant by this.]119:21:43 Irwin: Okay; PLSS fans, on.
119:21:44 LM Crew: (Garbled)
119:21:46 Scott: PLSS fan to on.
119:21:47 Irwin: PLSS fan, on. Vent flag, clear. Cleared.
119:21:54 Scott: Okay; mine's clear.
119:21:55 Irwin: "Don helmets with LEVAs. Check drink bag position."
119:21:58 Scott: Okay. How's that look? (Pause)
[They have drink bags suspended inside the neckring so that they could get sips of water from time to time during the EVAs. The bags have to be carefully positioned so that, when the suit is inflated, the drink valve is in easy reach. A detail from training photo 71-HC-724 shows Jim's drink valve.]119:22:03 Irwin: Okay. (Garbled) ought to get to it. (Pause) Okay.
119:22:17 Scott: Okay. (Pause) (Laughing) Get the drink valve, here. And lunch. (Pause) Okay. (Pause)
["Lunch" is a several-inch-long food bar suspended inside the neckring in a small pouch. The astronauts could tilt their heads down, grab the end of the bar with their teeth, pull it up and take a bite.]119:22:34 Irwin: Here, I can line it up.
119:22:35 Scott: Yeah, you line it up. (Pause)
119:22:41 Irwin: Should be lined up, right there.
119:22:44 Scott: Okay. (Long Pause)
[Scott - "We're getting the drink bags and the fruit bars for lunch, which was another innovation for this long duration mission, driven by the long-duration backpack which changed so many things. When you're in the suits for seven hours, you've got to have something to eat and drink. So, this step of doubling the time (that is, the length of the EVAs) did a lot of things in terms of how you live and work on the Moon. This is an example."]119:23:00 Scott: (The click of the neckring lock on Jim's helmet is audible) Yeah, that's the sound. Clicked and lock. Get your flaps back here. (Long Pause)
["As you know, we did two types of geology training: field exercises without suits, and 'rock pile' exercises, with the suits, where we trained on the equipment and procedures. And we discovered as we were doing both types of exercises - which often took us six hours - boy, you get real thirsty. So you say 'Hey, suit guys. You know what? I'm real thirsty. Can you think of a way that we can have a drink? And they came up with not only the drink bag - and mine worked great - but also the fruit bar, which was terrific. And that little bit of energy, just taking a couple of bites and recharging your battery, in a sense, was very refreshing."]
[Jones - "During the training exercises at some point in Apollo, they started circulating ice water through the LCGs. That is, there was somebody walking around behind you with a pack of ice-cooled water in a pack on his back that would feed through the hoses into the suit and circulate in the LCG. Jack said that the guys with the ice water did a real good job of staying out of the way. Do you remember if water was present during 12 or 15 training?"]
[After I talked to Dave, I discovered that the use of ice water in the training suits started with Apollo 16.]
[Scott - "No. We never did that much extended work in suits. In 12, I don't think we did any suit work, geology-wise. In 15, we did (a lot of suit work) because they built the rock pile there at the Cape. We had so many more things to go through (that) we felt it was necessary to have a suit exercise on the rock pile. But, on 12 as I recall, we never did any suit work. The geology was all shirt sleeve. But, when you go to 15, you have so many more things to do with so much more equipment that it was important to get the interfacing squared away between the equipment and the procedures. On 12, you had the bags and the tongs; and you could pretty well practice that in shirt sleeves. But, now, you had bags hanging on the PLSS, etc., the suit becomes such an integral part of what you do that you can't practice or prepare or write the procedures without them."]
["Another part of the exercise that was accomplished at the Cape at the rock pile - and also in Houston, because we had a rock pile in Houston - was development of the procedures. Remember, this (planning for Apollo 15) all started with essentially a blank piece of paper, building on what 11, 12, and 14 did. From a procedural aspect, one big job was to integrate all this equipment into a set of smoothly-flowing procedures; and once you could write those, you had to verify them. And the only way you could really verify them was with all the hardware present; because, if one piece of hardware was not present, you could have a glitch that you would never know until you got to the Moon. And then you may have a big glitch. So, from a procedural aspect - and we found this all the way through Apollo - you don't just go put these things on and do them. You have to write procedures and they have to be operationally oriented - but with the real hardware. That's why the rock pile and that's why the water. Working outside at the Cape in June or July in the Sun...I'll bet we drank gallons and gallons of Gatorade. 'Cause I can remember taking our breaks and going down and sitting in a little shady place and they brought this wonderful Gatorade, and we would just consume that stuff. And I'm not promoting Gatorade, either. I'm just saying it was a great fluid to replenish a lot of stuff in the body. Unfortunately, not potassium because we didn't know we needed that at the time; but I remember how refreshing that was, to sit down and gulp the Gatorade and put all the stuff back on and go back out."]
[Both Dave and Jim experienced heart irregularities during the mission which were later ascribed to a potassium deficiency.]
[As a final note on suited training at the Cape, although Dave and Jim wore lightweight PLSSs, the suits were very heavy in terrestiral gravity and, when they arrived at a 'station' at the rock pile, they needed help in getting out of the 1-g trainer. Motion picture film shot turning a training session shows three people helping Dave get to his feet.]
[With Jim's drink bag and food stick in position, Dave his now getting him into his helmet.]
[The flaps are on the back of Jim's LEVA and overlap the suit shoulders to provide thermal protection.]119:23:17 Scott: I've got a high-frequency tone on the comm. Do you?
119:23:20 Irwin: I have...I guess I do. Way way in the background.
119:23:25 Scott: Yeah.
119:23:26 Irwin: Yeah. Pretty low.
119:23:28 Scott: Okay; you're all buttoned up. (Pause)
119:23:34 Irwin: Okay...
119:23:37 Scott: Let's get your...
119:23:38 Irwin: (Tool harness) straps.
119:23:38 Scott: ...strap here. Okay, 1 (strap). (Pause) There's 2. Okay...
119:23:48 Irwin: Get yours.
119:23:4 Scott: ...There's 3. (Long Pause)
[Next, they will get Dave into his helmet and visor assembly. Apparently, Dave is holding his helmet and is lowering it onto his neckring while Jim clears the LEVA, etc., out of the way.]119:24:05 Scott: I'll line it up for you.
119:24:08 Irwin: Hold it, Dave. Let me get your...Keep coming down. I'll push this in.
119:24:10 Scott: Okay.
119:24:12 Irwin: Okay; you're clear of the suit.
119:24:15 Scott: Okay; it's lined up if you can...
119:24:17 Irwin: Should be down all the way. (The click of Dave's neckring lock is audible) Okay; it's locked.
119:24:23 Scott: Okay.
119:24:25 Irwin: LEVA's not locked though. (Pause) I'll have to rotate your helmet after I get the LEVA locked.
119:24:43 Scott: Okay. (Pause) Okay.
119:24:49 Irwin: Still lined up?
119:24:50 Scott: Yeah, it's okay. (Pause) Rear flap first? (Long Pause)
119:25:11 Irwin: Okay. (Pause) Okay; let me get your straps with the tool harness.
119:25:16 Scott: Yeah. (Pause)
119:25:23 Irwin: Right one. (Pause) And the left one. (Pause) Okay. (Reading) "LCG, cold, as required."
119:25:35 Scott: It sure is.
119:25:36 Irwin: Okay; I'll go around and...
119:25:38 Scott: Okay.
119:25:39 Irwin: ...take care of it (that is, open the LM LCG water pump circuit breaker) (Pause) Okay; LCG Pump coming open.
119:25:50 Scott: Okay. (Pause)
[Scott- "One reason for this verbal procedure - reading it out - is so the guys on the ground can check us. They are listening to us, and they are going down the checklist - the guys with whom we worked in training, in particular. They are going down the checklist with instructions to watch us and make sure that we say everything we do and we do everything we're supposed to do. So, we have a double-check. Jim's checking me, I'm checking him and we have I don't know how many guys in the suit room checking us."]119:25:54 Irwin: Okay; next.
[Jones - "Who had not only been through it in training with you but who had probably done it themselves."]
[Scott - "That's exactly right. In fact, there was one guy that I worked with a lot, named John Covington, who had done a lot of this suit work himself in developing procedures. So, he's sitting there making sure that we do everything we're supposed to do. Which is comforting, because you get the double-check in there. You certainly don't want to leave anything unhooked or unconnected or unlocked in this kind of exercise. So, when it's finished, it gives us the comfort that everybody's watched us and now we can go outside and you don't have to think about it any more. It's all done, you take it out of your mind. You exclude this whole suit system and you go do your geology and never even think about it unless a warning light comes on, and then you go take care of whatever that is. I think this procedural aspect of everybody checking everybody was a really comforting part of getting ready to go and then doing things. Like we commented earlier, we sleep better if we know you guys are going to wake us up if there's a problem. Checks and balances. Worked good."]
[Jones - "Which raises an interesting issue with regard to Mars."]
[Scott - "Different problem."]
[Jones - "The three guys are going to have to do it for themselves and they're going to have to do it every day for 30 days."]
[Scott - "Which says, for each guy, you've got two checks. Which says you've got to have at least three people, because you need to have a check on the check. Two guys, buddy system, that always works good, but there's an added dimension of safety if you've got a third person."]
119:25:59 Scott: Okay; (Reading) "CB(16) ECS: LCG Pump is open, and disconnect the LM water hose, and connect the PLSS water hose."
119:26:05 Irwin: Okay; in work. (Long Pause) Okay; mine's connected, Dave.
119:26:25 Scott: Okay; mine's connected. (Pause) Okay. "Stow LM hoses."
119:26:33 Irwin: That's in work.
119:26:34 Scott: Okay; I'll put mine up here on the...by the handhold. Out of your way. Right there by the ISS; that works good. (Long Pause)
119:27:08 Irwin: Okay; mine are stowed.
119:27:10 Scott: Okay, standby (Pause) Okay; mine are stowed. (Pause) "Verify the following."
119:27:20 Irwin: I'll turn around.
119:27:22 Scott: Okay. (Pause) Where are we getting any flow from, I wonder?
119:27:33 Irwin: (PLSS) Fan.
119:27:34 Scott: Oh, yeah. Just straight through the cabin; that's right. (Pause)
[They turned their PLSS fans on at about 119:21:43 and, since they haven't donned their gloves yet, there may be some flow at the wrist rings.]119:27:38 Scott: Okay. "Helmet and visor aligned and adjusted."
119:27:41 Irwin: It is. Verified.
119:27:43 Scott: Okay. "O2 connectors; three of them locked."
119:27:46 Irwin: Okay; and I'll put your booties on.
119:27:49 Scott: Yeah. (Pause)
[By "booties", Jim is referring to the dust covers on the hose connections on Dave's suit.]119:27:57 Irwin: Okay; they're all three locked.
[The three oxygen connectors are (1), the OPS hose, (2), the PLSS-to-suit oxygen hose, and (3), suit-to-PLSS return-flow hose.]119:27:59 Scott: Okay. "Purge valves, one, locked."
119:27:57 Irwin: Okay. They're all three locked.
119:27:59 Scott: (Repeating the step) Okay. "Purge valves, one, locked."
119:28:02 Irwin: Locked.
119:28:03 Scott: "H2O connector, locked."
119:28:04 Irwin: Okay. It's locked.
119:28:06 Scott: "Comm connector, locked."
119:28:07 Irwin: Locked.
119:28:08 Scott: "PGA diverter valve to vertical."
119:28:10 Irwin: Vertical.
119:28:11 Scott: Okay. You read to me.
119:28:12 Irwin: Okay. "Helmet and visor, aligned and adjusted."
119:28:15 Scott: Okay. It's verified.
119:28:17 Irwin: "O2 connectors, three locked."
119:28:19 Scott: Okay. One, two, get the bootie down. Three, and the bootie's down.
119:28:28 Irwin: Okay. "Purge valves, one, locked."
119:28:30 Scott: Purge valve's on and locked.
119:28:32 Irwin: Okay. "Water connectors, one, locked."
119:28:34 Scott: Locked.
119:28:35 Irwin: "Comm connectors..."
119:28:37 Scott: On and locked.
119:28:38 Irwin: "PGA diverter valve, vertical."
119:28:40 Scott: Diverter valve is vertical.
119:28:41 Irwin: Okay. "Verify EVA circuit breaker configuration."
119:28:45 Scott: Okay. (Long Pause as Dave turns and checks the circuit breaker panel ( CB(11) ) on his side of the cabin) Okay. Mine are verified.
119:29:08 Irwin: Stand by. I'll check mine.
119:29:11 Scott: Okay. (Pause)
119:29:18 Irwin: Okay. Mine are verified.
[Jones - "With regard to the EVA circuit breaker configuration, it just occurred to me that one of the reasons you might be doing it here is that you've been swinging around in there with PLSSs on and there were at least a couple of occasions in these missions where circuit breakers were hit by a PLSS"]119:29:20 Scott: Okay. "Don EV gloves."
[Scott - "That's true, but also, before you go outside, you want to make sure that everything's set the way it's supposed to be set - as a last check before you take off. You know, like you would check the flaps and all that sort of stuff in an airplane. Even if the previous crews hadn't had problems, we probably would have had this check."]
119:29:23 Irwin: Okay; in work.
[Comm Break. Readers should note that Joe Allen hasn't had anything to say to the crew since 119:15:34. Houston is following along closely, but there have been no crew errors. As Dave mentioned previously, Jim is a very methodical person and has set the tone of this nearly flawless performance.]MP3 Audio Clip ( 11 min 46 sec )
119:30:51 Scott: Got yours on yet?
119:30:52 Irwin: Yeah, yeah.
119:30:53 Scott: Okay.
119:30:53 Irwin: I'm waiting for you.
119:30:54 Scott: Okay; just a second. (Long Pause) Don't bump me for just a second, if you can. (Pause) You'll have to turn around and give me a hand here.
119:31:37 Irwin: Okay. (Long Pause)
119:31:50 Scott: Just hold the glove.
119:31:51 Irwin: Well, you're not in engage position.
119:31:52 Scott: Yeah, I know, but...
119:31:54 Irwin: Okay.
119:31:55 Scott: I can't even get...(Pause)
119:31:59 Irwin: Here, let me do it. (Pause)
119:32:08 Scott: Okay. (Pause)
119:32:13 Irwin: Okay; push. (Pause) Okay?
119:32:19 Scott: Okay; good. Okay. You verify mine; I'll verify yours. Okay. Locked and locked.
119:32:28 Irwin: And you're locked.
119:32:30 Scott: Okay. (Pause)
119:32:42 Irwin: Pull up our cuffs. Go to work.
119:32:45 Scott: (Chuckling) Yeah. (Pause) Okay. "(If) PGA biting, PLSS O2 On/Off." No, it's not. "PLSS Diverter valve to Min, verify." (Pause)
[Here, the checklists suggests that, if the suit is pinching them anywhere, they can briefly turn on the PLSS oxygen flow and partially inflate the suit. The PLSS diverter valve - as opposed to the PGA Diverter valve - is located at the lower, front, right corner of the PLSS and controls the flow rate of feedwater into the sublimator that provides cooling.]119:33:08 Irwin: That's verified.
119:33:10 Scott: Okay, mine's verified. PLSS (water) pump to on, (by turning the switch on the PLSS to the) right.
119:33:14 Irwin: Okay, my pump's going on now.
[The PLSS pump circulates a closed-loop water supply through the Liquid Cooled Garment (LCG).]119:33:16 Scott: Mine's on. Press Reg A and B to Egress.
119:33:19 Irwin: A and B to Egress.
[Here, they are preventing the demand regulators from trying to provide oxygen to the cabin when they depress.]119:33:21 Scott: Okay. Now, we run through the pressure integrity check (as per Surface 3-10). Okay, "PLSS O2 to On."
119:33:28 Irwin: Okay. (Pause) O2 is On. (Pause) My pressure's coming up.
119:33:50 Scott: Okay. My O2 is On. My pressure's coming up. (Pause) Okay. Got a press flag (as expected). (Pause) Okay.
[The flag indicates that the suit is not fully pressurized and, also, that the sensor is working.]119:34:33 Irwin: Okay. My pressure's off the peg (on) the cuff gauge.
119:34:38 Scott: Okay. (Pause) And mine's off the peg. (Pause) My pressure flag's clear at about 3.2 (pounds per square inch, as expected) . (Long Pause) Okay, I'm stabilized about 3.8 (psi), and the O2 flag is clear.
119:35:24 Irwin: Same here.
119:35:26 Scott: Okay. Now we got to do that tricky little maneuver with the PLSS O2.
[Next, they will turn off the PLSS O2 and monitor their pressure gauges. A decrease of about 0.2 psi in one minute is expected due to breathe-down, minor leaks, and flow into nooks and crannies in the suit.]119:35:31 Irwin: Coming Off.
119:35:32 Scott: Okay. Coming Off now.
119:35:34 Irwin: Okay; mine's Off.
119:35:35 Scott: Okay; mine's Off. Mark. A minute, Houston.
119:35:39 Allen: Roger. (Long Pause)
119:36:10 Scott: Man, you can really tell the pump's running, can't you?
119:36:12 Irwin: Uh-huh. Sounds like an airplane - wa-wah - getting ready for takeoff.
119:36:17 Scott: Yeah. (Long Pause)
119:36:33 Irwin: That should be about a minute, Dave, right there. I'm 3.7.
119:36:36 Scott: Yeah. They'll give us a mark.
119:36:39 Allen: That's good.
119:36:43 Scott: Okay, that's our minute, and I'm reading 3.7. Okay; PLSS O2, On.
119:36:49 Irwin: O2 coming on.
119:36:50 Scott: Okay. Verify the...Okay, I got a tone. And verify the O2 flag is clear. (Pause) Okay, Houston. I guess here at Hadley Base, we're standing by for a Go for the Depress.
119:37:06 Allen: Roger, Falcon. You're Go for Depress. Let's take a look at Hadley.
119:37:14 Scott: Good show. Okay, Jim. You ready with the circuit breakers?
119:37:17 Irwin: Yeah.
[Scott - "Exactly two hours. To the minute. He gave us a Go at 119:37:06, and we started it two hours before at 117:37:01. So, within a few seconds, we're exactly two hours from the time we said we're starting the suiting exercise. I don't know how long it was supposed to have taken."]119:37:18 Scott: "CB(16), ECS Cabin Repress, open."
[The checklist does not contain explicit times for the start of the EVAs. At 118:36:41, Houston said that they expected the EVA to start at about 119:27, indicating that, from that point, Dave and Jim took an hour to accomplish tasks planned to take 50 minutes.]
119:37:20 Irwin: Cabin Repress, open.
119:37:24 Scott: "CB(16), Comm, TV, closed."
119:37:26 Irwin: Comm, TV, closed.
[The Apollo 15 TV coverage promised to be much better than that on any of the prior missions. See an account by Apollo 15-17 RCA Project Engineer Sam Russell. Documentation for the various TV systems flown during Apollo have been assembled by Bill Wood.]119:37:29 Scott: Okay, "Cabin Repress valve to Close."
119:37:31 Irwin: Cabin Repress, Closed.
119:37:35 Scott: Okay, and you can come around to the dump valve.
119:37:37 Irwin: Okay. (Pause)
[In order to open the Cabin Repress circuit breaker and close the TV breaker, Jim had to turn to face the circuit breaker panel ( CB(16) ) at his right shoulder. Then he had to turn and face aft while he closed the repressurization valve. Now, he has to turn forward again so that he can reach the dump valve in the forward hatch. Because of the location of the valve, it is easier from him to bend over to reach it than it would be for Dave to reach it.]119:37:44 Scott: Okay, I got a tone. Do you have a tone?
119:37:47 Irwin: So do I.
119:37:48 Scott: Yeah. It's gone.
119:37:50 Irwin: (Garbled)
119:37:51 Scott: Can you get around all right?
119:37:52 Irwin: Yeah.
119:37:53 Scott: See if I can get out of your way a little bit.
119:37:54 Irwin: Oh, is that what's blocking me?
119:37:55 Scott: Yeah. Move back in the corner (probably the right rear).
119:37:57 Irwin: Okay.
[With both of them in pressurized suits and wearing PLSSs, there is very little room to move. Jim is having trouble getting turned around because Dave is poorly positioned and Dave asks him to back into the right rear corner, at the intersection of the ECS cabinet and the right bulkhead, so that Dave can get in a better position. The lateral movements probably involve no more than a few inches.]119:37:58 Scott: Let me get turned around here a little bit. (Pause) Okay, now I'm a little bit more out of the way for you.
[Jones - "Is there anything you'd like to say about the problem of just physically moving around inside that tiny little closet in a pressurized suit?"]
[Irwin - "Well, it's a little tight. And we were always concerned about hitting circuit breakers or hitting a piece of equipment and breaking it. You kind of almost feel like you're in a suit of armor and how insensitive you are to the things around you."]
[Jones - "You can't feel the suit bumping up against anything."]
[Irwin - "No. As you know, I think all of the crews managed to break off something. Circuit breakers or valve controls. You're just so isolated."]
[Jones - "Were there guards on switches?"]
[Irwin - "Well, hopefully there were guards, but, in some case, we managed to get through the guards. You're just like a bull in a china closet. Everything's so sensitive around you, and yet you feel like you're insensitive in your environment."]
[Jones - "You're standing on the right side, and Dave's standing over on his side and, if you're standing side by side, you're basically filling up the space?"]
[Irwin - "Uh-huh."]
[Jones - "And the hatch is in the center between you. So you're problem, when he starts to go down to get the hatch, is to get..."]
[Irwin - "Really over, with my back against the circuit breaker panel on the right wall."]
119:38:13 Irwin: Okay. I'm ready to go down (to get the dump valve)
119:38:15 Scott: Okay.
[Jones - "There were two dump valves: one in the rendezvous hatch overhead and one in the egress hatch. Here, you were going to reach down and open the valve in the forward hatch?"]119:38:18 Irwin: I'm at the dump valve.
[Irwin - "Yeah. That's what I meant about 'getting ready to go down'. Physically go down - not go down in pressure."]
[Jones - "The suit's pressurized at this time. How difficult was it to bend. Was it easier to bend in the LM? Were there things you could grab on to and pull yourself down."]
[Irwin - "Sure. And you really didn't have to get down that much. The dump valve...I'm trying to think. I think it was in the center of the hatch, so it would have been maybe a foot and a half off the floor. So you're just reaching down to that level."]
[Jones - "So, standing, you've just got to get over a few inches."]
[Irwin - "Yeah, right."]
[Nonetheless, several of the astronauts had a fair bit of difficulty reaching down far enough to get the dump valve.]
[Irwin - "I wonder now, thinking back, why we didn't use the overheadvalve to dump the pressure, rather than the one in the hatch."]
[Jones - "Easier to get at? Was reaching up in the pressurized suit do-able? Could you get your arm overhead?"]
[Irwin - "You could, but I guess it was probably easier to go down than up."]
[Gene Cernan, who was one of the taller astronauts, used the overhead valve on Apollo 17, as did Charlie Duke on Apollo 16.]
119:38:19 Scott: Okay; let me get a hold of the cabin pressure, here.
119:38:21 Irwin: Okay.
[Dave will watch the cabin pressure gauge while Jim opens the dump valve. Let the pressure drop to 3.5 psi and then will close the valve and watch their suits respond to the change in relative pressure.]119:38:22 Scott: Open and then Auto at 3 and a half. Okay?
119:38:24 Irwin: Okay, I'm Open?
119:38:25 Scott: Okay, we're down to 4 and a half. 4.
119:38:33 Scott: Mark. 3.5.
119:38:34 Irwin: Back to Auto.
119:38:38 Scott: Okay. "Verify cuff gauge has not dropped below 4.6." I'm looking at 5.1.
119:38:44 Irwin: Okay. Same here.
119:38:46 Scott: Roger. Okay. "Verify cabin at 3.5", and it is at 3.5. "LM suit circuit lockup at 4.3", and it's at about 4.5. Okay; "PGA greater at 4.6 and decaying". And that's a verify on mine. And something about the clock here.
[They are probably going to use the stop watch function on the Omega Speedmaster Professional wristwatches to time the EVA and will start them now as they re-open the dump valve to start the EVA.]119:39:08 Scott: And got it. Okay; overhead or forward dump valve to Open.
119:39:12 Irwin: Okay. I'm going Open.
119:39:13 Scott: Okay. "Verify tone on, water flag A at about 1.2 to 1.7." (Pause)
[As the cabin pressure drops, PLSS sensors will note that they have not yet started the flow of feedwater into the sublimators.]119:39:23 Scott: Okay; we're down to 2.5. (Pause) 2.0. Gee, I can see condensation in here.
119:39:32 Irwin: Say you can?
119:39:33 Scott: Yeah, a little fog.
119:39:35 Irwin: Ah!
[The pressure drop causes an expansion and cooling of the remaining oxygen in the cabin and, because the oxygen is quite moist, they are getting some momentary condensation.]119:39:36 Scott: Okay; 1.5.
119:39:37 Irwin: Okay, I've got a water tone.
119:39:40 Scott: Okay. And I have a water (flag) and a tone. Okay; down to 1.0. (Pause) Okay. When it gets all the way down, I'll partially open the forward hatch; so you can come back up.
[Based on the experience of prior crews, they won't be able to open the hatch until the cabin pressure drops below 0.2 psi. As the cabin pressure drops, the relative pressure in the suit increases to over 5 psi and Jim is having to strain against a very "hard" suit. Now that they are sure that the depressurization is going normally and that the suits are air tight, he can stand up, rest, and get out of the way so that Dave can bend over to get the hatch handle. It will be some while before breathe-down will "soften" the suits to their normal working pressure of 3.7 psi.]119:39:58 Irwin: Okay; I'll just leave the dump valve in Open. Okay.
119:40:03 Scott: Now if you could slide back over to the right a tad there.
119:40:05 Irwin: Yeah. (Pause)
119:40:17 Scott: That jettison bag sure fills up (the cabin). I need that right there, old buddy.
119:40:22 Irwin: Yeah, I've got to swing it around so I can get your (PLSS/OPS) antenna, too. (Pause) Whenever you can move over to the left. I want to swing around to the left.
119:40:31 Scott: Okay. Let me get the jettison bag out of the way.
119:40:32 Irwin: Okay.
119:40:34 Scott: The world's biggest jettison bag. (Pause) Okay. (Pause) Okay; hold off. Better get the cabin (pressure) down so I can open it (the hatch) partial here. (Pause)
119:41:10 Irwin: Get down there okay?
119:41:11 Scott: (Straining) Yeah. Okay; it's open. (Pause)
119:41:19 Allen: Roger, Dave. And we've got that mark.
119:41:20 Irwin: (Looking out his window) We're blowing moisture, but...(Stops to listen to Allen) It's blowing ice crystals out the front hatch. It's really beautiful. You should see the trajectory on them. (Laughter)
[Irwin - "I wonder where it was coming from. Must have been moisture. I didn't remember that. I know that when we had the water leak and then the air blew a lot of ice crystals out the front hatch. It went out the dump valve. The water was just sucked up and went through the dump valve and the formed ice crystals that had beautiful trajectories. But I just wonder where the water was coming from at this point."]119:41:29 Scott: I can't keep it open because of the pressure.
[Jones - "Well, there was some mention back here (at 119:39:23) about a little bit of fog. Was the air inside the cabin reasonably humid?"]
[Irwin - "Well, there is humidity, you know. There is some moisture there. That has to be the source of it."]
[Jones - "Was it a very fine ice crystal? Do you have any sense of that?"]
[Irwin - "I don't remember that. But you should see the trajectory on it. I just forget that. I remember it later on. I got real sensitive to it, later on, I had an abundance of water coming out."]
[Jones - "I think it gets mentioned virtually every time the hatch opened on any of these missions, except for 11."]
119:41:34 Allen: I bet they're flat, aren't they, Jim? The trajectories.
119:41:36 Scott: Can you hold it open, Jim? Hold it open there.
119:41:40 Irwin: (Answering Joe) Very flat, Joe.
119:41:45 Scott: Oh, man. (Pause)
119:41:47 Irwin: (As the hatch starts to close again) Whup! Hold it.
119:41:48 Scott: Yeah.
119:41:48 Irwin: There you go.
[At most, the hatch comes to knee height and, in order to catch it, Jim probably has to bend at the knees to get his hand low enough.]119:41:49 Scott: Go on back over to where you were.
119:41:53 Irwin: It went back closed. What's that getting caught on our feet? Is that that Velcro? Straps? (Pause)
[Scott - "The Velcro straps on the floor were used to hold our feet to the floor during landing and take-off."]119:42:01 Irwin: Let me get back in my corner, here.
[There were mating Velcro patches on the soles of the pressure-suit boots, as can be seen in a pre-flight photo of Buzz Aldrin's suit.]
[The hatch was supposed to swing open in front of Jim's knees but, apparently, has only opened a little more than half way.]
[Irwin, from the 1971 Technical Debrief - "When we stowed the bracket that holds the PLSS to the floor, we didn't get that pin fully secured, and that bracket did not go down flush with the floor, so the hatch would not open fully. This caused a subsequent problem for me, getting out and getting back in...I guess we lacked about 40 degrees on hatch motion"]
[In 2002, Frank O'Brien provided a photo of him standing in a LM simulator with a PLSS mock-up on the floor immediately aft of the hatch.]
[Scott - "One might ask, 'why didn't it open to the outside, instead of the inside'. Which is another long, but interesting story. In the beginning of Apollo, on both the Command Module and the Lunar Module, the hatches were designed to open to the inside such that, when they were closed, the pressure of the cabin would keep them closed. And we found out the hard way on the Command Module (because of the Apollo 1 fire that killed Gus Grissom, Ed White, and Roger Chaffee) that that's the wrong way to go. Because, when we had the fire - not that it ever would have mattered - the hatch was sealed from the inside. One of the problems with that Block I Apollo Command Module (in contrast with the Block II Command Module flown on Apollo 7 and all subsequent missions) was, once you had pressure, by golly, you couldn't get that big plate off. They re-designed the Command Module so that the hatch opened outward, and the sealing was fine once you locked it in."]
["They never re-designed the Lunar Module because it's not a good idea unless you have a lot of locking mechanisms - which the Command Module could afford in terms of weight, but the LM could not afford. So, when they went through the re-design rationale, they probably left the LM alone because the hatch was very light."]
["In the early days, they were worried about all sorts of weird things like, in the Command Module, they had us practice putting on our suits in case we got a hole in the Command Module. So you have three guys unsuited and you have a fire drill because, somehow a projectile has punched a hole in the Command Module. It had a bleed rate which was limited by design specs; and you had whatever it was, say five minutes, for three guys to get their suits on. And I remember McDivitt, Schweickart and I tried it, and it was a joke. There was no way for three guys to get their suits on in five minutes or ten minutes or whatever it was. So people had to go back and think through whether that was really necessary and, as with a number of things in the beginning, this had to do with the mysteries of the game in the beginning and the uncertainties and the unknowns of what happens in a vacuum when you try to operate spacecraft. Things like that led to a final design, which was really quite good."]
["People don't have to go through that any more, because we understand all that. And I bring that up to show how many uncertainties there were in that era and how many trails people followed that were empty. Today it looks easy - piece of cake - because we got to the answer. But in the process of getting down the right trail, people wandered off on all sorts of different, endless, unfulfilling trails. It was a lot of work and it eventually converged on a good system. Much of what you're seeing here was necessarily a result of trial and error. Here's a design concept. Let's try it. Does it work?"]
[Jones - "I was interested to hear your story about the suit exercise because the first thing that came to mind was the science fiction stories I read as a kid in the fifties - back when they didn't know what the meteorite threat was. I seems to me, now, that in virtually every space travel story of that time, one of the moments of drama was a meteor strike and somebody would rush over and slap a metal plate on it or somebody would go sit on it or whatever."]
[Scott - "It's sort of the dike story. The guy in Holland put his finger in the dike to plug the hole."]
[Jones - "And I'll betcha a lot of those engineers had read those same stories and had been trained to think about those issues by the science fiction writers."]
[Scott - "I'm not so sure the science fiction got into that, so much. I think the unknown of the space domain and how many projectiles would be out there and who would be hit by what, because there was a lot of design consideration in the Command Module for impacts. We went through a big exercise on how thick are the windows and how thick is the shell, to make sure you don't get holed by some of these things. And the Lunar Module, when they got to that, was very, very thin, because it had to be very thin (because of weight constraints)."]
["In the early days, just from an engineering/design consideration, 'what's the maximum leakage - maybe not even from a projectile - out of the Command Module you could survive by putting your suits on?' Which got into subsequent exercises of when do you wear the pressure suits? Do you wear them all the time? Do you wear them on launch, on entry? And, on 15, as you probably know, a month before we went, the Russians lost three guys because they had a valve open during descent and they couldn't get protected in time - because they were in shirtsleeves. I know that on Apollo 9 we didn't have suits on and, a month before 15, there was a big exercise on whether or not we should wear our suits on re-entry. And, finally, the people who exercised this got persuaded that, in fact, our system was quite different from theirs and, in fact, was quite safe. So, no, we weren't going to wear suits for re-entry. So this suit on, suit off, when do you wear them issue had been exercised quite a bit over the years."]
[Jones - "Gene Cernan described the LM to me, one time, as an oil can. That when you pressurized it or depressurized it, you could see it and hear it flex."]
[Scott - "Probably. Yeah. It was thin, but strong."]
119:42:03 Scott: Yeah, you really have to.
119:42:04 Irwin: More room. Let me turn around to the right. (Pause)
119:42:17 Scott: Can't keep it open! (Pause) There. (Pause) Okay. (Long Pause)
MP3 Audio Clip ( 10 min 53 sec )
119:42:45 Irwin: Listen, maybe I...Can you hold it open?
119:42:48 Scott: Yeah, I got it open. But I wish I had a mirror. (Long Pause) I feel like I'm caught on something!
[Because of the bulk of the suit, the tight quarters, and the RCU mounted on his chest, Dave's view is very restricted. Some of the astronauts wore wrist mirrors that let them look at the front of their suits.]119:43:06 Irwin: I think it's the Velcro straps on the floor.
[Jones - "Jack and Gene each had a wrist mirror."]
[Scott - "So did I. In fact, I had a mirror on Gemini VIII to look at connectors and things like that. And, in fact, I think Jim and I even practiced with them. I know we had mirrors."]
[Jones - "Note to myself to thumb through the pictures and see if I can spot them on the suits. (No luck as of late 1998.) This statement puzzles me."]
[Scott - "It puzzles me, too. Maybe I didn't have one available or in the right place. But mirrors were pretty common."]
119:43:08 Scott: No, it's my back. (Pause) Okay. I can't tell. Okay. "PLSS primary water, open." Ready to do that?
119:43:25 Irwin: Yeah. (Pause) Let's see. Can't get around to it.
119:43:33 Scott: Yeah, I'm going to have to move the...Can you look around and...
119:43:37 Irwin: Let me turn around here and...
119:43:38 Scott: Yeah.
119:43:40 Irwin: ...see what might be...(Pause) Feel like I'm caught on something. (Long Pause) I'm hung up on something.
119:44:07 Scott: Yeah.
[Scott - "This is taking so long because you've got to be very, very careful. And, if you feel like you're hung up on something, you don't try to pull away. You stop! Even the slightest feeling of something abnormal, you don't just jerk. That's why this takes so long. You stop and think 'Well, maybe I'm hung up on a circuit breaker and, if I pull hard, maybe I'll break it!' When you're in the real world, you tend to be very careful."]119:44:09 Irwin: You see what I'm hung up on?
119:44:10 Scott: No. (Pause) No, wait a second.
119:44:11 Irwin: Okay; I'm swinging around now. Let me check you. (Pause) (Breathing into the mike) Let's see.
119:44:21 Scott: See anything hung?
119:44:22 Irwin: Oh, this thing. It's your (LM) hoses. Here.
119:44:25 Scott: The hoses.
[See the discussion after 119:16:30.]119:44:27 Irwin: Okay. Oh, I think that strap. I think the hoses were...Let me adjust that strap (probably a strap on Dave's tool harness).
119:44:36 Scott: Okay.
119:44:37 Irwin: Your right side. It was hung up on these hoses. (Pause) Stand by.
119:44:45 Scott: Okay.
119:44:46 Irwin: Did you get your (feedwater) water on?
119:44:48 Scott: No, I never got it. Let me get it now. (Pause) There, I've got it on.
119:45:01 Irwin: See if I can get around (that is, reach back with his right hand) and get mine. (Pause)
119:45:06 Scott: You know, one thing we never did was to tie this jettison bag up. (Long Pause)
119:45:27 Scott: Get it all right? (Jim is breathing hard) Don't work too hard.
119:45:40 Irwin: Yeah, I'm doing fine. (Long Pause)
[Jones - "I gather that, some of the times when it sounds like someone's breathing heavily, it's just that they're looking down and it's mike position."]119:46:03 Scott: Get it on?
[Scott - "Yes, exactly. Because you're into the mike and you're triggering the mike. Although he was working pretty hard, here."]
119:46:05 Irwin: Yeah, it's on. The only question is whether it's on completely all the way. I think it is. I'll know as soon as the cooling comes in. (Long Pause)
[Irwin, from the 1971 Technical Debrief - "Another problem that I noticed was the (PLSS) strap length. It's measured in one g, and I think that's a mistake. Because my controls (on the right, forward corner of the bottom of the PLSS) were just too high at one-sixth g. The PLSS was riding too high. I had a difficult time getting to the controls."]119:46:30 Scott: I wish I could get this jettison bag out of the way. (Pause) Here, let me pass this over. Put this on the engine cover?
[Scott, from the 1971 Technical Debrief - "I thought the strap length was measured in the rig that supported the PLSS at one-sixth the weight."]
[Irwin, from the 1971 Technical Debrief - "It was (measured) on the rig, but something was different."]
[Scott, from the 1971 Technical Debrief - "You felt your controls were a lot higher. Mine felt fine. I didn't have any trouble reaching the controls, other than when my fingers got sore. I noticed your PLSS seemed to be sitting in an angle, too, where your controls were further behind."]
119:46:48 Irwin: I'll try. (Pause)
119:46:54 Scott: Get it?
119:46:56 Allen: Jim, this...
119:46:57 Irwin: (Lost under Joe's transmission)
119:46:58 Allen: ...is Houston. Your water looks good to us.
119:46:59 Irwin: Here. Let me just hold it. (Responding to Joe) Oh, good. Thank you, Joe. (To Dave) I'll just hold it here, Dave, until you've moved down.
119:47:06 Scott: Okay.
119:47:07 Irwin: Before you get out, let me get that...your (PLSS/OPS) antenna.
119:47:10 Scott: Yeah. But, you can get that as I get through the door.
119:47:12 Irwin: Yeah. (Long Pause)
[Jones - "In the photos, the antenna looks like it was a thin, flat wire."]119:47:24 Scott: I can start (getting into) position here. (Pause) There. (Pause)
[Irwin - "It was a strip of aluminum. There was a piece of Velcro (on the top of the OPS). The antenna went into a Velcro loop and you just pulled it out of the Velcro loop and would just spring up."]
[Dave turns to face the left rear and lowers himself to his knees, backing his feet partway out the hatch. Normally, he would then move over to get centered in the hatch and, as he backs out a little farther, gets down on his hands, being careful not to hit his helmet on the midstep. Here, with the hatch only partly open, he is probably staying over on his side of the spacecraft more than he normally would.]119:47:41 Scott: Don't know how we missed that. Put it on the midstep. (Pause)
[Jones - "I gather that the open hatch is essentially filling the space up to knee level."]
[Irwin - "Yeah. And it's interesting that, in the original design, it was a round hatch. Really circular. And I think it was Bill Anders who said, 'Do you really want a round hatch (with a square PLSS)?'"]
[It is possible that Dave has noticed the pin that is keeping the door from opening completely, although it seems a little early in the egress for that to have happened.]119:47:52 Irwin: Okay; my water flag's clear. Getting cooling. Min cooling. You might want to go to Intermediate.
119:48:00 Scott: Yeah. (Long Pause)
[The heart of the sublimator is a porous plate open to the lunar vacuum. As feedwater flows through the plate, expansion of water vapor at the surface causes cooling and the formation of an ice layer which then prevents free escape of the feedwater. The flag doesn't clear until that ice layer has built up, a process that takes about 4 minutes]119:48:29 Irwin: Did you go to Intermediate?
119:48:30 Scott: Yeah. But I haven't got a flag clear yet.
119:48:35 Allen: Dave, it should clear in a minute.
119:48:37 Scott: It just...(Hearing Joe) Yeah, it just went. I just looked at it. Must take the right pair of eyes. (Long Pause) See what's next on the agenda here. (Pause)
119:49:16 Irwin: Sep light's on.
[As per checklist, Jim has checked the status of the ECS warning system.]119:49:19 Scott: "Lower EV visor." Okay. (Pause) Yeah, I'm beginning to get a little bit [of cooling] now.
119:49:28 Irwin: Get your visor?
119:49:29 Scott: I'll get it. Thought I'd do it down at the door so I don't scratch it...
119:49:36 Irwin: Okay.
[The outer visor is electroplated with a thin layer of gold to provide protection from solar ultraviolet radiation which, on Earth, is mostly blocked by the atmosphere. Journal Contributor Ken Glover notes, however, that the bubble helmets must have provided reasonably good UV protection all by themselves, because Jack Schmitt often had his gold visor up during Apollo 17 and didn't get any noticeable sunburn.]119:49:37 Scott: ...moving around in here. Hey, Houston. By the way, you got TV picture down there?
119:49:45 Allen: Not yet, Dave. We're working on it. (Pause)
119:49:54 Scott: Say again. (Long Pause)
[The TV is currently mounted on the Modular Equipment Stowage Assembly, a table like structure currently folded against the side of the LM below Jim's window. Once he gets to the top of the ladder, Dave will pull a lanyard to release the MESA so that it can rotate down 120 degrees to a comfortable working height. The TV is positioned so that Houston can watch Dave and Jim come down the ladder. Because Dave hasn't yet gone through the hatch, there is no TV picture. Joe's next comment and tone of voice suggests that Houston is not sure if Dave has started out the hatch yet.]119:50:16 Allen: Dave, this is Houston. Is the MESA deployed?
119:50:22 Scott: (Laughs) That might have something to do with it, huh, Joe? Not yet. Okay. I'm ready.
119:50:31 Irwin: Okay.
119:50:3 Scott: Hey! Can you move back a tad?
119:50:39 Irwin: Yeah, (garbled). (Pause)
119:50:45 Scott: Yeah; Here we go.
119:50:53 Allen: Dave, this is Houston. Jim's feedwater pressure is a little high. We wonder if you are in a position to see water coming from his sublimator. Over.
119:51:06 Scott: Ha! I'm sure not, Joe. Not really...
119:51:08 Irwin: Look, let's check it out when we get out, Joe.
119:51:12 Allen: Roger. (Pause)
119:51:22 Irwin: Okay. Down a little further, Dave.
119:51:24 Scott: Yeah.
119:51:25 Irwin: The back of the PLSS is just hitting the DSKY desk.
[The DSKY panel sticks out into the cabin about a foot from the instrument panel. Dave has to get his PLSS and helmet under it as he crawls out backwards. As he suggests in his next transmission, he probably has the jettison bag right in front of him on the ascent engine cover and was trying to stay clear of that.]119:51:28 Scott: Yeah, I was caught on the jettison bag. (Pause)
[Irwin - "Where Dave says he was caught on the jettison bag, I don't understand that because the jettison bag, at that point, should have been up on the ascent engine cover."]119:51:32 Scott: How's that?
[Jones - "Unless the spacecraft just isn't very deep in that direction and he has his helmet caught on it or something."]
[Irwin - "Yeah, it could be that his helmet might have been somehow caught up on that jettison bag, 'cause his head would have been just about at the ascent engine cover. Yeah."]
119:51:34 Irwin: You're clearing it now. Over a little to your...little to your left. [Pause] Down a little more; a little to your left.
119:51:43 Scott: Okay. How's that?
119:51:45 Irwin: Good. Okay. Let me get the antenna. Hold right there. (Long Pause) Okay. Your antenna's deployed.
119:52:02 Scott: Okay. (Pause)
[Jim has just released Dave's PLSS/OPS antenna.]119:52:07 Scott: Ease out here (on the porch). (Pause) Okay! (Pause) Okay. Let's try the MESA. (Pause as Dave pulls the lanyard attached to the north side of the ladder) Down it comes. MESA's down!
[The small area available to the crew at the front of the cabin is best illustrated by images taken during final Apollo 16 (LM 11, Orion) and Apollo 17 (LM 12, Challenger) LM close-out on the pad at the Cape prior to launch.]
[A view from above shows the LMP's PLSS (without the OPS) and two helmet bags (containing the LEVAs) filling the space. As detailed on pages LV-4 and 5 in the Lunar Module News Reference, the useable floor area measures about 55 inches (140 cm) from side to side and about 36 inches (91 cm) from the hatch to the base of the 18-inch (46 cm) 'midstep' behind the crew stations. Note that the PLSS dimensions are about 26 inches (66 cm) long, 19 inches (48 cm) wide, 9.5 (24 cm) inches thick at the base, and 8.75 (22 cm) inches thick at the top. The photographer was standing on the midstep, with its edge near the bottom of the frame.]
An Apollo 16 frame taken through the open hatch shows a member of the close-out team standing on tiptoes on the midstep, with the ECS on his right and stowed itens behind the Commander's station on his left. A similar Apollo 17 frame shows a member of the close-out team sitting on the Ascent Engine cover. Finally, an Apollo 16 frame shows the top of the engine cover with Velcro strips and cloth straps where the LM crew secured the helmet bags after re-installing the drogue and probe in preparation for undocking from the CSM.]
[Jones - "With Jim in there, there's not much room for you to get out. He's over behind the door, with the door open against his knees. You turn around and face the back of the cabin. Do you actually go to your knees, or do you walk down with your hands?"]
[Scott - "As I recall, you actually go to your knees, although I'd have to think about it. As I hear this, probably one of the problems is having the jettison bag in the way."]
[Jones - "That Jim is holding or has on the engine cover."]
[Scott - "It's like a third person."]
[Jones - "So you go to your knees and then slide your feet out until you can get your hands down, and then get centered in the hatch."]
[Scott - "It wasn't really tough. There was a lot of chatter here, but it really wasn't a big deal. You go very carefully. This is not just throw your body out the door. You don't want to ding anything in the spacecraft, you don't want to ding your PLSS or the monitor (RCU) on the front. You go slow, take it easy, stop if anything isn't just right. So you hear a lot of chatter, but it's not because there's any particular problem."]
[Jones - "I gather that it wasn't more difficult for the Commanders to get out than the LMPs. The LMPs had a little bit more room, but my impression is that the difference in the transcript is that there were two people in the cabin so you had a lot more chatter about it. When the LMP is getting out, the other guys out on the surface, so there isn't as much chatter."]
[Scott - "And there is more room, because he can get the door all the way open. And there isn't the jettison bag."]
[Another factor may have been the fact that, because the Commanders got out first, their suit pressures may not have decreased all the way to the normal 3.7 psi working pressure. The LMPs got out ten or more minutes later and probably had softer suits for egress.]
[Dave and Jim are now on the first pages of the cuff checklists that they will use throughout the EVA. Pages LMP-2 and CDR-2 have procedures for reconnecting to LM water - probably in the event of PLSS malfunctions - and pages CDR-3 and LMP-3 have the first tasks and procedures for the normal EVA.]
Video Clip 2 min 45 sec ( 0.7 Mb RealVideo or 25 Mb MPG )
119:52:36 Irwin: Okay, Dave. I'm going to put the jett bag in the hatch.
119:52:39 Scott: Okay. (Pause)
119:52:45 Allen: Okay, Dave; and superb television picture down here.
119:52:49 Scott: Oh, that's encouraging.
[Those listening to the audio track may have noticed a high-pitched beep at the start and end of each of Joe's transmissions. Markus Mehring has provided a discussion of these Quindar Tones.]
[Scott, from the 1971 Technical Debrief - "I didn't have any particular trouble getting out. I think that's because you were guiding me as I went out. I remember you gave me a couple of 'move rights' or 'move lefts' - something like that, and I didn't have any trouble getting out."]
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