Jack Lousma (CAPCOM)

What I'm saying, Jim, is the guys who are working on this attitude situation for the burns haven't made their final conclusions yet, but in the interim period, we want to come up with something you can use, in the event that you lose COMM.

Jim Lovell (CDR)

Houston, Aquarius. The Earth is going through the 10-degree line or angle of the LPD.

Jack Lousma (CAPCOM)

Okay, We copied 10 degrees. Is that Earth or Moon, Jim?

Jack Lousma (CAPCOM)

Okay. Earth 10 degrees. Thank you.

Jim Lovell (CDR)

And, Houston … As we … No! … has an angle of about 24 degrees on the LPD.

Jim Lovell (CDR)

Jack, … the LPD on the Moon now is 22 degrees.

Jack Lousma (CAPCOM)

Okay. I'm reading you better, Jim. Say again, please.

Jim Lovell (CDR)

Roger. The LPD now on the Moon is 22 degrees. I missed the Earth last time. I'll get it this time.

Jack Lousma (CAPCOM)

Okay. Twenty-two degrees, and looks like we've come up with a procedure for the attitude control on the upcoming burns. Probably the ones that we'll use from here on out.

Jim Lovell (CDR)

Okay, Jack. Stand by 1.

Jack Lousma (CAPCOM)

It's going to be a few minutes before I'm ready to read it up to you.

Jim Lovell (CDR)

Jack, on the first of the LPD angles is about a minus 2 degrees and just slightly above the top line.

Jack Lousma (CAPCOM)

Okay. Just went by minus 2 degrees. Is that on the Earth?

Jim Lovell (CDR)

That's the Earth. Now, I don't know whether we're oscillating back and forth or not, Jack, or whether it's a continual motion. We'll have to see here.

Jim Lovell (CDR)

Okay, Jack. The Moon now has an LPD angle of 10 degrees

Jack Lousma (CAPCOM)

Roger. The Moon at 10 degrees.

Jack Lousma (CAPCOM)

Okay, Jim. Just as kind of a lead-in to this procedure that we're going to use for the mid-course to use AGS and it's going to be a manual burn. The attitude will be controlled manually; the start/stop on the engine will be controlled manually. So we have a pretty good vector on you now, and it turns out you're coming in a little bit too shallow. So what that means is we're going to make our burn to come in a little more steeply, and we're going to be coming in around the dark side of the Earth. Therefore, to come in more steep, our thrust should be in the direction of the Sun. Does that all make sense to you?

Jim Lovell (CDR)

I think so. We're going to use AGS for a burn monitor. The burns are going to be manual, and they're going to be started manually and stopped manually.

Jack Lousma (CAPCOM)

Okay. And your reentry is around the dark side of the Earth, and since we're coming in shallow, we're going to have to burn toward the Sun to make it steeper. Do you follow that?

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Spoken on April 15, 1970, 10:18 a.m. UTC (47 years, 5 months ago). Link to this transcript range is: Tweet

Jim Lovell (CDR)

That's affirm. Especially these burns will be perpendicular to our flight path and to the Sun giving a steeper entry angle.

Jack Lousma (CAPCOM)

Okay, Jim. I heard you say perpendicular to your flight path, which is affirmative, and I didn't get the rest of your statement.

Jim Lovell (CDR)

I understand the technique, Jack. We're burning to give us time to steepen our entry angle, and it will be perpendicular to our flight path for corridor control.

Jack Lousma (CAPCOM)

Okay. That's affirmative. So, in general terms, what we're going to have to do is to power up the AGS and bring up the AGS eight-ball, and then to set up your attitude, put the COAS in the front window, and guidance control will be in AGS, of course. But manually orient the spacecraft to place the center of the Earth directly out the Z-axis. Then rotate about the Z-axis to place the point of the crescent on the Y-axis of the COAS. And this will have your plus X-axis in the direction of the Sun as we discussed before. So the crescent will be up with the point down. Copy that?

Jim Lovell (CDR)

Okay, Jack. We'll have to go over what again. The COAS will be out front window; we'll place the Earth in the center of the COAS, and, let's see, the center of the Earth right now is parallel to the LPD which is about parallel to our X-axis. And we'll have to rotate about 90 degrees

Jack Lousma (CAPCOM)

Okay, Jim. So we want to get the Y-axis of the spacecraft parallel to the terminator by putting the points of the crescent on the Y-axis.

Jim Lovell (CDR)

Seriously, Jack, when I stop the spacecraft looking at—at the Earth, I'm going to have to roll—in LM terms, roll the spacecraft 90 degrees to get the tip of the Earth all on the Y-axis.

Jack Lousma (CAPCOM)

That's affirmative, Jim. You're going to have to roll 90 degrees to point your plus X-axis at the Sun and put the crescent—the points of the crescent on the Y-axis. The points of the crescent on the Y-axis with the COAS pointed at the center of the Earth will take care of your yaw and your pitch.

Jack Lousma (CAPCOM)

Okay, Jim. After you get that orientation to come in a little more steeply, we perform an AGS body-axis aline which is at 400 plus 5 on the DEDA. If the AGS ball is up at this time, the AGS ball will go to 000. We can talk more about control modes later, but we'd recommend doing this, of course, in AGS ATTITUDE HOLD—ATTITUDE HOLD. Put your YAW to MODE CONTROL and leave PITCH and ROLL in PULSE, therefore, controlling your attitude with the TTCA. We don't want to use the gimbal, so have ENGINE GIMBAL OFF. We'll make these burns at 10-percent thrust. We'll use a manual start and stop. For ullage, we'll use the PLUS-X TRANSLATIONAL button, and ullage will be for 10 seconds. Over.

Jim Lovell (CDR)

Okay. I understand what you're saying, but you'll have to repeat it here.

Jack Lousma (CAPCOM)

Okay. We'll perform the burn in GUIDANCE CONTROL to AGS. And MODE CONTROL to ATTITUDE HOLD. Your ATTITUDE CONTROL switches will be ROLL to PULSE, PITCH to PULSE, and YAW to MODE CONTROL. So the AGS will control your yaw and you will use the TTCA to control pitch and roll. ENGINE GIMBAL OFF; 10-percent thrust. Start and stop manual. For ullage, use the plus-X translational button; 10 seconds ullage. Over.

Jim Lovell (CDR)

Okay. For the burn there will be go to GUIDANCE CONTROL AGS, MODE CONTROL ATT HOLD, ATTITUDE CONTROL switches will be ROLL PULSE, PITCH PULSE, YAW MODE CONTROL. We'll use TTCA control for pitch and roll. ENGINE GIMBAL will be OFF; we'll be using 10-percent thrust; we'll start and stop manually, the … control ullage will be a PLUS-X TRANSLATIONAL button. And also our thrust will still be, but before that we are going to do an AGS aline … ball …

Jack Lousma (CAPCOM)

That's affirmative, Jim. After you get oriented in the attitude you want to burn in, do an AGS aline which is—an AGS body-axis aline which is 400 plus 5. When you get ENTER, this will bring ball up to 000, and I want to confirm that you—that you said ENGINE GIMBAL OFF. O-F-F. Over.

Jim Lovell (CDR)

Roger. Confirm that ENGINE GIMBAL will be off.

Jim Lovell (CDR)

And, Jack, how long do you estimate the length of the burns will be?

Jack Lousma (CAPCOM)

Okay. The length of the burns are going to be probably less than a minute. And we want you to have cut-off based on time. So we will give you a burn time. And I have a P30 maneuver pad for midcourse-7 in the event that we lose COMM if you are ready to copy.

Jim Lovell (CDR)

Okay, Jack. Ready to copy.

Jack Lousma (CAPCOM)

Okay, Jim. P30 LM maneuver pad: the purpose is midcourse-7. NOUN 33 is 134:59:42.98. NOUN 81 is N/A. HA is N/A. HP is plus 0020.5. DELTA-V R is 0019.3. Burn time, 0:39; 008, 000; the rest is N/A; thrust will be at 10 percent. Read back.

Jim Lovell (CDR)

All right. This is midcourse-7 corridor control, and it's in case we lose COMM: 134:59:42.98; NOUN 81 is N/A; 42, N/A; plus 0020.5; 0019.3. Burn time, 0:39; 008, 000. All the rest is N/A: thrust 10 percent.

Jack Lousma (CAPCOM)

Okay, Jim. That's a good readback, and in the event of lost COMM, use the procedures that I gave you. It may be that between now and tomorrow these procedures will change a little bit, so we'll go with what we've got now, and stand by for something better if it comes. Over.

Jim Lovell (CDR)

Okay, Jack. I'm looking at your burn pad and I see that the … total gimbal … 19.3 feet per second.

Jack Lousma (CAPCOM)

Okay, Jim. We verify 19.3 feet per second for 39 seconds.

Jim Lovell (CDR)

The old midcourse technique sounds like something that we came up with on Apollo 8.