Spacelog Apollo 13

Affirmative. Under “VHF/S-band Activation and Checkout,” scratch step 1. Under step 2, change “DOWN VOICE BACKUP” to VOICE. Scratch step 3. Under “PGNS turn on,” scratch entire procedure. Under “DAP Set/Gimbal Drive,” scratch entire procedure. Over.

Okay. Under “VHF/S-band Activation and Checkout,” scratch step 1. Do step 2 with the following change, “DOWN VOICE BACKUP” to “VOICE.” Scratch step 3. Scratch the entire remaining events that page. Over.

That's affirmative, Jim, Going on to page 29. We've got—At this point, there's a write-in required. It's about a six or seven liner, and I'll try to go fairly slowly and let you write it down, if you're ready to copy. Over.

Ready to copy.

Okay. At this point, we'd like you to “Verify RCS heaters in AUTO for 15 minutes.”

Is that the first step, Charlie?

That's affirmative. What we're trying to do here is we're getting you set up in an attitude so you can damp your rates and come out of PTC. And this is the configuration I'm reading you now, the next—in the next six lines, the procedure for getting you into a configuration to damp the rates and stop PTC. Over.

Okay. So the first thing will be to—“Go to AUTO on the RCS SYSTEM A and B”?

It's the “Verify that the heaters have been in AUTO for 15 minutes.” Back on the first page of this procedure, you put the heaters in AUTO and you pushed the breakers in, and we'd like for them to warm up the quads for 15 minutes before we start to—stop at—stopping PTC. Over.

Roger, “Verify heaters RCS on for 15 minutes.”

Okay. Step 2: “BALANCE COUPLE, OFF; DEAD BAND, MINIMUM; ATTITUDE CONTROL: PITCH and ROLL to PULSE; YAW to DIRECT; MODE CONTROL: AGS, ATT HOLD; GUIDANCE CONTROL to ACS; damp rates; pitch and roll with the TTCA, yaw with the ACA with the Earth in the front window.” Over.

Okay, let's see if I got it. Step 2 is “BALANCE COUPLE's OFF; DEAD BAND, MIN; ATTITUDE CONTROL: PITCH and YAW at PULSE; YAW, DIRECT. MODE CONTROL will be in AGS, ATT HOLD; GUIDANCE CONTROL will be in AGS; we'll damp the rates; pitch and roll with the TTCA, and yaw with the ACA; and we'll probably have to have some reference point, so I have to try and stop on the Earth.” Over.

Roger, Jim. We were hoping that in your PTC that you occasionally see the Earth coming through the window; and, if that's true, then we'd like you to have to—just damp the rates with the Earth in the forward window. And then we'll give you the burn attitude via the forward window on the Earth momentarily. Over.

Roger.

Okay. That was the entire procedure for damping the rates, only—though I only gave you—said it was step 2, that was the entire procedure. Now, continuing on to what's printed on page 29—Correction, you had one error in the readback under ATTITUDE CONTROL. It was PITCH and ROLL to PULSE; YAW to DIRECT. Continuing on, on page 29 with the printed procedure, the first four lines, scratch. Step 3, scratch. Under “AGS Activation,” one change: add a step. First step will be “Verify ASA CB(16) in for 10 minutes.” The rest of the AGS activation is as printed. Over.

Okay. “Verify ASA circuit breaker 16 in for 10 minutes”; and, I take it, 10 minutes back in our procedures we'll have a note saying to put that in.

It's—the circuit breaker goes in on the circuit breaker activation page, Jim. So, by the time we get here and have the rates all damped, we feel that—that the PIPAS will be up to temperature by this time, and we can go ahead and turn it—turn the AGS on at this time. Over. But we just want you to verify that.

Okay. And one other question, Charlie. I'd like to know if the note you gave me about damping the rates is before the other information on page 29.

That's affirmative. Add that in to the top of the page. The—What we're really doing—Let's—let's put it in to right before the “AGS Activation.” The other—the other procedure on the top of the page belongs with the “DAP Set Gimbal Trim,” and we're just omitting all of that procedure. So the addition that—on the damping, the rates should really go in right before the “AGS Activation.” Over.

Understand.

What we're really trying to do is get you in a posture so that when you see the Earth come through the window, you can damp her out and hold—hold the Earth in the window. Proceeding on to the rest of page 29, under “RCS PRESS,” scratch the entire three steps as printed. On page 30, scratch step 4 under the “RCS PRESS.” Over.

Roger. Under “AGS Activation,” well, I included that step on the ASA circuit breaker and we'll do step 1 and 2 under “AGS Activation.” But then we'll scratch steps 1, 2, and 3 under “RCS PRESS” and, on page 30, we'll scratch step 4.

Affirm. Under “DPS PRESS,” step 1, line 1, scratch. Line 4, “DESCENT HELIUM REG 1, talkback barber pole.” Under step 2, scratch; step 3, scratch; “LANDING GEAR DEPLOY,” scratch. Over.

Okay. Under “DPS PRESS,” we'll scratch the first line and we'll have the “DESCENT HELIUM REG, talkback to barber pole.” We'll scratch steps 2 and 3, and we'll scratch the “LANDING GEAR DEPLOY.”

Roger. Now we got, on the back of page 30, Jim, you've got a blank page in your checklist, or should have, and we'd like to add a procedure to get you to burn attitude. Over.

Okay. A procedure to get the burn attitude.

Okay. First statement is a statement: “Verify AGS in OPERATE for 5 minutes.” Then we go to “AGS address 400 plus 5, then 400 plus zero. ATTITUDE CONTROL: PITCH and ROLL to PULSE; YAW, MODE CONTROL. Maneuver using TTCA pitch and roll.” The computer is controlling yaw, but you can override with ACA. You with me? Over.

Okay, Charlie. I'm with you so far.

Okay, Jim. “When in attitude, ACA out of detent to zero error needle. Then set EVENT TIMER,” and we'll give you a countdown on that when you get to that step. Over.

Okay. “When in attitude, ACA out of detent to null needles, and set DET.”

Roger. Now, that—the burn attitude will be coming up on a pad, but, basically, we're looking for a local horizontal retrograde burn, which means, using a COAS, if you put the horizontal line on the COAS on the horns of the Earth and then roll to place the X-axis in the direction of the Sun, we'll—that will put us in both burn attitude; and you can check that via the Sun which will be in the AOT detent 2. Should lie right along the cursor at the top. We'll have some more words on that for you momentarily. Now, I'd like to go on to page 31 if you're ready. Over.

Okay. I figure I have a handle on the attitude, the way the Earth should look in the COAS, and you're going to give me some words on what the Sun would look like in the AOT. Is that right?

That's affirmative, Jim. We haven't got a picture of it yet. It's going to be in the top part of the COAS—Correction, top part of the AOT at the top of the—the top of detent 2 and the top part of the AOT, and it should, in attitude, if you're right on the Sun, should split the cursor, though that roll angle is not too critical; if we're in about 10 degrees, we'll be okay. We—but I think—we think you should be able to get it better than that. On page 31, under the “DPS Burn Technique,” you can scratch the bottom part below the little diagram there since the gimbal is locked. Over.

Understand scratch the bottom part underneath the diagram because the gimbal is locked.

That's affirmative; and, since the gimbal was trimmed out at the big burn yesterday, we should be still through the c.g., and we'd like to make sure that Jack sits in the same place for this burn that he did yesterday. That way, we'll—you should have no trouble controlling attitude. Now I'm ready to go over to page 32. Over.

Okay. Let me see if I have that right, now. You want Jack to sit in the same attitude so that the gimbals are the same place so you don't have trouble controlling attitude. I got it.

Okay. Now on page 32, top of the page, first line, scratch “VERB 76.” Third line, “MODE CONTROL: AGS, ATT HOLD.” At “Minus 6 minutes,” scratch lines 1, 2, and at “Burn Attitude,” scratch “VERB 40 NOUN 20.” Scratch lines 2, 3, and 4. Now at “Burn Attitude,” we want you to do a “400 plus 5” and then a “VERB—a 400 plus zero.” And we have a caution note at this point. Over.

Go ahead.

Okay. The caution is after “400 plus zero”: Do not go out of detent on ACA again." Over.

Okay. After the last “400 plus zero,” “Do not go out of detent with ACA.” Is that correct?

That's a Roger, Jim. What happens is, of course, we set—when you go out of detent, you reset the AGS error needles and you—and you lose your attitude reference. You establish a new attitude reference, and it might not be the burn attitude since, at this point, we're controlling attitude with the TTCA. Now, picking up with the “VERB 37, ENTER,” scratch. Scratch everything down to the “404 plus zero,” and we want you to perform those AGS steps with 404 down through 470. Over.

Okay. We'll scratch everything down to “404 plus zero,” and we'll perform those four steps.

Roger. Turning over to page 33. Minus 4 minutes. Okay. Moving down the page, it's about line 7, to “ENGINE GIMBAL”: “ENGINE GIMBAL, OFF.” Down to “MODE CONTROL,” make that read “MODE CONTROL: AGS, ATT HOLD,” and then scratch “PROPELLANT QUANTITY MONITOR, DESCENT 1.” Over.

Okay. At 4 minutes, “ENGINE GIMBAL” will be “OFF”; “MODE CONTROL” will be to “AGS, ATT HOLD”; “PROPELLANT QUANTITY MONITOR, DESCENT 1,” scratched.

Roger. Picking up at minus 1 minute, scratch “MASTER ARM, ON.” Minus 35 seconds, scratch first two lines. At minus 10 seconds, change that to “Minus 9 seconds”; so, at “Minus 9 seconds,” it will be “Manual Ullage.” At 2 seconds, scratch “CMC MODE, FREE,” and scratch “ACA out of detent.” At—after “IGNITION,” at plus 1 second, “Terminate Ullage.” Are you with me? Over.

Okay. At 1 minute, “MASTER ARM,” we scratch. At 35 seconds, scratch the first two lines. “Manual Ullage” will start at 9 seconds; we're scratching the blocks at 02 seconds; and the line beneath that, at plus 1 second, we “Terminate Ullage.”

That's affirm. Picking up at plus 5 seconds; scratch the rest of the page. “TTCA, attitude control; and MASTER ARM, OFF.” Over.

Scratch the remainder of the page.

Okay. Now, like to verify that under the 35 seconds, minus 35 seconds, the only thing you have remaining is “ENGINE ARM to DESCENT.” Over.

— if we had an overburn, we'd be impinging on our command module to try to trim it out, so that's our reasoning there. Over.

Okay. Understand.

Okay. Picking up in the middle of the page, that—a block “CMS resume attitude control,” scratch. Scratch the next line; “PRO VERB 96.” Scratch the third line; “PROPELLANT QUANTITY MONITOR, OFF.” Over.

Okay. We'll scratch the blocks, and we'll scratch the “PRO VERB 96”; then we'll scratch “PROPELLANT QUANTITY MONITOR, OFF.”

Roger. Now, at the bottom of that page, I have a procedure for you to reestablish PTC. Over.

To reestablish PTC. Go ahead.

Okay. First line, “ATTITUDE CONTROL, three to PULSE”; line 2, “Roll with the TTCA until attitude is roll, plus or minus 90; pitch, 0; yaw, 0.” Over.

Okay. Step 1, “ATTITUDE CONTROL, three to PULSE”; 2, “Roll with the TTCA … pitch is 0 and yaw is 0,” and I think that will be on the AGS ball.

That's affirmative. You broke up there for a minute, Jim. We'll do that on the AGS ball from the burn attitude. We just want you to roll either way 90 degrees, keep pitch 0 and yaw 0. Now, step 3; “When at—when at attitude, ACA out of detent.” Step 4; “ATTITUDE CONTROL: YAW, to MODE CONTROL. When rates are less than 0.05, ATTITUDE CONTROL: YAW, to PULSE.”

Okay, Charlie. Can you hold up here a second? I lost you.

Roger.

Start with step 3 again. “When attitude—When at attitude, ACA out of detent.”

That's Roger. Next step, step 4: “ATTITUDE CONTROL to YAW”—Correction, “ATTITUDE CONTROL: YAW, to MODE CONTROL.” Over.

Okay. Step 4 is “ATTITUDE CONTROL: YAW, to MODE CONTROL.”

Roger. Step 5: “When rates are less than 0.05 degrees per second, ATTITUDE CONTROL: YAW, to PULSE.”

Okay. “When rates are less than 0.05 degrees per second, ATTITUDE CONTROL: YAW, to PULSE.”

Roger. Step 6: “Spin up to 0.3 degree per second in yaw,” and that takes about 21 pulses. Step 7—Yes.

Okay. Go ahead.

Okay. Step 7: “MODE CONTROL, AGS, OFF.”

Okay. Step 6 was “Spin up to 0.3 degrees per second in yaw”; that's about 21 pulses. Step 7 was “MODE CONTROL, AGS, to OFF.”

That's affirm. Step 8: “Power down per power”—Correction, “Power down per contingency checklist page Power 5.” Over.

Okay. And step 8 is Power down per contingency checklist Power 5," and I take it that's been revamped considering our situation. Okay.

That's affirmative, Jim. That's the one we gave you last night after the big burn, and we'll use that one as modified by—by us. This—we tried this PTC under AGS in the simulator and, of course, no slosh or anything, but it seemed to work pretty good by nulling the rates using the TTCA in pitch and roll and letting the ACS do it in yaw. You null the rates by looking at the error needles and just watching those, and when they don't—when they stop moving, then you got it within the limits of what we want. Over.

Okay. And I guess, Charlie, you have no—Do you have a ATT hold mode in pitch and roll at all in this configuration we're in, or do we have to use the TTCA?

We feel like we have to use the TTCA. The AGS gains are not too good in pitch and roll in this configuration. It'll hold it in yaw but it won't in pitch and roll. Over.

Okay.

And you'll have—During the burn, of course, you'll be controlling pitch and roll via the error needles with the TTCA also, and it's the little scheme that we've practiced in some of the SIMs. Over.

Right. Understand.

And, Houston, want to make sure that we allow enough time to get to the proper attitude for the burn so that we can be sure we establish the proper attitude and don't have to rush the burn.

Roger, Jim. We -we're looking right now, tentatively, at starting this about 45 minutes before the burn and our sensitivity is—not too bad on this burn. We can go 30 minutes either way and not affect our DELTA-V. Over.

Okay. Fine. And do you have a handle on just how long the burn will be? In time?

It's looking like at about 7.8 seconds and about 15—Correction, 7.8 feet per second and about 15 seconds. Over.

In about 18 seconds?

Negative. 15. 1 5.

1 5. Okay.

And one other point is that we'd like to remind you that this is going to be in blowdown and both REGs B closed but we've got plenty at the 10 percent.

Understand.

And, Jim, in the simulator with our configuration that we had here, the thing is real stable at 10 percent, so we don't think you'll have to tweak very much at all using the TTCAs. Over.

Okay. Understand.

And I'll give you back to Vance. Thank you.

And thank you.

Aquarius, Houston.