Spacelog Apollo 13

Hey, 13; Houston. Go ahead.

Okay, Joe. I've started into P52 here. I've proceeded on option 3, and on the dis—1520—1525 display, I've called up 1691. I'm going to let you observe and see while the—the shaft angle while the OPTICS are still in ZERO.

Okay. Roger that, Jack. We're looking at it, and I'll give you a mark as soon as GNC is happy.

Okay. Real fine.

13, Houston. Jack, could you give us a readout on your counter now?

Okay. I'm showing a shaft of 0.2 and a trunnion of 359.92.

Roger. Copy that. Is there any jumping around on the shaft?

You mean on the TPAC readout?

Yes.

As a matter of fact, it went from 0.2 to 0.21.

Okay. Copy that. Stand by 1.

Okay. Now it went down—It went down as low as 0.15.

Okay.

Jack, Houston. Let us watch that for another minute or so.

Okay. I'm in no hurry. It looked like it burned between 0.14 and 0.8 with an occasional spike up to 0.2.

Roger.

Apollo 13, Houston.

Apollo 13, Houston. You can press on with P52 now. Over.

Hey, Houston, are we clear to torque? Are you reading the torquing angles?

13, Houston. Go ahead and torque.

Okay. Time of torquing will be 49 hours 8 minutes 35 seconds.

Roger that.

Apollo 13, Houston.

Go ahead, Houston.

Roger. For Jack, we missed the star angle difference on the P52. Would you read us that?

Roger, Houston. It was all balls.

Hey, Houston; 13.

13, Houston. Go ahead.

Okay, Joe. I got into P52 about 49:34. We loaded the planet—or Bennett Comet vectors into the planet option, and P52 tracked it all the way across except that it was always occulted by the LM, and we're in a roll angle of 155 now.

Roger. We're copying your roll angles. At what roll angle were you able to start tracking it, Jack?

Okay. At the time we entered it there, we were about 66 degrees roll, so either we started too late, or maybe somehow we got a wrong calculation on the roll angle.

Okay. Let me have GNC comment on that. I suspect that the roll angles we gave you were calculated for exactly 90 degrees pitch, and you're probably wobbling enough that they're not exactly correct.

Yes, I think you—You probably got the right idea.

13, Houston. Over.

Go ahead.

Okay, Jack. Notice you've secured from that, and that was going to be our recommendation, anyway. We're going to have the guys in the back room look at it and see if they can come up with some—with some better numbers based on the cone angle that—that you're traveling through, whether there are any roll angles that—that are available to you. And if there are, and we have time, we might give it another try; if not, we just will forget it.

Apollo 13, Houston. Over.

Go ahead, Joe.

Okay, Jack. I'd like to pass you a switch configuration on the CRYO O₂ TANKS and give you the reason. Right now, we'd like you to go to HEATERS tank 1, OFF; tank 2, AUTO, which is the opposite of the way you've got them now. Over.

Okay. Is this O₂ or H₂?

This is O₂, and stand by for a minute and we'll have a—Excuse me. This is H₂, Jack; it's H₂.

… is AUTO, … 2 OFF.

Okay, Joe. Do we have you back again?

Okay, Jack. We're getting you back, and I hope you copied my—my correction of my mistake. I'm talking about the H₂ CRYO TANKS. We'd like the tank 1 HEATER to OFF; tank 2 to AUTO. Over.

Okay. We lost you again. Here's our heater configuration now. H₂ HEATERS 1, OFF; 2, AUTO. Both O₂ HEATERS are in AUTO.

Okay. That's the configuration we want you in, and here's what we're thinking about. When we went to tank 1 AUTO, tank 2 OFF; we found that the heater cycle had a tank 1 pressure of about 233 psi, which is well above the caution and warning limit, and if we go to that configuration for sleep, we'll keep from getting CAUTION AND WARNING lights during the sleep cycle. Okay. In order to do that comfortably, we want to spend the rest of the day using more H₂ out of tank number 2, so as to get an unbalance in favor of tank 1, so at the end of the sleep cycle it'll all come out even. And that's why we have you in tank 1 OFF, tank 2 AUTO, now. We expect to get about a 3-percent unbalance over the next 10 hours; and prior to sleep, we'll call you to reverse the configuration again. Now the only disadvantage here is that, during the day, you will probably get a few CAUTION AND WARNINGS, and we just figured it would be better to get them now than while you were sacked out. Over.

Houston, 13. We're ready to copy.

Okay, Jim. These are gyro compensation terms. They've already been uplinked, and we're just updating your onboard charts now. In column A, number 11, change from 77646 to 00114; number 12, change from 77332 to 77546; number 13, change from 76617 to 77201. Over.

The changes are as follows, and all in column A: number 12, the new change is 77546; number 11, the new change is 00114; and 13, the new change is 77201. Over.

Roger. Readback correct.

And, Joe, do you know—Are you going to try and let us spot the Bennett Comet on this next revolution there? Or do you want me to turn the OPTICS power off now?

Stand by 1, Jack. Okay, Jack. We don't have confidence on those roll angles yet, so why don't you turn the OPTICS off, and we'll update you later.

Okay. Going off now.

Apollo 13, Houston.

Go ahead.

Go ahead, Houston.

Roger, Jim. If you've got a couple of minutes now, I'd like to read up to you the change to the LM entry procedure that we'd like you to observe at 55 hours, and the rationale for it. Over.

Okay, Stand by.

Roger.

Go ahead, Joe.

Okay. Before you start copying, this procedure is—is basically simply to activate the supercritical helium pressure gaging so that you can read it. And the concern here is lest this supercritical helium pressure reach 1800 psi by 103 hours, at which point we'd be within a possibility of rupturing the burst disk when you activate the DPS. Now, based on the pressure at launch, and based on a nominal rise time of about 6-1/2 psi per hour between then and now, the pressure should read about 710 psi. Stand by, 13, until we get better COMM.

Houston, you were cut out. Would you say again about the helium pressure.

Roger. Based on the prelaunch pressure in the SHe tank and the nominal rise time of about 6-1/2 psi per hour, the pressure should be about 710 at 55 hours. Are you reading? Over.

Jim, Houston. Did you read that last?

Okay, Joe. I 'm on OMNI C now. How do you read?

13, Houston. You're loud and clear now. INCO tells me he's having a little problem at Goldstone and wants me to stand by for a minute.

Okay. How do you read now, Joe? I'm going from OMNI C to D now.

You're still loud and clear on—on D, Fred. Stand by 1.

Okay. I'll put her back to OMNI B if you all want to take command again?

And the last thing we heard, Joe, was that the SUPERCRIT should be reading about 710 psi.

Okay. That's the last thing I passed up. And while we're waiting for INCO to decide here, let me continue. The deadband that is considered acceptable is between 660 and 770 psi. In other words, any rise time that'll give you one—a pressure between those two, will keep you below the critical pressure at 103 hours or so. So, we expect it to read in that—in that band and if it does, there will be no problem. If it reads between 770 and 800 psi, we will want you to check the pressure again at about 59 hours, and I'll get the detailed procedures in a minute. If the pressure is equal to or greater than 800 psi, we're going to have to go into some more detailed procedures; we're going to try to—to get PCM data on it, for one thing. We may have to have you sit there and stare at the gage for a while to find out when it clicks up and get an accurate rise time on it, and then in extreme case, we are even thinking about a DPS burn, but we don't really think that will happen. Now, if you are ready to copy, what I have for you is a change or an addition to the LM Activation checklist between pages TLC-1 and TLC-2, which consists of seven steps, and if you can find a blank side to write it down on, I would like to pass it up. Over.

Okay. How do you read on OMNI C, now?

Okay. You're loud and clear on OMNI C. Stand by 1 while we get INCO synced up.

Okay. The rest of your update was that it's okay if it is anywhere between 660 and 770 psi. If it's above 770, you are going to ask us to consider going back in at 59 hours and either get PCM going or sit there and give you gage reading changes on the basis of that. And you said something about an extreme measure. We may have to consider some sort of DPS maneuver.

That's correct, Fred. We don't have procedures for that yet, and we don't have any real expectation of getting into it. The procedure I'd like to read up to you now is simply the steps required to get the supercritical helium pressure reading at 55 hours. Over.

Okay.

Okay. We're calling this TLC-1A, step 6, “Transfer to LM power.”

All right. Stand by 1, Joe.

Okay.

Okay, Joe. He's ready to copy.

Okay. Step 6, “Transfer to LM power (floodlights blank), CAUTION WARNING POWER CAUTION light ON. Report GET to MCC. Panel 11, CIRCUIT BREAKER EPS TRAESLUNAR BUS TIE, CLOSED. Circuit breaker panel 16, EPS TRANSLUNAR BUS TIE, CLOSED. Circuit breaker panel 11, LIGHTING UTILITY, CLOSED. And activate utility lights.” Over. And, 13, Houston. Select OMNI Bravo, please.

Okay, Joe. I've created a new page here called TLC-1A, item 6, Transfer to LM power and the usual check that the floodlight's blank and that I've got the CAUTION WARNING POWER light ON; I get a GET from Jack, and I will pass that on down to you. Item 7, CIRCUIT BREAKER EPS TRANSLUNAR BUS TIE, panels 11 and 16, CLOSED. Step 8, circuit breaker lighting and utility on panel 1, CLOSED, and turn on the utility lights. However, the lighting is such that I don't really need those. They are in stowage, right now, I guess, in the ISA, and I'll probably just leave them there.

Okay. That's optional. The way we had page TLC-1A written, that was all part of step 6. You haven't even gotten to step 7 yet. Step 7 is as follows.

Fred, Houston. Are you with me?

Apollo 13, Houston. Are you reading me now?

Okay. Houston, 13. How do you read?

13, Houston. Loud and clear. What OMNI you on now?

I'm going to stay OMNI B, if you all want to take command back and you can let INCO jockey them around between B and D. And how many steps we got, so I know whether to write big or small here, Joe?

Okay. We got steps 6 through 12, but step 7 is the same size as 6, and 8 through 12 are short. They're only one line each.

Okay.

Okay. Step 7 follows: “Circuit breaker panel 11, AC BUS B, HELIUM PQGS PROPELLANT DISPLAY, CLOSED. Circuit breaker 11, AC BUS B, NUMERIC LIGHTING, CLOSED. Circuit breaker 11, AC BUS B, BUS TIE INVERTER 1, CLOSED. Circuit breaker panel 11, EPS INVERTER 1, CLOSED. Circuit breaker panel 16, INSTRUMENTATION SIG SENSOR, CLOSED. INVERTER 1” —

Hold on a minute, Joe.