Spacelog Apollo 13

Okay. Good deal. One other detail for you, Jack; GNC tells us that the OPTICS jitter is very similar to what we had on Apollo 12. It's no problem, but when you're not using the OPTICS, we recommend that you turn the OPTICS POWER switch to OFF to guard against a possible degradation as the flight progresses. Over.

Okay. Will do.

Okay. Apollo 13, Houston. I have one more little update for you, and it's another update to the erasable memory onboard crew charts on page G/9-2. 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.

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.