Spacelog Apollo 13

Roger, Joe. We're standing by for that P37 block data if you have it for us.

Okay. Got it right here, Jim, and it follows. This is the P37 pad for lift-off plus 60. The reason for the update is for weather avoidance in the MPL at 119 hours. It's the same one we passed you yesterday, and it's the same weather, but we still don't expect a problem at the end of the mission. GETI is 060:00, DELTA-V_T 6079, longitude minus 153, GET 400K 118:04. Over.

GETI of 060:00, 6079, minus 153, 118:04.

Roger. That's correct. I've got a consumables update for you, Jim, if you're ready for that.

Ready to copy.

Okay. As of 47 hours, RCS total 1096, quad Alfa 270, Bravo 278, Charlie 270, Delta 278, and the H₂ — They gave me the H₂s in percent, 76 percent; and on the O₂ we have 81 percent. However, we show the O₂ tank 2 reading off-scale high now. We're quite sure it's a sensor failure. We'd like you to verify it with your onboard reading.

Okay. Stand by.

Joe, we confirm. Our gage reading is—on the number 2 O₂ tank is reading off-scale high now, but Jack just tells me that it was okay when we first looked at it this morning.

We verify that. At 46:45 we had 82 percent and apparently when he stirred the, the cryos, the sensor broke.

Okay.

So it's no problem. You're above nominal on all your consumables. On the H₂ tank problem, we have a procedure that we'd like you to carry out which is simply turning the H₂ tank 2 heaters to OFF at this time, and we want to see whether that won't solve the problem of the tank pressure setting off caution and warning. We want to look at it that way for a few hours.

Okay. You want both H₂ tank 2 heaters to OFF. Is that correct?

That's negative; just tank 2. We want tank 1 to stay in AUTO.

Okay. Tank 2 heaters off at this time.

Okay. Good deal. That's been the high tank and apparently while waiting for that pressure switch to close, to start the heater cycle, the tank 1 pressure has been dropping even a little bit lower and just setting off caution and warning, so we feel if we turn off the tank 2 heater and let tank 1 activate the heater cycle, we won't get into the caution and warning range.

Roger.

Okay, Jim. At your convenience we'd like P00 and ACCEPT. We're ready for—to uplink your state vector now since we will not do midcourse 3. Over.

Roger. You're in P00 and ACCEPT, no midcourse 3, and we're all set for a state vector update and I'm giving you the LM/CM DELTA-P here shortly.

Okay. Good deal. And I have flight plan updates for you later, at your convenience.

Houston, Apollo 13. The LM/CM DELTA-P is 1.0 psi.

Copy, 1.0, Jim.

Houston, Apollo 13. I'm about ready for any flight plan updates that you have.

Okay, 13. To start off with, got a minor procedural change for Jack on his next P52, if he's ready to listen to that.

Okay. Jack's still off COMM. We'll hold off on that a little bit and then we'll pick it up when he gets on COMM.

Okay; fine. I've got two updates for you, Jim. One is a procedure for looking for Comet Bennett at about 49:45, and I'll wait till Jack gets up before passing you the details on that. The other update is concerned with going into the LM 3 hours early, and I think Vance mentioned to you last night that this was a possibility, that we'd like to look at the SHe tank pressure early. And since we're not going to do midcourse 3, we'd like LM entry at 55 hours. Is that okay with you?

Okay. Right, that's fine with us. We'll move up LM entry to 55 hours.

Okay. I've got some details on the flight plan for you as follows. Of course, since there's no MCC-3 you'll be deleting all the midcourse 3 stuff including the—the P52, which is called out at about 54-1/2, and we'll be slipping that until later, which I'll—which I'll tell—which I'll tell—which I'll tell you in a minute. Okay. Then you—we want to move the battery charge up 3 hours to about 52:30. And we want to move the—moving the LM tunnel vent valve to LM/CM DELTA-P up 3 hours to 52:45, and at that point you can simply go to the 57-hour point in the flight plan and change your number from 57 hours to 54 hours and start through that. In the remarks section at about 57:50 it says, “O₂ fuel cell purge and waste water dump,” here. If not performed earlier, we want you to do that at 54 hours and 50 minutes. The TV pass then, will be at 55 hours to 55:30. You'll go right through the LM Activation checklist stuff. I'm losing you; let's wait a minute.

13, Houston. How do you read me?

13, Houston. You back with us?

Apollo 13, Houston. Are you back with us?

We're back with you.

Okay. I've gone through the battery charge, the LM vent valve, the fuel cell purge, and then stop PTC at 55 hours, and your roll attitude there will be 285 degrees, which is per the flight plan. The high gain antenna angles are slightly different, pitch 23 and yaw 267 degrees. The TV pass till 55:30, the standard LM activation except for some special steps we'll give you to take a look at SHe tank pressure, which I don't have yet. Restart PTC at about 56:30 or whenever you're through with the LM activities, and after that, at your convenience, we'd like you to—to do the P52 option 3 that we cancelled at 54-1/2 hours. Over.

Okay. That last comment was that we'll do the P52 after we start PTC at about 56:30.

That's right. Any time after that; it's not time critical.

Okay. Let's see if I have some of this, Joe. Around 52:30 we're to do the battery charge on BAT—battery B.

That's correct.

And then about 52:40 we're going to do the LM tunnel vent valve, and the LM/CM DELTA-P which has been written up at 55:40.