Spacelog Apollo 13

Roger.

Aquarius, Houston. In regards to the CO₂ canisters, by the way the PCO₂ is reading 1.6 down here now. We expect that we can get 6 more hours out of the two canisters that we have there—6 hours at least. However, at 112 hours, when we've got several people up, we're going to rig up two more and we have the new simplified procedure for doing this. However, in the meantime, should we need to have a canister change, we plan to switch to the LM primary canister. Over.

Okay. Copy that, Jack.

And, Aquarius, how's your PTC holding up?

Well, we got a little bit off Jack. The—It starts high in the LMP's window and goes low in the CDR window.

Houston, Aquarius.

Go ahead, Aquarius.

Okay. Thank you, Jack. Copying that.

Aquarius, Houston. We'd like to get a little better idea of how PTC is going. So, what we'd like for you to do is what we did last time. That is to give us a reading on the center of the Earth and the center of the Moon on the—LPD.

On the LPD. Okay, It's shifted. Let's see, the Moon's gone by and the Earth didn't come into the LPD last time.

Okay. But when it goes by the plane of the LPD, tell us where it was. Okay?

Okay, Jack. This pass, the Earth came into view at the top left-hand corner of the LMP's window and was going down. However, when it passed it wasn't as high up as the last pass. It did pass into view at the CDR window, but too high up to get an LPD reading.

Roger. Understand it went high in both windows then.

Yes, last time it wasn't even visible in the CDR's window; this time it was visible if you squatted down, but too high up to get an LPD reading.

Okay, Houston; Aquarius.

Go ahead. Over.

Okay. The moon came into view at the middle of the LMP's window, passed through the CDR's window at an LPD of 5 degrees.

Houston, Aquarius.

Go ahead, Aquarius.

Okay, Jack. On this pass, the Earth came into the view at the top part of the LMP's window, and we got an LPD angle on it as it passed through the CDR's window of a minus 4 degrees.

Okay. A minus 4. Thank you, Jack —

It's—it's above the—Okay. Are you familiar with the minus 4 being halfway through the sky part, huh?

Okay, Houston; Aquarius.

Go ahead, Aquarius.

Okay. On this pass, the Moon came into view at the top part of the LMP's window, came across higher. Jim estimates the LPD angle at a minus 15 degrees.

Okay. A minus 15 on the moon, and sounds like it's set up pretty well.

Everybody's happy with it down there?

Aquarius, it's a little too early to tell exactly how the PTC is going. We'd like to get a few more points, so keep reading them off, and we're still looking for that SUPERCRIT to go anytime.

Houston, Aquarius.

Go ahead, Aquarius.

The Earth was just fairly high in the LMP's window and across the 14-degree LPD line.

Houston, Aquarius.

Go ahead, Aquarius.

The Moon went by the LPD at 6 degrees, plus 6 degrees.

Okay. Earth at plus 6. Thank you.

That's the Moon, the Moon.

That's right.

On the basis of the data we have so far, your entry angle is 5.99. The block data we gave you on the pad for a no-COMM midcourse-7 last night is no longer valid because we made this midcourse.

Okay. Understand, the no-COMM pad is no longer valid because of the midcourse. Entry angle based on the last 2 hours' tracking is 5.99, and I take it you're going to keep tracking for some time now to see whether we need another midcourse or not.

That's affirmative.

Are you planning any no-COMM midcourse at 134 and change anyway right now, or are you going to wait?

We're discussing that now, Jim, and it looks like we're going to wait on the tracking. For the time being, since you're in the corridor, why, there's no need to pass it up. But we're going to keep looking at the tracking, and we'll probably come up with one.

All right. I'm not too sure what the venting is going to do to us so—when this SHe tank ruptures, what it's going to do for us.

Roger. We don't presently expect the SHe tank to have any effect on your trajectory, and the pressure's up to 1921 now.

Hey, it's going a lot better than we ever expected. What a way to get a data point.

And, Jack, just think. You thought you were going to sleep through all your watches.

Say again, Jim.

I said, you thought you were going to sleep through all you watches.

Well, you keep waking me up.

Aquarius, Houston. You notice anything?

Yes, Jack. I was just about ready to call you. Underneath quad 4, I noticed a lot of sparklies going out.

Can you hear or feel anything?

No, I sure can't, but I think it changed our—it changed our PTC. Let me check and see what the drift is.

Okay. She's going down through 600 now.

I think we're probably going to have to reestablish PTC. Yes, we got pretty fast yaw drifting, Jack.

Houston, Aquarius. What are your plans?

We're thinking about them right now. Did you say it yawed some?

Yes, I was in a right yaw and now I'm in a left yaw; at a much faster rate than the one we put in PTC.

Okay, Jim. We're talking it over. Stand by.

What's the SHe tank down to now, Jack?

Okay, Jim. It's going through 125 pounds now. And we understood you to say —

Okay.

— that it reversed your yaw. Is that affirmative?

Sure did, Jack. It reversed my yaw completely and put in a little pitch, I think.

But more than anything, it reversed my yaw.

Roger. Have you effectively established PTC in the opposite direction then?

Well, you could say that. I'm not too sure just what kind of pitch or roll I've got, coupled with the yaw. I just saw the Earth go by the LMP's window here, not too long ago at a rather faster rate than we had going the other direction.

Perhaps you can tell how fast I'm having to shift OMNIs.

Yes, we can tell the COMM cycling back and forth.

Is that what they call a nonpropulsive vent?

Right. I'd hate to see a propulsive one.

You and me both.

It's going through 50 pounds now. So, are you seeing fewer sparklies?

Yes. Much fewer. Not any at all, now. I'm not sure whether that vent gave me reverse yaw and roll—left roll—that's—if that's what it gave me.

You say you think it might have given you some left roll as opposed to opposite yaw.

I'm sure it gave me the yaw, Jack, but I'm not too sure …

Okay. We'd kind of like to watch it, see what happens for a little while before we make a recommendation. However, we'll need some inputs from you on that.

Well, we're in no trouble up here as far as—as far as the yaw goes. Everything's fine. It's faster than we had set up before. We just wanted to get into proper thermal constraint, and it's going to take me 15 minutes to get the thrusters up anyway.

Okay, Skipper. We don't see any thermal problems as a result of this change. If we see some communications problems, we may have to do something different, but so far, so good. And we'd kind of like to hear from you on LPD numbers, if you get anything going by the window.

Okay. Will do.

Okay, Jack. The Earth just went through at an LPD of 26 degrees.

Okay. The Earth went through at 26 degrees going the opposite direction this time—left to right. Is that right?

From left to right. That's affirmative.

Of course, the only other thing that we'd be concerned about is what change in your velocity this might have had and what DELTA-V it imparted, and we'll have to look at that for a while before we are able to determine it. And, if there is no significant change, why, we prefer just to leave it the way it is.